RADIOACTIVITY RELEASES TO THE ENVIRONMENT BY NUCLEAR POWER PLANTS-LOCALLY AND FOR THE TOTAL FUEL CYCLE Robert C. Marlay MIT Energy Laboratory Report No. MIT-EL 79-014 March 1979 RADIOACTIVITY RELEASES TO THE ENVIRONMENT BY NUCLEAR POWER PLANTS-LOCALLY AND FOR THE TOTAL FUEL CYCLE Robert C. Marlay Dept. of Nuclear Engineering Massachusetts Institute of Technology Cambridge, Massachusetts 02139 March 15, 1979 ABSTRACT The nuclear fuel cycle is categorized into nine components. Each component is described with respect to its operations and radioactive effluent streams. Engineering estimates of radioactive releases to the environment are summarized for each component from the 1976 report of the Nuclear Regulatory Commission entitled, "Final Generic Environmental Statement on the Use of Recycle Plutonium in Mixed Oxide Fuel and Light Water Cooled Reactors." Actual radioactivity release data reported semiannually by licensed facilities in the U.S., plus actual release data found in the literature for Canadian and European facilities, are summarized to the extent that data are available for the years 1970 through 1976. These actual data are compared with the engineerParticular emphasis is ing estimates of the NRC. given to a comparison of reactor types, including: pressurized water reactors, boiling water reactors, high temperature gas cooled reactors, European gas cooled reactors and several types of heavy water Figures showing cooled and/or moderated reactors. relative magnitudes of releases for the different reactor types and trends versus time are drawn. Estimates of world population exposures for each fuel cycle component are calculated for the actual release data from information provided for the estimated release data. Similarly, total radiological health effects resulting from the production of one giga-wattyear of power for the various nuclear fuel cycles are estimated. Lastly, a comparison is made of these health effects to the radiological health effects of the fossil fuel cycles of natural gas, oil and coal. No attempt is made to characterize the non-radiological health effects of any fuel cycle. Table of Contents page I. II. Introduction 1 "Front End" of the Nuclear Fuel Cycle 8 A. B. C. D. E. III. V. VI. 29 A. 31 VIII. Light Water Reactors-1. Pressurized Water Reactors (PWR) 2. Boiling Water Reactors (BWR) Gas Cooled Reactors (HTGR and GCR) Heavy Water Reactors (HWR, PHWR, SGHWR) Liquid Metal Fast Breeder Reactors (LMFBR) 51 61 62 "Back End" of the Nuclear Fuel Cycle 73 A. B. C. 73 74 74 Away From Reactor Waste Disposal Transportation (AFR) Spent Fuel Storage Summary for the Nuclear Fuel Cycle 75 Addendum--Radioactivity Releases Fuel Fired Power Stations 82 A. B. C. D. E. VII. 8 13 19 20 26 Power Reactors B. C. D. IV. Uranium Mining Uranium Milling UF 6 Conversion Enrichment U0 2 Fuel Fabrication Natural Gas Oil Coal Over What Period of Time? Coal Impacts from Fossil 82 83 83 84 88 Conclusion 91 Notes and References 95 -1RADIOACTIVITY RELEASES TO THE ENVIRONMENT BY NUCLEAR POWER PLANTS--LOCALLY AND FOR THE TOTAL FUEL CYCLE Electric power in the United States has been characterized by remarkably strong and steady growth for more than eight decades, increasing by more than 100 fold since 1900.1 Today, thermal inputs to the electric utility sector account for thirty percent of total US energy consumption, and this trend is projected to continue by virtually all econometric models of national energy use.2 By the year 2000, thermal inputs to the electric utility sector may reach 50 percent of total energy use. Similar trends have been established abroad in other industrialized nations, and less developed countries are beginning their own programs for electrification.4 Add to these scenarios the consequences of the gradual depletion of world oil and gas reserves,5 and one envisions either an energy future that is quite different from that of today, or one that is heavily dependent upon electric generation for its energy needs. The source of this power has yet to be determined, but the choices are limited. In the United States, additional increments to existing generating capacity will likely be from either coal fired power plants or nuclear reactors. In Europe and Japan, where coal is not readily available, nuclear power is currently the favored choice. Even oil exporting nations continue to maintain, despite recent controversies regarding nuclear safety, waste disposal and proliferation, nuclear power development plans. In sum, it is quite possible that within a relatively short period of 50 years fission reactor technology of one form or -2- another may be responsible for producing a large fraction of world power demand. By the year 2025, it has been estimated that there may be three- to five-thousand reactors operating worldwide. 6 Radioactive effluents released to the environment by these nuclear power plants, and by the supporting facilities in the fuel cycle, begin to take on a much larger significance when the annual environmental burden is enlarged by several thousand reactors over those of today and accumulated in the biosphere indefinitely. Consequently, it is important to identify the sources of these releases, characterize their isotopic compositions, quantify by means of pathway modeling the resulting occupational and population dose commitments, and estimate their respective contributions to specific world health effects dences, mortalities and genetic mutations). (i.e., cancer inciOne can then assess the relative impacts of various levels of nuclear power development, reflect upon the adequacy of current environmental regulations for the different components of the nuclear fuel cycle and make appropriate modifications to these standards where warranted. The beginning point in these investigations is the identification and measurement of the radioactive effluent releases to the environment, both gaseous and liquid, from each of the nuclear fuel cycle components. For the purposes of this paper, the nuclear fuel cycle will be regarded as consisting of the following discrete components (Figure 1) and assumes no reprocessing: -3- (1) mining (6) reactor operations (2) milling (7) spent fuel storage (3) UF 6 conversion (4) enrichment (8) transportation of radioactive materials (4) enrichment (5) U02 fu(9) waste repository and ultimate disposal (5) U0 2 fuel fabrication ultimate disposal Reprocessing and mixed oxide fuel fabrication are not included within the scope of this paper; however, mention is made in the Summary section, of the anticipated changes in effects due to the implementation of the mixed oxide fuel cycle, relative to the "no recycle" option. This paper addresses each component in turn, starting with the mining of uranium ore. For each component, a brief description of the process is provided, followed by a characterization of the radionuclides found in the effluent streams and their sources. When easily accessible, actual effluent release data, required by law to be reported semi-annually by all licensed operators to the Nuclear Regulatory Commission (NRC), has been used to quantify releases. Otherwise, engineering estimates of anticipated releases are shown as found in various Preliminary Safety Analysis Reports (PSAR's) or Final Safety Analysis Reports (FSAR's) for representative operations. Lacking these, engineering estimates for "model facilities" are used. A considerable portion of this effort was devoted to the statistical comparison of actual release data for several different reactor types. The reactor types investigated are characterized as follows: -4- iEs FUEL SPENT FUEL LW POWER REACTORS •iL REACTOR STORAGE 1 UO 2 FUEL FABRICATION A s r LOW-ENRICHED UF 6 SPENT FUEL Ij - ENRICHMENT NATURAL UF 6 FEDERAL WASTE REPOSITORY CONVERSION TO UF6 URANIUM MINES & MILLS Figure -1 Light Water Reactor Fuel Cycle - No Uranium or Plutonium Recycle From GES'iO Final Report, Summary Volume, NUREG-0002/1, August 1976, p-. 5-13 -5- (PWR) (1) pressurized water reactors (2) boiling water reactors (3) gas cooled reactors (BWR) (HTGR and GCR) (4) heavy water reactors (HWR, PHWR, SGHWR), (5) liquid metal fast breeder reactors and (LMFBR) Emphasis was also placed on the "front end" of the fuel cycle; but due to limitations of time, only a cursory treat- ment was given to the "back end" components (away from reactor storage of spent fuel and waste repository operations), and to transportation of radioactive materials. Summaries of the re- lease estimates and the anticipated accumulated dose commitments are provided, nevertheless, for all components, as they were published in the Final Generic Environmental Statement on the Use of Recycle Plutonium in Mixed Oxide Fuel in Light Water Cooled Reactors (no recycle option) In reporting effluent in September 1976.7 releases, dose commitments and health effects, it is convenient to express this information in terms of a common unit of productive output. In the following dis- cussions, the chosen unit is the "gigawatt-year" (GWe-yr), repre- senting an amount of net electrical output equivalent to a 1,000 MWe electric generating station operating continuously at full power for one year. Assumptions must be made for all components of the fuel cycle except reactors about what level of production is required to support one GWe-yr of output, and these assumptions are stated where appropriate. Lastly, in arriving at US and foreign population dose commitments, complex computer models of radionuclide transport) -6- accumulation and decay, and pathways to man must be used. Schematically, these pathways are represented very simplistically in Figure 2. Information on dose commitments stated in this paper are all quoted from either the GESMO Final Report (NRC) or from various publications of the US Environmental Protection Agency (EPA). -7- aqualC Pathways for exposure of man from atmosphere ana 2 Fig. releases of radioactive effluents. Portsmouth Gaseous Diffusion From: Final Environmental Statement, 1977, pp. 3-65 Plant Expansion, ERDA-1549, Vol. 1, September -8- "Front End" of the Nuclear Fuel Cycle Uranium Mining The natural uranium requirements for a 1,000 MWe LWR designed to operate on low enriched fuel (3.2 percent U-235) and having burn-up values of 33,000 MWD per tonne are about 550 to 625 short tons of U 3 0 8 for initial fuel loading and about 200 short tons for annual refueling. If one assumes a 30 year operating lifetime, the average annual fuel requirement is about 215 short tons U 3 0 8 per reactor year. 8 It is assumed here that a reactor year is equivalent to 0.650 gigawatt years of net electrical output, hence, the annual fuel requirement for the production of one GWe-yr is about 330 short tons of U308. Uranium is mined principally from sandstone deposits containing U 3 08 in concentrations ranging from 800 to 2,000 ppm.9 The average concentration of ore mined in 1975 was about 1600 ppm. 10 As the price of U308 rises, as it has done over the last decade from about $8/lb to $43/lb, the average concentration of the ore which is economically feasible to mine will decrease, with a consequent increase in the volume of the mill tailings. Ore that is 0.2 percent by weight U 3 0 8 must be mined in quantities of 165,000 short tons per GWe-yr; ore that is 0.1 percent must be mined in quantities of 330,000 tons per GWe-yr. In 1974, the domestic uranium mining industry produced 12,000 tons of U308 by two major methods: (1) open pit mining -9- accounting for 58 percent of production from 31 facilities, and (2) underground mining accounting for 40 percent from 123 underground mines. 1 Underground mining is normally em- ployed when the ore lies below 400 feet of overburden. The radioactive nuclides present in the ore are those of the U-238 and U-235 decay chains, as shown in Figure 3. The principal decay chain, responsible for about 95 percent of the radioactivity, is that of U-238, having daughter products U-234, Th-230, Ra-226, Rn-222, Pb-210, and Po-210, before decaying to the stable end product Pb-206. Assuming that secular equilibrium has been achieved in all ore deposits (requiring 100,000 years), ore that is 0.2 percent by weight U 3 0 8 contains 0.00056 grams of Ra-226 per metric tonne. is 1 curie Noting that the activity of 1 gram of radium (3.7x1010 disintegrationsper second) and that the daughter products in the decay chain are in secular equilibrium, hence their activity is also one curie, the ore would contain about 500 pico-curies meter. (10 -12 curies = 1 pCi) of radon gas per cubic Measured values for ores range typically from 700 to 800 pCi/m3,12 implying a slightly higher grade ore for these measurements. When the ore is disturbed, as in extraction, the radon gas diffuses through the exposed mine walls and ore particle surfaces at rates both estimated and measured to be about 500 pCi/m2-sec, 1 3 thus contaminating both mine environment and global atmosphere. -10- 0 N a. 0N (E+ur) n 0(1 0N u3eynN rsrr, c 0 N N 0 I n N 8 I rlr rOZ o 11 to_,y r I 7'* L Ir pen Zpa Nlln n .,, rl b r o r'- Ba :: * 0 oOn i 8------------------ i: * I _R C C E-43 =I C dk * i;; d ,0 II ao Di o_ 0) Ocd o ar crl= m C rIL p~I o ii ILdl 0 a Cd I E2 io ,c F F I 1 I o n~ O 0U 4i 3z>C z =aI ,N _ n 0) C i _I _ * 3 t ' ml i n ni3§8w ;X5 C - " F 4 P4" c ·· t . :a)r3 04 H. a4) uJ0 04 Co (',= In (1)4n3 r, rd0 W -I s Zid -r-i U-P -P P tTbFH r Q (Z--) INOjOONnarrr tn NNNNNHNNN OI Q u3sonm ssvn ID OIO r,7, yl ,0 cdtl-ii, o O --- fo oo C/)z O En Qc ) IO ?r :x,1 Po_ ,II m N L-CrL* 2 N 3·1 o·2 3 '0 ' r I1;;LhfNX 0H a, a, rd 4 Id O F0 )m C) fd04:)X 04 U r- · c~ aZu >r I_ Ic =ci-re P r'ril rQI · 10 0 11 e a r '8 ,"a 8a ·) io rr ,u I IN N LI n 4 D · r· -------- ro Q Ck " 0 II ·r 0 "0 I O \I'IlIIo 0 r'l Od O id t*- cd >2 P g X su ,o IP 4a r 1 u FIL, n f (L) H _ t a x r-i -11- Hence, uranium mining has several radiological health effects: (1) mine workers are exposed to gamma radiation from the U-238 and U-235 decay chains, (2) they are also exposed externally to radon gas in the mine environment and to radon daughter products deposited on mine dust, (3) they are exposed internally to these same radionuclides when inhaled, and (4) both local and global populations are exposed to radon gas released to the atmosphere and dispersed. Because radium-226 is relatively long-lived (half-life is 1620 years), the production and escape rate of radon-222 is essentially constant for hundreds of years. The effluent re- lease of radon from a mine, unless it has been well sealed and stabilized, will continue long after the exhaustion and abandonment of the mine. Hence, in calculating the healtheffects due to the production of a single GWe-yr of electricity, one must make some assumptions regarding the period of consideration. The GESMO Final Report calculated health effects only over the period form 1975 through the year 2000 (a 26 year period), during which 35 trillion kwhrs of net electrical output were produced by light water reactors (about 4,000 GWe-yrs). For the "no recycle" option, the GESMO Final Report estimated that 2.4x107 curies of radon would be released over the 26-year period due to mining operations (excluding the mills and tailings piles).14 Dividing this by the net production of electricity over the same period (which is not really correct because the release figure is an integrated value over -12- 26 years, accumulating annual releases from past power output), one gets an accumulated release figure of about 5000 curies per GWe-yr. Further, dose commitments due to mining of uranium ore were estimated to be 910 person-rem per GWe-yr to the whole body, consisting of 256 occupational, 628 environmental to US residents, and 26 foreign person-rems per GWe-yr.1 5 These are the figures that will be used in a later summary of the fuel cycle radioactivity releases and health effects. It is noted that radon-222 has a relatively short halflife of 3.62 days and does not accumulate in large amounts over time, as do other radionuclides released from the fuel cycle, such as krypton-85. Hence, the 26 year period of consideration will not give a large error in estimating the same "per GWe-yr" dose commitments due to radon. There may be some longer term effects, however, due to uptake by plants and animals of radon daughters Pb-210 (5 day half-life) and Po-210 (138 day half- life), the effects of which have not been considered in the GESMO Final Report. In summary, radioactivity released in effluents from uranium mining operations will likely contain small amounts of all the U-238 and U-235 decay chain radionuclides, but the release of radon-222 is so overwhelming in comparison to the combined activity of the other radionuclides, that they are often ignored in the modeling of dose commitments and health effects. Based on radon-222 alone, the activity released to the environment is figured to be 5,000 Ci/GWe-yr, and the dose commitment is 910 person-rems/GWe-yr. -13- Uranium Milling In milling operations, uranium is extracted from the uranium bearing ore and concentrated into a semi-refined product called "yellowcake", which is usually 90 percent U 308. Two principal methods of extraction are practiced: (1) sul- furic acid leach, and (2) sodium carbonate and alkaline leach processes. A third method of solution mining and milling is in an R & D stage of development.1 6 The sulfuric acid leach process is typical of the kinds of stages by which uranium is extracted: the ore is crushed and finely ground; the resulting particles are leached with sulfuric acid to extract the uranium; the leach liquors are then purified and concentrated by solvent extraction, after which the uranium is precipitated as ammonium diuranate by the addition of ammonia; the yellowcake slurry is washed, watered, and dried to produce a solid product which is pulverized into a powder and drummed for shipment.l7 This pro- duct is the feed material to the UF6 conversion plants. In 1975, 14 conventional mills were operating in the U.S., processing about 7 million tons of ore annually containing 12,442 tons U 3 08 (average ore concentrations were 0.18 percent).18 A typical mill in the future is characterized by the GESMO study as having the capacity to process 3,500 MT of 0.10 percent U 3 0 8 ore per day, operating 300 days per year, recovering 90.5 percent of the U 30 8 for an annual output of 1080 tons of U 3 0 8 as yellowcake. In earlier discussions, it was noted that -14- 330 tons of U 3 0 8 was required for each Gwe-yr of electric output, given today's LWR plant characteristics; hence, one such mill can provide enough fuel for approximately three Gwe-yr of output. Radionuclides in the material flows are the same radio- nuclides mentioned in the section on mining: Th-230, Ra-226, Rn-220, Po-210 and Pb-210. found at the Lucky Me U-238, U-234, For ore grades Uranium mine in Freemont County, Wyom- ing, ranging from 0.19 to 0.26 percent U 3 0 8 , the equilibrium activity of each of the U-238 chain radionuclides ranged from 460 to 728 pCi per gram of ore. Activity for the U-235 decay chain, having only one long-lived radio nuclide, Pa-231 (halflife of 3.43 x 104 years), ranged from 20 to 34 pCiper gram, amounting to only 5 percent of the total activity.l9 At the mill, the ore is stored on pads to provide a continuous supply for processing. Storage for ten days results in the production of 85 percent of the secular equilibrium activity of Rn-222, which is partially released to the atmosphere by the diffusion process. Subsequent ore handling, crushing and pulverizing operations release all the remaining radon gas. In addition, dust from these operations becomes airborne, carrying off-site the U-238 and daughter radionuclides which have attached themselves to these particles. Further, liquid effluent releases also have concentrations of up to 22,000 pCi per liter of Th-230. After these processes have removed the uranium, 97 percent -15- of the original activity in the ore, and virtually all of the radium-226, remains in the mill tailings, which are ponded for water evaporation and then piled for ultimate disposal and stabilization. The concentration of radium in these piles for a 0.2 percent ore grade is about 700 pCi per gram. As mentioned earlier, because the half-life of radium is 1620 years, concentration of this radionuclide is effectively constant for several centuries, even though its source, U-238, has been removed by the mill. Radon-222 reaches its secular equilibrium concentration within a few weeks and diffuses through the mill tailings surface at a rate of about 600 pCi/ 2 m -sec. 20 Taking as an example a milling operation capable of supporting one Gwe-yr of electric power, the following numbers are detailed: (1) 330 short tons of U 3 0 8 from an ore of grade 0.20 percent extracted at 90 percent efficiency, leaves 185,000 short tons of tailings; (2) after crushing, grinding and sett- ling, the average density of these tailings is assumed to be 1.33 short tons per m (inferred from several data sources), giving a tailings volume of about 140,000m3; (3) the tailings pile is assumed to be shaped to a height of 3 meters giving a surface area of about 46,000m2; finally (4) applying the diffusion rate of 600 pCi/m2-second, one can estimate the annual radon release rate to the atmosphere to be 870 curies per Gwe-yr of power per unit. Integrating this exponentially decreasing release rate with respect to time from zero to -16- infinity until all the radium has decayed, the total consequence of one Gwe-yr of power is the eventual release of 2 million curies of Ra-222. The U.S. Environmental Protec- tion Agency has estimated the "100-year" dose commitments, for example, to be more than 200 times larger than the dose commitments calculated over the 30 year period of mill operation,21 owing to the continued release of radon and the growing world population. In this discussion, we take notice of the above considerations, but for the purpose of comparing the relative contributions of the various components of the uranium fuel cycle, we return to the GESMO Final Report and its 26-year period of analysis. The GESMO Final Report estimates the radionuclide releases to the environment by the uranium milling industry for this period from 1975 through 2000 (no recycle option). estimates are displayed in Table 1. These The GESMO Final Report used radiological health assesment models to estimate dose commitments, and data tables found in Section J of Chapter IV, Volume 3 of the GESMO Final Report enabled the compiling of the dose commitments over this period for each Gwe-yr; the estimates so derived are shown in Table 2. Recently, the Nuclear Regulatory Commission has been studying various means for stabilizing the mill tailings piles and capping them to retain the radon gas within the pile for a sufficiently long period of time to allow decay. Typically, -17- Table 1: Estimated Radioactive Effuents Released to the Environment by the U. S. Uranium Milling Industry for the Period 1975 through 2000 Radionuclide Release in Curies Release in Curies/Gwe-yr U-238 260 0.055 U-234 260 0.055 U-235 12 0.003 Th-234 19 0.004 Th-230 24 0.005 Ra-226 13 0.003 Rn-222 4,400,000 930. Totals 4,400,588 930. Source: GESMO Final Report, Chapter IV, Table IV-F-6, Vol. 3, September 1976. A factor of 4,732 Gwe-yr of power was assumed for the 26 year period per Table IV-J(E)-17. such schemes commence after the six to eight years required for evaporation and natural drying of the tailings ponds. They involve spreading the tailings out over a considerable land area, applying a clay blanket (impermeable to gas), overlaying the clay by 3.5 feet or more of subsoil, adding topsoil, grading to natural terrain to limit erosion and revegetating. 2 2 If such stabilization methods were both successful and remain intact for 10 half-lives of radium (16,200 years), it would reduce considerably the longer term health effects of the milling operations, ignored by the GESMO Final Report estimates. -18- Table 2: Estimated Total Dose Commitment from the U.S. Uranium Milling Industry for the Period 1975 through 2000 and per Gwe-yr (no recycle option) Organ Integrated Dose Commitment Person-rem* Dose Commitment Person-rem/ Gwe-yr* Whole body 579,000 248 22,400 52 1,870,000 303 449,000 144 2,130,000 146 1,500 148 Lung 175,000 163 Skin 1,500 165 GI tract Bone Liver Kidney Thyroid *Includes occupational, U.S. populations, and foreign exposures Source: GESMO Final Report, Chapter IV, Tables IV-F-7 and IV-J(E)-9 through IV-J(E)-16, Vol. 3, September 1976. -19- UF 6 Conversion The next step in the uranium fuel cycle requires that the uranium concentrate milled from the ore be converted to a volatile (gaseous) compound of uranium hexafluoride (UF 6 ) in order to be enriched by the gaseous diffusion processes. Two industrial processes are used to produce the UF 6 . The "hydrofluor process" consists of reduction, hydrofluorination and fluorination of the ore concentrates to produce crude UF 6 , followed by fractional distillation to obtain the pure product. The "wet solvent extraction process" uses a wet chemical solvent extraction step at the beginning of the process to prepare the high purity feed, then proceeds to the reduction, hydrofluorination and fluorination steps.2 3 The two commercial plants operating in the US are located at Metropolis, Illinois and Sequoyah, Oklahoma, and have a combined capacity of converting 10,000 metric tonnes of uranium metal (MTU) into UF 6 per year. 24 Recalling that the annual fuel requirement for 1 GWe-yr is 330 short tons U 3 0 8 , containing 255 metric tonnes of uranium metal, the annual conversion capacity requirement to convert this quantity into UF be 375 MT. At 10,000 MTU capacity utilization factor of 0.65), 6 would (assuming an average LWR 60 LWR's can be supported by the existing plants, indicating the need for expansion in the near future. Radionuclides handled in the material flows consist, again, only of the U-238 and U-235 decay chain members. The distribution -20- of radionuclide concentrations have, of course, been altered by the milling process which, for example, left behind most of the radium-226. Nevertheless, all members of the chains are present to some degree. Some decay products appear as impurities in the mill concentrate; others appear as a result of the continuing decay processes. Uranium, present in almost all of the process flows, appears in liquid effluents and is the predominant source of radioactivity in the gaseous effluents. Radium, thorium and decay products are separated from the uranium in the conversion process and, hence, also appear in the liquid effluents or in solid wastes. Gaseous effluents contain natural uranium in several forms: U 30 8 U0 2 ',UF 4 UF , 6 , U0 2 F 2 and (NH4 )2 U 2 07.25 Omitting further discussion and simply citing the results of the GESMO study, the radioactive effluent releases for UF 6 conversion plants were estimated to be those shown in Table 3. Also, radiological modeling estimates both for the accumulated dose commitments from these effluents over the 1975-2000 period and for each GWe-yr were developed as shown in Table 4. Enrichment Naturally occurring uranium, containing 0.71 percent of the fissile isotope U-235, must be slightly enriched to a concentration of 2 to 4 percent to provide fuel for light water moderated reactors. The processes by which this can be accomplished are several, but the only one currently in use in the US is gaseous diffusion. -21- Table 3: Estimated Radioactive Effluents Released to the Environment by UF 6 Conversion Plants for the Period 1975 through 2000 (no recycle option) Releases in Curies Radionuclide U-238 U-234 U-235 Th-234 Th-230 Ra-226 Rn-222 Totals Releases in Curies/GWe-yr 137.50 137.50 5.95 138.20 40.0 1.51 1.54 0.0344 0.0344 0.0015 0.0346 462.20 0.1016 0.0100 0.0004 0.0004 Source: GESMO Final Report, Chapter IV, Table IV-F-9. Volume 3, September 1976. A factor of 4,551 GWe-yr of power was assumed for the 26 year period per Table IV-J(E)-17. Table 4: Estimated Dose Commitments from US UF 6 Conversion Plants for the Period 1975 through 2000 and per GWE-yr (no recycle options) Organ Whole body GI tract Bone Liver Kidney Thyroid Lung Skin Integrated Dose Commitment Person-rem* 49,151 8,647 164,291 9,102 25,486 4,551 35,953 13,653 Dose Commitment Person-rem per GWe-yr* 10.8 1.9 36.1 2.0 5.6 1.0 7.9 3.0 *Includes occupational, US population and foreign population exposures. Source: GESMO Final Report, Chapter IV, Tables IV-F-11 and IV-J(E)-9 through IV-J(E)-16, Volume 3, September 1976. -22- The gaseous diffusion process is based on the principle that the rate at which a gas (in this case monotomic UF 6) escapes through a small hole is proportional to the average speed of the gas molecules. The average speed of gas mole- cules at any given temperature is inversely proportional to the square root of their masses.26 The ratio of the average velocities of two molecules of UF6 , one consisting of (U-235)F6 and the other of (U-238)F6, is accordingly proportional to the square root of the ratio of their respective molecular masses-1.0043. Hence, the maximum theoretical enhancement in the isotopic content for a single stage is the factor 1.0043. To enrich natural uranium to 4 percent U-235 requires, given today's plant efficiencies, 1200 stages. 2 7 All enrichment services in the US are currently provided by three gaseous diffusion plants owned by the Federal government and operated by private contractors. These facilities are located at Oak Ridge, Tennessee, at Paducah, Kentucky and at Portsmouth, Ohio. The capacity of these three plants is 17.2 million kilograms of "separative work units" (SWU) per year. In 1972, these plants produced 10.5 million SWU, only a portion of which was dedicated to commercial nuclear power enrichment services.28 One GWe-yr of electrical output requires approxi- amtely 130,000 SWU.29 Uranium, including the isotopes U-234, U-235, U-236, and U-238, constitutes the major portion by weight of the radionuclides found in diffusion plant effluents. The fission product Tc-99 (technetium), present by way of spontaneous -23- fission of U-235, contributes the most radioactivity. The uranium daughter Th-234 is the only other radio-nuclide found in significant concentrations in plant effluents. Although not usually detected in effluent samples because of the very short half-life (1.17 minutes), Pa-234m must be present if Th-234 is present, and is allocated in radiological health effects studies a portion of the gross beta activity. is attributed All alpha decay to uranium; the beta decay is attributed to Th-234, Tc-99 and Pa-234m.3 0 Actual release data for the three US plants is reported annually and can be found among the publications of the US Department of Energy. These data are displayed for the calendar year 1976 in Table 5. If one assumes that annual production from the three plants amounted to a level similar to that for 1972, roughly 10.5 million SWU, and that only about one-third of this separative work was dedicated to commercial nuclear power productions, and if one ignores the radionuclides not directly associated with the gaseous diffusion process (include only U, Th, Pa and Tc isotopes), one can arrive at an estimate of about 0.8 Curies released per GWe-yr, most of which is due to Tc-99. The GESMO Final Report estimates radioactive release rates as those shown on Table 6. These release rates are two orders of magnitude less than the above estimate. Either figure is very low, however, compared to other components of the fuel cycle. Table 7 estimates the radiological dose commitments -24- Table 5: Reported Radioactive Effluents Released to the Environment in 1976 by US Gaseous Diffusion Plants Radionuclide Uranium Th-234 Pa-234m Cs-137 Xe-133 I-131 Pu-106 Tc-99 Su-90 Kr-85 Co-60 H-3 1976 Oak Ridge Curies 1.55 -. Totals for U, Th, Pa & Tc only 1976 Paducah Curies 1976 Portsmouth Curies 1.08 1.08 1976 Totals Curies 3.71 .. -- -- -- 0.20 56,000.00 1.33 .20 30.80 4.50 11,500.00 0.90 8,420.00 ----16.20 ----- ----19.10 ----- 32.35 17.28 20.18 -- 0.20 56,000.00 1.33 0.20 66.10 4.50 11,500.00 0.90 8,420.00 69.81 Source: Environmental Monitoring Reports for Calendar Year 1976 for each of the three plants found compiled in ERDA Report No. ERDA-77-104/2. Table 6: Estimated Radioactive Effluents Released to the Environment by Gaseous Diffusion Enriched Plants (two sources of date) Radionuclide "no recycle" GESMO (1) Release Est. Ci/26-yr - U-232 U-233 U-234 U-235 U-236 U-238 Transneptunium Np-237 Tc-99 Pu-109 Zr-95 & Nb-95 Cs-137 Ce-144 Other Fission Products Totals 3.5 "no recycle" GESMO (2) Release Est. pC i/GWe-yr - 0.1 760. 20. 0.5 110. _ - .0275 .00015 32.5 1.25 .92 5.30 .00000033 .00017 450. 6.0 1.25 .092 .092 .092 _ 4.1 890. "recycle" 1976-EPA (3) Release Est. pCi/GWe-yr Ci 497.524 Source: (1) GESMO Final Report, Chap. IV, Table IV-F-16, Vol. 3, September 1976; for the 26-year period from 1975 through 2000; (2) a factor of 4.603 GWe-yr of power output for the 26-year period was applied per Table IV-J(E)-17; and (3) US EPA, Environmental Analysis of the Uranium Fuel Cycle--Part IV, Supplementary Analysis. Table 3.0-2, pp. 57, July 1976. -25- Table 7: Estimated Dose Commitments from US Gaseous Diffusion Plants for the Period 1975 through 2000 and per GWe-yr (no recycle option) Organ Whole Body GI Tract Bone Liver Kidney Thyroid Lung Skin Integrated Dose Commitment Person-rem* 3,371 3,820 5,541 5,646 5,751 5,907 6,810 7,448 Dose Commitment Person-rem per GWe-yr* 0.7323 0.8299 1.2037 1.2265 1.2495 1.2833 1.4794 1.6181 *Includes occupational, US population and foreign population exposures. Source: GESMO Final Report, Chapter IV. Tables IV-F-14 and IV-J(E)-9 through IV-J(E)-16, Volume 3, September 1976. It is noted that there is a considerable discrepancy between these figures and Tabel S(4)-1 of the same report, the latter showing whole body dose commitments to be 3,500 person-rems. -26- to occupational workers, the US population and foreign populations due to the operation of the US plants for the period 1975 through 2000, as well as for a GWe-yr of production. Again, these values are extremely small compared to other fuel cycle components. It is noted that these estimates are for the "no-recycle" option. If uranium and plutonium recycle were allowed, these estimates are projected by the GESMO Final Report to increase 100 fold due to the presence of more U and Pu radioactive isotopes in the feed material streams. 31 For comparison purposes, estimates of radioactivity releases under this option per GWeyr, developed by EPA, are also shown on Table 6. UO 2 Fabrication The uranium hexafluoride (UF6) from the gaseous diffusion plants, after having been enriched to 2 to 4 percent U-235, is shipped in large 2300 kg containers to LWR fuel fabrication plants. The UO 2 and fuel fabrication process involves hydrolyz- ing the UF 6 touranylfluoride (UO2 F 2), precipitating ammonium diurante by the addition of ammonium hydroxide, dewatering the precipitate by centrifuging or filtering, then drying and reducing the precipitate to U0 2 powder in a cracked ammonia atmosphere. The UO2 powder is then pretreated to obtain the desired consistency, formed into pellets, sintered to the required density, ground and polished to finished dimensions, washed and dried and, finally, loaded into zircaloy tubing and sealed with a welded cap. These tubes, or fuel elements, -27- are then assembled into arrays to be handled as fuel assemblies.3 2 ' 3 3 Scrap material is collected, dissolved in nitric acid, purified by solvent extraction, calcined and again reduced to UO2 for recycling. 3 4 Current capacity of the nine fabrication plants in the US can process 2,700 metric tonnes of uranium metal year. (MTU) per One GWe-yr of electric power requires about 40 MTU of fabrication throughput per year.35 Radionuclides present in the effluent streams are strictly those at the beginning of the U-238 decay chain and other isotopes of uranium. The radionuclides are the result of leakage, spillage and breakage in the fabrication processes and small quantities escape to the environment, most probably UO2F UO 2 . 2 and Decay of uranium isotopes U-234, U-235 and U-238 in natural uranium provides about 0.7 Ci per MTU processed; decay of these same isotopes in 3.2 percent enriched uranium provides about 1.8 Ci per MTU.3 6 Reported effluent releases by the General Electric facility in Wilmington, North Carolina and the Westinghouse facility in Columbia, South Carolina for 1972 are 1.36 and 0.50 curies per year respectively, as scaled to a model 900 MTU plant.37 Using the 40 MTU per GWe-yr assumption, these two facilities reported releases in 1972 of 0.0604 and 0.0222 Ci/GWe-yr respectively. These figures compare well with those estimated from information provided in the GESMO Final Report, and these estimates are shown in Table 8. The GESMO Final Report radiological health effects modeling, estimated dose commitments for this step in the fuel cycle to be those shown in Table 9. -28Table 8: Estimated Radioactive Effluents Released to the Environment by U0 2 and Fuel Fabrication Facilities for the Period 1975 through 2000 (no recycle option) Radionuclide U-234 U-235 U-236 U-238 Th-234 Totals Release Curies 237.0 6.4 0.0 29.5 29.5 302.4 Release Curies/GWe-yr 0.0454 0.0015 0.0000 0.0068 0.0068 0.0696 Source: GESMO Final Report, Chapter IV, Table IV-F-16, Volume 3, September 1976. A factor of 4346 GWe-yr of power was assumed for the 26 year period per Table IV-J(E)-17. Table 9: Estimated Dose Commitments from US U0 2 and Fuel Fabrication Facilities for the Period 1975 through 2000 and per GWe-yr (no recycle option) Organ Integrated Dose Commitment Person-rem* Dose Commitment Person-rem per GWe-yr* . Whole body GI Tract Bone Liver Kidney Thyroid Lung Skin 54,455 57,237 61,583 51,152 51,935 51,935 1,978,647 11,256 12.53 13.17 14.71 11.77 11.95 11.95 455.28 2.59 *includes occupational, US population and foreign population exposures Source: GESMO Final Report, Chapter IV, Tables IV-F-20 and IV-J(E)-9 through IVJ(E)-16, Volume 3, September 1976 -29- POWER REACTORS In the process of generating electricity, nuclear power reactors accumulate very large amounts of radioactivity by irradiating fuel, structures and coolant with neutron fluxes on the order of 10 14 neutrons per cm 2 per second, and by the accumu- lation of a spectrum of fission product elements, and their decay chain daughter elements, having atomic numbers ranging from 70 to 160, most of which are found between Br-84 and Ce-144. A typical 1000 MWe power reactor will contain hundreds of millions of curies of radioactivity; the isotope I-131 by itself represents as much as 70 megacuries of the total. Among the more important radionuclides are: (1) the halo- gens bromine and iodine, which are volatile at reactor operating temperatures and diffuse as agas out of the ceramic matrix of the fuel element, and which are chemically active and mobile along the pathways to man; (2) the noble gases krypton and xenon, both of which may be released to the atmosphere and inhaled, are water soluble and can be ingested; (3) the alkali metals cesium and rubidium, which are also water soluble in the form of dissolved salts; (4) the alkaline earths barium and strontium (mem- bers of the same periodic family as calcium), which are water soluble and bone seekers; (5) coolant activation products, which are generally gases, such as the radionuclides (tritium), argon, fluorine, nitrogen and oxygen; and of hydrogen (6) structural activation products having fairly long half-lives, including zirconium, manganese, nickle, iron, carbon, chromium, -30- cobalt and copper, most of which remain fixed within the structural. materials, but some of which may be released by way of mechanical wear or erosion to the coolant and, hence, to liquid effluent streams. The vast majority of the radioactivity is isolated from the environment by several constructed barriers: (1) the fuel cladding, which remains air tight and sealed unless it fails, (2) the reactor vessel and closed coolant systems, and (3) the reactor and auxiliary containment buildings. Nevertheless, measurable amounts of radioactivity are released to the environment on a routine basis within permissible limits established by the Nuclear Regulatory Commission (NRC). examines the nature and quantities This section of these routine releases for five reactor types: (1) pressurized water reactors (PWR) (2) boiling water reactors (BWR) (3) high temperature gas cooled reactors (HTGR and GCR) (4) heavy water reactors (HWR, PHWR and SGHWR), and (5) liquid metal fast breeder reactors (LMFBR) In each case an attempt is made to identify and briefly explain the principal sources of the radioactivity releases and to quantify them in terms that allow comparisons among reactor types per GWe-yr of net power produced. Data for these com- parisons is compiled from the semi-annual radioactive effluent release reports filed by law with the NRC, when available, or from engineering estimates as found in the Preliminary Safety Analysis Reports (PSAR) for reactors not yet operating. Some -31- data on foreign reactors has been analyzed, although it is very sketchy by comparison to the US data. Quantities of radioactivity released are expressed in curies (10 (Ci), or micro-curies Ci = 1 Ci), per GWe-yr of net power output for four classes of radionuclides: (1) noble gases, (2) tritium, (3) halogens and airborne particulates, and (4) mixed fission (MF) and various coolant and structural activation products. Light Water Reactors In the analysis of the radioactive effluent releases of light water moderated reactors, thirty PWR's and 25 BWR's were investigated. These reactors, their rated power levels and actual operating thermal power levels for the years 1975 and 1976 are shown in Tables 10 and 11. Net electrical output was assumed to be 32 percent of thermal power. For boiling water reactors a direct steam cycle is used whereby the contaminated coolant in its steam phase passes directly through the turbine. Entrained radioactive gases, air which has leaked into the condenser and hydrogen and oxygen which result from the radiolytic dissociation of water are removed from the main turbine condenser by means of a steam jet air ejector (off-gas ejector), which is used to maintain the condensor vacuum. These gases are removed at a rate of about 300 cubic feet per minute. In the absence of any failed fuel cladding, the principal radioactive nuclide released by this -32- Pressurized Water Reactors (PWRs) Included in Effluent Data Analysis for 1975 and 1976 Table 10: Rated Name of Unit (PWR) Power Mwe 1975 Thermal Ojtput 10 Mwd 1976 Thermal Ogtput 10 Mwd 0.563 1976 Electrical Output Gwe-y 0.441 Arkansas One 1 836 642 Calvert Cliffs 1 850 584 1090 608 895 0.533 0.785 Fort Calhoun 501 280 298 0.245 0.261 Ginna 517 404 291 0.354 0.255 Haddem Neck 600 558 540 0.489 0.473 2087 685 561 0.601 0.492 Kewaunee 563 451 450 0.395 0.395 Maine Yankee 830 612 811 0.537 0.711 Millstone Point 2 860 D.C. Cook Indian Point 1,2 & 3 503 1975 Electrical Output Gwe-y 0.512 0.553 631 2766 1960 1650 1.718 1.447 Palisades 811 371 403 0.325 0.353 Point Beach 1 & 2 994 872 946 0.764 0.829 Prairie Island 1 & 2 1076 938 858 0.822 0.752 H.B. Robinson 772 566 661 0.496 0.580 San Onofre 450 417 323 0.366 0.283 1576 1210 1050 1.061 0.921 870 734 580 0.644 0.508 1520 1160 1120 1.017 0.982 185 168 177 0.147 0.155 2100 1370 1290 1.201 1.131 21854 14590 14038 12.791 12.307 Oconee 1,2 & 3 Surrey 1 & 2 Three Mile Island Turkey Point 3 & 4 Yankee (Rowe) Zion 1 & 2 Totals (30 PWR's) Source: Data compiled from "Summary of Radioactivity Released in EfU.S. fluents from Nuclear Power Plants from 1973 thru 1976," List is not Environmental Protection Agency, December 1977. all inclusive. Gigawatt years of electrical output assumes 32 percent conversion efficiency. -33- Table 11: Boiling Water Reactors (BWRs) Included in Effluent Data Analysis for 1975 and 1976 1975 Name of Unit (BWR) Rated Power Mwe Thermal Output 103 Mwd 1976 Thermal O0tput 10 Mwd 1975 Electrical Output Gwe-y 1976 Electrical Output Gwe-y 75 41 35 0.036 0.031 Brown's Ferry 1,2 & 3 3195 365 560 0.320 0.491 Brunswick Units 1 & 2 1580 233 332 0.204 0.291 Cooper Nuclear Station 778 231 494 0.203 0.433 Dresden 1 200 106 143 0.093 0.125 1600 534 1150 0.468 1.008 Duane Arnold 1 569 309 334 0.271 0.293 J.A. Fitzpatrick 2 821 284 527 0.249 0.462 E.I. Hatch 1 786 407 574 0.357 0.503 Humbolt Bay 3 65 55 28 0.048 0.025 La Crosse 53 38 25 0.033 0.022 Millstone Point 1 652 502 485 0.440 0.425 Monticello 545 370 514 0.324 0.451 Nine Mile Point 1 625 430 545 0.377 0.478 Oyster Creek 1 640 409 492 0.359 0.431 2130 1390 1550 1.219 1.359 Pilgrim 1 664 338 317 0.296 0.278 Vermont Yankee 514 469 425 0.411 0.373 1600 964 476 0.845 0.417 17092 7475 9006 6.553 7.896 Big Rock Point Dresden 2 & 3 Peach Bottom 2 & 3 Quad Cities 1 & 2 Totals Source: (25 BWRs) Data compiled from "Summary of Radioactivity Released in Effluents from Nuclear Power Plants from 1973 thru 1976," U.S. Environmental Protection Agency, December 1977. List is not all inclusive. Gigawatt years of electrical output assumes 32 percent conversion efficiency. -34- means would be nitrogen-13, the product of an (n,) on oxygen-16. reaction In the Brown's Ferry (BWR) Final Safety Analysis Report (FSAR), the annual discharge of this radionuclide was estimated to be 8,580 curies per year, or about 10,000 curies per GWe-yr.3 8 Assuming, instead, that 0.25 percent of the fuel elements developed cladding leaks of some appreciable size to allow noble gases under pressure to escape, the Brown's Ferry FSAR estimated that the annual discharge of the noble gases would be 2,500,000 curies per year, or about 3,000,000 curies per GWe-yr, overwhelming the N-13 radionuclide. 3 9 Hence, it clear from this comparison that the combination of BWR direct cycle and failed fuel cladding can result in a significant source term for radioactive gas effluents. Off-gas hold-up systems, however, can reduce the activity of many of the krypton and xenon radioisotopes; only 5 percent of the predicted activity is represented by radioisotopes having halflives greater than 10 hours. In pressurized water reactors compound is added to the coolant for the purposes of poison reactivity control. This boron is a source of tritium by way of neutron capture in boron-10. (1) an an (PWR's), a soluble boron Two reactions are possible: (n,2a)T reaction producingtritium directly, and (2) (n,n'a) reaction producing Lithium-6, which in turn has a large cross section (950 barns tritium. ) for an (n,a) reaction producing As in the BWR, the PWR coolant also contains nitrogen-13 and any volatile fission products that may have leaked from failed fuel. -35- Further, in a PWR the boron introduced for reactivity control at the beginning of a fuel removed as the fuel is burned up. cycle, must be gradually This is accomplished by con- tinually bleeding off a small portion of the coolant to a boron recovery system, wherein entrained gases are evolved by a gas stripper and routed to a waste gas hold up and treatment system. Hence, the gas stripper is another source term for noble gases, halogens, tritium, and other gases. In both PWR's and BWR's there are some small but inevitable leaks of the primary coolant directly to the reactor containment building environment: from coolant pumps and valve seals, most of which is captured and returned to the coolant system, from many smaller valves, from radiological sample taking and other routes and activities. Liquids are collected and processed in the liquid waste systems; noble gases, volatile halogens and some particulates will escape to the containment building atmosphere. The containment building atmosphere is vented several times per year on a periodic basis to reduce temperature and activity levels prior to plant maintenance and to reduce containment vessel pressure if excessive steam leakage exists. In a BWR, some additional sources of radioactivity releases are: the gland seal at the turbine generator shaft, the turbine building atmosphere venting and a mechanical vacuum pump used in place of the steam powered off-gas ejectors at the time of reactor start-up. significant. Of these, the turbine gland seal is the most -36- Tables 12 through 25 compile statistical average releases per GWe-yr for 30 PWR's and 25 BWR's for the years 1975 and 1976 for each of the aforementioned categories of radionuclides (a total of 14 tables are presented). The source of data for all of these tabels on light water reactors was a 118 page report published by the US Environmental Protection Agency, entitled, "Summary of Radioactivity Released in Effluents from Nuclear Power Plants from 1973 through 1976." 4 0 From this data a statistical average was obtained and plotted on Figures 4 through 7, shown in the summary of this section on power reactors. Occasionally, one or two data points representing statistical extremes (low or high) were excluded form the reactor type average, for the purpose of portraying a release figure "representative" of that type of reactor. These exclusions are noted, along with the average including all data points, on each of the tables where this was done. -37Table 12: Name of Unit (PWR) Noble Gases Released to the Environment in 1975 by Pressurized Water Reactors (PWRs) Rated Power Mwe 1975 Electrical Output Gwe-y Noble Gases Airborne Curies Noble Gases Dissolved Curies Noble Gases Total Curies Curies of Noble Gases Per Gwe-y 185 0.147 25 .2 25 170 2087 0.601 8566 .8 8567 14255 450 0.366 4.7 600 0.489 1795 480 4904 Haddem Neck 1790 480 Ginna H.B. Robinson 517 772 0.354 0.496 10500 1170 .1 29661 2359 Palisades 811 0.325 2610 .1 Maine Yankee 830 0.537 4120 10500 1170 2610 4120 Fort Calhoun Kewaunee 501 563 0.245 429 429 0.395 2450 .2 2450 1751 6203 Three Mile Island 870 0.644 3630 1.1 3631 5638 Arkansas One 1 836 0.563 1040 33.1 1073 1906 Calvert Cliffs 1 D.C. Cook 1 850 0.512 13.1 0.533 7733 3 15104 1090 7720 3 Yankee (Rowe) Indian Point 1, 2 & 3 San Onofre .3 982 8031 7672 6 Millstone Point 2 860 Point Beach 1 & 2 994 0.764 45300 .5 45301 59295 Surry 1 & 2 Turkey Point 1 & 2 1576 1.061 8040 28.1 8068 7604 1520 1.017 13400 4.8 13405 13181 Oconee 1,2 & 3 Zion 1 & 2 2766 2100 1.718 1.201 15200 45300 2.9 15203 45300 8849 37719 Prairie Island 1 & 2 1076 0.822 2180 2.8 2183 2656 173953 92.8 174046 13607 Totals Statistical extremes (#1, 14, 16) Total excluding statistical extremes Source: 12.791 45329 1.441 11.350 - 128717 11341 Data was compiled from "Summary of Radioactivity Released in Effluents from Nuclear Power Plants from 1973 through 1976," U.S. EPA. December, 1977. This list of PWRs is not all inclusive. -38Table 13: Noble Gases Released to the Environment in 1976 by Pressurized Water Reactors (PWRs) Power Mwe Unit Name (PWRs only) 1976 Equivalent Power Gwe-y - Yankee (Rowe 185 0.155 San Onofre 450 0.283 Haddam Neck 600 Ginna Noble Gases Aerosols Curies 27 Noble Gases Dissolved Curies Total Curies of Noble Noble Gases Gases Per Curies Gwe-y - 27 174 430 492 1519 5913 23188 13 0.473 417 492 517 0.255 5520 393 H.B. Robinson 772 0.580 791 791 1364 Palisades 811 0.353 30 85 Maine Yankee 830 1300 Kewaunee Three Mile Island 563 0.711 0.395 30 1300 0.508 1600 2760 4051 870 1600 2760 Arkansas One I 902 0.441 5690 90 5780 13107 1090 0.785 975 1 1243 Millstone Point 2 860 0.553 1550 4 976 1554 St. Lucie 802 0.013 1790 1790 137692 Beever Valley 833 0.072 1 2010 2425 Point Beach 1 & 2 994 0.829 2010 19230 20879 Surrey 1 & 2 Turkey Pt. 3 & 4 1576 1520 0.921 0.982 19200 30 19230 20879 15600 1 15601 15887 Oconee 1, 2 & 3 Zion 1 & 2 2766 1.447 44000 1 44001 30408 2100 1.131 142000 142000 125553 Prairie Isl. 1 & 2 1076 0.752 1740 2 1742 2316 Indian Pt. 1,2, & 3 2087 Totals 0.492 13 10613 21571 12.392 10600 260243 552 260795 21045 1.724 143848 - 143848 82576 Total excluding statistical extremes 10.668 Best plant averages (#1 & 6) 0.508 116395 552 - 116947 57 10962 142000 125553 D. C. Cook Statistical extremes (#1, 6, 14, 15, 20) Worst plant averages Source: (#20) 1.131 57 142000 - 1040 1828 5433 2810 112 Data compiled from "Summary of Radioactive Released in Effluents from Nuclear Power Plants from 1973 through 1976," U.S. EPA. December, 1977. This list of 31 PWRs is not all inclusive. -39- Table 14: Noble Gases Released to the Environment in 1975 by Boiling Water Reactors (BWRs) Rated 1975 Electrical Power Mwe Output Gwe-7 Noble Gases Airborne Curies 200 0.093 520,000 Big Rock Point 75 0.036 50,600 Humbolt Bay 3 65 0.048 La Crosse 53 Name of Unit (BWR) Noble Gases Dissolved Curies Noble Gases Total Curies Curies of Noble Gases per Gwe-y 520,000 5,591,398 0.00 724 50,600 1,405,556 296,000 0.00 800 296,000 6,166,667 0.033 57,100 0.40 700 57,100 1,730,303 640 0.359 206,000 0.42 600 206,000 573, 816 Nine Mile Point 1 625 0.377 1,300,000 0.10 400 1,300,000 3,448,276 Millstone 1 652 0.440 2,970,000 1.11 000 2,970,001 6,750,002 Monticello 545 0.324 155,000 - 155,000 478,395 Vermont Yankee 514 0.411 3,360 - 3,360 8,175 Pilgrim 1 664 0.296 105,000 0 ..00 071 105,000 354,730 Cooper Station 778 0.203 19,700 0.00 550 19,700 97,044 Duane Arnold 1 569 0.271 1,540 1,540 5,683 Hatch 1 786 0.357 1,550 1,550 4,342 Fitzpatrick 2 821 0.249 4,080 4,080 16,386 Brunswick 2 780 0.204 185 185 907 Dresden 2 & 3 1600 0.468 369,000 - 369,000 788,462 Quad Cities 1 & 2 1600 0.845 110,000 - 110,000 128,805 Brown's Ferry 2134 0.320 25,200 25,200 78,750 Peach Botton 2 & 3 2130 1.219 13,000 13,000 10,664 6.553 6,207,315 2.44652 6,207,317 947,248 Dresden 1 Oyster Creek 1 Totals Source: - 0.23 400 0.00 107 0.14300 Data was compiled from "Summary of Radioactivity Released in Effluents from Nuclear Power Plants from 1973 through 1976," This list of BWRs is not all incluDecember, 1977. U.S. EPA. sive. -40- Noble Gases Released to the Environment in 1976 Table 15: by Boiling Water Reactors Rated Power Mwe Name of Unit (BWR) 1976 Electrical Output Gwe-y Noble Gases Airborne Curies (BWRs) Noble Gases Dissolved Curies Noble Gases Total Curies Curies of Noble Gases per Gwe-y 200 0.125 460,000 460,000 3,680,000 Big Rock Point 75 0.031 15,200 15,200 490,323 Humbolt Bay 3 65 0.025 93,000 0.00415 93,000 3,720,000 La Crosse 53 0.022 124,000 0.09300 124,000 5,636,364 Oyster Creek 640 0.431 166,000 0.04640 166,000 385,151 Nine Mile Point 625 0.478 176,000 0.00558 176,000 368,201 Millstone Point 1 652 0.425 507,000 0.35600 507,000 1,192,941 Monticello 545 0.451 11,400 11,400 25,277 Vermont Yankee 514 0.373 2,870 0.00628 2,870 7,694 Pilgrim 1 664 0.278 183,000 0.00122 183,000 658,273 Cooper Station 778 0.433 38,100 0.04620 38,100 87,991 Duane Arnold 1 569 0.293 5,260 5,260 17,952 Hatch 1 786 0.503 3,110 3,110 6,183 Fitzpatrick 2 821 0.462 46,200 46,200 100,000 Dresden 2 & 3 1600 1.008 32,400 32,400 32,143 Quad Cities 1,2 & 3 1600 0.417 31,500 31,500 75,540 Brown's Ferry 1,2 & 3 3195 0.491 80,400 0.10900 80,400 163,747 Peach Bottom 2 & 3 2130 1.359 209,000 2.84000 209,003 153,792 1580 0.291 18,500 0.70300 18,501 63,577 7.896 2,202,940 4.31403 2,202,944 278,995 Dresden 1 Brunswick 1 Totals & 2 .79 0.10400 _ -41- Table 16: Tritium Released to the Environment in 1975 by Pressurized Water Reactors (PWRs) Rated Power Mwe 1975 Electrical Output Gwe-y 185 0.147 2 247 249 1694 Indian Point 1 & 2 2087 0.601 25 366 391 651 San Onofre 1 450 0.366 34 4000 4034 11022 Haddam Neck 600 0.489 70 5670 5740 11738 Ginna, RE 517 0.354 6 260 266 751 Robinson, HB 772 0.496 193 624 817 1647 Palisades 811 0.325 42 42 129 Maine Yankee 830 0.537 5 177 182 339 Fort Calhoun 501 0.245 2 111 113 461 Kewaunee 563 0.395 37 277 314 795 Three Mile Island 1 Arkansas One 1 870 0.644 40 463 503 781 836 0.563 1 460 461 819 Calvert Cliffs 1 850 0.512 1 263 264 516 1090 0.533 56 56 105 994 0.764 420 1020 1440 1885 Suny 1 & 2 1576 1.061 32 442 474 447 Turkey Point 1 & 2 1520 1.017 3 793 796 783 Oconee 1 & 2 2766 1.718 1660 3550 5210 3033 Zion 1 & 2 2100 1.201 40 40 33 Prairie Island 1 & 2 1076 0.822 10 763 773 940 12.791 2541 19624 22165 1733 2.056 104 9710 9814 4773 Totals excluding statistical extremes 10.735 2437 9914 12351 115 0 Unit Name (PWRs) Yankee (Rowe) Cook, DC Point Beach 1 & 2 Totals Satistical extremes (#3, 4, 19) Tritium Gases Curies Tritium Liquids Curies Total Tritium Curies Curies of Tritium per Gwe-y -42- Table 17: Tritium Released to the Environment in 1976 by Pressurized Water Reactors (PWR's) Rated Power Mwe 1976 Thermal Output 1000 MwL 1976 Equivalent Power GWe-y 185 450 600 517 772 811 830 501 563 870 902 1090 860 802 833 994 1576 1520 2766 2100 177 323 540 291 661 403 811 298 450 580 503 895 631 15 82 946 1050 1120 1650 1290 0.155 0.283 0.473 0.255 0.580 0.353 0.711 0.261 0.395 0.508 0.441 0.785 0.553 0.013 0.072 0.829 0.921 0.982 1.447 1.131 1076 858 0.752 2087 561 Ci of Tritium per GWe-y Tritium Gases Curies Tritium Liquids Curies Total Tritium Curies 2 47 793 24 158 156 3380 4850 242 980 10 368 54 214 189 212 192 277 13 9 695 782 770 2190 1 158 3427 5643 266 1138 10 372 57 215 906 219 192 292 15 3729 1090 1154 775 2692 1 1019 12110 11930 1043 1962 29 523 218 544 1783 497 245 528 1154 51792 1315 1253 789 1860 1 33 1930 1963 2610 0.492 24 332 356 724 12.392 6824 17846 24670 1991 Statistical extremes (#2,3,6,14,15,20) 2.325 4562 8263 12825 5516 Totals excluding statistical extremes 10.067 2262 9583 11845 1177 1 1 1 8230 9070 11997 Unit Name (PWR's only) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. Yankee (Rowe) San Onofre Haddam Neck Ginna H. B. Robinson Palisades Marine Yankee Fort Calhoun. Kewaunee Three Mile Island Arkansas One 1 D. C. Cook Milstone 2 St. Lucie Beaver Balley 1 Point Beach 1 & 2 Surrey 1 & 2 Turkey Point 3& 4 Oconee 1,2& 3 Zion 1 & 2 Prairee Islands 1 & 2 Indian Pt. 1, 2 & 3 TOTALS Best plant averages (#20) 1.131 Worst plant averages (#2 and 3) 0.756 Source: 4 3 1 717 7 15 2 3720 395 372 5 502 840 Data compiled from "Summary of Radioactivity Released in Effluents from Nuclear Power Plants from 1973 thru 1976," U.S. EPA, December 1977. This list of 31 PWR's is not all inclusive. -43- Table 18: Tritium Released to the Environment in 1975 by Boiling Water Reactors (BWR's) Name-of Unit (BWR) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. Dresden 1 Big Rock Point Humbolt Bay 3 La Crosse Oyster Creek 1 Nine Mile Point 1 Millstone 1 Marticello Vermont Yankee Pilgrim 1 Cooper Station Duane Arnold 1 Hatch 1 Fitzpatrick 2 Brunswick 2 Dresden 2 & 3 Quad Cities 1 & 2 Brown's Ferry 1&2 Peach Bottom 2&3 Rated Power Mwe 1975 Electrical Output GWe-y 200 75 65 53 640 625 652 545 514 664 778 569 786 821 780 0.093 0.036 0.048 0.033 0.359 0.377 0.440 0.324 0.411 0.296 0.203 0.271 0.357 0.249 0.204 1600 1600 1975 Tritium Gases Curies 1975 Tritium Liquids Curies 1975 Tritium Total Curies Curies of Tritium per GWe-y 34 7 2 17 3 92 17 1 6 20 127 18 28 80 35 13 22 144 21 120 97 376 361 458 4364 58 318 220 7 74 43 - 19 - 17 311 251 70 22 2 6 7 92 51 19 8 2 3 5 25 0.468 0.845 221 39 54 39 275 78 588 92 2134 0.320 5 10 15 47 2130 1.219 31 31 25 Totals Statistical extremes (#4, 16) Totals excluding statistical extremes 18 8 6.553 584 449 1033 158 .501 238 181 419 836 6.052 346 268 614 LZ01 x x -44- Table 19: Tritium Released to the Environment in 1976 by Boiling Water Reactors (BWR's) Rated Power Mwe 1976 Electrical Output GWe-y 200 75 65 53 640 625 652 545 514 664 778 569 786 821 0.125 0.031 0.025 0.022 0.431 0.478 0.425 0.451 0.373 0.278 0.433 0.293 0.503 0.462 61 8 1 13 1 19 29 77 14 37 67 16 1 15 2 7 41 39 2 20 2 47 8 9 4 61 10 8 54 40 21 49 77 16 84 75 16 10 19 488 323 320 2455 93 44 115 171 43 302 173 55 20 41 1600 1600 1.008 0.417 14 297 20 23 34 320 34 767 3195 2130 1580 0.491 1.359 0.291 1 27 22 4 74 6 5 101 28 10 74 96 Totals 7.896 720 308 1028 130 Statistical. extreme #16 0.417 297 23 320 767 Totals excluding stat. extremes 7.479 423 285 708 Name of Unit (BWR) 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. Dresden Big Rock Point Humbolt Bay 3 La Crosse Oyster Creek Nine Mile Point Millstone Point 1 Monticello Vermont Yankee Pilgrim 1 Cooper Station Duane Arnold Hatch 1 Fitzpatrick 2 15. 16. 17. Dresden 2 & 3 Quad Cities 1 & 2 Brown's Ferry 1, 2, & 3 Peach Bottom 2 & 3 Brunswick 1 & 2 18. 19. 1976 Tritium Gases Curies 1976 Tritium Liquids Curies - 1976 Total Tritium Curies Curies of Tritium per GWe-y x -45- Table 20: Halogens and Particulates Released to the Environment in 1975 by Pressurized Water Reactors (PWR's) 1975 Total Halogens & Particulates m Ci 1975 m Ci of H&P per GWe-yr Name of Unit (PWR) 1975 Electrical Power Output GWe-yr 1. Yankee Rowe 0.147 3 8 11 75 1975 Halogens m Ci 1975 Particulates m Ci 2. Indian Point 1 & 2 0.601 410 1279 1689 2810 3. San Onofre 0.366 246 36 282 770 4. Haddam Neck 0.489 1 2 3 6 5. Ginna 0.354 65 65 184 6. Robinson 0.496 23 1 24 48 0.325 427 1 428 1317 7. Palisades 8. Maine Yankee 0.537 6 6 11 9. Fort Calhoun 0.245 7 7 29 10. Kewanee 0.395 20 666 1686 11. Three Mile Island 1 0.644 1 1 2 12. Arkansas One 1 0.563 22 11 33 59 13. Calvert Cliffs 1 0.512 36 11 47 92 14. DC Cook 0.533 15. Point Beach 1 & 2 0.764 189 94 283 370 16. Suny 1 & 2 1.061 133 78 211 199 17. Turkey Point 3 & 4 1.017 465 59 494 486 18. Oconee 1, 2, & 3 1.718 11 11 6 19. Zion 1 & 2 1.201 217 2 219 182 20. Praire Island 1 & 2 0.822 21 4 25 30 12.791 2303 2202 4505 Totals 646 0 n0 G352We -~GWe-yr -46- Table 21: Halogens and Particulates Released to the Environment by Pressurized Water Reactors (PWR's) in 1976 Name of Unit (PWR) 1976 Electrical Power Output GWe-yr 1. Yankee Rowe 1976 Total Halogens & Particulates Ci p Curies of H& P per GWe-yr 1976 Halogens Ci 1976 Particulates I Ci 0.155 134 40 174 1,123 2. San Onofre 1 0.283 4,470 1,110,000 1,114,470 3,938,057 3. Haddam Neck 0.473 733 900 1,633 3,452 4. Ginna, RE 0.255 33,500 90 33,590 131,725 5. Robinson, H.B. 0.580 254,000 568 254,090 438,086 6. Palisades 0.353 30,600 14,300 44,900 127,195 7. Maine Yankee 0.711 1,640 433 2,073 2,916 8. Fort Calhoun 0.261 71,700 1,630 73,330 280,958 9. Kewanee 0.395 3,270 468 3,738 9,463 10. Three Mile Island 1 0.508 8,640 4,430 13,070 25,728 11. Arkansas One 1 0.441 40,800 1,660 42,460 96,281 12. DC Cook 0.785 1,370 2 1,374 1,750 13. Millstone Point 2 0.553 49,000 536 49,536 89,577 14. Point Beach 1 & 2 0.829 6,262 18,200,000 15. Suny 1 & 2 0.921 545,000 311,000 856,000 929,425 16. Turkey Point 3 & 4 0.982 552,000 76,500 77,052 78,464 17. Oconee 1, 2 & 3 1.447 156,000 310,000 466,000 322,046 18. Zion 1 & 2 1.131 89,200 2,860 92,060 81,397 19. Prairee Island 1 & 2 0.752 24,600 226 24,826 33,013 20. Indian Point 1, 2 & 3 0.492 273,000 28,100 301,100 611,992 Totals 12.307 1,594,473 20,063,265 21,657,738 1,759,790 pCi Totals in mCi 12.307 1,594 20,063 21,658 1,758 mCi Statistical extremes (#2, 14) Net excluding statistical extremes Power apportioned Average mCi per GWe-yr 18,206,262 21,961,715 19,310 1,594 753 12.307 11.195 130 "'7 I E17 I mCi L l_.I GWe-y -47- Table 22: Halogens and Particulates Released to the Environment in 1975 by Boiling Water Reactors (BWR's) Name of Unit (BWR) 1975 Electrical Power Output GWe-yr 1975 Halogens Released mCi 1975 Particulates Released mCi 1. Dresden 1 0.093 5,700 359 2. Big Rock Point 0.036 267 3. Humboldt Bay 3 0.048 4. La Crosse 5. 1975 Total H &P Released mCi 1975 mCi of Released H&P per GWe-yr 6,059 65,151 98 365 10,139 1,070 839 1,909 39,771 0.033 133 79,200 79,333 2,404,030 Oyster Creek 1 0.359 41,300 178 41,478 115,538 6. Nine Mile Point 1 0.377 5,960 441 6,401 16,979 7. Millstone Point 1 0.440 62,900 188 63,088 143,382 8. Monticello 0.324 15,200 673 15,873 48,991 9. Vermont Yankee 0.411 398 2 400 973 10. Pilgrim 1 0.296 6,220 660 6,880 23,243 11. Cooper Station 0.203 419 31 450 2,217 12. Duane Arnold 1 0.271 406 9 415 1,531 13. Hatch 1 0.357 6 6 17 14. Fitzpatrick 2 0.249 18 18 72 15. Brunswick 2 0.204 3 4 7 34 16. Bresden 2 & 3 0.468 11,700 4,160 15,860 33,889 17. Quad Cities 1 & 2 0.845 2,920 415 3,335 3,947 18. Brown's Ferry 1 & 2, 3 0.320 597 59 656 2,050 Peach Bottom 2 & 3 1.219 36 4 40 33 Totals 6.553 155,253 87,320 242,573 37,017 0.033 133 79,200 79,333 2,404,030 6.520 155,120 8,120 163,240 2 5' 0 3 7 19. Statistical extreme (La Crosse #4) Totals excluding La Crosse #4 GWe-y -48- Table 23: Halogens & Particulates Released to the Environment in 1976 by Boiling Water Reactors (BWR's) Name of Unit (BWR) 1976 Electrical Power Output GWe-yr 1976 Halogens Released m Ci 1976 Particulates Released m Ci 1976 Total H &P Released m Ci 1976 mCi of H &P Released per GWe-yr 1. Dresden 1 0.125 2,340 470 2,810 22,480 2. Big Rock Point 0.031 16 58 74 2,387 3. Humboldt Bay 3 0.025 368 27 395 15,800 4. La Crosse 0.022 101 95,200 95,301 4,331,864 5. Oyster Creek 1 0.431 46,400 220 46,620 108,167 6. Nine Mile Point 1 0.478 8,640 103 8,743 18,291 7. Millstone Point 1 0.425 36,500 149 36,649 86,233 8. Monticello 0.451 1,020 50 1,070 2,373 9. Vermont Yankee 0.373 71 6 10. Pilgrim 1 0.278 1,980 332 2,312 8,317 11. Cooper Station 0.433 91 14 105 242 12. Duane Arnold 1 0.293 108 7 115 392 13. Hatch 1 0.503 4 4 8 14. Fitzpatrick 2 0.462 5,770 19 5,789 12,530 15. Dresden 2 & 3 1.008 12,900 4,550 17,450 17,312 16. Quad Cities 1 & 2 0.417 4,260 538 4,798 11,506 17. Brown's Ferry 1, 2 & 3 0.491 598 60 658 1,340 Peach Bottom 2 &3 1.359 1,880 44 1,924 1,416 Brunswick 1 & 2 0.291 463 19 482 1,656 Totals 7.896 123,510 101,866 225,376 28,543 0.022 101 95,200 95,301 4,331,864 7.874 123,409 6,666 1.30,075 18. 19. Statistical extremes (La Crosse #4) Totals excluding La Crosse 77 206 16 520GWe-y ' GWe-y -49- Table 24: Mixed Fission and Activation Products Released to the Environment in 1975 and 1976 by Pressurized Water Reactors (PWR's) 1976 1975 Electrical Output Name of Unit (PWR) GWe-yr MF and Activation Products Curies Curies per GWe-yr 1. Yankee Rowe 0.147 0.010 0.068 2. Indian Point 1& 2 0.601 6.250 10.399 3. San Onofre 0.366 1.220 3.333 4. Haddam Neck 0.489 1.240 5. Ginna, RE 0.354 6. Robinson, HB 7. Electrical Output GWe-yr Curies per GWe-yr 0.009 0.058 0.283 7.430 26.254 2.536 0.473 0.130 0.275 0.420 1.186 0.255 0.685 2.686 0.496 0.440 0.887 0.580 0.375 0.647 Palisades 0.325 3.450 10.615 0.353 0.441 1.249 8. Maine Yankee 0.537 3.200 5,959 0.711 2.840 3.994 9. Fort Calhoun 0.245 0.133 0.543 0.261 0.549 2.103 10. Kewaunee 0.395 0.447 1.132 0.395 2.850 7.215 11. Three Mile Island 1 0.644 0.065 0.101 0.508 0.102 0.201 12. Arkansas One 1 0.563 3.110 5.524 0.441 13.100 29.705 13. Calvert Cliffs 1 0.512 1.490 2.910 14. DC Cook 0.533 0.260 0.488 0.785 0.282 0.359 15. Millstone Point 2 0.553 0.420 0.759 16. Point Beach 1 & 2 0.764 3.350 4.385 0.829 3.560 4.294 17. Suny 1 & 2 1.061 31.900 30.066 0.921 33.600 36.482 18. Turkey Point 3&4 1.017 3.070 3.019 0.982 8.650 8.809 19. Oconee 1, 2&3 1.718 5.060 2.945 1.447 6.670 4.610 20. Zion 1 & 2 1.201 0.009 .007 1.131 21. Prairie Island 1 & 2 0.822 0.454 0.552 0.752 0.012 0.016 0.492 5.900 11.992 12.307 87.605 I7118 22. 0.020 Indian Point 1, 2 & 3 (see #2) Totals 12.791 65.578 15I l=TlI 0.155 MF and Activation Products Curies (see #22) -50- Table 25: Mixed Fission and Activation Products Released to the Environment in 1975 and 1976 by Boiling Water Reactors (BWR's) 1976 1975 Name of Unit (BWR) Electrical Output GWe-yr MF and Activation Products Curies Curies per GWe-yr Electrical Output GWe-yr MF and Activation Products Curies Curies per GWe-yr 1. Dresden 1 0.093 0.840 9.032 0.125 0.353 2.824 2. Big Rock Point 0.036 2.020 56.111 0.031 0.770 24.839 3. Humboldt Bay 3 0.048 3.470 72.292 0.025 1.080 43.200 4. La Crosse 0.033 14.100 472.273 0.022 5.680 258.182 5. Oyster Creek 1 0.359 0.408 1.136 0.431 0.221 0.513 6. Nine Mile Point 1 0.377 21.000 55.703 0.478 0.214 0.448 7. Millstone Point 1 0.440 199.000 452.273 0.425 9.650 22.706 8. Monticello 0.324 Zero 0.451 Zero Zero 9. Vermont Yankee 0.411 10. Pilgrim 1 0.296 2.060 6.959 0.278 2.340 8.417 11. Cooper Station 0.203 1.730 8.522 0.433 0.653 1.508 12. Duane Arnold 1 0.271 0.003 0.011 0.293 0.007 0.024 13. Hatch 1 0.357 0.058 0.162 0.503 0.042 0.083 14. Fitzpatrick 2 0.249 9.390 37.711 0.462 6.010 13.009 15. Brunswick 2 0.204 1.920 9.412 16. Dresden 2 & 3 0.468 0.810 1.731 1.008 1.210 1.200 17. Quad Cities 1 & 2 0.845 17.100 20.237 0.417 6.990 16.763 18. Brown's Ferry 1, 2 & 3 0.320 2.790 8.719 0.491 3.950 8.045 19. Peach Bottom 2 & 3 1.219 0.929 0.762 1.359 2.820 2.075 20. Brunswick 1 & 21 0.291 3.280 11.271 7.896 45.270 5.733 Totals 6.553 Zero 0.373 277.628 2.367 42.3671 -51- HTGR and GCR In gas cooled reactors, a non-reactive gas such as helium or carbon dioxide is used to transport heat from the core to the steam generators. Moderation of the fast neutrons is accompolished, instead of by water, by the placement of graphite within the core. tures Helium coolants can be heated to higher tempera- (7750) than carbon dioxide coolants (3750) and there is usually a distinction made between the two, naming the former a "high temperature gas cooled reactor" simply a "gas cooled reactor" (HTGR) and the latter (GCR). The HTGR at Fort St. Vrain utilizes small fuel spheres (100 micrometers in diameter) coated by two layers of pyrolytic graphite. Most fission products in the HTGR fuel will remain fixed within the fuel pellet ceramic; however, some may escape through the two pyrolytic graphite coatings into the graphite structure of the fuel elements and diffuse into the primary helium coolant. Very small amounts of radioactivity also result from the activation of the primary coolant. impurities which may be circulating in Helium-4 is not easily activated, having a neutron absorption cross section that is effectively negligible: a trace amount of helium-3 is found in nature a large (n,p)T cross section, forming tritium. (130 ppm) having The impurities found in the helium coolant are most likely to be hydrogen and oxygen leakages from the fission products. steam generators, in addition to escaped -52- The principal source of high activity radioactive gaseous waste originates from the helium coolant purification system. Small amounts of potentially contaminated gases also come from: the sampling of the primary coolant, purging of fuel storage and handling systems, purging of the helium circulator handlingcask and from the reactor vessel support floor vent and liquid waste tank vent headers. Additional sources of radioactive effluent gases containing lower levels of activity are: the secondary system and the reheat steam-jet air ejectors, the deaerator vent steamline relief valves.41 Gases from all of the above sources are collected and processed. Low activity gaseous waste is normally vented after filtration; high activity gaseous waste is treated and held up for a minimum time of 60 days. It is interesting to note on Table 26 that, because of this station's intermittent startup and shut-down record, one can observe from the monthly release data this 60-day hold-up period. The Atomic Energy Commission's Environmental Statement for Fort St. Vrain estimated that noble gas releases, after the hold-up period, would amount to 993.5 curies per year (960.8 from the off-gas regeneration systme; 27.5 from the reactor building leaks; and 5.2 from the air ejector). 42 Fort St. Vrain was rated at the time of this 1972 report at 330 MWe of net electrical output. Assuming a yearly utilization factor of 0.65, one would expect the reactor to produce about 0.215 GWe-yr of power. Hence, the noble gas release all Kr-85) was estimated to be about 4,620 Ci/GWe-yr. (almost -53- Fort St. Vrain was scheduled to go into commercial operation in December 1976. As of December 1978, the reactor was not yet in commercial operation. Between January 1977 and June 1978, the station had produced 500,000 kwhrs of electric power, a tiny fraction (about 0.02 percent) of its expected power output. Effluent releases for each of the four categories of radionuclides (noble gases, tritium, halogens and particulates, and mixed fission and activation products) were compiled for each month of operation from the station's Semi Annual Effluent Release Reports on file at the NRC's public domument room at 1717 H street, N.W., Washington, D.C., and are shown in Tables 26 through 29. Actual noble gas releases were on the order of 400 Ci for the 18-month period. Because the net power output was so low, the average noble gas release was calculated to be about 95,000 Ci/GWe-yr. Liquid radioactive wastes arise principally from decontamination operations. Smaller quantities accumulate in the regeneration section of the helium purification system; additional sources of radioactive liquid wastes result from the reactor vessel linear cooling system and from leaks in the steam generator feedwater system. The liner coolant contains neutron activation products; the steam generator feedwater contains tritium which has diffused through the walls of the steam generators from the primary coolant, and contains small amounts of fission products. 4 3 -54Table 26: MONTH OF HTGR OPERATION Noble Gases Release to the Environment (1/77 thru 6/78) by HTGR at Fort St. Vrain Monthly Electrical Output Mwhrs Noble Monthly Gases Electrical Airborne Output 10- bGWe-yrs Curies Noble Gases Dissolved Curries Curies of Noble Gases Released per Gwe-yr C DEC 1976 18 +JAN 1977 45 394 0.138 NSA FEB 0 0 8.600 NSA MAR 0 0 0.148 NSA 22,553 APR 4 35 5.980 NSA 170,857 MAY 9 79 0.238 8(10) 6 JUN 0 0 JULY 0 0 0.005 0.149 (10)NSA AUG 10 8 7.600 NSA 91,862 SEP 41 359 9.950 (10) 27,716 OCT 74 648 54.400 <(10) 83,951 NOV 41 359 <(10) DEC 0 0 7.120 70.010 30 0 263 0 0.488* 19.900 NSA <(10) MAR 0 0.003 NSA APR MAY 61 93 0 534 +JUN 92 JAN 1978 FEB JULY 86 NSA 214,847 77,532 <(10)3 138,951 815 74.200 48.100 0.005 59,018 806 97.100 <(10) 120,471 *On Jan 23, 1978 an accident released 113 lbs of primary coolant containing 4.06 Ci of Noble gases; this release is not reported in the Effluent Release Report submitted by Ft. St. Vrain for 1-6-78 Totals (1/77-6/78) 4300 404.129 Totals (1977) 1882 164.338 (Negl.) - 93,983 87,321 Totals (1978-1st half 2418 239.791 year) 99,169 Sources: (1) Monthly electrical output was compiled from the report summarv published by the NRC ("Grev Books" 12/7610/78): (2) Release data dompiled from Ft. St. Vrain semi annual reports on Radioactive Effluent Releases to the Environment, Public Doc. Room, NRC, DC. -55- Table 27: Tritium Released to the Environment 1977 by HTGR at Fort St. Vrain Monthly Electrical Output Gwe-yr 10 & 1978 Curies of Tritium Released per Gwe-yr Tritium Gases Curies Tritium Liquids Curies Tritium Total Curies 394 0.104 4.860 4.964 FEB 0 0.180 5.560 5.740 MAR 0 0.054 4.410 4.464 38,497 APR 35 0.026 6.850 6.876 196,457 MAY 79 0.086 1.510 1.596 20,203 JUN 0 0.007 6.790 6.797 JUL 0 0.013 1.800 1.813 AUG 8 0.066 0.293 0.359 103,092 SEP 359 0.221 7.000 7.221 20,114 OCT 648 1.250 2.780 4.030 6,219 NOV 359 0.204 3.590 3.794 DEC 0 0.353 6.180 6.533 263 0.189 9.750 9.939 FEB 0 0.482 33.300 33.782 MAR 0 0.014 12.000 12.014 211,920 APR 534 0.409 13.500 13.909 26,047 MAY 815 59.700 96.400 156.100 191,533 JUN 806 1.01 7.800 8.810 10,931 MONTH OF HTGR OPERATION JAN 1977 JAN 1978 Totals (1977) Totals (1978- 1st half) Total 6/7 8) 28,766 1882 2.564 51.623 54.187 28,792 2418 61.804 172.750 234.554 97,003 43 0 64.368 224.373 288.741 67,149 (1/77- -56- Table 28: Halogens & Particulates Released to the Environment 1/77 thru 6/78 by HTGR at Fort St. Vrain Monthly a-Activity Gross 3,y Electrical in MONTH OF Activity Output in Halogens in Particul. Particulates HTGR Curil Cur'i Gwe-yr Curiy OPERATION 10 X10 x10 X10 Total Halogens & Partic. Curies X10- 1 394 NSA NSA NSA FEB 0 NSA NSA NSA MAR 0 NSA NSA NSA APR 35 NSA NSA NSA MAY 79 NSA NSA NSA JUN 0 NSA NSA NSA JUL 0 NSA 3.22 0.89 4.11 AUG 8 NSA 3.50 1.31 4.81 SEP 359 NSA 5.48 3.93 9.41 OCT 648 NSA 5.46 1.87 7.33 NOV 359 NSA 4.91 1.01 5.92 DEC 0 NSA 3.50 0.80 4.30 263 NSA 3.95 1.98 5.93 FEB 0 NSA 4.79 0.89 5.68 MAR 0 NSA 3.10 0.84 3.94 APR 534 NSA 4.46 1.42 5.88 MAY 815 NSA 6.02 1.47 7.49 JAN 1979 806 NSA 7.56 1.45 9.01 JAN 1977 JAN 1978 10 - 9 Curies per Gwe-yr. 7-12/77 1374 26.07 9.81 35.88 26.11 1-6/78 2418 29.88 8.05 37.93 15.69 Totals (7/77-6/78 only) 3792 55.95 17.86 73 81 19. -57- Table 29: Mixed Fission & Activation Products Released to the Environment 1/77 thru 6/78 by HTGR at Fort St. Vrain MF & Monthly Electrical 4gutput 10- u Gwe-yr Gross Activity iCi Gross a Activity pCi Act. Prod. Total Activity pCi 394 8.56 0.18 8.74 FEB 0 32.90 0.59 33.49 MAR 0 22.30 0.49 22.79 APR MAY 35 79 8.60 37.00 0.35 1.20 8.95 38.20 JUN 0 5.70 0.45 6.15 JUL 0 7.37 0.29 7.66 AUG 8 SEP 359 7.71 54.10 0.30 2.97 8.01 57.07 OCT NOV 648 359 14.40 4020.00 6.42 0.58 DEC 0 0.29 263 3.84 35.30 FEB MAR 0 190.00 1.05 9.54 0 54.10 3.00 57.10 APR MAY 534 815 120.00 49.80 0.38 0.53 120.38 50.33 JUN 806 94.90 27.90 122.80 Month of HTGR Operation JAN 1977 JAN 1978 4034.40 *Exclude this month as a statistical 7.00 extreme. 4.13 36.35 199.54 Curies per Gwe-yr Totals 1977 1882 208.90 4027.69 4236.59 2.251 Total ½ 1978 2418 544.10 42.40 586.50 0.243 Total (18 months) 4300 753.00 4070.09 4823 09 1.122 1234 194.50 7.69 202.19 0.164 3652 738.60 50.09 788.69 0.216 1977 (less Oct) 18 Month (less Oct) -58- The AEC's Environmental Statement estimated that the maximum release of all tritium, mxed fission and activiation products by way of liquid waste systems would be 0.041 curies per year for an expected release of about 0.2 Ci/GWe-yr. 4 4 Actual data for the 18-month operating period shows that mixed fission and activation products (Table 29) have amounted to 1.12 Ci/GWe-yr. Tritium releases (Table 27) amounted to 288 curies; this is the equivalent of 67,000 Ci/GWe-yr. No esti- mates were made for halogens and particulates; actual data (Table 23) reveals that these radionuclides are very rarely found in the releases, having a value of less than 20 nano-curies (10 9 curies) per GWe-yr. The relatively large amount of tritium is presumed to arise form (n,p)reactions on helium-3 and from tri-fission. Some additional tritium may leak from (n,2a) reactions on B-10 in the control assemblies. Some data from European gas cooled reactors was found for the years 1970 through 1974,45 and the radioactive effluents for noble gases in tritium were analyzed as shown in Tables 30 and 31. This data is sketchy and incomplete. Noble gas data for GCR's in the United Kingdom, for example, were not routinely or systematically measured during these years. Net power output for each reactor over these years was not available and had to be estimated from rated power. Never- theless, average figures for both noble gases and tritium were calculated, and found to be 118,760 Ci/GWe-yr and 858 Ci/GWe-yr respectively. These points are plotted on Figures 4 and 5 among similar data for the other reactors. -59Table 30: Name of Unit (GCR) Chinon TR-1, France Noble Gases Released to the Environment (1971-1974) by European Gas Cooled Reactors (GCRs) 1971 Noble Gases 1972 Noble 1973 Noble Curies Curies Curies Curies 4225 11515 2808 3425 3863 Curies per 1974 Estimate Gwe-yr. Noble Max Gases Gases Gases of Noble of Elect Gases Output Released Released Released Re leased Output Mwe Released* Gwe-y* 2082 17,000 0.304 4967 4338 = 10,500 0.398 70 Chinon TR-2 210 Chinon TR-3 480 St Laurent des Eaux, TR-1 480 St Laurent des Eaux, TR-2 515 I Bugey TR-1 540 NA 641 3097 4475 17,500 0.216 Latina, 153 2470 3600 2050 3011 =180,000 0.061 - 32000 =400,000 0.079 - 10000 =100,000 0.100 Italy Calder, UK 200 Chapelcross 198 Brodwell 250 Berkeley 276 For GCRs in the UK Hunterston A 300 Noble gases were not Trawsfynydd 390 systematically measured; 40000 =250,000 0.156 Hinkley Point A 460 these are estimates for 80000 -435,000 0.184 Dungness A 410 Argon-41 (99% of Sizewell A 420 Noble Gases released). Oldbury 400 Wylfa 840 =177900 =118,760 1.498 French GCRs UK GCRs Italy GCRs "HTGR" Total GCRs = 14,995 309,550 180,000 94,000 =145,770 - Assumed annual averages *Estimate of annual electrical output assumes capacity factor (utilization factor) of 40%. - Mwe Represented 1535 1298 153 330 3316 "Radioactive Effluents from Nuclear Power Stations in Europe Source: 1970-1974," appearing in Nuclear Safety, Vol. 18, No. 3, May-June 1977, pp. 370-380. -60- Table 31: Name of Unit (GCR) Tritium Released to the Environment (1970-1974) by European Gas Cooled Reactors (GCRs) 1970 1971 1972 1973 1974 Avg. Curies Est of Tritium per Rated Elect. Liquids Gwe-yr Power Output Released of Tritium Mwe Gwe-yr Curies Curies Curies Curies Curies Curies Released Chinon TR-1, France 70 Chinon TR-2 210 Chinon TR-3 480 (Data not available) St Laurent des Eaux TR-1 480 St Laurent des Eaux TR-1 515 Bugey TR-1 540 0.216 Latina, Italy 153 0.061 Calder, UK 200 Chapelcross Brodwell 198 0.079 5.3 250 0.100 95.3 Berkeley Hunterston A 276 300 0.110 60.1 Trawsfynydd 390 0.156 67.7 41.9 46.0 Hinkley Point A 460 0.184 18.6 24.9 38.6 Dungness A Sizewell A 410 420 0.164 0.168 18.6 20.9 35.5 Oldbury Wylfa 400 840 0.160 0.336 17.3 - 0.120 824 17 159 13 12.7 102 43.1 17 9.3 251 44.2 33 7 11.7 1.2 198 200 117 56.7 67.0 824 3815 17.4 285 8.0 101 152.7 1527 80.8 102.4 60 66.3 735 853 425 30.0 39 30.2 164 28.9 30.5 20.0 26.7 163 77 53.2 208.0 253.0 729 64.4 30.2 15.0 82.7 13.6 275 37.4 122.4 29.5 162 37.5 86.7 116 134 130.5 184 388 UK Totals 1.577 749.5 475 Avg European GCR Avg 1.854 1590.9 858 Avg Source: "Radioactive Effluents from Nuclear Power Stations in Europe 19701974," appearing in Nuclear Safety, Vol. 18, No. 3, May-June 1977, pp. 370-380. -61- Heavy Water Reactors The radionuclide inventory in heavy water reactors is similar to that in light water reactors with respect to the escape of fission products from failed fuel, neutron induced activation of coolant and circulating impurities and corrosion products. However, a major difference arises from the fact that heavy water forms tritium upon neutron capture. The inventory of tritiated water in the primary heat transport system at equilibirum into a CANDU reactor is about 1 curie per kilogram. 4 6 The rates at which fission products escape from failed fuel depends directly on the rate of fuel failure. However, CANDU reactors can replace fuel without shut-down and, when failed fuel is detected, remove it, thus keeping leaked fission products in the coolant to a minimum. Because heavy water represents a large capital investment, there are strong economic incentives to reduce heavy water leaks to a minimum, and to capture all that does leak to the maximum extent possible. Consequently, heavy water reactors have complete- ly closed. ventilation systems fitted with molecular-sieve dryers to, recover heavy water vapor. These filters remove tritiated water as well, and also remove iodine and soluble cesium radionuclides. Further, the closed system serves as a hold-up system for noble gases. Similarly, all leaks of liquid of heavy water from the low pressure systems are collected so far as possible in tanks for -62- heavy water recovery. Vacuum cleaning systems are used to collect smaller amounts of heavy water. The heavy water collection tanks and recovery systems, again, serve to contain tritiated water and serve as a hold-up system for dissolved fission products. Actual release data for heavy water reactors was very limited. Some data was obtained, however, for: at Karlsruhe, Germany; (1) the PHWR (2) the HWR at Marts d'Arree, France; (3) and for four early CANDU reactors: NRX and NRU, WR-1, NPD and Douglas Point. From this sketchy information, figures for both noble gases and tritium were calculated as shown on Tables 32 and 33; thesedata points are shown also on Figures 4 and 5. It appears from this limited picture that because of the tight control on heavy water leaks, heavy water reactor systems enjoy some additional features of radioactivity protection that light water reactors may not have. As a consequence, al- though one would expect a higher tritium release than for light water reactors, it seems to be about the same as the US PWR; also the release of noble gases seems to be about the same as for other closed primary coolant systmes in the US. Liquid Metal Fast Breeder Reactors Radioactivity concentrations in the liquid metal coolant and cover gas are produced from the following sources, presuming a LMFBR design similar to that for Clinch River: (1) neutron activation of the sodium coolant, its trace impurities, -63Table 32: Noble Gases Released to the Environment (1970-1974) by Heavy Water Reactors (HWR, PHWR, SGHWR, CAWDU) 1970 1971 1972 1973 1974 Avg Estimate Noble Noble Gases Curies Rated of Elect Gases Name of Unit Power Output Released Released per Gwe-yr Curies Curies Curies Curies Curies Curies Gwe-yr (HWR) Mwe Karlsruhe (PHWR) 51 0.0204 Marts d'Arre (HWR) 70 0.0280 Winfrith (SGHWR) 92 0.0368 (Not measured) NA NRX & NRU (CAWDU) = 10 0.0040 6400 6400 1600000 WR-1 30 0.0120 Y-·mT- z .,s NPD 25 0.0100 Estimated Douglas Point 220 250 Gentilly 0.0880 440 0.1000 Data not available (NA) - 540 0.2160 Data not available (NA) - Pickering 526 955 228 952 665 53810 144450 130051 164460 -_ t- lllla _--- tUL > NA (not avail.) 123192 27708 4.4(10) E NA 30 2500 45 4500 440 5000 NA NA NA NA Averages 0.1624 124436 766232 Avg excl stat extreme 0.1344 1244 9256 Source: "Radioactive Effluents from Nuclear Power Stations in Europe 19701974," appearing in Nuclear Safety, Vol. 18, No. 3, May-June 1977, pp. 370-380 -64- Table 33: Name of Unit (HWR) Rated Power Mwe Tritium Released to the Environment (1970-1974) by Heavy Water Reactors (PHWR, HWR, SCHWR, CAWDU) Estimate of Elect Output in Gwe-yr Karlsrahe (MZFR), Ger. (PHWR 51 0.0204 Maits D'Aree, France (HWR) 70 0.0280 Winfrith, UK (SGHWR) 92 0.0368 NRX & NRU, Canada 10 0.0040 WR-1 30 0.0120 NPD 25 0.0100 Douglas Point 220 0.0880 Gentilly 250 Pickering 540 1970 1971 1972 1973 1974 Curies Curies Curies Curies Curies Avg Curies Liquid effluent discharged to decontamination center; separate data not available. 5 42 116 116 Liquid effluent data not available 11 NA NA NA NA NA NA NA NA 30.6 NA NA NA NA 30.6 32.6 NA NA NA NA 32.6 0.1000 NA NA NA 0.2160 NA NA NA 11 Estimates from sketchy and old data 0.1300 Average Curies per Gwe-year 190.2 1463 Sources: 1. For PHWR, HWR & WGHWR: "Radioactive Effluents from Nuclear Power Stations in Europe 1970-1974." Nuclear Safety, Vol. 18, No. 3. May-Jun 1977 pp 370-380. 2. For CANDU reactors: "Some aspects of the Releases of Radioactivity and Heat to the Environment from Nuclear Reactors in Canada", AECL4156. Atomic Energy of Canada, April 1972. -65- the argon cover gas and structural components; (2) fission product releases to the primary coolant through cladding failures in both the reactor core and blanket assemblies; (3) plutonium isotope inventory and production in the core and blanket released to the coolant through cladding failures; and (4) the production of tritium by neutron capture in boron in the control assemblies, by tri-fission and by neutron capture in lithium-6 impurities in the sodium coolant. 4 8 No actual release data for LMFBR's could be readily obtained for this report. Data on the Phenix at Gard, France is not reported among the data on other European reactors. Estimates of releases are made for the CRBR, however, in both the FSAR 49 and the Environmental Report. These data are summarized for noble gases and tritium in Tables 34 and 35 and indicated schematically on Figures 4 and 5. Released rates per GWE-yr for noble gases, halogens and particulates, and mixed fission and activation products are estimated to be so low that the data points cannot be plotted on the Figures comparing other reactor types. Only tritium is of a comparable level, about the same as the PWR, about one order of magnitude greater than the BWR. Summary for Power Reactors Figures 4, 5, 6, and 7 summarize graphically the information collected on the five reactor types for noble gases, tritium, halogens and particulates, and mixed fission and activation products, respectively. -66- Table 34: Noble Gases Estimated to be Released to the Environment by the CRBR-LMFBR Noble Gas Isotope Total Leakage Ci/day Ne-23 5.3x10 Ar-39 3.3x10 Ar-41 5 3.300 1.8x10 Kr-85 Kr-88 6.3x10 -4 5.0xlO0 -4 4.2x10 -4 8.7x10 Xe-13lm 1.4x10 5 0.014 Xe-133 1.6x10 3 1.600 Xe-133m 8.9x10 5 0.089 Kr-87 0.180 0.006 0.500 0.420 0.870 -3 Xe-135 Xe-135m Xe-138 Totals 6.7xl0 -4 1. lxl10 6.700 0.110 1.8x10 0.180 1.44x10 23.3% 0.120 -4 4 Kr-83m Kr- 85m Gwe-yr 0.053 -4 1.2x10 Curies of Noble Gases Released Total Leakage Ci/d X10 2 14.142 11.3% 47.4% 82 CRBR rated at 380 Mwe gross 350 Mwe net Assume 6C) percent utilization Net power output at Gwe-yr = 350(.60) 100 0 Source: % 24.58 Curies per Gwe-yr of Noble Gases Principally: Xe-135 Ar-39 Xe-133 0.210 Gwe-yr Environmental Report, CRBR, Volume II, Table 5.2-1. -67Table 35: Tritium (Estimated) to be Released to the by the CRBR - ------- - -- Environment - Category of tritium Tritium Release Estimate (units). 8.7x10 Ci/day 3 1. Released from gaseous RodWaste System 2. Released from 1.02x10 Liquid Rodwaste M Ci/cc System (low level activity) 3. Released from Liquid Rodwaste System (Intermediate level activity) 1.50x10 4 9 Curies of Tritium Released Per Gwe-yr. Annyalization Factor Annual Tritium Released Curies 365 days yr. 3.2 3.2x10 12 cc yr 326.4 1554.3 329.6 1570 15.2 3.2x1012 cc yr Net power output = 0.210 Gwe-yr. Source: Environmental Report CRBR, Tables 5.2-1 and 5.2-2, VD II. -68- '10,000 1,000 BWR s V;f L -cl.`; ' &-1,A5 lLI C: I 0 2 a, 'D 100 4sTE 03 SK\1v Tweak +; - I I ·4 /0 It 10 \I 1.0 I II I I 1I ,I , . I pI I I III I I II . I PWR I I / I 70 71 72 73' 74 YEAR OF EFFLUENT RELEASE Figure 4 __ I , 75 1 1 "is RRr K -69- / 10,000 TFRT ST Vole . 4% -t '"a CC6R snrAite s 1 C.s 1,000 "2]- -e '~_- -- El PWR ,S I· AI .0 IfJ a3: , 100 10 BWR. .... I . I I I I I I 70 71 72 73 74 YEAR OF EFFLUENT RELEASE 16 14 TI 1q I Figure 5 -70100 -BWR 10 w LU K 1.0 / - z~~~~ / ~ I~~ /~~ /~~ 1 z w I / /~~ U~~ ! II 1:3 -",ll· \PW ---.-PW R II ! 0.1 I CD irfi A, 0.01 I _ ___ I I __ I I Figure 6 1 __I__ 70 71 72 73 74 YEAR OF EFFLUENT RELEASE I' o x Ilo ------- 1 -~, I I I- -71- IAA 1UU !-, I 0 I 01 Ci, I' p, vR >1 > OF I I, z 03: cal 1 0"I CV, LL, x UJI _, / w a:' 1.0 i I I I . 74 73 72 71 70 YEAR OF EFFLUENT RELEASE 0.1 -'1 Figure 7 _ I- ----'S 76 11 - -72- In general, one observes a gradual trend toward improvement over time for reactors having had higher release rates relative to other reactors. BWR's seemed to have improved dramatically with respect to noble gas releases since 1974, although they still release about 10 times as much as PWR's. From a closer inspection of individual BWR plant performances, shown on Table 15, it can be seen that some BWR plants are doing about as well as PWR's; witness, for example, Dresden 2 and 3 in 1976. Similarly, PWR's are improving over time with respect to tritium releases. Tables 16 and 17 show an interesting extreme for Zion 1 and 2, having nearly zero release of tritium in both 1975 and 1976, while generating at a significant level of power output. Both. PWR's and BWR's have shown improvement in the release of mixedf:Eission and activation products. -73- "BACK END" OF THE URANIUM FUEL CYCLE Spent Fuel Storage Every 12 to 18 months, depending upon both plant design and utilization, reactors must be refueled. CANDU reactors refuel as well, but do not have to shut down while doing so. The spent fuel discharged from the reactor is highly radioactive and must be cooled for a period of time to allow for the dissipation and reduction of decay heat. This cooling period is usually not less than 60 or 90 days, and can extend indefinitely. The spent fuel is first placed in "spent fuel pools" at the reactor site, containing water as the cooling and shielding medium. All radionuclides present in the irradiated fuel can potentially escape to the atmosphere within the storage space or building, and may consequently escape to the environment through gaseous and liquid effluent streams. If no recycling or reprocessing of spent fuel occurs, as is presently the case, these spent fuel pools must be relied upon indefinitely to safely store the irradiated fuel assemblies accumulating at the rate of about 35 to 50 metric tonnes per GWe-yr. Federal plans call for the construction of a geologic repository to receive this spent fuel after a period of 5 to 10 years of cooling at the reactor site, but due to complex institutional and political factors, recent estimates of when such a repository may actually receive its first spent fuel have been extended to the mid-1990's. In -74- the meantime, additional "away from reactor" (AFR) spent fuel pooling capacity is being considered. Radioactive effluent releases from spent fuel pools at reactor sites are not itemized in the monthly and semi-annual reports; releases from such sources are presumably included in Hence, no data was found specifical- the overall site reports. ly relating to spent fuel pool operations. The GESMO Final Report, however, does estimate the accumulated release of krypton-85 from spent fuel pools over the period from 1975 to 2000 to be 560,000 curies.50 This would be a commitment over the 26-year period of an average of 182 curies per GWe-yr of power produced. Similarly, estimates for dose commitments are 11,000 person-rem for the 26-year period; 3.8 person-rem per GWe-yr. Waste Disposal and Transportation At present, the spent fuel pool located at the reactor site or at an AFR location proposed) (Barnwell, South Carolina, has been is the end of the fuel cycle, and will remain as such until at least 1993 (latest US Department of Energy esti- mate for the opening date of a full scale geologic repository). The GESMO Final Report does estimate for the "no recycle" case, however, what the potential releases and dose commitments would be if spent fuel were stored for 10 years at the reactor site and then shipped to a geologic repository. These estimates are shown in summary form in Tables 36 and 37 of the concluding section of this paper. -75- SUMMARY FOR THE NUCLEAR FUEL CYCLE In the preceding sections, each component of the nuclear fuel cycle has been examined, some in more depth than others, with respect to the release of radioactivity to the environment. Both actual data on releases of operating plants and estimates made for "model" plants have been presented and compared. Much use was made of the "Final Generic Environmental Statement on the Use of Recycle Plutonium in Mixed Oxide Fuel in Light Water Cooled Reactors," published by the Nuclear Regulatory Commission (NRC) in 1976, as it provided a consistent methodology for translating estimates of isotopic releases into "person-rems" for each fuel cycle component. By making use of this report, referred to as the GESMO study, a first approximation of the radiological health effects resulting from 1 GWe-year of nuclear power can be made for each of the various reactor types, presuming that the GESMO modeling is valid, by taking into consideration the comparison of actual release data to the estimated releases used in the GESMO analysis. Table 36 summarizes the radioactivity release estimates used in the GESMO analysis for each component of the nuclear fuel cycle. Table 37 presents the results of the pathway modeling of these released estimates in terms of total -76- Table 36: Estimated Radioactive Effluents Released to the Environment by the Fuel Cycle Components for the Period 1975 through 2000 (no recycle option) Fuel Cycle Component Mining Milling UF6 Conversion Enrichment U0 2 Fabrication Reactors Spent Fuel Storage Waste Management Transportation Totals Estimated Effluent Releases Curies Estimated Equivalent Power GWe-yr 24,000,0)00 4,400,0)00 4L62 4 2!71 60,820,0'00 560,0)00 20 4,732 4,732 4,551 4,603 4,346 4,036 3,072 3,857 3,146 5,072. 930. .102 .001 .062 15,069. 182. .005 89,780,625 21,253. Source: GESMO Final Report, Summary Volume, Table Volume 3, Table IV-J(E)-17 Table 37: Estimated Releases Ci/GWe-yr 5(A)-l and Estimated Dose Commitments for the US Light Water Fuel Cycle for the Period 1975 through 2000 (no recycle option) Whole Body Dose Commitment 26-yr Period Person-rem Fuel Cycle Component Mining Milling UF6 Conversion Enrichment U0 2 Fabrication Reactors Spent Fuel Storage Waste Management Transportation Totals Whole Body Dose Commitment Person-rem per GWe-yr % 49.4 13.5 0.6 3,000 6,900 909.7 248.0 10.8 0.7 12.5 656.3 3.8 0.4 0.5 8,224,800 1842.7 100.0 4,200,000 1,100,000 46,000 3,500 54,400 2,800,000 11,000 0.7 35.6 0.2 Source: GESMO Final Report, Summary Volume Table 5(A)-l and Volume 3, Table IV-J(E)-9, September 1976. Data includes occupational exposures (51.8 percent), US population exposures (45.4 percent) and foreign population exposures (2.8 percent) -77- population exposures--U.S., foreign, and occupational. If the release estimates used to develop these numbers fairly represent actual operating experience, and if the pathway modeling is valid, then one can conclude that the population exposure due to 1 GWe-year of nuclear power is approximately 1850 person-rems, of which about 63 percent is due to the mining and milling operations and 35 percent is due to the operations of the reactors. Less than 2 percent is attributed to the six other components of the nuclear fuel cycle. Table 38 translates these population exposures into health effects, giving 1.170 health effects per GWe-year, consisting of: (a) 0.273 cancer deaths; (b) 0.372 non- fetal cancers; and (c) 0.525 genetic defects per GWe-year. Data on actual releases compares favorably with the estimates used in the GESMO study, except for the case of power reactors. The GESMO study assumes that reactor releases would be of the order of 15,000 curies per GWeyear. While this is true for the recent experience of the PWR, it significantly understates the releases of the other power reactors, as Table 39 shows. -78- Table 38: Estimated Health Effects from Radioactive Releases to the Environment by US LWR Industry for the Period 1975 through 2000 (no recycle option) Type of Health Effect Health Effects Bone cancer deaths Thyroid cancer deaths Lung cancer deaths Other cancer deaths 140 60 390 510 0.035 0.015 0.097 0.126 Total cancer deaths 1,100 0.273 Benign and malignant thyroid nodules 1,500 0.372 Specific genetic defects 1,300 Defects w/complex etiology 820 0.322 0.203 Total genetic defects 2,120 0.525 Total health effects 4,720 1.170 Health Effects per GWe-yr Source: GESMO Final Report, Chapter IV, Table IV-J-14, Vol. September 1976. A factor of 4036 GWe-yr of electric power was assumed for the 26-year period, per Table IV-J(E)-17 for LWR reactor operations. 3, -79- Table 39: Reactor Type Summary Table of Averages Radioactivity Releases by Various Power Reactor Types for Recent Years Noble Gases (Ci/GWe-yr) Tritium (Ci/GWe-yr) Approximate Total (Ci/GWe-yr) BWR 300,000 100 300,000 HTGR 100,000 1,800 100,000 GCR 100,000 700 100,000 HWR 10,000 1,800 12,000 PWR 10,000 1,200 11,000 - - 15,000 GESMO Source: See pages 68-71. Accordingly, one might expect that the health effects predicted by the GESMO study would apply to the PWR and HWR, but not to the BWR, HTGR or the European GCR's. In the latter case, knowing that reactor operations account for approximately 35 percent of the total fuel cycle estimate of 1.170 health effects per GWe-yr, one can estimate what the health effects would be for the larger releases by scaling up the reactor component of the total. By doing this, the impact figures rise to about 9.0 health effects per GWe-yr for the BWR, and to 3.5 for the HTGR and GCR. It is interesting to note that in the cases of the PRW and -80- HWR, health effects are dominated by the mining and milling operations; in the cases of the BWR, HTGR and GCR, health effects are dominated by the operations of the reactors. Lastly, one might propose that that uranium and plutonium recycle could reduce the health effects of mining and milling operations by extending the productivity of already mined ore, thereby reducing mining operations. Table 40 presents a comparison of the population dose commitments of the two options: plutonium recycle. (a) no recycle and (b) uranium and Although the recycle option does reduce exposures (and the consequent health effects) due to mining and milling, these reductions are more than offset by increases due to reprocessing. The net increase in expo- sures for the recycle option is about 8 percent, rising from 1850 to 2000 person-rem per GWe-year. The breeder option is not examined here. In conclusion, the radiological impacts of nuclear power appear to range between 1 and 10 health effects per GWe-year, depending upon the type of reactor. For each "health effect," there are 0.23 deaths, 0.32 non-fetal cancers and 0.45 genetic defects. Mining and milling operations account for the majority of the health effects for a fuel cycle involving reactors releasing less than 15,000 Ci/GWe-year (PWR's and HWR's) of radioactive gases, -81- Table 40: A Comparison of Estimated Population Dose Commitments for the US Light Water Reactor Fuel Cycle for the Period 1975-2000 between the U and Pu Recycle and the No Recycle Options Fuel Cycle Component Mining Milling UF6 Conversion Enrichment U02 Fabrication MOX Fabrication Reactors Spent Fuel Storage Reprocessing Waste Management Transportation Total Person-rem Person-rem/GWe-yr Source: Whole Body Dose Commitments for No Recycle Option (Person-rem) Whole Body Dose Commitments for U and Pu Recycle (Person-rem) 4,200,000 1,100,000 46,000 3,500 54,400 3,000 6,900 3,240,000 880,000 35,300 2,800 46,200 25,300 2,820,000 3,350 1,848,000 3,000 10,100 8,224,800 8,888,750 1,850 42,000 2,800,000 11,000 GESMO Final Report. Summary Volume, Tables S(A)-l and S(A)-3, September 1976. Note that the above estimates are accumulated occupational, US and foreign population exposures for the 26-year period 1975-2000 based on a US nuclear scenario of 500 gigawatts of installed capacity in the year 2000. this apportionment changes dramatically for certain other reactors releasing one to two orders of magnitude more radioactivity per GWe-year (BWR's, HTGR, and GCR's). Trends in the release data over the period from 1970 through 1976, shown graphically in Figures 4, 5, 6 and 7, show significant improvements being made in the case of the BWR; trend data for the H:TGR and the European GCR's are not available. A 0 0 + +o -82- ADDENDUM--RADIOACTIVITY RELEASES FROM FOSSIL FIRED POWER STATIONS Little is known about the radiation exposures caused by the various fossil fuel cycles. Some data at particular sites are available and some estimates have been made for overall population exposures by scaling sparse and sometimes atypical data upwards, but a comprehensive evaluation has yet to be made. For the purposes of perspective, however, a brief analysis is made here of some of the available data as presented in a recent EPA report entitled, "Radiological Quality of the Environment in the U.S., 1977." Natural Gas As with the rest of our natural environment, all fossil fuels contain some level of radioactivity. Natural gas drawn from sandstone deposits, normally associated with radiumbearing geological strata, has been estimated 5 1 , on the average, to contain approximately 20 pCi per liter of radon. Use of this gas in the home has been estimated to expose the U.S. population to a total dose commitment of 2,730,000 person-rems per year; using the conversion factor of 200 cancer deaths and 400 total radiological health effects per million person-rem (the same factor applied to the nuclear fuel cycle), this use of natural gas results in approximately -83- 550 cancer deaths and 1100 total health effects per year. This annual dose commitment is very large by comparison to any other energy option, and is exceeded in absolute terms only by three other categories of exposure: natural back- ground, medical and dental x-rays and radio-pharmaceuticals. A natural gas fired generating station producing 1 GWeyear of net electrical power is benign by comparison. It requires approximately 1011 cubic feet of natural gas per GWe-yr, or 2.75 x 1012 liters. At 20 pCi/liter, the radio- activity released to the environment would be 55 curies of radon per GWe-year, resulting in 10 person-rem of exposure and 0.004 health effects. Oil Trace concentrations of natural radioactive decay chains in oilare generally considered so small as to be negligible. 5 2 Coal Coal deposits are known to contain concentrations of uranium and thorium, ranging from 0.001 to 0.100 percent uranium in Western coal samples from Wyoming and Idaho, with an average concentration of 0.008 percent. 5 3 Recall, as a comparison, that conventionally mined uranium ores contain concentrations of 0.090 percent or higher. Eastern coals have been found to contain approximately one-tenth the concentration of Western coals. -84- For coal-fired generating stations there are two major sources of radioactivity releases due to plant operations: gaseous effluents and flyash residues. One estimate for a 1000 MWe station, equiped with electrostatic precipitators of 99.7 percent efficiency, gives the release in gaseous effluents to be about 2.1 Ci/yr, or about 3.2 Ci/GWe-year, consisting mostly of Rn-222 and Po-210.54 In the same study flyash residues were estimated to contain not more than 5.0 pCi/gram of radium-226. Coal-fired stations operating at 35 percent efficiency require about 4 million tons of coal (about 3.7 x 1012 grams) per GWe-year. Assuming that the flyash residue is about 4 percent by weight of the original coal, the radium-226 discharge, given the above concentration estimate, would be 0.74 Ci/GWe-yr. By another calculation, assuming the average uranium concentration for Western Coal is 0.008 percent by weight and knowing that for every gram of uranium-238 in secular equilibrium with its decay chain daughters there is 3.59 x 10- 7 grams of radium-226, one can calculate the radium "throughput" at about 100 grams per GWe-year. This radium is the equivalent of 100 Ci/GWe-yr and implies a flyash concentration of about 7000 pCi/gram, which is at considerable variance with the earlier quoted estimates. Nevertheless, the fact remains that a coal facility using Western coal will receive about 100 grams of radium-226 in its fuel -85- stream and this radium must end up somewhere. The radon- 222 release from the radium-226 is, likewise, about 100 Ci/GWe-yr. Use of Eastern coal would result in about one- tenth this amount. Over What Period of Time? Before continuing, a significant point must be raised regarding the period of time into the future over which one "counts" the accumulating release of radon due to the production of power in some past year. In the case of nuclear power, the parent of radon-222 (radium-226) is unearthed by mining and remains in the tailings piles on the surface for thousands of years. Likewise, approximately 10 percent of the original uranium is left behind in the tailings piles after milling. Together, the radium and uranium continue to decay, continue to produce and release radon to the environment, and continue to expose future populations to an incremental amount of radioactivity long after the power from the ore was produced. Similarly, the uranium and radium concentrations in coal are unearthed by mining and dispersed to the environment by stack effluents or deposited on the surface in the flyash residues. Worse, the flyash is used in construction materials, thus enhancing the exposure pathways to man. Natural gas is different, however, in that the parent radionuclides of radon are left in the ground. Once the -86- radon concentration in the gas is dispersed by the combustion exhaust, there is no more. The "total release commitment" of radon to the environment due to 1 GWe-year of power, strictly speaking, would be the incremental release rate resulting from the unearthing of the ore (uranium or coal), which is decaying function of time, integrated over all remaining time, from zero to infinity. Likewise, the "total dose commitment" would be the incremental population exposure rate resulting from these "technologically enhanced pathways," integrated over time from zero to infinity. Clearly, these numbers will be very large, even though both rates are slowly diminishing over time. As an example, some numbers have been put together using the release estimates developed in this paper. For the LWR case, it is assumed that 5,000 curies of radon are released in the mining and milling operations in the first year, 870 curies per year are released from the remaining radium as it decays in the piles, and 10 percent of the original uranium is left in the piles after extraction, giving a new equilibrium release rate of 87 curies per year after the original radium decays. The assumptions for the fossil fuels are stated in the Table. -87- Table 41: 1 GWe-yr from... A Comparison of Radon-222 Releases from 1 Year of Power Peak Annual Annual Release Rate Release Release Rate Rate in year After After of ex2 traction 1st Yr. 0,000y (curies) (curies) (curies) Radon Source LWR mines & mills Coal (Western) ash piles, stack Natural gas exhaust gas Coal (Eastern) ash piles, stack GWe- Total Radon Release Commitment (curies) 5,870 870 87 565,000,000,000 100 100 100 650,000,000,000 55 0 0 10 10 10 55 65,000,000,000 Over what length of time should today's population be concerned about the health effects it imposes on future generations? This is a very difficult question. If a specific length of time is proposed, such as the 26 year period used by the GESMO study, a non-zero "discount rate" on the value of human life is implied, meaning that the present value of life after some period of time is negligible and should not be included in the health effects analysis. Conversely, a zero discount rate would imply that no health effect should be discounted regardless of whether it occurred today or millions of years in the future. The ethical arguments surrounding this issue will not be addressed here, but are fundamentally important, nevertheless. -88- Coal Impacts Returning to the discussion on coal, it is noted that stack gas emissions and radon effluents from flyash storage piles are but two of several exposure pathways to man. Three other pathways are: mine runoff, flyash runoff and the use of flyash in construction materials cement and cement block). (concrete, Using EPA published data 5 4 ' 55 Table 42 has been constructed to show the projected number of health effects per GWe-year. According to these estimates, the radiological health effects of a coal-fired power plant amount to 140 per GWeyr. This figure seems very large; it is two orders of magnitude larger than those estimated for a typical PWR. It should be noted, however, that the largest contributor (%130 health effects per GWe-yr) construction materials. is the use of flyash in Neglecting this, the next largest contributor is stack gas emissions GWe-yr), BWR (12 health effects per which is the same order of magnitude as a typical (9 health effects per GWe-yr), though still ten times Lastly, the health effects due to the larger than the PWR. radon effluents from the flyash storage piles (0.62) is nearly identical to those from radon from the uranium tailings piles (0.74). "typical" coal use; These figures are estimated for figures would be higher for Western coal and lower for Eastern coal. -89- Table 42: EPA Estimated Population Dose Commitments and Health Effects from Coal Fired Power Stations Per GWe-Year. Fuel Cycle Component Projected Health Population Dose Effects (person-rem x 106 per GWe-yr) Stack effluents 556,000 11.65 Mine runoff and acid drainage 1,850 0.06 Runoff from flyash storage areas not available Flyash in construction materials 2,123,000 129.20 615,000 0.62 Radon effluents from flyash piles TOTALS Source: %3,300,000 not available %140 Radiological Quality of the Environment in the U.S., 1977. EPA-520/1-77-009, Table 3-10, pp. 93, September 1977. All data has been adjusted from 1,000 MWe power plant to 1 GWe-yr by dividing by utilization factor of 0.65. Ranges have been expressed as log mean averages. Health effects include 50 percent fatal and 50 percent non-fatal at conversion rate of 16 per 106 person-rem. -90- To repeat, however, these exposure levels for coal seem to be very high--so high, in fact, that one should question whether the data in the EPA source document have been accurately presented. If they have been, coal burning, together with the practice of using flyash in construction materials, would appear to represent a significantly greater radiological risk to the general public than nuclear power--by perhaps as much as two orders of magnitude! -91- CONCLUSION As part conclusion and part perspective, Table 43 is presented showing the population exposures to the U.S. population from all sources as estimated by the U.S. Environmental Protection Agency. exposure are: The three largest categories of natural background, medical and dental x- rays and radio-pharmaceuticals. These three sources represent more than 90 percent of all radiation exposures as measured in person-rems. Surprisingly, natural gas use accounts for the fourth largest exposure source--more than 2,700,000 person-rems per year. The total fuel cycle for coal-fired power stations would appear to present, based on the discussion of the preceeding section, a very hazardous situation. A single GWe-year of power is said by EPA to cause a 3,300,000 person-rem exposure, resulting in 140 health effects per year! Given that this figure is so large, it is presumed that some error has been made in either the source document or its interpretation. For this reason, no exposure level is given for coal in Table 43. The use of liquified petroleum gas (LPG) is estimated by EPA to result in a population exposure of about 70,000 person-rems. -92- Table 43: Estimated U.S. Exposures to All Sources Category of U.S. Population Exposure 1. Ambient exposures a. cosmic radiation b. Th-232 series c. K-40 series d. U-238 series 2. Medical and dental x-rays 3. Radio-pharmaceuticals Technologically enhanced natural radiation a. Rn-222 in natural gas b. Coal fired power stations c. Inactive uranium mines d. Rn-222 in LPG e. Oilfired power stations U.S. Exposures (Breakdown Person-rems per year Radiation from U.S. Exposures Person-rems per year Estimated U.S. Cancer Deaths per year 19,800,000 9,700,000 4,600,000 3,100,000 2,400,000 19,800,000 3,960. 14,800,000 14,800,000 2,960. 3,300,000 3,300,000 660. 3,000,000 2,730,000 (see text) 70,000 30,000 15 3,000,000 600. 400,000 400,000 80. 45,000 21,000 24,000 45,000 9.0 4. 5. Fallout Uranium fuel cycle (1976) a. U.S. population only b. occupational only 6. 7. Other occupational 4,400 4,400 0.9 8. Consumer products 6,100 6,100 1.2 TOTALS Source: NA 41,355,500 8,270. "Radiological Quality of the Environment in the U.S., 1977," EPA-520/1-77-009, US EPA, September 1977; and the GESMO Final Report, NUREG-0002, Volume 105, USNRC, September 1976 -93- The nuclear fuel cycle was estimated by EPA in the original of Table 43 to result in about 2000 person-rem of population exposure per year given current levels of deployment. These data have been replaced in Table 43 by higher estimates consistent with the information developed in this paper. While it is often said that population exposures resulting from energy technologies are negligible compared to background, this is apparently not true for natural gas use in general, nor does it appear to be true for large scale deployment of coal and nuclear power stations. Further, any statement which gives a specific number for the expected exposure level resulting from a single GWe-year of power production, presumes a specific and limited period of time over which one "counts" the continuously accumulating total exposure; otherwise, such a number would be very large, indeed. This period of time appears to have been arbitrarily chosen in the studies reviewed by this paper. On a more optimistic note, however, recent rulings by the Nuclear Regulatory Commission indicate that mill tailings piles in the future may release only a small fraction of that released by the exposed piles of today, due to stringent stabilization methods, and the release rates from many of the newer reactors, including BWR's, show continuing improvements. -94- The use of radium-bearing flyash in construction materials would seem to be inconsistant with the health standards imposed on the nuclear fuel cycle, and this practice may be banned. Flyash accumulation and the stack releases, however, would remain as problems to be solved for coal, not to mention the non-radiological health effects associated with emissions of the oxides of nitrogen, sulfur and carbon, and of particulates. -95- Notes and References 1. Statistical Yearbooks, 1900 to present, Edison Electric Institute. 2. An assessment by Dr. David O. Wood, MIT Energy Lab, of current econometric models forecasting electricity prices vs. the cost of fossil fuels and the consequent implications, November 1978. 3. For example, the MIT version of the Baughman-Joskow Regional Electricity model, April 1978. 4. Giraud, Andre, "World Energy Resources," appearing in Transactions: Proceedings of the Plenary Sessions, International Conference on World Nuclear Energy, November 1976, pp. 1.7-23. 5. Wilson, Carroll L., McGraw-Hill, 1977. 6. Giraud, op. cit., pp. 21. 7. GESMO Final Report; "Final Generic Environmental Statement on the Use of Recycle Plutonium in Mixed Oxide Fuel in Light: Water Cooled Reactors," (GESMO), NUREG-0002, Volumes 1 through 5, September 1976. 8. GESMO Final Report, Vol.3, Chapter IV, pp. IV-F-1. 9. "Conventional ores" are 800 to 1900 ppm and above, GESMO Final Report, Vol. 3, Chapter IV, pp. IV-F-10. Energy: Global Prospects 1985-2000, 10. "Radiological Quality of the Environment in the US, 1977," EPA-520/1-77-009, US Environmental Protection Agency (EPA), September 1977, pp. 141. 11. "Statistical Data on the Uranium Mining Industry," GJO-100 (75), ERDA, Grand Junction Office, January 1, 1975, pp. 24 and 27. 12. "Environmental Analysis of the Uranium Fuel Cycle, Part I-Fuel Supply," Fuel Cycle Part I, EPA-520/9-73-003-B, US EPA, October 1973, pp 57. 13. Goodwin, Ansel, "Consequences of Effluent Releases," Nuclear Safety, Vol. 14, No. 6, Nov-Dec 1973, pp. 643-650. 14. GESMO Final Report, Summary Volume, Table 5(A)-l, Vol. 1, pp. 5(4)-3. -96- 15. GESMO Final Report, Chapter IV, Table IV-J(5)-9, Vol. 3, pp. IV-J(E)-9. 16. EPA, Fuel Cycle Part I, op. cit., pp. 23. 17. Draft Environmenal Statement for the Lucky Mc Uranium Mill, Freemont County, Wyoming, Docket No. 40-2259, prepared by the Nuclear Regulatory Commission, Washington, DC, June 1977, pp. 3-1 through 3-1. 18. GESMO, Final Report, Chapter IV, VOl1. 3, pp. IV-F-23. 19. Lucky Mc, op. cit., pp. 3-13. 20. EPA, Fuel Cycle Part I, op. cit., pp. 54. 21. Ibid., pp. 73. 22. Lucky Mc, op. cit., pp. 3-15 and 3-16. 23. EPA, Fuel Cycle Part I, op. cit., pp. 74. 24. GESMO Final Report, Chapter IV, Vol. 3, pp. IV-F-33. 25. EPA, Fuel Cycle, Part I, op. cit., pp. 80. 26. The velocity distribution for gas molecules is characterized by a Maxwellian distribution, for which the average kinetic energy is given by E = 1.5(kT) where k is Boltzmann's constant. Hence, the average speed of the gas molecules is given by v = 3kT/m. 27. GESMO Final Report, op. cit., pp. IV-F-44. 28. Ibid., pp. IV-F-44. 29. Ibid., pp. IV-F-45 and Table IV-J(E)-17 (after correction of typographic error), pp. IV-J(E)-17. 30. Goodyear Atomic Coropration, "Portsmouth Gaseous Diffusion Plant Environmental Monitoring Report for Calendar Year 1976, August 1977, pp. 14. Microfisch, ERDA-77-104/2, pp. 1152. 31. GESMO Final Report, op. cit., pp. IV-F-54. 32. GESMO Final Report, op. cit., pp. IV-F-17. 33. EPA, Fuel Cycle, Part I, op. cit., pp. 114. 34. Ibid., pp. 114. 35. GESMO Final Report, op. cit., Table IV-J(E)-17, pp. IV-J(E)-17. -97- 36. EPA, Final Cycle, Part I, op. cit., pp. 122. 37. Ibid., Table 5-4, pp. 123. 38. Brown's Ferry FSAR as taken from Table 5 in "Environmental Analysis of the Uranium Fuel Cycle, Part II--Nuclear Power Reactors," US EPA, EPA-520/9-73-003-C, November 1973, pp. 23. 39. Ibid., pp. 23 40. "Summary of Radioactivity Released in Effluents from Nuclear Power Plants from 1973 through 1976," EPA-520/3-77-012, US Environmental Protection Agency, December 1977. 41. "Environmental Statement (Final) for the Fort St. Vrain Nuclear Generating Station," prepared by the Directorate of Licensing, AEC, Docket No. 50-267-51, August 1972, pp. III-23. 42. Ibid., pp. III-26. 43. Ibid., pp. III-28 through III-33. 44. Ibid., Table III-5, pp. III-33. 45. "Radioactive Effluents from Nuclear Power Stations in Europe, 1970 - 1974," appearing in Nuclear Safety, Vol. 18, No. 3, May-June 1977, pp. 370-380. 46. Barry, P.J. and Marko, A.M., "Release of Radionuclides to the Environment from CANDU-Type Reactors--A Summary of Canadian Experience," an article appearing in an AECL report on "Some Aspects of the Release of Radioactivity and Heat to the Environment from Nuclear Reactors in Canada," AECL-4156, Atomic Energy of Canada Limited, April 1972, pp. 12-18. 47. Ibid., pp. 14. 48. Preliminary Safety Analysis Report (PSAR) for the Clinch River Breeder Reactor Plant, Vol. 7, Section 11, Project Management Corp., undated, pp. 11.1-1. 49. Environmental Report (ER) for the Clinch River Breeder Reactor Plant, Vol. 2, Section 5, Project Management Corp., undated, pp. 5.2-9 through 5.2-12. 50. GESMO Final Report, op. cit., Table 5(A)-l, Summary Volume, pp. 5(A)-3. -98- 51. Johnson, R.H., Jr., Bernhardt, D.E., Nelson, N.S., Calley, H.W., Jr., Assessment of Potential Radiological Health Effects from Radon in Natural Gas, EPA-520/1-73004, 1973. 52. Natural Radioactivity Contamination Problems, EPA-520/ 4-77, February 1978, pp. 31. 53. Vine, J.D., Uranium Bearing Coal in the US, Geological Survey Professional Paper 300, 1956. 54. Boothe, G.F., An Evaluation of the Radiological Aspects of the Proposed Pioneer Coal-Fired Plant (Pioneer near Boise, Idaho), Department of Health and Welfare, State of Idaho, 1976.