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Annual Report of China Institute of Atomic Energy 2005
Radioactive Waste Treatment and Disposal
1 Study on Treatment of Rinsing Waste of Film Evaporator for Bituminization
ZHANG Yan，YAO Jun，WANG Shu-juan，XIA Li-li，BAO Liang-jin，LIN Mei-qiong
A factory was founded in 1984 for evaporator bottom waste bituminization. The hot demonstration
has been implemented smoothly based on cold run many times. This project is the first one adopting
bituminization technics to treat evaporator bottom of low-level radioactive water. However，in this
process，both the scraping evaporator and the blender would agglutinate a certain amount of asphalt and
salt，which must regular be rinsed with the mixture of trichloroethylene(TCE) and water to insure a
smooth run process. Up to now，more than 200 barrels waste containing TCE，water，asphalt has been
accumulated， and as the process going on，the amount of the problematic waste is increasing rapidly. The
radioactivity，causticity and toxicity of the waste will be harmful to the environment in the long term
storage.
Considering the low boiling point and high density of TCE，underpressure distillation，based on firm
small-scale experiment，should be the appropriate way to eliminate TCE from the mixture. Underpressure
distillation has the merits as security，reliability and adjustable output. The 1 L/h scale device was
established，and the simulating tests were finished. The recoverying rate of TCE is more than 85%. The
flexing point of the recoveried asphalt ranges from 53 ℃ to 55 ℃.
2
A New Polymer Absorbent for Immobilization Liquid Wastes*
BAO Liang-jin，XIA Li-li，LIN Mei-qiong
The combined research project between CIAE and Pacific Nuclear Solution(USA) began discussions
about a new absorbent and its application in the field of liquid waste. Preliminary tests were conducted in
the Department of Radiochemistry，CIAE using general spent solvent TBP/kerosene from reprocessing
plant and organic spent oil with 3H from nuclear power plant and other nuclear facilities，such as vacuum
pump oil，lubricating oil，scintillation liquids “Cocktail”. Based on the further discussing between both
parties，it was decided to proceed with a more formal test programs. In April and October 2005，
simulation tests were smoothly implemented twice. The simulated liquid wastes include slurry resins with
a anion/cation resin ratio of 2∶ 1，30% TBP/kerosene，scintillation liquid，inorganic acid and alkali
solution with different concentrations. The simulated waste stream was solidifined by polymer absorbent
to confirm the optimum ratio of polymer to waste stream，and determine the leach rates，stability，
compression capability，waste minimization and effect of irradiation on the solidified samples for the
immobilization of the waste streams.
FUNDAMENTAL AND APPLIED FUNDAMENTAL RESEARCH·Radioactive Waste Treatment and Disposal
171
This research project focuses on the minimization of the liquid wastes volume and the reduction of
disposal costs.
* Supported by the Director Foundation of Department of Radiochemistry，CIAE
3
Study on Dissolving Behavior of S-119 Organic Filth
ZHOU Hui，LIU Li-jun，QIE Dong-sheng，ZHAO Yu-long，LI Bao-jun，
XU Jian-hua，JIANG Yao-zhong
The dissolving behavior of the S-119 organic filth was studied in different solvents with the
oscillator to screen out the better solvent，which is used in the next experiments. The results show that the
organic filth has very low solubility in common organic solvents，such as alcohol，TBP，kerosene，as well
as inorganic acid and alkali. However，the solubility of S-119 in the solvent A1 is high.
Then，the factors which cause effects on the dissolving performance，such as concentration，time，
temperature，amount of the solvent，acidity and so on，were investigated. Based on the series of
experiments，concentration of the solvent A1 was selected，and the best ratio of liquid to solid (the volume
of solvent A1 to the mass of S-119 organic filth) was gained.
According to above experiment results，the circulating dissolution experiments of S-119 organic filth
were carried out with self-regulating circulator. Three experiments were studied at the selected best
condition. Two of them were operated after mixing the S-119 organic filth and solvent. The third one was
operated after the S-119 organic filth and solvent were mixed for some time. The result shows that the
third is better for the dissolution of the filth than the two others. The products were composed of three
phases: organic phase，liquious phase and very fractional solid. The volume ratio of organic phase to
liquious phase is 1∶ 5.6 and the mass of the non-dissolving matter is less than 0.1% of the whole original
filth mass，which shows that the organic filth has good solubility under the selected experiment
conditions.
4 Adsorption Behavior of Pu in Ca-Bentonite
ZHANG Ying-jie，SU Xi-guang，ZENG Ji-shu，FAN Xian-hua
The adsorption behavior of Pu in Ca-bentonite is studied with batch experiment and 2 mol/L HClO4
is used to dissolve the Pu adsorbed on Ca-bentonite at ambient temperature. Sorption experiments are
performed under atmospheric and anaerobic conditions (in an argon glove box with an oxygen content of
－
－
less than 5.0×10 6 mol·mol 1). Experimental results show that the sorption ability of Pu on Ca-bentonite
is increased with increasing pH value(3.0-10.0) of the aqueous phase and carbonate ion concentration
－
－
(4.0×10 3-1.0×10 1 mol/L) in the aqueous phase，and decreased with increasing DOC concentration in
the aqueous phase. The oxygen concentration of the experimental condition is less influence on the
sorption of Pu on granite. The adsorption behavior of Pu on granite are irreversible. The adsorption
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Annual Report of China Institute of Atomic Energy 2005
isotherms of Pu on granite can be well described by the Freundlich’s equation.
5 Diffusion Behavior of Np in Simulated Groundwater
ZHANG Ying-jie，ZENG Ji-shu，SU Xi-guang
The diffusion rate of radio-nuclides in groundwater is one of the most important factors to be
considered for risk assessment of disposal of high-level waste in deep geological repository. However，the
reported data are very scarce. In the present work，the diffusion behavior of Pu in simulated groundwater
with variations of pH (5.0，6.0，7.0，8.0，8.5，9.6)，temperature (35.0，40，45，50，55 ℃)，and viscosity
(0.579，0.627，0.680，0.739，0.807 mPa·s) has been studied by the capillary method. At the same time，
－
－
－
－
we also studied the influence of Fe2+ concentration (5.0×10 6，1.0×10 5，5.0×10 5，1.0×10 4，5.0×
10
－4
，1.0×10
－3
mol/L) on the diffusion of Pu in simulated groundwater under Ar atmosphere.
Experimental results show that the diffusion ability of Pu in simulated groundwater increases with
increasements of temperature，pH，Fe2+ concentration in solution，and decreases with increasing viscosity
of solution；the average apparent activation energy is 150.60 kJ/mol for self-diffusion of Pu in simulated
groundwater within the temperature range from 35 to 55 ℃.
6 Study on Adsorption Behavior of Pu
ZHANG Ying-jie，FAN Xian-hua，SU Xi-guang，ZENG Ji-shu
The present research concerns in the adsorption behavior of Pu on Fe，FeO，Fe2O3，Fe3O4 powder，
granite and its major component minerals (quartz and feldspar，biotite，hornblende，pyrite，sphene，and
clay minerals). The results indicate that the adsorption mechanism is formation of surface complex，and
can be described by the Freundlich equation of the adsorption isotherm. The sorption ability of Pu is
increased with increasing aqueous phase pH，and decreased with increasing aqueous phase carbonate ion
－
concentration (4.0×10 3-1.0×10
－1
mol/L). The oxygen concentration is less influence on the sorption of
Pu. The main species of Pu in the aqueous phase and on the surface of the solid phase are all
quadricvalence at the adsorption equilibrium. The pyrite and clay mineral are the key minerals，which
affect the adsorption of Pu on the granite. The adsorptions of Pu on the mixture of quartz with feldspar
and sphene are linear adsorption，and on biotite，hornblende，pyrite，and clay mineral are nonlinear
adsorption.
7 Measurement of Species and Solubility of Pu in Underground Water
ZHANG Ying-jie，FAN Xian-hua，SU X-iguang，ZENG Ji-shu
Results of the measurements of the species and solubility of Pu in BS03 well underground water
FUNDAMENTAL AND APPLIED FUNDAMENTAL RESEARCH·Radioactive Waste Treatment and Disposal
173
(from the Beishan region，Gansu province，which is being investigated as a potential candidate of
high-level waste repository site) indicate that when stabilizing agent (NaNO2，FeO powder) is added in
the groundwater，the main valence state of Pu in the underground water is Pu(Ⅳ)；the effect of pH (6.98，
7.95，8.78，9.92) in solution is little effect on the solubility of Pu(Ⅳ) in the BS03 well underground water；the main species of Pu(Ⅳ) existed in the BS03 well underground water may be Pu(OH)4，
－
Pu(OH)5 ，and a series of the complex of Pu(Ⅳ) with carbonate ion. When none stabilizing agent is added
in the underground water，the main valence state of Pu in the underground water is Pu(Ⅳ)，and co-existed
with the Pu(Ⅲ) and Pu(Ⅴ).
The calculated results from the geochemical modeling code EQ3/6(Version 7.2a) indicate that with
the variation of the cations in the underground water，all of the plutonium solubility plots have similar
shapes. Solubilities are highest at low pH values (pH<5) and decrease to minimum at pH values in the
range of 5 to 8. When the redox potential is in the range of －0.35 V≤Eh<0.6 V，the main species of Pu
－
in the BS03 well underground water is Pu(OH)5 .
8
Comparison Between Simulated Groundwater
With BS03/04 Well Underground Water
ZHANG Ying-jie，YAO Jun，SU Xi-guang，ZENG Ji-shu
The chemical composition of the underground water in the candidate area for high-level waste
geological repository is one of key factors for the security and risk estimate and assessment of the
repository site confirmation. This work concerns in the estimation and comparison of the difference of the
chemical composition among the simulated groundwater and BS03/04 Well underground water. The
analysing results of chemical composition show that the simulated groundwater composition reaches to
equilibrium，and the dissolved minerals (quartz and feldspar) concentration in the simulated groundwater
is same as that in the BS03/04 Well underground water.
－
－
－
－
The concentration of K+，Na+，Ca2+，Mg2+，HCO3 ，SO42 ，Cl ，NO3
in BS03/04 Well underground
water is all larger than that in the simulated groundwater. Because the Beishan area is a drought region，
the evaporation quantity is very large，and the dissolved minerals，for example sylvite，halite and
anhydrite，are concentrated during the long-time evaporation. This natural weather environment is a
－
－
－
special reason for the concentration of K+，Na+，Ca2+，Mg2+，HCO3 ，SO42 ，Cl
Well underground water.
－
and NO3
in BS03/04