RADIATION SAFETY IN INDUSTRY
INVOLVING NORM/ TENORM
National Committee for the Certification of
Radiation Protection Officer
Contents
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Introduction
Sources of Radiation
Naturally Occurring Radioactive Materials (NORM)
Non-series Radionuclide Contribution to Background Radiation
Technologically Enhanced Radioactive Materials (TENORM)
Radionuclide in Oil and Gas Scales
Radionuclide in Coal and Coal Ash
Uranium-Thorium Decay Series
Radiation Risk Control
Classification of Working Area
Radiation Control
Radiation Monitoring
Handling and Storage of NORM/TENORM
National Committee for the Certification of Radiation Protection Officer
Introduction
 Man is continuously exposed to ionizing radiation which
originates from naturally occurring radiation.
 Radioactive materials and man-made radiation sources
are always present in his environment.
 In some places background radiation contributes
significantly to human annual radiation dose exposures.
 Sometimes Naturally Occurring Radioactive Materials
(norm) are technologically enhanced following extraction
of other valuable minerals yielding TENORM or
Technologically Enhanced Radioactive Materials (e.g. oil
and gas industry and tin mining).
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Sources of Radiation
 NORM are scattered in low concentration or
abundance in various samples such as soil,
sediment, air, water and living organisms.
 Natural radiation originates from 3 types of
sources:
 Cosmic rays
 Cosmogenic radionuclides
 Primodial radionuclides
National Committee for the Certification of Radiation Protection Officer
Sources of Radiation
 Cosmic radiation:
 Originate from the stars of outer space.
 Consist of proton (~ 85 %), alpha particle (~ 14 %)
and heavy nucleus (~ 1 %).
 Primary cosmic rays interact with the upper
atmosphere and produce secondary cosmic rays
consisting of muon (~70%) and electron (~30%).
 Cosmic rays contribute around 300 Sv of total
natural radiation exposure.
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Sources of Radiation
 Cosmogenic radionuclides:
 Are radionuclides produced following
interactions of cosmic rays with particles in
the atmosphere.
 Examples of cosmogenic radionuclides
are C-14, H-3, N-15.
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Sources of Radiation
 Primordial radionuclides:
 Radionuclide that coexisted during the
creation of earth.
 Radionuclide have very long half life, i.e.
t1/2 >108 years e.g. U-235, U-238, Th-232,
K-40 and Rb- 87.
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Sources of Radiation
Annual per
Capita Dose
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Naturally Occurring Radioactive
Materials (NORM)
 Examples of NORMS are:
 Natural uranium consisting of U-238 (99.28%), U-235 (0.715%)
and U-234 (0.005%) Natural uranium consisting of U-238
(99.28%), U-235 (0.715%) and U-234 (0.005%).
 U-238 decay series consists of 14 radionuclide.
 At secular equilibrium, total U-235 activity is 11 times higher
than any of its progenies.
 This series consists of 7 alpha emitters and 4 beta emitters and
finish with a stable Pb-207 nuclide.
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Naturally Occurring Radioactive
Materials (NORM)
 Radon (Ra-222) is a gaseous decay product of Ra-226 (from U-238
series).
 Thoron (Rn-220) is a gaseous decay product of Ra-224 (from Th232 series).
 Actinium series does not play a significant role in industrial
TENORM due to its very low presence (1/6 of U-238) in the natural
environment.
 If not subjected to chemical or physical separation, each of these
series attains a state of secular radioactive equilibrium.
 Technological enhancement of NORM as well as natural physical
and chemical reactions often interferes with this balance.
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Naturally Occurring Radioactive
Materials (NORM)
Radionuclides
in Uranium
Mining
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Naturally Occurring Radioactive
Materials (NORM)
Radionuclides’
Half-Lives
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Naturally Occurring Radioactive
Materials (NORM)
Radionuclides’
Half-Lives
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Non-Series Radionuclides Contribution
to Background Radiation
Two primary non-series radionuclides that
contribute to background dose are K-40 and Rb87.
 Potassium-40:
• K-40 is a beta (87.3%) and gamma (10.67%) emitter and
contributes to both internal and external doses.
• K-40 exists as a constant fraction of stable potassium
(0.0117%).
• Its contribution to external dose varies depending on its
concentration in rocks and soil.
• Average concentration K-40 is about 0.6 Bq/g (17 pCi/g) in
crustal rock.
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Non-Series Radionuclides Contribution
to Background Radiation
 Rubidium-87:
• Ru-87 is a pure beta emitter and is found in crustal rock in
concentrations of about 0.07 Bq/g (2 pCi/g).
 It is not an external hazard and is rarely considered in
dose calculations.
 The remainder of the non-series radionuclides has
combinations of half-lives, isotopic abundances, and
elemental abundances such that they have negligibly
small specific activities and are not significant in
background dose calculations.
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Technologically Enhanced Radioactive
Materials (TENORM)
 Significant amounts are TENORM derived from tin mining, tin slag
and amang processing activities.
 TENORM is also found in waste of petroleum sludge, oil scale,
material or contaminated apparatus or facilities.
 Estimates suggest that up to 30 % of domestic oil and gas wells
may produce some elevated TENORM contamination.
 Uranium and thorium compounds are mostly insoluble in oil and
gas and will remain in the underground reservoirs.
 Radium and radium daughter are soluble in formation water and
extracted with oil and gas.
National Committee for the Certification of Radiation Protection Officer
Technologically Enhanced Radioactive
Materials (TENORM)
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Radionuclides of TENORM/NORM:
 TENORM can be emitters of low and high LET radiation.
 Hazards associated with different LET radiation may be
divided based on the modes of exposures, i.e. external
and internal:
• External exposure:
o Hazards from gamma emitter radionuclide.
o Actual exposure dose depends on the volume of
source, the distance between the worker and the
source, the working hours and the shielding used.
• Internal exposure:
o Exposure to radon (Rn-222) and thoron (Rn-220).
o Rn-220 and Rn-222 are radioactive gases and pose
internal hazards if inhale.
National Committee for the Certification of Radiation Protection Officer
Technologically Enhanced Radioactive
Materials (TENORM)
Radionuclides of TENORM/NORM:
 These alpha emitters will be trapped in the inhalation system
especially in the bifurcations in the lungs producing radiation “hot
spots”.
• Thoron:
o A daughter of Th-232 decay series, with t1/2 of 55 sec.
o Upon decay, it too produces alpha emitters that pose
internal radiation hazard.
• Radon:
o A daughter from the U-238 decay series, and with a half
life of 3.8 days.
o Hazardous if inhale into the body because it will decay
and produce more hazardous alpha emitter progenies
e.g. Po-218, Pb-214, Bi-204 and Po-214.
National Committee for the Certification of Radiation Protection Officer
Technologically Enhanced Radioactive
Materials (TENORM)
Radionuclides of TENORM/NORM:
 Internal hazards may also be a consequence of
ingestion of NORM or entry of NORM through other
means such as cuts and open wounds
 Surface contamination:
• NORM found in coal ash, tin slag, amang mineral
or petroleum production processes may cause
surface contamination of the apparatus/facilities
and working area.
• Such contamination may cause internal and/or
external radiation exposure.
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Radionuclide in Oil and Gas
Scales
 Radium-226
is
generally
present in scales, and in
higher concentrations than
Ra-228.
Radionuclides
Concentration,
Bq/g (pCi/g)
Ra-226
13.3 (360)
 Typically, Ra-226 in scales is
in equilibrium with its progeny,
but Ra-228 is not.
Pb-210
13.3 (360)
Po-210
13.3 (360)
 The nominal activity appears
to be about three times
greater for Ra-226 than for
Ra-228.
Ra-228
4.44 (120)
Th-228
4.44 (120)
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Radionuclide in Coal and Coal
Ash
 Coal ash contains TENORM that requires proper management and
disposal.
 Coal contains naturally occurring uranium and thorium, coal ash
may present a potential radiological risk to exposed individuals.
 The degree of risk will depend on the physical and radiological
properties of the ash.
 The radioactivity of coal may vary over two orders of magnitude
depending on the type of coal and the region from which it was
mined.
 The concentrations of U-238 and Th-232 in coal average about
0.022 and 0.018 Bq/g (0.6 and 0.5 pCi/g), respectively.
National Committee for the Certification of Radiation Protection Officer
Radionuclide in Coal and Coal
Ash
Radionuclides
Concentration, Bq/g (pCi/g)
U-238
0.12 (3.3)
U-234
0.12 (3.3)
Th-230
0.085 (2.3)
Ra-226
0.14 (3.7)
Pb-210
0.25 (6.8)
Po-210
0.26 (7.0)
U-235
0.0037 (0.1)
Pa-231
0.0059 (0.16)
Ac-227
0.0059 (0.16)
Th-232
0.077 (2.1)
Ra-228
0.066 (1.8)
Th-228
0.19 (3.2)
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Uranium-Thorium Decay Series
National Committee for the Certification of Radiation Protection Officer
Radiation Risk Control
• The best method of managing radiation hazard and risk
in industries involved with NORM is through engineering
control.
• Serious attempt must be made to reduce suspension of
dust containing TENORM in the air, and the discharge
into the effluent.
• The hierarchy of radiological hazard control is
engineering design followed by management control
and Personal Protection Equipment (PPE) should be
considered last.
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Classification of Working Area
 One method of controlling TENORM hazards and risks
is by classifying the working areas.
 Classification of working areas involves engineering as
well as administrative controls.
 Engineering control refers to the design of such working
areas to meet the classification requirements.
 Administrative
instructions.
control
refers
to
procedures
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and
Classification of Working Area
 Working areas should be classified as clean, supervise
or control areas.
 Working area is classified as control area when:
 External Dose rate is > 7.5 µSv/hr
 Surface contamination > 7 Bq/cm2
 Contamination of Suspended particles is > 1 x 10-2 Bq/m3
 Working area is classified as supervise area when:
 External Dose rate is between 2.5 - 7.5 µSv/hr
 Surface contamination 2 - 7 Bq/cm2
 Contamination of Suspended particles is between 3 x 10-3 - 1 x
10-1 Bq/m3
National Committee for the Certification of Radiation Protection Officer
Radiation Control
Next best method of controlling radiation risk
after elimination, is engineering control.
Safe work procedure is one method
administrative control.
A practical and appropriate safe working
procedure is necessary to avoid or reduce the
effects of external and internal radiation
exposures from NORM/TENORM.
National Committee for the Certification of Radiation Protection Officer
of
Radiation Control
 The basic principle of external radiation protection (i.e.
time, distance, and shielding) should be considered in all
safe working procedures.
 All safe working procedures must be clear, concise and
easy to follow by the users.
 Training on the use of procedures must be given.
 Safe working procedures must be reviewed periodically
to ensure its intended effectiveness and efficiencies.
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Radiation Control
 Personal Protective Equipment (PPE) is last choice in radiation
protection methods.
 PPE is used to reduce radiological risk, i.e. the probability of
exposure and/or the impact of any accidental radiation exposure.
 PPE must be used in conjunction with other hazards and risks
controls.
 Examples of PPE that should be considered when working with
NORM/TENORM include:
 Respirators: to reduce the inhalation of dust containing
radionuclide.
 Gloves and apron: to reduce contamination of the body.
 Goggles: to reduce contamination of the eyes.
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Radiation Monitoring
Areas and personal dose exposure
monitoring shall be conducted as
prescribed according to the classification
of the working areas.
Records of area and personal dose
monitoring should be kept and maintained
as required by the relevant authorities.
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Handling and Storage of
NORM/TENORM
 Activities related to NORM/TENORM usually involve
large quantities but low activity concentrations of
radionuclides.
 Amang processing produces large quantity of valuable
minerals containing TENORM that are usually stored in
open spaces and exposed to the elements (rain and
wind).
 Storage areas with radiation level exceeding the
permissible limit should be isolated and classified as
restricted or prohibited area.
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Handling and Storage of
NORM/TENORM
 Guidelines for amang storage areas:
 The storage area should be far enough from the office, workers
quarters or residential area;
 If a close store room is used, it should be equipped with good
ventilation system;
 The storage area must be fenced and locked;
 The storage area must be clearly labeled with radiation
warning signs.
 General transportation procedure within and outside
premise:
 Follow instructions related to LSA-1 category.
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Handling and Storage of
NORM/TENORM
 Environmental surveillance/monitoring program:
 Radiological Impact Assessment (RIA) is required and must be
carried out at all stages of operations:
• Before Operation: to assess potential radiological risk to
workers and the environment before operation begins.
• During Operation: to assess new radiological risk not
considered during the planning stage or that may arise as a
consequence of changes made during operation.
• After or Shut Down Operation: to asses radiological risk
during shut down and return to normalcy operations.
 RIA for area and personal monitoring should be part of the
organization Radiation Safety Management System (RSMS).
National Committee for the Certification of Radiation Protection Officer
Summary
National Committee for the Certification of
Radiation Protection Officer
THANKS YOU FOR YOUR
ATTENTION
National Committee for the Certification of Radiation Protection Officer