U.S. NUCLEAR REGULATORY COMMISSION Revision 1

February 1996

REGULATORY GUIDE

OFFICE OF NUCLEAR REGULATORY RESEARCH

REGULATORY GUIDE 8.29

(Draft was issued as DG-8012)

INSTRUCTION CONCERNING RISKS

FROM OCCUPATIONAL RADIATION EXPOSURE

A. INTRODUCTION

Section 19.12 of 10 CFR Part 19, "Notices, Instructions and Reports to Workers: Inspection and Investigations," requires that all individuals who in the

course of their employment are likely to receive in a

year an occupational dose in excess of 100 mrem (1

mSv) be instructed in the health protection issues associated with exposure to radioactive materials or radiation. Section 20.1206 of 10 CFR Part 20, "Standards

for Protection Against Radiation," requires that before

a planned special exposure occurs the individuals involved are, among other things, to be informed of the

estimated doses and associated risks.

This regulatory guide describes the information

that should be provided to workers by licensees about

health risks from occupational exposure. This revision

conforms to the revision of 10 CFR Part 20 that became effective on June 20, 1991, to be implemented

by licensees no later than January 1, 1994. The revision of 10 CFR Part 20 establishes new dose limits

based on the effective dose equivalent (EDE), requires

the summing of internal and external dose, establishes

a requirement that licensees use procedures and engineering controls to the extent practicable to achieve

occupational doses and doses to members of the public

that are as low as is reasonably achievable (ALARA),

provides for planned special exposures, establishes a

dose limit for the embryo/fetus of an occupationally

exposed declared pregnant woman, and explicitly

states that Part 20 is not to be construed as limiting

action that may be necessary to protect health and

safety during emergencies.

Any information collection activities mentioned in

this regulatory guide are contained as requirements in

10 CFR Part 19 or 10 CFR Part 20. These regulations

provide the regulatory bases for this guide. The information collection requirements in 10 CFR Parts 19 and

20 have been cleared under OMB Clearance Nos.

3150-0044 and 3150-0014, respectively.

B. DISCUSSION

It is important to qualify the material presented in

this guide with the following considerations.

The coefficient used in this guide for occupational

radiation risk estimates, 4 x 10- 4 health effects per

rem, is based on data obtained at much higher doses

and dose rates than those encountered by workers.

The risk coefficient obtained at high doses and dose

rates was reduced to account for the reduced effectiveness of lower doses and dose rates in producing the

stochastic effects observed in studies of exposed

humans.

The assumption of a linear extrapolation from the

lowest doses at which effects are observable down to

USNRC REGULATORY GUIDES

Regulatory Guides are Issued todescribe and make availableto thepublic

such information as methods acceptable to the NRC staff for Implementing specific parts of the Commission's regulations, techniques used by

the staff in evaluating specific problems or postulated accidents, and

data needed by the NRC staff In Its review of applications for permits and

licenses. Regulatory guides are not substitutes for regulations, and compliance with them Is not required. Methods and solutions different from

those set out In the guides will be acceptable If they provide a basis for the

findings requisite to the Issuance or continuance of a permit or license by

the Commission.

This guide was Issued after consideration of comments received from the

public. Comments and suggestions for Improvements In these guides are

encouraged at all times, and guides will be revised, as appropriate, to

accommodate comments and to reflect new information or experience.

Written comments may be submitted to the Rules Review and Directives

Branch, DFIPS, ADM, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.

The guides are issued in the following ten broad divisions:

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obtained by writing NTIS, 5285 Port Royal Road, Springfield, VA22161.
I 

the occupational range has considerable uncertainty.

The report of the Committee on the Biological Effects

of Ionizing Radiation (Ref. 1) states that

"... departure from linearity cannot be excluded at low doses below the range of observation. Such departures could be in the direction of either an increased or decreased risk.

Moreover, epidemiologic data cannot rigorously exclude the existence of a threshold in

the 100 mrem dose range. Thus, the possibility that there may be no risk from exposures

comparable to external natural background

radiation cannot be ruled out. At such low

doses and dose rates, it must be acknowledged that the lower limit of the range of uncertainty in the risk estimates extends to

zero. "

The issue of beneficial effects from low doses, or

hormesis, in cellular systems is addressed by the

United Nations Scientific Committee on the Effects of

Atomic Radiation (Ref. 2). UNSCEAR states that "...

it would be premature to conclude that cellular adaptive responses could convey possible beneficial effects

to the organism that would outweigh the detrimental

effects of exposures to low doses of low-LET

radiation."

In the absence of scientific certainty regarding the

relationship between low doses and health effects, and

as a conservative assumption for radiation protection

purposes, the scientific community generally assumes

that any exposure to ionizing radiation can cause biological effects that may be harmful to the exposed person and that the magnitude or probability of these effects is directly proportional to the dose. These effects

may be classified into three categories:

Somatic Effects: Physical effects occurring in

the exposed person. These effects may be observable after a large or acute dose (e.g., 100

rems1 (1 Sv) or more to the whole body in a

few hours); or they may be effects such as

cancer that may occur years after exposure to

radiation.

Genetic Effects: Abnormalities that may occur in the future children of exposed individuals and in subsequent generations (genetic effects exceeding normal incidence have not

been observed in any of the studies of human

populations).

Teratogenic Effects: Effects such as cancer or

congenital malformation that may be observed in children who were exposed during

the fetal and embryonic stages of development (these effects have been observed from

In the International System of Units (SI), the rem is replaced by the sievert; 100 rerns is equal to 1 sievert (Sv).

high, i.e., above 20 rems (0.2 Sv), acute exposures).

The normal incidence of effects from natural and

manmade causes is significant. For example, approximately 20% of people die from various forms of cancer

whether or not they ever receive occupational exposure to radiation. To avoid increasing the incidence of

such biological effects, regulatory controls are imposed

on occupational doses to adults and minors and on

doses to the embryo/fetus from occupational exposures of declared pregnant women.

Radiation protection training for workers who are

occupationally exposed to ionizing radiation is an essential component of any program designed to ensure

compliance with NRC regulations. A clear understanding of what is presently known about the biological

risks associated with exposure to radiation will result in

more effective radiation protection training and should

generate more interest on the part of the workers in

complying with radiation protection standards. In addition, pregnant women and other occupationally exposed workers should have available to them relevant

information on radiation risks to enable them to make

informed decisions regarding the acceptance of these

risks. It is intended that workers who receive this instruction will develop respect for the risks involved,

rather than excessive fear or indifference.

C. REGULATORY POSITION

Instruction to workers performed in compliance

with 10 CFR 19.12 should be given prior to occupational exposure and periodically thereafter. The frequency of retraining might range from annually for licensees with complex operations such as nuclear

power plants, to every three years for licensees who

possess, for example, only low-activity sealed sources.

If a worker is to participate in a planned special exposure, the worker should be informed of the associated

risks in compliance with 10 CFR 20.1206.

In providing instruction concerning health protection problems associated with exposure to radiation, all

occupationally exposed workers and their supervisors

should be given specific instruction on the risk of biological effects resulting from exposure to radiation.

The extent of these instructions should be commensurate with the radiological risks present in the workplace.

The instruction should be presented orally, in

printed form, or in any other effective communication

media to workers and supervisors. The appendix to

this guide provides useful information for demonstrating compliance with the training requirements in 10

CFR Parts 19 and 20. Individuals should be given an

opportunity to discuss the information and to ask questions. Testing is recommended, and each trainee

should be asked to acknowledge in writing that the instruction has been received and understood.

8.29-2
D. IMPLEMENTATION

The purpose of this section is to provide information to applicants and licensees regarding the NRC

staff's plans for using this regulatory guide.

Except in those cases in which an applicant or licensee proposes acceptable alternative methods for

complying with specified portions of the Commission's

regulations, the guidance and instructional materials in

this guide will be used in the evaluation of applications

for new licenses, license renewals, and license amendments and for evaluating compliance with 10 CFR

19.12 and 10 CFR Part 20.

REFERENCES

1. National Research Council, Health Effects of Exposure to Low Levels of Ionizing Radiation, Report of the Committee on the Biological Effects of

Ionizing Radiation (BEIR V), National Academy

Press, Washington, DC, 1990.

2. United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), Sources

and Effects of Ionizing Radiation, United Nations, New York, 1993.

8.29-3
APPENDIX

INSTRUCTION CONCERNING RISKS

FROM OCCUPATIONAL RADIATION EXPOSURE

This instructional material is intended to provide the user with the best available information about the

health risks from occupational exposure to ionizing radiation. Ionizing radiation consists of energy or small

particles, such as gamma rays and beta and alpha par- ticles, emitted from radioactive materials, which can

cause chemical or physical damage when they deposit

energy in living tissue. A question and answer format is

used. Many of the questions or subjects were developed by the NRC staff in consultation with workers,

union representatives, and licensee representatives experienced in radiation protection training.

This Revision 1 to Regulatory Guide 8.29 updates the material in the original guide on biological effects

and risks and on typical occupational exposure. Additionally, it conforms to the revised 10 CFR Part 20,

"Standards for Protection Against Radiation," which

was required to be implemented by licensees no later

than January 1, 1994. The information in this appen- dix is intended to help develop respect by workers for

the risks associated with radiation, rather than unjusti- fied fear or lack of concern. Additional guidance concerning other topics in radiation protection training is

provided in other NRC regulatory guides.

1. What is meant by health risk?

A health risk is generally thought of as something

that may endanger health. Scientists consider health

risk to be the statistical probability or mathematical

chance that personal injury, illness, or death may result from some action. Most people do not think about

health risks in terms of mathematics. Instead, most of

us consider the health risk of a particular action in

terms of whether we believe that particular action will,

or will not, cause us some harm. The intent of this ap- pendix is to provide estimates of, and explain the bases

for, the risk of injury, illness, or death from occupa- tional radiation exposure. Risk can be quantified in

terms of the probability of a health effect per unit of

dose received.

When x-rays, gamma rays, and ionizing particles interact with living materials such as our bodies, they

may deposit enough energy to cause biological damage. Radiation can cause several different types of

events such as the very small physical displacement of

molecules, changing a molecule to a different form, or

ionization, which is the removal of electrons from

atoms and molecules. When the quantity of radiation

energy deposited in living tissue is high enough, biolog- ical damage can occur as a result of chemical bonds

being broken and cells being damaged or killed. These

effects can result in observable clinical symptoms.

The basic unit for measuring absorbed radiation is

the rad. One rad (0.01 gray in the International System of units) equals the absorption of 100 ergs (a small

but measurable amount of energy) in a gram of material such as tissue exposed to radiation. To reflect biological risk, rads must be converted to rems. The new

international unit is the sievert (100 rems = 1 Sv). This

conversion accounts for the differences in the effectiveness of different types of radiation in causing damage. The rem is used to estimate biological risk. For

beta and gamma radiation, a rem is considered equal

to a rad.

2. What are the possible health effects of exposure to radiation?

Health effects from exposure to radiation range from no effect at all to death, including diseases such

as leukemia or bone, breast, and lung cancer. Very high (100s of rads), short-term doses of radiation have

been known to cause prompt (or early) effects, such as

vomiting and diarrhea,' skin burns, cataracts, and

even death. It is suspected that radiation exposure may be linked to the potential for genetic effects in the children of exposed parents. Also, children who were exposed to high doses (20 or more rads) of radiation

prior to birth (as an embryo/fetus) have shown an increased risk of mental retardation and other congenital malformations. These effects (with the exception of

genetic effects) have been observed in various studies

of medical radiologists, uranium miners, radium workers, radiotherapy patients, and the people exposed to

radiation from atomic bombs dropped on Japan. In

addition, radiation effects studies with laboratory animals, in which the animals were given relatively high doses, have provided extensive data on radiation-induced health effects, including genetic effects.

It is important to note that these kinds of health

effects result from high doses, compared to occupa- tional levels, delivered over a relatively short period of

time.

Although studies have not shown a consistent

cause-and-effect relationship between current levels of

occupational radiation exposure and biological effects,

it is prudent from a worker protection perspective to

assume that some effects may occur.

IThese symptoms are early indicators of what is referred to as the acute radiation syndrome, caused by high doses delivered over a short time period, which includes damage to the blood- forming organs such as bone marrow, damage to the gastroin- testinal system, and, at very high doses, can include damage to the central nervous system.

8.29-4
3. What is meant by early effects and delayed

or late effects?

EARLY EFFECTS

Early effects, which are also called immediate or

prompt effects, are those that occur shortly after a

large exposure that is delivered within hours to a few

days. They are observable after receiving a very large

dose in a short period of time, for example, 300 rads

(3 Gy) received within a few minutes to a few days.

Early effects are not caused at the levels of radiation

exposure allowed under the NRC's occupational limits.

Early effects occur when the radiation dose is large

enough to cause extensive biological damage to cells so

that large numbers of cells are killed. For early effects

to occur, this radiation dose must be received within a

short time period. This type of dose is called an acute

dose or acute exposure. The same dose received over a

long time period would not cause the same effect. Our

body's natural biological processes are constantly repairing damaged cells and replacing dead cells; if the

cell damage is spread over time, our body is capable of

repairing or replacing some of the damaged cells, reducing the observable adverse conditions.

For example, a dose to the whole body of about

300-500 rads (3-5 Gy), more than 60 times the annual occupational dose limit, if received within a short

time period (e.g., a few hours) will cause vomiting and

diarrhea within a few hours; loss of hair, fever, and

weight loss within a few weeks; and about a 50 percent

chance of death if medical treatment is not provided.

These effects would not occur if the same dose were

accumulated gradually over many weeks or months

(Refs. 1 and 2). Thus, one of the justifications for establishing annual dose limits is to ensure that occupational dose is spread out in time.

It is important to distinguish between whole body

and partial body exposure. A localized dose to a small

volume of the body would not produce the same effect

as a whole body dose of the same magnitude. For example, if only the hand were exposed, the effect would

mainly be limited to the skin and underlying tissue of

the hand. An acute dose of 400 to 600 rads (4-6 Gy)

to the hand would cause skin reddening; recovery

would occur over the following months and no longterm damage would be expected. An acute dose of this

magnitude to the whole body could cause death within

a short time without medical treatment. Medical treatment would lessen the magnitude of the effects and the

chance of death; however, it would not totally eliminate the effects or the chance of death.

DELAYED EFFECTS

Delayed effects may occur years after exposure.

These effects are caused indirectly when the radiation

changes parts of the cells in the body, which causes the

normal function of the cell to change, for example,

normal healthy cells turn into cancer cells. The potential for these delayed health effects is one of the main

concerns addressed when setting limits on occupational doses.

A delayed effect of special interest is genetic effects. Genetic effects may occur if there is radiation

damage to the cells of the gonads (sperm or eggs).

These effects may show up as genetic defects in the

children of the exposed individual and succeeding generations. However, if any genetic effects (i.e., effects

in addition to the normal expected number) have been

caused by radiation, the numbers are too small to have

been observed in human populations exposed to radiation. For example, the atomic bomb survivors (from

Hiroshima and Nagasaki) have not shown any significant radiation-related increases in genetic defects

(Ref. 3). Effects have been observed in animal studies

conducted at very high levels of exposure and it is

known that radiation can cause changes in the genes in

cells of the human body. However, it is believed that

by maintaining worker exposures below the NRC limits

and consistent with ALARA, a margin of safety is provided such that the risk of genetic effects is almost

eliminated.

4. What is the difference between acute and

chronic radiation dose?

Acute radiation dose usually refers to a large dose

of radiation received in a short period of time. Chronic

dose refers to the sum of small doses received repeatedly over long time periods, for example, 20 mrem (or

millirem, which is 1-thousandth of a rem) (0.2 mSv)

per week every week for several years. It is assumed

for radiation protection purposes that any radiation

dose, either acute or chronic, may cause delayed effects. However, only large acute doses cause early effects; chronic doses within the occupational dose limits

do not cause early effects. Since the NRC limits do not

permit large acute doses, concern with occupational

radiation risk is primarily focused on controlling

chronic exposure for which possible delayed effects,

such as cancer, are of concern.

The difference between acute and chronic radiation exposure can be shown by using exposure to the

sun's rays as an example. An intense exposure to the

sun can result in painful burning, peeling, and growing

of new skin. However, repeated short exposures provide time for the skin to be repaired between exposures. Whether exposure to the sun's rays is long term

or spread over short periods, some of the injury may

not be repaired and may eventually result in skin

cancer.

Cataracts are an interesting case because they can

be caused by both acute and chronic radiation. A certain threshold level of dose to the lens of the eye is

required before there is any observable visual impairment, and the impairment remains after the exposure

is stopped. The threshold for cataract development

8.29-5
from acute exposure is an acute dose on the order of

100 rads (1 Gy). Further, a cumulative dose of 800

rads (8 Gy) from protracted exposures over many

years to the lens of the eye has been linked to some

level of visual impairment (Refs. 1 and 4). These doses

exceed the amount that may be accumulated by the

lens from normal occupational exposure under the

current regulations.

5. What is meant by external and internal exposure?

A worker's occupational dose may be caused by

exposure to radiation that originates outside the body, called "external exposure," or by exposure to radiation from radioactive material that has been taken

into the body, called 'internal exposure." Most NRClicensed activities involve little, if any, internal exposure. It is the current scientific consensus that a rem of

radiation dose has the same biological risk regardless of whether it is from an external or an internal source.

The NRC requires that dose from external exposure and dose from internal exposure be added together, if

each exceeds 10% of the annual limit, and that the

total be within occupational limits. The sum of external

and internal dose is called the total effective dose

equivalent (TEDE) and is expressed in units of rems

(Sv) .

Although unlikely, radioactive materials may enter the body through breathing, eating, drinking, or

open wounds, or they may be absorbed through the

skin. The intake of radioactive materials by workers is

generally due to breathing contaminated air. Radioactive materials may be present as fine dust or gases in

the workplace atmosphere. The surfaces of equipment and workbenches may be contaminated, and these

materials can be resuspended in air during work

activities.

If any radioactive material enters the body, the

material goes to various organs or is excreted, depend- ing on the biochemistry of the material. Most radioisotopes are excreted from the body in a few days. For

example, a fraction of any uranium taken into the

body will deposit in the bones, where it remains for a

longer time. Uranium is slowly eliminated from the

body, mostly by way of the kidneys. Most workers are

not exposed to uranium. Radioactive iodine is prefer- entially deposited in the thyroid gland, which is located

in the neck..

To limit risk to specific organs and the total body,

an annual limit on intake (ALI) has been established

for each radionuclide. When more than one radionuclide is involved, the intake amount of each radionuclide is reduced proportionally. NRC regulations speci- fy the concentrations of radioactive material in the air

to which a worker may be exposed for 2,000 working hours in a year. These concentrations are termed the

derived air concentrations (DACs). These limits are

the total amounts allowed if no external radiation is

received. The resulting dose from the internal radiation sources (from breathing air at 1 DAC) is the

maximum allowed to an organ or to the worker's whole

body.

6. How does radiation cause cancer?

The mechanisms of radiation-induced cancer are

not completely understood. When radiation interacts

with the cells of our bodies, a number of events can

occur. The damaged cells can repair themselves and

permanent damage is not caused. The cells can die, much like the large numbers of cells that die every day in our bodies, and be replaced through the normal biological processes. Or a change can occur in the cell's

reproductive structure, the cells can mutate and subsequently be repaired without effect, or they can form

precancerous cells, which may become cancerous. Radiation is only one of many agents with the potential for causing cancer, and cancer caused by radiation

cannot be distinguished from cancer attributable to

any other cause.

Radiobiologists have studied the relationship between large doses of radiation and cancer (Refs. 5 and

6). These studies indicate that damage or change to

genes in the cell nucleus is the main cause of radiationinduced cancer. This damage may occur directly through the interaction of the ionizing radiation in the

cell or indirectly through the actions of chemical products produced by radiation interactions within cells.

Cells are able to repair most damage within hours; however, some cells may not be repaired properly. Such misrepaired damage is thought to be the origin of

cancer, but misrepair does not always cause cancer.

Some cell changes are benign or the cell may die; these

changes do not lead to cancer.

Many factors such as age, general health, inherited traits, sex, as well as exposure to other cancercausing agents such as cigarette smoke can affect susceptibility to the cancer-causing effects of radiation.

Many diseases are caused by the interaction of several

factors, and these interactions appear to increase the

susceptibility to cancer.

7. Who developed radiation risk estimates?

Radiation risk estimates were developed by several

national and international scientific organizations over

the last 40 years. These organizations include the National Academy of Sciences (which has issued several

reports from the Committee on the Biological Effects

of Ionizing Radiations, BEIR), the National Council on

Radiation Protection and Measurements (NCRP), the

International Commission on Radiological Protection

(ICRP), and the United Nations Scientific Committee

on the Effects of Atomic Radiation (UNSCEAR). Each of these organizations continues to review new

research findings on radiation health risks.

8.29-6
Several reports from these organizations present

new findings on radiation risks based upon revised estimates of radiation dose to survivors of the atomic

bombing at Hiroshima and Nagasaki. For example,

UNSCEAR published risk estimates in 1988 and 1993

(Refs. 5 and 6). The NCRP also published a report in

1988, "New Dosimetry at Hiroshima and Nagasaki

and Its Implications for Risk Estimates" (Ref. 7). In

January 1990, the National Academy of Sciences released the fifth report of the BEIR Committee,

"Health Effects of Exposure to Low Levels of Ionizing

Radiation" (Ref. 4). Each of these publications also

provides extensive bibliographies on other published

studies concerning radiation health effects for those

who may wish to read further on this subject.

8. What are the estimates of the risk of fatal

cancer from radiation exposure?

We don't know exactly what the chances are of

getting cancer from a low-level radiation dose, primarily because the few effects that may occur cannot be

distinguished from normally occurring cancers. However, we can make estimates based on extrapolation

from extensive knowledge from scientific research on

high dose effects. The estimates of radiation effects at

high doses are better known than are those of most

chemical carcinogens (Ref. 8).

From currently available data, the NRC has

adopted a risk value for an occupational dose of 1 rem

(0.01 Sv) Total Effective Dose Equivalent (TEDE) of

4 in 10,000 of developing a fatal cancer, or approximately 1 chance in 2,500 of fatal cancer per rem of

TEDE received. The uncertainty associated with this

risk estimate does not rule out the possibility of higher

risk, or the possibility that the risk may even be zero at

low occupational doses and dose rates.

The radiation risk incurred by a worker depends

on the amount of dose received. Under the linear

model explained above, a worker who receives 5 reins

(0.05 Sv) in a year incurs 10 times as much risk as

another worker who receives only 0.5 rem (0.005 Sv).

Only a very few workers receive doses near 5 rems

(0.05 Sv) per year (Ref. 9).

According to the BEIR V report (Ref. 4), approximately one in five adults normally will die from cancer

from all possible causes such as smoking, food, alcohol, drugs, air pollutants, natural background radiation, and inherited traits. Thus, in any group of

10,000 workers, we can estimate that about 2,000

(20%) will die from cancer without any occupational

radiation exposure.

To explain the significance of these estimates, we

will use as an example a group of 10,000 people, each

exposed to 1 rem (0.01 Sv) of ionizing radiation. Using

the risk factor of 4 effects per 10,000 rem of dose, we

estimate that 4 of the 10,000 people might die from

delayed cancer because of that 1-rem dose (although

the actual number could be more or less than 4) in

addition to the 2,000 normal cancer fatalities expected

to occur in that group from all other causes. This

means that a 1-rem (0.01 Sv) dose may increase an

individual worker's chances of dying from cancer from

20 percent to 20.04 percent. If one's lifetime occupational dose is 10 rems, we could raise the estimate to

20.4 percent. A lifetime dose of 100 rems may increase chances of dying from cancer from 20 to 24

percent. The average measurable dose for radiation

workers reported to the NRC was 0.31 rem (0.0031

Sv) for 1993 (Ref. 9). Today, very few workers ever

accumulate 100 rems (1 Sv) in a working lifetime, and

the average career dose of workers at NRC-licensed

facilities is 1.5 rems (0.015 Sv), which represents an

estimated increase from 20 to about 20.06 percent in

the risk of dying from cancer.

It is important to understand the probability factors here. A similar question would be, "If you select

one card from a full deck of cards, will you get the ace

of spades?" This question cannot be answered with a

simple yes or no. The best answer is that your chance is

1 in 52. However, if 1000 people each select one card

from full decks, we can predict that about 20 of them

will get an ace of spades. Each person will have 1

chance in 52 of drawing the ace of spades, but there is

no way we can predict which persons will get that card.

The issue is further complicated by the fact that in a

drawing by 1000 people, we might get only 15 successes, and in another, perhaps 25 correct cards in

1000 draws. We can say that if you receive a radiation

dose, you will have increased your chances of eventually developing cancer. It is assumed that the more radiation exposure you get, the more you increase your

chances of cancer.

The normal chance of dying from cancer is about

one in five for persons who have not received any occupational radiation dose. The additional chance of

developing fatal cancer from an occupational exposure

of 1 rem (0.01 Sv) is about the same as the chance of

drawing any ace from a full deck of cards three times in

a row. The additional chance of dying from cancer

from an occupational exposure of 10 rem (0.1 Sv) is

about equal to your chance of drawing two aces successively on the first two draws from a full deck of cards.

It is important to realize that these risk numbers

are only estimates based on data for people and research animals exposed to high levels of radiation in

short periods of time. There is still uncertainty with regard to estimates of radiation risk from low levels of

exposure. Many difficulties are involved in designing

research studies that can accurately measure the projected small increases in cancer cases that might be

caused by low exposures to radiation as compared to

the normal rate of cancer.

8.29-7
These estimates are considered by the NRC staff

to be the best available for the worker to use to make

an informed decision concerning acceptance of the

risks associated with exposure to radiation. A worker

who decides to accept this risk should try to keep exposure to radiation as low as is reasonably achievable

(ALARA) to avoid unnecessary risk.

9. If I receive a radiation dose that is within

occupational limits, will it cause me to get cancer?

Probably not. Based on the risk estimates pre- viously discussed, the risk of cancer from doses below

the occupational limits is believed to be small. Assessment of the cancer risks that may be associated with

low doses of radiation are projected from data available at doses larger than 10 rems (0.1 Sv) (Ref. 3). For

radiation protection purposes, these estimates are

made using the straight line portion of the linear quadratic model (Curve 2 in Figure 1). We have data on

cancer probabilities only for high doses, as shown by the solid line in Figure 1. Only in studies involving radiation doses above occupational limits are there dependable determinations of the risk of cancer, primarily because below the limits the effect is small compared

to differences in the normal cancer incidence from

year to year and place to place. The ICRP, NCRP, and

other standards-setting organizations assume for radiation protection purposes that there is some risk, no

matter how small the dose (Curves 1 and 2). Some

scientists believe that the risk drops off to zero at some

low dose (Curve 3), the threshold effect. The ICRP

and NCRP endorse the linear quadratic model as a

conservative means of assuring safety (Curve 2).

For regulatory purposes, the NRC uses the straight line portion of Curve 2, which shows the number of

effects decreasing linearly as the dose decreases. Because the scientific evidence does not conclusively

demonstrate whether there is or is not an effect at low

doses, the NRC assumes for radiation protection purposes, that even small doses have some chance of causing cancer. Thus, a principle of radiation protection is

to do more than merely meet the allowed regulatory limits; doses should be kept as low as is reasonably

achievable (ALARA). This is as true for natural carcinogens such as sunlight and natural radiation as it is

for those that are manmade, such as cigarette smoke,

smog, and x-rays.

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I

I

I

I

I

I

I

I

I

I

i /

DOSE (REMS) 50 REMS

Figure 1. Some Proposed Models for How the Effects of Radiation Vary With Doses at Low Levels

8.29-8
10. How can we compare the risk of cancer from

radiation to other kinds of health risks?

One way to make these comparisons is to compare

the average number of days of life expectancy lost

because of the effects associated with each particular

health risk. Estimates are calculated by looking at a

large number of persons, recording the age when death

occurs from specific causes, and estimating the average

number of days of life lost as a result of these early

deaths. The total number of days of life lost is then

averaged over the total observed group.

Several studies have compared the average days of

life lost from exposure to radiation with the number of

days lost as a result of being exposed to other health

risks. The word "average" is important because an individual who gets cancer loses about 15 years of life

expectancy, while his or her coworkers do not suffer

any loss.

Some representative numbers are presented in

Table 1. For categories of NRC-regulated industries

with larger doses, the average measurable occupational

dose in 1993 was 0.31 rem (0.0031 Sv). A simple calculation based on the article by Cohen and Lee (Ref.

10) shows that 0.3 rem (0.003 Sv) per year from age

18 to 65 results in an average loss of 15 days. These

estimates indicate that the health risks from occupational radiation exposure are smaller than the risks associated with many other events or activities we encounter and accept in normal day-to-day activities.

It is also useful to compare the estimated average

number of days of life lost from occupational exposure

to radiation with the number of days lost as a result of

working in several types of industries. Table 2 shows

average days of life expectancy lost as a result of fatal

work-related accidents. Table 2 does not include nonaccident types of occupational risks such as occupational disease and stress because the data are not

available.

These comparisons are not ideal because we are

comparing the possible effects of chronic exposure to

radiation to different kinds of risk such as accidental

death, in which death is inevitable if the event occurs.

This is the best we can do because good data are not

available on chronic exposure to other workplace carcinogens. Also, the estimates of loss of life expectancy

for workers from radiation-induced cancer do not take

into consideration the competing effect on the life expectancy of the workers from industrial accidents.

11. What are the health risks from radiation

exposure to the embryo/fetus?

During certain stages of development, the embryo/

fetus is believed to be more sensitive to radiation damage than adults. Studies of atomic bomb survivors exposed to acute radiation doses exceeding 20 rads (0.2

Gy) during pregnancy show that children born after

receiving these doses have a higher risk of mental retardation. Other studies suggest that an association exists between exposure to diagnostic x-rays before birth

and carcinogenic effects in childhood and in adult life.

Scientists are uncertain about the magnitude of the

risk. Some studies show the embryo/fetus to be more

sensitive to radiation-induced cancer than adults, but

other studies do not. In recognition of the possibility of

increased radiation sensitivity, and because dose to the

Table 1 Estimated Loss of Life Expectancy from Health Risksa

Estimate

of Life Expectancy Lost

Health Risk (average)

Smoking 20 cigarettes a day 6 years

Overweight (by 15%) 2 years

Alcohol consumption (U.S. average) 1 year

All accidents combined 1 year

Motor vehicle accidents 207 days

Home accidents 74 days

Drowning 24 days

All natural hazards (earthquake, lightning, flood, etc.) 7 days

Medical radiation 6 days

Occupational Exposure

0.3 rem/y from age 18 to 65 15 days

1 remly from age 18 to 65 51 days

aAdapted from Reference 10.

8.29-9
Table 2 Estimated Loss of Life Expectancy

from Industrial Accidentsa

Estimated Days of Life

Industry Type Expectancy Lost (Average)

All industries 60

Agriculture 320

Construction 227

Mining and Quarrying 167

Transportation and

Public Utilities 160

Government 60

Manufacturing 40

Trade 27

Services 27

aAdapted from Reference 10.

embryo/fetus is involuntary on the part of the embryo/

fetus, a more restrictive dose limit has been established

for the embryo/fetus of a declared pregnant radiation

worker. See Regulatory Guide 8.13, "Instruction Concerning Prenatal Radiation Exposure."

If an occupationally exposed woman declares her

pregnancy in writing, she is subject to the more restrictive dose limits for the embryo/fetus during the remainder of the pregnancy. The dose limit of 500 mrems (5

mSv) for the total gestation period applies to the embryo/fetus and is controlled by restricting the exposure

to the declared pregnant woman. Restricting the woman's occupational exposure, if she declares her pregnancy, raises questions about individual privacy rights,

equal employment opportunities, and the possible loss

of income. Because of these concerns, the declaration

of pregnancy by a female radiation worker is voluntary. Also, the declaration of pregnancy can be withdrawn for any reason, for example, if the woman believes that her benefits from receiving the occupational

exposure would outweigh the risk to her embryo/fetus

from the radiation exposure.

12. Can a worker become sterile or impotent from normal occupational radiation

exposure?

No. Temporary or permanent sterility cannot be

caused by radiation at the levels allowed under NRC's

occupational limits. There is a threshold below which

these effects do not occur. Acute doses on the order of

10 rems (0.1 Sv) to the testes can result in a measurable but temporary reduction in sperm count. Temporary sterility (suppression of ovulation) has been observed in women who have received acute doses of 150

rads (1.5 Gy). The estimated threshold (acute) radiation dose for induction of permanent sterility is about

200 rads (2 Gy) for men and about 350 rads (3.5 Gy)

for women (Refs. 1 and 4). These doses are far greater

than the NRC s occupational dose limits for workers.

Although acute doses can affect fertility by reducing sperm count or suppressing ovulation, they do not

have any direct effect on one's ability to function sexually. No evidence exists to suggest that exposures within the NRC's occupational limits have any effect on the

ability to function sexually.

13. What are the NRC occupational dose limits?

For adults, an annual limit that does not exceed:

a 5 rems (0.05 Sv) for the total effective dose equivalent (TEDE), which is the sum of the deep dose

equivalent (DDE) from external exposure to the

whole body and the committed effective dose

equivalent (CEDE) from intakes of radioactive

material.

* 50 rems (0.5 Sv) for the total organ dose equivalent (TODE), which is the sum of the DDE from

external exposure to the whole body and the committed dose equivalent (CDE) from intakes of radioactive material to any individual organ or tissue, other than the lens of the eye.

* 15 rems (0.15 Sv) for the lens dose equivalent

(LDE), which is the external dose to the lens of

the eye.

* 50 rems (0.5 Sv) for the shallow dose equivalent

(SDE), which is the external dose to the skin or to

any extremity.

For minor workers, the annual occupational dose

limits are 10 percent of the dose limits for adult workers.

For protection of the embryolfetus of a declared

pregnant woman, the dose limit is 0.5 rem (5 mSv)

during the entire pregnancy.

The occupational dose limit for adult workers of 5

rems (0.05 Sv) TEDE is based on consideration of the

potential for delayed biological effects. The 5-rem

(0.05 Sv) limit, together with application of the concept of keeping occupational doses ALARA, provides

a level of risk of delayed effects considered acceptable

by the NRC. The limits for individual organs are below

the dose levels at which early biological effects are observed in the individual organs.

The dose limit for the embryo/fetus of a declared

pregnant woman is based on a consideration of the

possibility of greater sensitivity to radiation of the embryo/fetus and the involuntary nature of the exposure.

14. What is meant by ALARA?

ALARA means 'as low as is reasonably achievable." In addition to providing an upper limit on an

individual's permissible radiation dose, the NRC requires that its licensees establish radiation protection

8.29-10
programs and use procedures and engineering controls

to achieve occupational doses, and doses to the public,

as far below the limits as is reasonably achievable.

"Reasonably achievable" also means "to the extent

practicable." What is practicable depends on the purpose of the job, the state of technology, the costs for

averting doses, and the benefits. Although implementation of the ALARA principle is a required integral

part of each licensee's radiation protection program, it

does not mean that each radiation exposure must be

kept to an absolute minimum, but rather that "reasonable" efforts must be made to avert dose. In practice,

ALARA includes planning tasks involving radiation

exposure so as to reduce dose to individual workers

and the work group.

There are several ways to control radiation doses,

e.g., limiting the time in radiation areas, maintaining

distance from sources of radiation, and providing

shielding of radiation sources to reduce dose. The use

of engineering controls, from the design of facilities

and equipment to the actual set-up and conduct of

work activities, is also an important element of the

ALARA concept.

An ALARA analysis should be used in determining whether the use of respiratory protection is advisable. In evaluating whether or not to use respirators,

the goal should be to achieve the optimal sum of external and internal doses. For example, the use of respirators can lead to increased work time within radiation

areas, which increases external dose. The advantage of

using respirators to reduce internal exposure must be

evaluated against the increased external exposure and

related stresses caused by the use of respirators. Heat

stress, reduced visibility, and reduced communication

associated with the use of respirators could expose a

worker to far greater risks than are associated with the

internal dose avoided by use of the respirator. To the

extent practical, engineering controls, such as containments and ventilation systems, should be used to reduce workplace airborne radioactive materials.

15. What are background radiation exposures?

The average person is constantly exposed to ionizing radiation from several sources. Our environment

and even the human body contain naturally occurring

radioactive materials (e.g., potassium-40) that contribute to the radiation dose that we receive. The largest

source of natural background radiation exposure is terrestrial radon, a colorless, odorless, chemically inert

gas, which causes about 55 percent of our average,

nonoccupational exposure. Cosmic radiation originating in space contributes additional exposure. The use

of x-rays and radioactive materials in medicine and

dentistry adds to our population exposure. As shown

below in Table 3, the average person receives an annual radiation dose of about 0.36 rem (3.6 mSv). By age

20, the average person will accumulate over 7 rems (70

mSv) of dose. By age 50, the total dose is up to 18 rems

(180 mSv). After 70 years of exposure this dose is up

to 25 rems (250 mSv).

Table 3 Average Annual Effective Dose Equivalent to Individuals in the U.S.a

Effective Dose

Source Equivalent (mrems)

Natural

Radon 200

Other than Radon 100

Total 300

Nuclear Fuel Cycle 0.05

Consumer Productsb 9

Medical

Diagnostic X-rays 39

Nuclear Medicine 14

Total 53

Total about 360

mrems/year

aAdapted from Table 8.1, NCRP 93 (Ref. 11).

bIncludes building material, television receivers, luminous watches, smoke detectors, etc. (from Table S.1,

NCRP 93, Ref. 11).

16. What are the typical radiation doses received

by workers?

For 1993, the NRC received reports on about a

quarter of a million people who were monitored for

occupational exposure to radiation. Almost half of

those monitored had no measurable doses. The other

half had an average dose of about 310 mrem (3.1

mSv) for the year. Of these, 93 percent received an

annual dose of less than 1 rem (10 mSv); 98.7 percent

received less than 2 rems (20 mSv); and the highest

reported dose was for two individuals who each received between 5 and 6 rems (50 and 60 mSv).

Table 4 lists average occupational doses for workers (persons who had measurable doses) in various occupations based on 1993 data. It is important to note

that beginning in 1994, licensees have been required to

sum external and internal doses and certain licensees

are required to submit annual reports. Certain types of

licensees such as nuclear fuel fabricators may report a

significant increase in worker doses because of the

exposure to long-lived airborne radionuclides and the

requirement to add the resultant internal dose to the

calculation of occupational doses.

8.29-11
Table 4 Reported Occupational Doses for 1993a

Average Measurable

Occupational Dose per Worker Subgroup (millirems)

Industrial Radiography 540

Commercial Nuclear Power Reactors 310

Manufacturing and Distribution

of Radioactive Materials 300

Low-Level Radioactive Waste

Disposal 270

Independent Spent Nuclear Fuel Storage 260

Nuclear Fuel Fabrication 130

aFrom Table 3.1 in NUREG-0713 (Ref. 9).

17. How do I know how much my occupational dose (exposure) is?

If you are likely to receive more than 10 percent of the annual dose limits, the NRC requires your employer, the NRC licensee, to monitor your dose, to main- tain records of your dose, and, at least on an annual basis for the types of licensees listed in 10 CFR

20.2206, "Reports of Individual Monitoring," to in- form both you and the NRC of your dose. The purpose of this monitoring and reporting is so that the NRC can be sure that licensees are complying with the occupa- tional dose limits and the ALARA principle.

External exposures are monitored by using indi- vidual monitoring devices. These devices are required to be used if it appears likely that external exposure will exceed 10 percent of the allowed annual dose, i.e., 0.5 rem (5 mSv). The most commonly used monitoring devices are film badges, thermoluminescence do- simeters (TLDs), electronic dosimeters, and direct reading pocket dosimeters.

With respect to internal exposure, your employer is required to monitor your occupational intake of ra- dioactive material and assess the resulting dose if it ap- pears likely that you will receive greater than 10 per- cent of the annual limit on intake (ALI) from intakes in 1 year. Internal exposure can be estimated by mea- suring the radiation emitted from the body (for example, with a "whole body counter") or by measuring the radioactive materials contained in biological samples such as urine or feces. Dose estimates can also be made if one knows how much radioactive material was in the air and the length of time during which the air

was breathed.

18. What happens if a worker exceeds the

annual dose limit?

If a worker receives a dose in excess of any of the annual dose limits, the regulations prohibit any occu- pational exposure during the remainder of the year in which the limit is exceeded. The licensee is also re- quired to file an overexposure report with the NRC and provide a copy to the individual who received the dose. The licensee may be subject to NRC enforcement ac- tion such as a fine (civil penalty), just as individuals are subject to a traffic fine for exceeding a speed limit. The fines and, in some serious or repetitive cases, suspen- sion of a license are intended to encourage licensees to comply with the regulations.

Radiation protection limits do not define safe or unsafe levels of radiation exposure. Exceeding a limit does not mean that you will get cancer. For radiation

protection purposes, it is assumed that risks are related

to the size of the radiation dose. Therefore, when your dose is higher your risk is also considered to be higher. These limits are similar to highway speed limits. If you drive at 70 mph, your risk is higher than at 55 mph, even though you may not actually have an accident.

Those who set speed limits have determined that the risks of driving in excess of the speed limit are not ac- ceptable. In the same way, the revised 10 CFR Part 20 establishes a limit for normal occupational exposure of S reins (0.05 Sv) a year. Although you will not neces- sarily get cancer or some other radiation effect at doses

above the limit, it does mean that the licensee's safety program has failed in some way. Investigation is war- ranted to determine the cause and correct the conditions leading to the dose in excess of the limit.

19. What is meant by a "planned special exposure"?

A "planned special exposure" (PSE) is an infrequent exposure to radiation, separate from and in ad- dition to the radiation received under the annual occu- pational limits. The licensee can authorize additional

dose in any one year that is equal to the annual occu- pational dose limit as long as the individual's total dose from PSEs does not exceed five times the annual dose limit during the individual's lifetime. For example, licensees may authorize PSEs for an adult radiation

worker to receive doses up to an additional 5 rems (0.05 Sv) in a year above the 5-rem (0.05-Sv) annual

TEDE occupational dose limit. Each worker is limited

to no more than 25 rems (0.25 Sv) from planned spe- cial exposures in his or her lifetime. Such exposures

are only allowed in exceptional situations when alter- natives for avoiding the additional exposure are not available or are impractical.

Before the licensee authorizes a PSE, the licensee

must ensure that the worker is informed of the purpose and circumstances of the planned operation, the esti- mated doses expected, and the procedures to keep the doses ALARA while considering other risks that may

8.29-12
be present. (See Regulatory Guide 8.35, "Planned

Special Exposures.")

20. Why do some facilities establish administrative control levels that are below the NRC

limits?

There are two reasons. First, the NRC regulations

state that licensees must take steps to keep exposures

to radiation ALARA. Specific approval from the licensee for workers to receive doses in excess of administrative limits usually results in more critical risk-benefit analyses as each additional increment of dose is

approved for a worker. Secondly, an administrative

control level that is set lower than the NRC limit provides a safety margin designed to help the licensee

avoid doses to workers in excess of the limit.

21. Why aren't medical exposures considered as

part of a worker's allowed dose?

NRC rules exempt medical exposure, but equal

doses of medical and occupational radiation have

equal risks. Medical exposure to radiation is justified

for reasons that are quite different from the reasons for

occupational exposure. A physician prescribing an xray, for example, makes a medical judgment that the

benefit to the patient from the resulting medical information justifies the risk associated with the radiation.

This judgment may or may not be accepted by the patient. Similarly, each worker must decide on the benefits and acceptability of occupational radiation risk,

just as each worker must decide on the acceptability of

any other occupational hazard.

Consider a worker who receives a dose of 3 rems

(0.03 Sv) from a series of x-rays in connection with an

injury or illness. This dose and any associated risk must

be justified on medical grounds. If the worker had also

received 2 rems (0.02 Sv) on the job, the combined

dose of 5 rems (0.05 Sv) would in no way incapacitate

the worker. Restricting the worker from additional job

exposure during the remainder of the year would not

have any effect on the risk from the 3 rems (0.03 Sv)

already received from the medical exposure. If the individual worker accepts the risks associated with the

x-rays on the basis of the medical benefits and accepts

the risks associated with job-related exposure on the

basis of employment benefits, it would be unreasonable to restrict the worker from employment involving

exposure to radiation for the remainder of the year.

22. How should radiation risks be considered in

an emergency?

Emergencies are "unplanned" events in which actions to save lives or property may warrant additional

doses for which no particular limit applies. The revised

10 CFR Part 20 does not set any dose limits for emergency or lifesaving activities and states that nothing in

Part 20 "shall be construed as limiting actions that may

be necessary to protect health and safety."

Rare situations may occur in which a dose in excess of occupational limits would be unavoidable in order to carry out a lifesaving operation or to avoid a

large dose to large populations. However, persons

called upon to undertake any emergency operation

should do so only on a voluntary basis and with full

awareness of the risks involved.

For perspective, the Environmental Protection

Agency (EPA) has published emergency dose guidelines (Ref. 2). These guidelines state that doses to all

workers during emergencies should, to the extent practicable, be limited to 5 rems (0.05 Sv). The EPA further states that there are some emergency situations for

which higher limits may be justified. The dose resulting

from such emergency exposures should be limited to

10 rems (0.1 Sv) for protecting valuable property, and

to 25 rems (0.25 Sv) for lifesaving activities and the

protection of large populations. In the context of this

guidance, the dose to workers that is incurred for the

protection of large populations might be considered

justified for situations in which the collective dose to

others that is avoided as a result of the emergency operation is significantly larger than that incurred by the

workers involved.

Table 5 presents the estimates of the fatal cancer

risk for a group of 1,000 workers of various ages, assuming that each worker received an acute dose of 25

rems (0.25 Sv) in the course of assisting in an emergency. The estimates show that a 25-rem emergency

dose might increase an individual's chances of developing fatal cancer from about 20% to about 21%.

Table 5

Risk of Premature Death from Exposure

to 25-Rems (0.25-Sv) Acute Dose

Estimated Risk

Age at of Premature Death

Exposure (Deaths per 1,000

(years) Persons Exposed)

20-30 9.1

30-40 7.2

40-50 5.3

50-60 3.5

Source: EPA-400-R-92-001 (Ref. 2).

23. How were radiation dose limits established?

The NRC radiation dose limits in 10 CFR Part 20

were established by the NRC based on the recommendations of the ICRP and NCRP as endorsed in Federal

radiation protection guidance developed by the EPA

8.29-13
(Ref. 12). The limits were recommended by the ICRP and NCRP with the objective of ensuring that working in a radiation-related industry was as safe as working in other comparable industries. The dose limits and the principle of ALARA should ensure that risks to workers are maintained indistinguishable from risks from background radiation.

24. Several scientific reports have recommended

that the NRC establish lower dose limits. Does the NRC plan to reduce the regulatory limits?

Since publication of the NRC's proposed rule in 1986, the ICRP in 1990 revised its recommendations

for radiation protection based on newer studies of radi- ation risks (Ref. 13), and the NCRP followed with a revision to its recommendations in 1993. The ICRP recommended a limit of 10 rems (0.1 Sv) effective dose equivalent (from internal and external sources),

over a 5-year period with no more than 5 rems (0.05 Sv) in 1 year (Ref. 13). The NCRP recommended a cumulative limit in rerns, not to exceed the individual's

age in years, with no more than 5 rems (0.05 Sv) in any year (Ref. 14).

The NRC does not believe that additional reduc- tions in the dose limits are required at this time. Because of the practice of maintaining radiation expo- sures ALARA (as low as is reasonably achievable), the

average radiation dose to occupationally exposed per- sons is well below the limits in the current Part 20 that became mandatory January 1, 1994, and the average doses to radiation workers are below the new limits

recommended by the ICRP and the NCRP.

25. What are the options if a worker decides that the risks associated with occupational radi- ation exposure are too high?

If the risks from exposure to occupational radi- ation are unacceptable to a worker, he or she can request a transfer to a job that does not involve exposure to radiation. However, the risks associated with the exposure to radiation that workers, on the average, ac- tually receive are comparable to risks in other industries and are considered acceptable by the scientific

groups that have studied them. An employer is not ob- ligated to guarantee a transfer if a worker decides not

to accept an assignment that requires exposure to radi- ation.

Any worker has the option of seeking other em- ployment in a nonradiation occupation. However, the studies that have compared occupational risks in the nuclear industry to those in other job areas indicate that nuclear work is relatively safe. Thus, a worker may find different kinds of risk but will not necessarily find significantly lower risks in another job.

26. Where can one get additional information on radiation risk?

The following list suggests sources of useful infor- mation on radiation risk:

* The employer-the radiation protection or health

physics office where a worker is employed.

* Nuclear Regulatory Commission Regional Offices:

King of Prussia, Pennsylvania (610) 337-5000 Atlanta, Georgia (404) 331-4503 Lisle, Illinois (708) 829-9500 Arlington, Texas (817) 860-8100

* U.S. Nuclear Regulatory Commission

Headquarters

Radiation Protection & Health Effects Branch

Office of Nuclear Regulatory Research

Washington, DC 20555

Telephone: (301) 415-6187

* Department of Health and Human Services

Center for Devices and Radiological Health

1390 Piccard Drive, MS HFZ-1

Rockville, MD 20850

Telephone: (301) 443-4690

* U.S. Environmental Protection Agency Office of Radiation and Indoor Air

Criteria and Standards Division

401 M Street NW.

Washington, DC 20460

Telephone: (202) 233-9290

8.29-14
REFERENCES

1. B.R. Scott et al., "Health Effects Model for Nuclear Power Plant Accident Consequence Analysis," Part I: Introduction, Integration, and Summary, U.S. Nuclear Regulatory Commission,

NUREG/CR-4214, Revision 2, Part I, October

1993.*

2. U.S. Environmental Protection Agency, Manual

of Protective Action Guides and Protective Actions for Nuclear Incidents, EPA-400-R-92-

001, May 1992.

3. International Commission on Radiological Protection, Annals of the ICRP, Risks Associated

with Ionising Radiation, Volume 22, No.1, Pergamon Press, Oxford, UK, 1991.

4. National Research Council, Health Effects of Exposure to Low Levels of Ionizing Radiation, Report of the Committee on the Biological Effects of

Ionizing Radiation (BEIR V), National Academy

Press, Washington, DC, 1990.

5. United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR); Sources,

Effects and Risks of Ionizing Radiation, Report

E.88.IX.7, United Nations, New York, 1988.

6. United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), Sources

and Effects of Ionizing Radiation, United Nations, New York, 1993.

7. National Council on Radiation Protection and

Measurements, New Dosimetry at Hiroshima

and Nagasaki and Its Implications for Risk Estimates, Proceedings of the Twenty-third Annual

Meeting of the National Council on Radiation

Protection and Measurements Held on April 8-

9, 1987 (1988).

8. National Council on Radiation Protection .and

Measurements, Comparative Carcinogenicity of

Ionizing Radiation and Chemicals, NCRP Report

No. 96, March 1989.

9. C.T. Raddatz and D. Hagemeyer, "Occupational

Radiation Exposure at Commercial Nuclear Power Reactors and Other Facilities, 1993," U.S.

Nuclear Regulatory Commission, NUREG-0713,

Volume 15, January 1995.'

10. B.L. Cohen and I.S. Lee, "Catalog of Risks Extended and Updated," Health Physics, Vol. 61,

September 1991.

11. National Council on Radiation Protection and

Measurements, Ionizing Radiation Exposure of

the Population of the United States, NCRP Report No. 93, September 1987.

12. U.S. Environmental Protection Agency, "Radiation Protection Guidance to Federal Agencies

for Occupational Exposure," Federal Register,

Vol. 52, No. 17, January 27, 1987.

13. International Commission on Radiological Protection, 1990 Recommendations of the International Commission on Radiological Protection,

ICRP Publication 60, Pergamon Press, Oxford,

UK, 1991.

14. National Council on Radiation Protection and

Measurements, Limitation of Exposure to Ionizing Radiation, NCRP Report No. 116, March

1993.

Copies are available for inspection or copying for a fee from the NRC Public Document Room at 2120 L Street NW., Washington,

DC; the PDR's mailing address is Mail Stop LL-6, Washington, DC 20555; telephone (202) 634-3273; fax (202) 634-3343. Copies

may be purchased at current rates from the U. S. Government Printing Office, P. O. Box 37082, Washington, DC 20402-9328 (telephone (202) 512-2249); or from the National Technical Information Service by writing NTIS at 5285 Port Royal Road, Springfield,

VA 22161.

8.29-15
BIBLIOGRAPHY

Abrahamson, S., et al., "Health Effects Models for Nuclear Power Plant Accident Consequence Analy- sis, " Part II: Scientific Bases for Health Effects Mod- els, U.S. Nuclear Regulatory Commission, NUREG/

CR-4214, Rev. 1, Part II, May 1989.1

Abrahamson, S., et al., "Health Effects Models for Nuclear Power Plant Accident Consequence Analysis, Modifications of Models Resulting From Recent Reports on Health Effects of Ionizing Radiation, Low LET Radiation," Part II: Scientific Basis for Health

Effects Models, U.S. Nuclear Regulatory Commission, NUREG/CR-4214, Rev. 1, Part II, Addendum 1, August 1991.'

Abrahamson, S., et al., "Health Effects Models for Nuclear Power Plant Accident Consequence Analysis, Modifications of Models Resulting From Addition of Effects of Exposure to Alpha-Emitting Radionuclides," Part II: Scientific Bases for Health Effects Models, U.S. Nuclear Regulatory Commission, NUREG/CR-4214, Rev. 1, Part II, Addendum 2, May 1993.1

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National Council on Radiation Protection and Measurements, Exposure of the Population in the United

'Copies are available for inspection or copying for a fee from the 

Washington, 

NRC Public Document Room at 2120 L Street NW., DC; the PDR's mailing address is Mail Stop LL-6, Washington, DC 20555-0001; telephone (202) 634-3273; fax (202) 634-3343. Copies may be purchased at current rates from the U.S. Government Printing Office, P.O. * Box 37082, Washington, DC 20402-9328 (telephone (202) 512-2249); or from the National Technical Information Ser- vice by writing NTIS at 5285 Port Royal Road, Springfield, VA 22161.

States and Canada from Natural Background Radi- ation, NCRP Report No. 94, De6ember 1987.

National Council on Radiation Protection and Measurements, Exposure of the U.S. Population From Oc- cupational Radiation, NCRP Report No. 101, June

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U.S. Environmental Protection Agency, "Radiation Protection Guidance to Federal Agencies for Occupa- tional Exposure," Federal Register, Vol. 52, No. 17, January 27, 1987.

U.S. Nuclear Regulatory Commission, "Instruction Concerning Prenatal Radiation Exposure," Regulatory Guide 8.13, Revision 2, December 1987.2

U.S. Nuclear Regulatory Commission, "Monitoring Criteria and Methods To Calculate Occupational Radi- ation Doses," Regulatory Guide 8.34, July 1992.2

U.S. Nuclear Regulatory Commission, "Planned Spe- cial Exposures," Regulatory Guide 8.35, June 1992.2

U.S. Nuclear Regulatory Commission, "Radiation

Dose to the Embryo/Fetus," Regulatory Guide 8.36, July 1992.2

2

Single copies of regulatory guides may be obtained free of charge by writing the Office of Administration, Attn: Distri- bution and Services Section, USNRC, Washington, DC 20555, or by fax at (301) 415-2260. Copies are available for inspection or copying for a fee from the NRC Public Document Room at 2120 L Street NW., Washington, DC; the PDR's mailing 

20555-0001; 

address is Mail Stop LL-6, Washington, DC telephone (202) 634-3273; fax (202) 634-3343.

8.29-16
REGULATORY ANALYSIS

A separate regulatory analysis was not prepared

for this Revision 1 to Regulatory Guide 8.29. A value/

impact statement, which evaluated essentially the same

subjects as are discussed in a regulatory analysis, accompanied Regulatory Guide 8.29 when it was issued

in July 1981.

This Revision 1 to Regulatory Guide 8.29 is needed to conform with the Revised 10 CFR Part 20, "Standards for Protection Against Radiation," as published

May 21, 1991 (56 FR 23360). The regulatory analysis

prepared for 10 CFR Part 20 provides the regulatory

basis for this Revision 1 of Regulatory Guide 8.29, and

it examines the costs and benefits of the rule as implemented by the guide. A copy of the 'Regulatory

Analysis for the Revision of 10 CFR Part 20"

(PNL-6712, November 1988), is available for inspection and copying for a fee in the NRC's Public Document Room at 2120 L Street NW., Washington, DC

20555-0001.

8.29-17
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