ML19254E721
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| Site: | Crane  |
| Issue date: | 10/31/1979 |
| From: | Fabrikant J PRESIDENT'S COMMISSION ON THE ACCIDENT AT THREE MILE |
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I cUMMARY OF THE PUBLIC HEALTH AND SAFETY TASK FORCE REPORT TO PRESIDENT'S COMMISSION ON THE ACCIDENT AT THPIE MILE ISLAND ADVANCE COPY NOT FOR PUBLIC RELEASE BEFORE AMs, WEDNESDAY, OCTOBER 31, 1979 1232 295 191Iopo M Y
e e
SUMMARY
OF THE PUBLIC HEALTH AND SAFETY TASK FORCE REPORT BY JACOB I.
FABRIKANT HEAD PUBLIC HEALTH AND SAFETY TASK FORCE OCTOBER 1979 WASHINGTON, D.C.
1232 296
TABLE OF CONTENTS Pace INTRODUCTION................................................
1 1.
SUMMARY
OF THE HEALTH PHYSICS AND DOSIMETRY TASK FORCE REPORT..................................................
2 1.1 Introduction.......................................
2 1.2 Radiation Dose to the General Population...........
3 1.2.1 Normal Radiation Exposure..........................
3 1.2.2 Radiation Exposure During the TMI Accident.........
5 1.3 Radiation Doses to the Workers at Three Mile Island.............................................
7 2.
SUMMARY
OF THE RADIATION HEALTH EFFECTS TASR FORCE REPORTS...
8 2.1 Introdaction.......................................
8 2.2 Radiation-Induced Cancer...........................
11 2.3 Concept of Estimation of Radiation-Induced Cancer.............................................
12 2.4 Genetically Related Ill-Health.....................
13 2.5 Developmental Abnormalities........................
14 3.
SUMMAAY OF THE BEHAVIORIAL EFFECTS TASK FORCE REPORT....
15 3.1 Introduction.......................................
15 3.2 Objectives...............s.........................
15 3.3 The Main Measures of Mental Health, Attitudes, and Behavior.......................................
17 3.4 Behaviorial Responses to the Accident at Three Mile Island.........................................
17 4.
SUMMARY
OF THE PUBLIC HEALTH AND EPIDEMIOLCGY TASK FORCE REPORT...........................................
19 4.1 Introduction........................................
19 4.2 General Issues......................................
20 4.2.1 Radiation Protection Standards...............
':0 4.2.2 Worker Protection from Radiation Exposure.... 21 4.2.3 Siting of Nuclear Power Plants...............
23 4.2.4 Radiological Health..........................
24 4.2.5 Response to Radiological Emergencies......... 24 4.2.6 The Use of Thyroid Blocking Agents for Protection of the Public.....................
25 4.3 Specific Issues - Three Mile Island Nuclear Station. 27 4.3.1 Metropolitan Edison..........................
27 4.4 Response to the Accident at Three Mile Island.......
28 4.4.1 Utility Response to the Accident.............
28 4.4.2 State Response to the Accident...............
29 4.4.3 Federal Response to the Accident.............
30
- 1212 297
1 INTRODUCTION In the Charter of the President's Commission on the Accident at Three Mile Island (TMI), the Commission was given the responsibility to evaluate "the actual and potential impact of the events (of the accident) on the public health and safety and on the health and safety of the workers."
Accordingly, the Public Health and Safety Task Force of the Commission set out the following objec-tives:
To identify and evaluate tne real and potential effects on the health and safety of the publ 3,
both the general population and the workers, resulting from the events of the nuclear reactor accident at TMI.
To assess the health hazards associated with the radiation exposure --
carcinogenic, teratogenic, and genetic -- based on an analysis of the radiation dosimetry and the task force's best scientific knowledge of the biological effects of radiation on exposed populations.
To assess the mental health and behavioral responses of the general population under stress during and following the accident, and of the nuclear plant workers during and following the accident.
To assess the impact of the accident on the eff ectiveness of the health care delivery system and its capacity to respond under nuclear accident emergency conditions.
To examine the, availability of information needed to make decisions on protection of the public health and safety.
To determine what measures can be taken to prevent physical illness resulting from low level radiation and emotional illness in the event of a nuclear reactor accident.
To identify areas requiring research and improvement to protect the health and safety of the public exposed as a result of the nuclear reactor accident.
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Four task group's were formed to carry out the investigations, namely, Health Physics and Dosimetry, Radiation Health Effects, Behavioral Effects, and Public Health and Epidemiology.
Each group consisted of a team of staff scientists expert in their respective fields, including physics, biophysics, medicine, epidemiology, preventive medicine and publi'c health, health administra-tion, radiology, psychiatry, pediatrics, social medicine, psychology, genetics, biochemistry, radiobiology, sociology, biostatistics, healch sciences, and computer sciences.
In all, over 75 scientists, consultants, and advisors (with assistance of colleagues from the legal staf f) contributed to the final Public Health and Safety Task Force Report to the Commission.
The following summary of the task force report defines the key issues and identifies the major findings of the accident concerned with four major health areas of the 1232 298
2 the radiation exposures to the general population and the workers; (2) the real and potential radiation risks to health of the general public and the workers, such as radiation-induced cancer, developmental abnormalities, and genetically-related ill-health; (3) the behavioral responses of the public and the workers to the stress of the nuclear emergency; and (4) the broad and substantive health issues
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that bear directly on public health and safety and health and safety of the workers during the normal operation of a nuclear power plant and during a nuclear accident, and specifically at TMI.
The body of the task force report consists of four inter-related reports, namely, those of the Health Physics and Dosimetry Task Force, the Radiation Health Effects Task Force, the Behavioral Effects Task Force, and.the Public Health and Epidemiology Task Force.
- 1.
SUMMARY
OF THE HEALTH PHYSICS AND DOSIMETRY TASK GROUP REPORT 1.1.
INTRODUCTION The general objectives of the Health Physics and Dosimetry Task Group included:
(1) to determine the radiation dose to the people living within the area of 50 miles around the Three Mile Island Nuclear Station during the period of March 28 to April 15, 1979; (2) to determine the radiation dose to the workers at the nuclear power plant during the period of March 28 to June 30, 1979, that is, the cut-off date necessitated by the deadline of the Commission's report; and (3) to evaluate federal, state, and utility company programs concerned with the protection of human populations and their environment from the possible hazards of ionizing radiation, and the efficacy of these radiation protection programs during the nuclear accident at TMI.
The task force identified the important events requiring analysis for the measurement of the radioactivity released into the environment, for the assessment of the rad.i i'_ ion doses to the public and to the workers, and the resconse 6f federal, state, and the ut.lity company programs for radiation protection.
Among these are the identifi-cation of initial damage to the nuclear fuel; the release of radioactivity into the atmosphere; the declaration of the site emergency and notification of the Pennsylvania State Bureau of Radiological Health; the notification of the national radiological assistance program to draw on exten-sive resources to provide assistance during the emergency; the radiological indicatior of the uncontrolled escape of large amounts of radioactivity into the containment building; 1232 299
3 the declaration of the general emergency because of high radiation levels; the earliest releases of radioactivity into the environment resulting in raised levels of radiation in the areas where the general public lived; and the identi-fication of the radioactive noble gases and iodine in the radiation releases.
1.2. RADIATION DOSE TO THE GENERAL POPULATION 1.2.1 Normal Radiation Exposure Radioactivity occurs naturally in the environment, and is constantly being created in nature.
Humans receive radiation exposure from this natural radioactivity, from cosmic rays from outer space, from the earth 's crust, and also from those various human activities involving radiation and unrelated to nuclear power.
Natural radioactivity occurs everywhere -- in air, in water, in soil, in foods, and in our own bodies -- and is called background radiation.
The radioactive elements (or radioisotopes) f ound in these various places in our external and internal environment are extremely varied in the energies of their dif ferent radia-tions, and in the time of their decay, that is, to undergo spontaneous disintegration with the emission of radioactive particles or rays.
The radiation dose absorbed in the cells and tissues of the body, whether from natural or man-made radiation, is frequently measured in rem; the rem is one form of physical radiation unit which takes into account the amount of radiant energy deposited in the body tissues, and the type of radiation -- alpha, beta, or gamma radiation, or neutrons.
When the dose is measured over a time period, say rem per hour, this is called dose-rate.
When the radiation dose level is low, as in the case of natural background, the radiation dose unit frequently used is the millirem (mrem),
or one thousandth of a rem.
Some f amiliarity with these quantitie. and radiation units is necessary for understanding the significance of normal or accidental radioactive releases to the environment from nuclear power plants.
Man is constantly exposed to naturally-occurring radiation; each year, the average American is exposed to about 100-200 millirers of natural background radiation depending on where that person lives.
The variation depends primarily on altitude and on the long-lived radionuclides in the earth's crust.
In Harrisburg, Pa.,
the average annual whole body dose to the individual due to natural background radiation is estimated to be 116 millirems.
In general, in Harrisburg, about 45 milli-rems per year of this whola body dose comes from cosmic radiation and 45 millirems per year from terrestial radiation.
By comparison, each of these annual dose-rate n 9O f
f
.UVi
d 4
values is about doubled in Denver, Colo., to about 75 millirems per year from cosmic radiation and 90 millirems per year terrestial radiation, respectively.
The internal radiation annual dose-rate is relatively constant in all individuals, about 28 millirems per year, from naturally-occurring radioisotopes in the body, primarily potassium-40.
About half of the radiation to which the general population is exposed annually comes from natural sources and the remainder from man-made sources.
The average annual background radiation exposure to an individual is very low; comparison between levels in Harrisburg, Pa. (average),
Denver, Colo. (high), Las Vegas, Nev. (low) and the overall range in the United States, in millirems per year (mrem /yr) are given in the following table:
Harrisburg,
- Denver, Las Vegas,
- Range, Radiation Source Pa.
Colo.
Nev.
U.S.
Cosmic Radiation 42.0 74.9 49.6 40-160 Terrestial Radiation 45.6 89.7 19.9 0-120 Internal Radiation 28.0 28.0 28.0 28 Total (mrem /yr) 116 193 98 70-310 mrem /yr mrem /yr mrem /yr mrem /yr The remainder of man's radiation exposure, due to man-made radiation, is primarily (an additional 40 percent) due to medical and dental x-rays.
Nuclear weapons testing and fall-out, technologically-enhanced natural radiation (e.g.,
uranium tailings), consumer products (e.g., microwave ovens, television sets) and nuclear energy plants provide only a very small fraction (about 0.15 percent) of the total amount. The 1978 estimates of the annual collective dose
( that is, the average yearl1 dose senmed up for the entire population) of radiation exposures to the U.S. population, somewhat more than 200,000,000 Americans, based on data summarized by the Interagency Task Force on Ionizing Radiation (1979), are listed below:
Annual Collective Dose Radiation Source (Person-rem per Year)
Natural background (e.g.,
cosmic and terrestial radiation) 20 million Medical and dental x-rays (e.g.,
x-ray diagnosis) 17 million Nuclear weapons (e.g., manufacture and testing) about 1.3 million 1232 301
5 Annual Collective Dose Radiation Source (Person-rem per Year)
Technology-enhanced (e.g.,
uranium tailings) 1 million Nuclear energy (e.g., nuclear power plants) 0.06 million Consumer products (e.g., microwave ovens, etc.)
0.006 million Total about 39 million Under normal conditions, the 2,16 3,000 persons living in the 50-mile area surrounding TMI would receive an annual collective dose of about 440,000 person-rem; about 240,000 person-rem would come from natural background radiation.
(In contrast, the collective dose to that population resulting from the radioactive releases during the TMI accident was approximately 0.5 percent of the normal annual exposure rate, or about 1 percent of natural background
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radiation. )
1.2.2. Radiation Exposure During the TMI Accident Nuclear radiation doses are measured with instruments or detectors called thermoluminescent dosimeters (TLD); TLD measurements formed the basis for estimating the total external gamma radiation doses (due almost exclusively to the radioactive noble gas xenon-133 and a few other short-lived radioactive gases in the radioactive cloud) to the population during the TMI accident.
The main TLD dosimetry instruments were located within a 15-mile distance of the plant.
Individual doses within a few miles of the nuclear plant were relatively low; some 260 people living mostly on the east bank of the Susquehanna River possibly each received between 20 to 70 millirems.
One person on a nearby island for 9-1/2 hours during the initial days of the accident received about 50 millirems.
All other persons living outside a 1-mile radius and within 10 miles from the plant could have received an average dose of less than 20 millirems.
Almost all recorded excess exposure above background levels occurred within a 10-mile radius.
There was no recordable radiation at levels above natural cackground at a distance greater than 10 miles from the nuclear plant at any time during the accident.
1ia2 302
6 The total release of radioactivity into the atmosphere from the damaged nuclear power plant during the period of March 28 to April 15, 1979, was calculated to be about 2.4 million curies,l/ primarily consisting of radioactive noble gases.2/
Approximately 10-15 curies of radioactive iodine were released into the environment.
This total release of radioactivity, known as the source term, was one way to determine the radiation doses to the entire population (collective ' dose) and to the individual in the population (average dose), taking into account meteorological conditions and population distribution demographic data at the time of the accident.
Another way to determine the collective dose was by use of the TLD radiation dose measurements.
The collective dose to the population is a measure of the potential health impact resulting from the total radiation dose received by the entire population; for the Three Mile Island site, a 50-mile radius and approximately 2,163,000 person's were included in the calculation.
Since this value is obtained by summing the estimated radiation doses, measured in rem, received by each person in the affected area, the collective dose unit is the person-rem.
The collective dose to all persons within a 50-mile radius of TMI and outdoors based on the TLD radiation dosimetry was estimated to be about 2,800 person-rem.
Since most people spent most of their time indoors and partially shielded by buildings, and assuming that the radiation dose indoors was about three-quarters of that outdoors, a more accurate collective dose to this exposed population is estimated to be about 2,000 person-rem.3/
Tne average dose to any individual in One population living within 50 miles of the nuclear reactor, therefore, is estimated to be about 1 mill. rem.
The average do.se to an individual living within 10 miles of the plant is estimated to be about 6.5 millirems.
There are a number of ways to evaluate the magnitude of the radiation releases and the exposures to the general population.
If the maximum dose to any member of the public exposed within just a few miles of the reactor site was no more than 70 millirems, this may be considered to be equiv-alent to about one-half of the normal exposure the average American receives from natural background radiation each year; probably no more than 250 persons out of the entire population could have received this dose, and most of them received less.
Another way of considering it is that this dose is equivalent to the difference between annual back-ground radiation exposure in Harrisburg and Denver, Colo. An average dose of 6.5 millirems is about 5 percent of the exposure from natural background radiation annually in Harrisburg, and equivalent to the difference of living 2 weeks in Denver.
1 <2 3 ^c.7 r0 3
7 The radioactivity released during the accident entered the air, water, soil and food, and could ultimately have bet sme incorporated into the human body by breathing, swallowing, and absorbing it through the skin.
This cocid result in an internal radiation dose to the tissues of the body.
During the TMI accident, the identity and concen-trations of radionuclides present in the environment were deternined by the utility company and by the various federal agencies.
Sampling analyses included milk, air, water, fruit and vegetable produce, soil, vegetation, fish, river sediment, and silt.
Any increace in internal radiation dose due to radioactivity released during the accident came primarily from radioactive xenon-133, iodine-131, and cesium-137.
Extremely small increases in the radionuclide concentrations of iodine-131 were reported in cows ' and goats' milk, and in water and air; of cesium-137 in fish, and of xenon-133 and krypton-85 in air.
The highest doses due to ingestion and inhalation of iodine-131 would occur in the thyroid gland, since iodine concentrates in that gland.
However, whole body scanning of a large number of the general public living near TMI during the accident detected no radioactive iodine in this population; no radioisotopes related to the TMI accident were found.
The internal radiation dose due to ingestion of cesium-137 was negligible.
The internal dose from inhalation of xenon-133 and krypton-85, primarily due to radiation expo-sure to the lung tissue, was only a small fraction of that of the external dose.
Overall, the internal doses due to the radioisotopes released at TMI were negligible, and would have been only a minute fraction of the average annual dose received due to naturally-occurring internally-deposited radioisotopes in the body.
1.3.
RADIATION DOSES TO THE WORKERS AT THREE MILE ISLAND The radiation exposure to the nuclear plant workers during the accident at TMI came primarily from external radiation and some from internal radioactivity.
Thermo-luminescent dosimeters in badges were used to measure the external gamma and beta radiation doses.
Before the accident, the collective dose to about 1,000 workers at TMI under normal operating conditions varied from about 20-150 person-rem each month.
About 5,000 workers were on-site at seme time during the March 23-June 30, 1979, interval; the majority received no recordable radiation exposure.
Most of these additional workers were brought to the Three Mile Island plant during the accident and did not receive measurable exposures.
About 1,000 workers received 1232 304
8 measurable doses of radiation, that is, greater than 50 millirems, during tne accident.
The collective dose for these 1,000 workers from the time of the accident on March 28, 1979, through to June 30, J979, was about 1,000 person-rem.
The average whole body dose to these 1,000 workers was about 1 rem during this 3-month period.
Two hundred and seventy-nine workers received more than 0.5 rem, but less than 3 rem of whole-body gamma radiation exposure, three workers received about 4 rem (on March 28 cr 29), and none received more than 5 rem, the annual limit permitted.
In addition to the three workers who received whole body overexposures during the accident -- greater than 3 rem whole body dose per quarter -- two workers received over-exposures to their hands of about 50 and 150 rems, respectively.
The worker who received 150 rem to his fingers also received a whole body dose of about 4 rems.
No overexposures were recorded due to beta radiation.
Whole body counting of plant personnel was inaccurate, and the procedures and the collec~tive records provided little reliable information on internal body doses of the workers.
A few showed measureable levels of radioactive iodine-131 and cesium-137; it is probable that the radiation recorded by whole body counting other than natural background was due to external contamination.
In spite of the high gamma radiation exposure rates of up to 1,000 R/hr measured in the axuilia*y building on March 28, the radiation doses to the workers were quite low.
However the collective dose to the workers of about 1,000 person-rem will increase as the decontamination and recovery at the TMI plant proceeds. It is difficult to predict the eventual total collective dose since that will depend on methods of decontamination and recovery of the containment building and the reactor vessel.
- 2.
SUMMARY
OF THE RADIATION HEALTH EFFECTS TASK GROUP REPORT 2.1.
INTRODUCTION The highly publicized events during the early days of the accident included:
(1) the various releases of radio-active materials into the atmosphere and into the Susquehanna River; (2) the accumulation of hydrogen generated in the reactor-pressure vessel; and (3) the risk of major releases of large amounts of radioactive debris from the damaged nuclear core.
These threatened the health and safety of the public and the workers and led to concern about possib.le acute and delayed health ef fects of exposure to ionizir T radiation.
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123h!305
9 Some release of low levels of radioactivity normally occurs into the environment during the routine operation of a nuclear reactor pover plant.
The accident at TMI set off a series of events that raised the threat of risks of much higher levels of radiation exposure of the public to uncontrolled releases of radioactivity.
Low-level ionizing radiations (e.g.,
radiation doses of a few rem or less) are thought to be able to contribute to three kinds of health effects.
First, some of the cells injured by radiation may occasionally transform into potential cancer cells, and after a period of time there may be an increased rc.sk of cancer developing in the exposed individual.
This health effect is called carcinogenesis.
Second, if the embryo or fetus is exposed during pregnancy, sufficient radiation damage of developing cells and tissues may lead to develop-mental abnormalities in the newborn.
This health effect is called teratogenesis.
Third, if radiation injures repro-ductive cells of the testis or ovary, the hereditary structure of the cells can be altered, and some of the injury can be expressed in the descendants of the exposed individual.
This health effect is called mutagenesis or genetic effect.
There are other health effects of ionizing radiations, but these three important health ef fects carcinogenic, teratogenic and genetic - stand out because it is possible that low levels of radiation may increase the risk of these effects.
Much scientific information on these effects has been gained from experimental animal experiments, and for carcinogenesis, from epidemiological studies of exposed human populations.
Scientists generally believe or assume that any exposure to radiation carries some risk of carcino-genesis, or, if reproductive cells are irradiated, some risk of genetic effect, and..at as the dose of radiation increases above low levels, the risk of these health effects increases in exposed human populations.
These latter observations have led to public confusion and fear about the possible health effects of low-level ionizing radiation from the radioactive releases during the nuclear accident at Three Mile Island.
Radiation scientists are generally in close agreement on the following broad and substantive issues of such health effects:
1.
Cancer arising in the various organs and tissues of the body is the principal late effect in ir.dividuals exposed to low ot intermediate levels of radiation.
The different organs and tissues vary in relative susceptibility to radiation-induced cancer; the female breast, the thyroid gland, especially in young children and females, and the blood-forming organs (in regard to leukemia), seem to be more susceptible than some other organs.
k232306
10 2.
The deleterious effects on growth and development of the embryo and fetus are related to the stage at which the radiation exposure occurs.
A threshold level of radia-tion dose may exist below which gross clinically evident developmental abnormalities will not be observed.
- However, these levels would vary greatly depending on the particular developmental abnormality.
3.
The paucity of data from exposed human populations has made it necessary to estimate the risks of genetically related ill health based mainly on laboratory mouse experi-ments.
Knowledge of fundamental mechanisms of radiation injury at the genetic level permits greater assurance for relating scientific information from laboratory experiments to man.
However, there is still very much scientists do not know about the potential health hazards of low-level radiation:
1.
We do not know what the radiation health ef fects are, if any, at dose rates as low as a few hundred millirem per year, that is, higher than natural background radiation.
It is probable that if health effects do occur, they will be impossible to detect from similar effects owing to non-radiation related environmental or other factors.
2.
The epidemiological data on exposed human populations are uncertain regarding the dose-response relationships for various radiation-induced cancers.
Since this is especially the case for low radiation levels, where no unequivocal data exist, it has been necessary to estimate human cancer risk at low radiation levels primarily from observations at relatively high radiation levels on the basis of various assumptions.
However, it is not known whether the carcinogenic effectiveness observed at high radiation dose levels applies also at low levels.
3.
There are no reliable methods of estimating the repair of injured cells and tissues of the body exposed to low radiation doses, nor is it possible to identify persons who may be particularly susceptible to radiation injury, (as for example, a genetically determined increase or decrease susceptibility to radiation injury).
4.
All epidemiological surveys of irradiated human populations exposed in the past are incomplete with respect to ascertainment of cancer incidence in terms of providing a basis for analysis and conclusions since there is limited information on the radiation doses in some of these studies, limited and incomplete data on cancer incidence,and/or variable follow-up data.
123k307
11 5.
We do not know~the role of competing. environmental and other host factors -- biological, chemical or physical factors -- existing at the time of exposure, or following exposure, which may affect and influence the carcinogenic, teratogenic, or genetic health effects of low-level radiation.
2.2.
RADIATION-INDUCED CANCER There are valid practical reasons for assuming proportionality in dose-effect relationships for the estimation of radiation-induced cancer risk in the general population exposed in the vicinity of TMI.
It should be recognized, however, that the assumption that the risk for low-level gamma radiation, the predominant radiation exposure at TMI, is proportional to observed risk at high levels, may overestimate the cancer risk; the actual risk would be much less.5/
It is estimated that the number of excess fatal cancers, if any, that might occur over the remaining lifetime of.the 2 million persons living within 50 miles of the nuclear power plant and exposed to an average whole body dose of about 1 millirem is much less than 1; a similar number is estimated for excess non-fatal cancers.
These numbers are estimated to be only a very small fraction of the potential lifetime risk of radiation-induced cancer which may arise in this population from natural background radiation exposure.
The estimated number of cancer cases from all causes normally occurring in this population of about 2 million people over its remaining lifetime is 541,000 (325,000 fatal cancers and 216,000 non-fatal cancers).
The estimated excess number of fatal and non-fatal cancers associated with the increase in radiation exposure due to the accident is extremely low, and could be zero, and it would not be possible to detect or to distinguish this excess either in the population or in the individual.
The number of excess ancers,.if any, would be so small that it would not be possible to detect such z.n increase statistically in ever half a million cancers that would occur in the population even if the TMI accident had not happened.
Furthermore, cancers caused by radiation are no different from any other cancers resulting from other causes; therefore, a particular cancer cannot be distinguished as having been caused by radiation.
The lifetime cancer risk in individuals exposed to maximum doses of approximately 70 mrem is about 1 or less chure in 100,000 for fatal and a like risk for ncn-fatal cancer, i.e.,
a total cancer risk of about 2 in 100,000 with zero not excluded.
The additional raciation-induced risk of skin, lung, or thyroid gland cancer due to beta radiation and internally-deposited 12h2308
12 radioisotopes are estimated to be extremely small, and may be regarded as encompassed within the cancer risk values expressed above for whole body radiation exposure.
We conclude, therefore, since the total amount of radioactivity released during the accident at TMI was so small, and the total population exposed so limited, that there may be no additional detectable cancers resulting from the radiation.
In other words, if there are any additional cancer cases, however, the number will be so small that it will not he possible to demonstrate this excess or to distinguish these cases among the 541,000 persons (of the 2 million population) living within a 50-mile radius of Three Mile Island, who would for other reasons develop cancer during the course of their lifetimes.
- 2. 3. CONCEPT OF ESTIMATION OF RISK OF RADIATION-INDUCED CANCER In all these calculations of the risk *of radiation-induced cancer, several different methods have been applied for estimating the number of cancer cases that may be caused by the radioactivity released.
While different methods may lead to different estimates, all of them arrive at a very small number, less than one, and possibly zero, in 2 million people.
For example, consider an estimate of "0.7 additional cancer deaths due to the released radioactivity."
What does this mean?
The number 0.7 is an esti'nate of en average, which is a mathematical concept such as the one thet appears in the statement:
"The average Arerican family tas 2.3 -hildren."
In the case of TMI what it really means is that each of some 2 million individuals have a very small additional chance of dying of cancer, and whe-all of these very small prob-abilities are added ur, -L ay add up to the number 0.7.
In such a situation a mdthemdtical law known as a Poisson distribution (named after a French mathematician) applies.
If the estimated average Ls 0.7, then the actual proba-bilities work out as follows: There is a roughly 50 percent chance that there will be no additional cancer deaths, a 35 percent chance that one individual will die of cancer, a 12 percent chance that two people will die of cancer, and it is practically certain that there will not be as many as five cancer deaths.
Similar probabilities can be calculated for the other estimates.
All of them have in common the folicwing fact:
It is entirely possible that not a single extra cancer death will result from the radioactivity released during the accident at Three Mile Island.
And for all the estimates, it is practically certain that the additional number of cancer deaths will be less than 10.
ZRO 3' 'd'
>U/
13 We know from statistics on cancer deaths that in a population of this size eventually some 325,000 people will die of cancer, for reasons having nothing to do with the nuclear power plant accident. Again, this number is only an estimate, and the actual figure could be as much as 1,000 higher or 1,000 lower.
Ther2 fore, there is no conceivable statistical method known by which fewer than 10 additional deaths could ever be detected. A cancer caused by nuclear radiation is no different than a cancer from other causes.
We conclude, there fo re, that there may be no additional 1 deaths due to this radiation, or if there are, they will be so few that it will never be possible to determine that even a single death had occurred as a consecuence of the accident at TMI.
2.4.
GENETICALLY RELATED ILL-HEALTH There is persuasive scientific evidence which suggests that if an average human population were exposed to 1 rem (1,000 millirems) of irradiation during their reproductive life span when they can produced children, we might expect to see about 5 to 75 cases of additional genetically related diseases (such as mental retardation or diabetes) in 1 million children born to the irradiated parents.
Geneti-
. cally related ill-health is extremely common in humans under normal conditions; about 10 percent of all live births are affected.
Therefore. the increase cue to 1,000 millirems of radiation would represent a very small number of cases of genetically related ill-health in addition to the 107,000 cases (an increase of only about 1/1000th of 1 percent) of genetic disorders expected to develop in that newborn population.
Since there are no direct data from human epidemio-logical studies, the basis for this estimate comes mainly from laboratory experiments in which the reproductive cells of the testes and Ovaries of mice are irradiated.
That such experiments in mice have applicability to man is suggested by the following:
(1) The hereditary material of life or genetic material of all organisms is chemically similar.
(2)
The reproductive cells of the testes and ovaries of mice are similar to those in humans and are expected to be pertinent for assessment of genetic ill-health due to irradiation.
(3) Radiation, as well as a great many other toxic agents, can produce similar kinds of changes in the hereditary material in both the mouse and humans, both within the genes and chrctosomes.
These changes or mutations in the genes of the parents can, under cu;tain circumstances, be transmitted to the offspring and thus result in inherited or genetically related diseases, that is, abnormal anatomical, physiological, or cenavloral health conditions. (4) Many of the inherited diseases appear to have analogues in inherited diseases in mice.
1232 3i0
14 Genetic mutations resulting in genetically related ill-health probably do not only come from exposures to radiation or chemicals.
Most of the newly arising genetic mutations in humans result from unknown or as yet uniden-tified events, called spontaneous mutations, within the reproductive cells that can lead to " mistakes" in genes when they are being formed and reproduced for newly formed reproductive cells.
Natural background radiation in our environment appears to account for only a very small fraction of mutations resulting in genetic disease.
We know very little about the precise contribution of chemicals in our envirorment to genetic ill-health. Radiation and other toxic agents will increase the probability of a genetic mutation occurring, but they will not produce any different kinds of genetic diseases than occur from other causes of mutations.
During the accident at Three Mile Island, the collective dose to the reproductive cells of the testes and the ovaries of the 2 million persons living within 50 miles of the plant was about 2,000 person-rems, with an average individual dose of 1 millirem.
In this population, assuming a 30-year generation time, we would expect about 3,000 cases of genetically related ill-health among the approximately 28,000 live children born each year; these are unrelated to the radiation from the nuclear power plant accident.
From an additional dose of 1 millirem above natural background radiation, we would expect about 0.0001 to about 0.002 additional radiation-induced cases of genetically related ill-health.
This 0.002 case is an " average" number and is miniscule, representing lesc than 1 in 19 million live births.
Furthermore, this may result ultimately in a total of no more than about 1 additional case of genetically related ill-health in a million liveborn children during a]l generations in the future.
This number of " additional cases" is so small that it can never be detected or dis-tinguished, if it does occur, among the cases of genetically related ill-health in each generation during all future human existence.
We conclude, therefore, it is probable that there will be no detectable cases of genetically related ill-health resulting from the radiation exposure to the general population followina the accident at Three Mile Island.
2.5. DEVELOPMENTAL ABNORMALITIES Approximately 2,160,000 peopla live within a 50-mile radius of Three Mile Island; it is estimated that in this population based on vital statistics data, about 28,000 children will be born in 1979.
In this newborn population, about 300 children would normally be expected to be born 123'nz
.7 l i
15 with developmental abnormalities in the absence of anv added radiation exposure as a result of the accident at TMI.
The estimated Tverage individual radiation dose' to the f etus of pregnant women exposed during the accident was below (perhaps only 1/2 of 1 millirem) any threshold dose level known to cause detectable cases of developmental abnormality in the human embryo or fetus, or in laboratory animal experimen,ts.
In addition, the estimated dose may be too high, since many pregnant women lef t the area in the vicinity of the nuclear plant.
Act finally, if the maximum dose received by the workers were received by a pregnant woman working at the plant during the accident, the dose level to the fetus would still not exceed a threshold to cause any detectable developmental abnormality.
We can conclude, therefore, that no case of develoomental abnor-mality may oe expected to occur in a newoorn child as a ra iation evjosure of a pregnant woman from the result of r
accident at Three Mile Island.
- 3.
SUMMARY
OF THE BEHAVIORAL EFFECTS TASK GROUP REPORT 3.1. INTRODUCTION The highly publicized events during the first week of the accident -- the release of radioactivity into the a tmosphere, the generation of a large hydrogen bubble in the reactor-pressure vessel, and the possibility of these events presenting a great threat to life -- led to the governor's advisories that all people living or working within a 10-mile radius remain indoors and all pregnant women and preschool-age children living within 5 miles of the plant leave the area immediately.
Nearby schools were closed.
Plans were considered for evacuation of almost a third of a million residents.
Although these plans were never carri2d out in the form of an of ficial order, a large number of f amilies decided to leave the area voluntarily.
3.2. OBJECTIVES The overall ob]ective of the Behavioral Effects Task Group was to examine the effects on the mental health, attitudes, and behavioral responses of the general popu-lation and the nuclear plant workers directly af fected by the accident at Three Mile Island.
Of particular interest were (1) the behavioral response of the general populaticn under stress during the accident, and (2) the behavioral response of the workers under stress during the accident.
For the purposes of this study, the accident at TMI was considered to take place between March 23 and April 10, the date of re-opening of the schools in the TMI area.
During or shortly af ter the ac:ident, several researchers from i232 312
16 colleges and universities near the TMI site began sample surveys of the approximately 750,000 people living within 20 miles of TMI.
Most of these studies employed reliable measures of psychological ef fects with small but carefully drawn samples of the general population and/or high risk groups, such as mothers of preschool children within the general population.
These studies formed the basis for identifying the immediate and short-term behavioral effects of the accident on the general pcpulation and several impor-tant groups within it.
To be of value to the Commission, the studies conducted by local researchers were focused and expanded.
The Behavioral Effects Task Group located studies of high risk groups in the general pcpulation and sought control groups from whom comparable data could be collected.
Each com-parison was selected in such a way as to provide an understanding of the mental health and behavioral effects from the time of the accident in late March and early April to September, when the findings of the Commission were to be analyzed and reported.
The task fo? ce added a study of the nuclear workers, expanded data collection in previously begun studies of the general population and of mothers of preschool children, and added a study of tha behavioral effects on 7th, 9 th, and lith grade students.
" Mental health" is a broad subject, and the data and limited time available for analyses made it possible only to cover narrow aspects of it.
Though narrow, these aspects, centering on measures of psychological distress, upset, and demoralization,6/ are important and appropriate to what is known about the most characteristic responses to stress situations.
Moreover, it has been possible to construct reasonably reliable measures of several other important behavioral effects.
The studies carried out by the Behavioral Effects Task Group are based on detailed surveys of about 2,500 persons from four different population groups:
(1) the general population of male and female heads of households located within 20 miles of TMI; (2) mothers of preschool children from the same area and a similar " control" population from Wilkes-Barre which is about 90 miles away; (3) teenacers in the 7 th, 9th, and lith grades from a school district within the 20 mile radius of TMI; and (4) nuclear workers employed at TMI at the time of the accident and a " control" group of workers from the Peach Bottom nuclear plant about 40 miles away.
In addition, an interview study was conducted of clients at community mental health centers.
These persons, most of whom were suffering from chronic mental disorders, provided valuable information that was used to identify unusually high scores on a mes.sure of demoralization.
k
17 The study of household heads in the general population consisted of three different surveys.
The first was conducted in April 1973, directly following the accident; the second in May; and the third, and largest, in July.
The mothers of preschool children from the TMI area were first studied in a sampling in May and then in an additional sampling in July, at the time that a control sample of Wilkes-Barre mothers with preschool children was added.
The study of the teen-agers was carried out in the ehd of May.
The study of the workers was begun in August and completed in the middle of September.
3.3. THE MAIN MEASURES OF MENTAL HEALTH, ATTITUDES, AND BEHAVIOR A core of similar measures of mental health, attitudes,
and behavior was used in each study, except for the study of teenagers, which was limited to specific measures of dis-tress developed for that study.
The areas covered by measures in the other three studies are: (1) recall of immediate upset at the time of the accident; (2) staying in or leaving the TMI area at the time of the accident; (3) demoralization since the accident; (4) perceived threat to physical health; (5) attitude toward continuing to live in the TMI area; (6) attitude toward nuclear power, including TMI; (7) trust in authorities; and (8) for the workers, their concern about the future of their occupation and their perceptions of hostility from the wider community.
In all the behavioral studies, the major measures of objective threat stemming from the accident were:
(1) living within or living outside the five mile radius of TMI; and (2) having or not having preschool age children in one's family.
For the workers, an added measure of objective threat was whether they worked at TMI, rather than Peach Bottom, at the time of the accident.
For teen-agers, an added measure was whether their families left the area or not following the accident, because this was a factor outside the control of the teenagers themselves.
3.4. BEHAVIORAL RESPONSES TO THE ACCIDENT AT THREE MILE ISLAND 3.4.1.
Demoralization was sharply elevated immediately after the accident, but dissipated rapidly among most groups.
A substantial minority, about 10 percent of the household heads, showed severe demoralization right after the accident that was directly attributable to the accident its e lf.
These 10 percent are an increase of about two-thirds over the 15 percent or so who would ordinarily show such a high level of demoralization for a variety of reasons other than i232 3i4
18 the accident.
The most demoralized persons were household heads and teenagers living within 5 miles of TMI, and mothers and teenage siblings of preschool children.
Teen-agers who left the area temporarily were more distressed than those who did not.
Levels of demoralization among workers at.TMI were high in comparison to Peach Bottom workers, and to males in the general population, several months af ter the accident.
3.4.2.
Although the perceived threat to chvsical health from the TMI accident was higher in the general population immediately af ter the accident than later on, most people were considerably reassured by July.
Workers at both TMI and Peach Bottom also expressed a f airly low level of concern about the threat of their work situation to their physical health.
However, workers at TMI were more uncer-tain about health ef fects than workers at Peach Bottom.
Household heads living within 5 miles of TMI were more uncertain than those living outside.. And mothers of pre-school children in the TMI area felt more uncertain than mothers cf preschool children in Wilkes-Barre.
3.4.3.
Feelings in the population within 20 miles of TMI about continuing to live in the area were mixed and uncertain.
Relatively unfavorable attitudes, though still generally uncertain rather than negative, were expressed by people living within 5 miles of TMI, and by mothers of preschool children.
The only group with somewhat negative attitudes was those at risk on two counts, mothers of preschool children who live within five miles of TMI.
3.4,4.
Attitudes toward nuclear cower and reactivation of the ".MI-l and -2 nuclear power plants in the general population living within 20 miles of the plant showed uncertainty, with a leaning toward negative f eelings.
Mothers of preschool children expressed the most negative attitudes.
3.4.5.
Among people living in the 20-mile area around TMI distrust of federal and state authorities and the utilities was high immediately after the accident.
Although it was somewhat lower by May, as early as can be estimated, it continued to be higher than the average in the nation throughout the ceriod of the study.
Workers at both TMI and Peach Bottom, like the general population, expressed con-siderable distrust of federal and state authorities.
They diverged from the general population, however, in expressing generally trusting attitudes toward the utilities.
I232
!;i5
19 3.4.6.
Workers at both TMI and Peach Bottom expressed fairly low levels of concern about the future of their occupation.
They also were similar in perceiving people in their communities as holding less than cositive attitudes toward them.
Since there was no evidence of a dif f erence between TMI and Deach Bottom on these matters, neither of these findings contributes to unde' l tanding the basis for the elevated level of demoralization among TMI workers that continued to be ovident in August, and through Septembar when the study ended.
In brief, the accident at TMI had a pronounced demoralizing effect on the general population in the TMI area, including its teenagers and mothers of preschool children.
.awever, this ef fect proved transient in all groups studied except the workers, who continue to show relatively high levels of demoralization.
Moreover, the groups in the general population and the workers, in their dif ferent ways, have continuing problems of trust that stem directly from the TMI accident.
For boF,h the workers and general population, the mental health and behavioral ef f ects are understandable in terms of the objective realities of the threats they faced during the accident at TMI.
- 4.
SUMMARY
OF THE PUBLIC HEALTH AND EPIDEMIOLOGY TASK GROUP REPQRT 4.1. INTRODUCTION The Public Health and Epidemiology Task Group, in carrying out its investigation, addressed broad and sub-stantive health issues, including the policies, practices, and procedures related to public and worker health and safety during the normal development and routine operation of a nuclear power plant, as well as during response to a nuclear accident.
The Task Group report examines and discusses:
1.
the measures taken to prevent or minimize public and worker exposure to radiation from the nuclear power plant, and to prepare for protective actions in response to the potential health hazards during a radiological emer-gerzy-2.
the designated authorities and responsibilities for these radiation-related health and safety matters at the federal, state and local agency levels, and in the utility; 3.
the means by i;hich health-related responsibilities are implemented, and; 4.
the response of f ederal, state, and local health agencies during the accident at TMI.
1232 3i6
20 4.2. GENERAL ISSUES Activities specifically oriented towards the protection of the health of the public and nuclear workers from expo-sure to radioactivity from commercial nuclear power plants include: (a) promulgation, implementation -- monitoring and surveillance -- and enforcement of radiation protection standards, (b) siting of plants in areas of low population density; (c) surveillance for radiation-related health effects; and (d) preparation for response to radiological accidents through emergency planning, education, and avail-able support resources.
The Nuclear Regulatory commission (NRC) has primary responsibility for, and almost exclusive authority over, the health and safety issues in the operation of commercial nuclear power plants.
The Public Health Service of the Department of Health, Education and Welf are (HEW), whose primary responsibility is to protect and promote the health of the public, has sc.ne limited responsibilities responding to.a radiological emergency, such as a nuclear reactor accident.
HEW, and or other federal health-related agencies do not, however, have specific authority in radiological health matters relating to the location, construction and routine operation of nuclear power plants; this authority rests almost exclusively with NRC.
4.2.1.
Radiation Protection Standards The Federal Radiation Council (FRC) (established under the Atomic Energy Act) provided guidance to federal agencies in the formulation of radiation protection standards.
In 1970, the FRC was dissolved and its activities transferred to the Environmental Protection Agency (EPA),
The EPA sets allowable off-site radiation exposure levels NRC standards for maximum exposu. es to individuals in the general popu-lation must be consistent with EPA standards.
EPA provides guidance for radiation exposure to on-site populatione; NRC, however, has sole authority to set occupational radiation standards in the commercial nuclear power industry.
NPC chooses, by policy, to follow EPA guides on such exposures, but is not compelled to do sc.
Radiation protection standards promulgated by the NRC take the form of (a) maximum permissible dose levels to individuals for on-site (worker) and off-site (public) populations, and (b) the design objectives for exposure lev.els that are "as low as reasonably achievable" (ALARA).
Numerical standards are set for maximum permissible dose levels to individuals; no numerical levels are set for collective dose to the entire population, or for ALARA design objectives.
.; I /
z.
yn l232
21 Off-site radiation exposure is monitored by means of mathematical models applied to radioactive emissions, and verified by direct environmental radiological measure-ments -- radiation sampling of air, soil, water, etc.
The NRC regulations for environmental monitoring leave details and methods of implementation to the licensee -- the utility company -- subject to NRC regulation and inspection.
The utility is required to report to the NRC radiation exposure levels that exceed natural background, and by an amount above prescribed maximum permissible limits.
On-site radiation exposures are monitored by environmental dosimetry, air sampling, placed throughout the restricted area, and in designated locations in the nuclear power plant such as stack monitors.
Measurement of occupational exposure to radiation and reporting of radiation exposures is required by the NRC for nuclear plant workers, who, in the utility's judgment, are likely to receive at least 25 percent of the permissible dose in a quarter, a designated 3-month period in a year.
The utility is required to report to NRC (1) annual summary statistics on these occupational exposures; (2) cases of occupational overexposure; and (3) accumulated individual occupational exposure upon termination of employment.
The NRC does not require data on worker's non-occupational exposure history -- medical and dental x-rays.
Cost-benefit analvsis is used by the NRC in making ALARA decisions about systems for off-site radiation dose reduction.
During construction of a nuclear power plant, installation of safety features designed to reduce of f-site exposures below the maximum permissible levels are to be considered by tb2 utility in terms of the cost of installing the safety feature versus the benefit of dose reduction valued arbitrarily at $1,000 per man-rem.
Cost-benefit analysis is not applied by the NRC for investment in safety features designed to reduce occupational exposure.
4.2.2. Worker Protection from Radiation E::posure The primary goal of radiation protection in occupational health, in the nuclear industry, is to minimize the total radiation dose delivered to workers and thus, to prevent any radiation health effects.
Maximum permissible dose limits for individual workers are inrended to ensure that the probability of harm is negligible for any one individual.
This permissible dose for an 4.ndividual takes into account the radiation dose from both a single exposure as well as that over a long period of time, the occupational lifetime of a radiation worker.
2*O Y.ob'd -) \\ U
22 The basic principles of radiation protection of nuclear workers are directed toward achieving exposure reduction while carrying out the work that must be done.
That is accomplished in three ways: time, distance, and biological shielding.
(1). Time.
The mechanical and engineering design and the operation of a nuclear power plant are directed to decreasing the time that plant personnel must spend in a radiation area in order to carry out the essential respons-ibilities and duties of their jobs.
Because radiation exposure is the product of dose-rate and time, the reduction in time spent in the job results in a decrease in total radiation exposure.
(2) Distance.
Radiation exposure is reduced with increasing distance from the source of the radiation.
- Thus, wherever possible, workers are kept at a distance from the source of radiation.
Where tasks require that they be close to the radiation source, special equipment is freqdently used to provide additional distance when carrying out their duties.
(3) Biological shielding.
There are two methods of shielding against radiation.
For penetrating radiations, physical shielding, such as walls, lead, concrete, etc.,
provide barriers to attenuate levels of radiation so that work can be carried out in a safe area.
For uncontained radioactive materials, a number of protective measures are used, including, adequate ventilation to remove the radio-active materials from the worker environment, respirators that prevent the inhalation or ingestion of radioactive materials in the air, grotective clothing to prevent absorption through the skin, etc.
The occupational exposure limit, the maximal permissible dose limit for nuclear workers covered under NRC rcgulations, limits radiation exposure to 3 rems (whole body) per quarter, but permits 12 rems (whole body) per year, under certain circumstances.
In 1978, among monitored workers in the United States, only a small proportion (129 out of 71,904 nuclear power plant workers) received doses greater than 6 rems.
The average whole body dose of reactor workers with measurable doses has been relatively constant, 600-800 mrem annually, and the percent of exposures under 2 rems has remained constant at about 95 percent cf all workers.
The occupational exposure experienced at TMI-l and
-2 prior to the accident indicated an average level of radiological protection.
For the 14-month period frcm January 1978 through February 1979, the average radiation i232 3i9
23 dose to the individ"al nuclear worker ranged from 38-126 millirems per month; the numbers of nuclear workers who were exposed ranged from 569 to 1179 per month.
There is no record of any exposure of nuclear workers at TMI over the maximum permissible limits during any quarter prior to the accident.
4.2.3. Siting of Nuclear Power Plants The NRC plant site-selection criteria established by regulation (10 CFR Part 100), require the following con-siderations for a proposed nuclear power plant site:
(1) physical suitability of the site -- geology / seismology, hydrology, etc.; and (2) current and projected population density living in the surrounding area.
Site suitability is also a function of estimated radiological consequences of a nuclear reactor accident.
The applicant for an NRC license is required t-
--cess the potential releases of radio-activity pro /
by a postulated design basis accident.
The magnituri aese potential releases is estimated on the basis of c
agineered safeguards designed into the plant. The boun : 2 ries of the exclusion area -- the lic-ensee's properti -- and the low pooulation zone (LPZ) the area surrounding the exclusion area in which the population size is sufficiently small, and distribution are such that " appropriate measures could be taken in their behalf in the event of a serious accident" -- are identi-fied by distances at which individuals would receive NRC-specified levels of radiation exposure in the event of the design basis accident.
The radial distance LPZ is thus dependent on the engineered safeguards designed into the proposed nuclear power plant, and the capacity to take protective action on behalf of the people living in the area in the event of a maximun design basis accident. The LPZ siting concept is incorporated into the NRC's emergency planning guidelines, which direct the licensee to arrange for protective action for the. people living in the LPZ in the event of a radio-logical accident.
Although NRC site-selection criteria must be satisfied, primary responsibility for nuclear power plant siting remains with the state and local authorities that maintain control over land-use decisions.
An increasing number of states have established boards or commissions to review and approve siting of proposed power plants; in the absence of such an authority, plant siting decisions r emain with local zoning boards and public utility commissions.
There was no nuclear power plant siting authority in the state of Pennsylvania at the time the TMI nuclear power plant was being considered.
An interagency state commission was created by legislation in 1978; the state department of Health is not included in the membership of that interagency commission.
s0 t?
1,c,3&
24 4.2.4.
Radiological Health Scientific information on the health effects of ionizing radiation is available from biomedical radiation health research, both from epidemiological studies of exposed human populations, and from la' 'ratory animal experiments.
These data are continually examined by scientists in an effort to understand the relationship between radiation dose, particularly exposure to low levels of radiation, and adverse health effects.
Although there is general consensus on the health effect= of high radiation doses, little is known about the eftects of exposure to low doses.
A number of federal agencias fund such biomedical research -- in fiscal year 1978
$76.5 million was spent by the federal government.
Of this amount, the Department of Energy (DOE) provided 63 percent; and the Department of Health, Education and Welfare (HEW), provided 20 percent.
The balance of funds was provided by the departments of Agriculture and Defense, the NRC, the EPA, the Veterans' Administration, and the National Aeronautic and Space Administration (NASA).
The DOE funded 78 percent of all federally-supported human health effects research (S13.6 million); more than half of this was allocated for follow-up studies of the Japanese A-bomb survivors in Hiroshima and Nagasaki.
The NRC has sole regulatory authority over radiological health matters directly related to the workers in commercial nuclear power plants.
No other federal health agency, including the National Institute for Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Administration (<0SHA) has authority in these matters. The NRC requires medical examinations of all applicants for initial or renewal nuclear reactor operatur licenses to assure "the physical condition and general health of the applicant are not such as might cause operational errors endangering the public health and safety. "
This NRC regulation and its accompanying guide do not address the use of required medical examinations for detection of possible radiation-related health effects, nor do they require medical examination of workers other than licensed reactor operators.
4.2.5. Response to Radiological Emergencies During a nuclear power 91 ant accident, emergency preparedness to protect the public health and safety involves a number of health authorities and a variety of federal, state, and local agencies, and activities.
Major efforts in this area include the following:
7,
,,b
{
b
25 1.
The NRC requires the utility to maintain site emergency clans that include:
(a) procedures for on-site management of emergencies; (b) protective actions, including evacuation of personnel; (c) arrangements for on-site, and off-site emergency medical care for injured contaminated workers; (d) arrangements for notifying off-site emergency preparedness agencies of a radiation incident at the reactor e
site; and (e) assurance of the capability of off-site agencies to take protective action on behalf of the LPZ population.
The utility is required to have annual drills of its site emergency plan, and to improve the plan based on critiques of the drill.
The NRC provides guidance, review and concurrence on emergency plans developed by states to respond to radiological emergencies.
There are no requirements placed on states to prepare and maintain such plans, however, and the NRC has not made c oncurrence of state plans a condition of nuclear power plant licensing.
2.
Protective action guides (PACS) are provided by federal agencies to assist states in developing emergency plans and responding to radiological emergencies.
The EPA indicates levels of airborne radioactivity at which pro-tective action, such as evacuation, should be considered.
The HEW PAGs, indicate.
(1) levels of radioactive contam-ination of food and animal feed at which protective action should be considered; and (2) plans for prevention of adverse health effects of exposure, including use of radioprotective agents, such as potassium iodide.
3.
Federal assistance in the event of a peacetime nuclear emergency is available through the Interagency Radiological Assistance Plan (IRAP), which was developed in 1961.
DOE is designatec lead agency in the agreement, and is responsible for administering and implementing the plan.
DOE has available, on request, the resources of IRAP signatory agencies, namely the Defense Civil Preparedness Agency, the Departments of Agriculture, Commerce, Defense, HEW, Labor, and Transportation, the EPA, Interstate Commerce Comrission, National Aeronautics and Space Administration, NRC, and the Postal Service.
DOE also has its cwn Radiological Assistance Program (RAP) vnich, in collaboration with the DOE network of national laboratories, such as Brookhaven National Labora-tory, Oak Ridge National Laboratory, prcvides technical assistance to the states, on request.
4.2.6. The Use of Thyroid Blocking Agents for Protection of the Public An important constituent of a release of a large quanti ty of radioactive materials to the environment would be a number of isotopes of radiciodine, which could affect large numbers of people af ter the incident.
Sngineered safeguards, in the form of elaborate technical and chemical 1232 322
26 systems in the plant, are used to protect the public from radioiodine and other radionuclides, by preventing the dissemination of these radioactive materials to the environ-
- ment, There are a number of chemical agents known to mitigate the consequences of radioactive materials once taken into the body.
However, only the use of stable iodide, as a thyroid blocking agent to prevent thyroid uptake of radiciodines, is considered sufficiently safe and reliable for human use.
Other thyroid blocking agents are available as counter measures against radiation, including other ionic agents such as thioyanate and iodate, and organic antithyroid agents that are used clinically --
propylthiouracil -- but iodide (as potassium iodide, KI) appears to be the most useful, effective, with the least side effects.
Iodide is the most suitable form for thyroid blocking purposes in humans.
Over th'e past 20 years there has been increasing interest in the potential of protective actions for alleviating some of the health effects of the release of radioactive materials in the event of a nuclear reactor accident.
Protective actions relating to the release of radiciodine have received considerable attention -- par-ticularly the administration of natural iodine in a form that would block the admission of radioactive iodine by the thyroid gland.
The pharmacology of the blocking action of iodide has been known for about 25 years, and the efficacy of its use in humans for some 15 years.
In 1977, the National Council on Radiation Protection and Measurements (NCRP) publishec a study on " Protection of the Thyroid Gland in the Event of Releases of Radiciodine."
In this rsport, the NCRP:
(1) considers the feasibility of utilizing thyroid blocking agents for protection of the public in case of off-site releases; (2) defines the efficacy of such agents and the contraindications for their use; and (3) assesses the potential for use of thyroid blocking agents.
- However, the NCRP does not take any position concerning the question of utilizing blocking agents in any given situation.
In the summary and recommendations of the NCRP Report, three important principles are presented:
(1)
"A major protective action to be considered after a serious accident at a nuclear power facility involving the release of radio-iodine is the use of stable iodide as a thyroid blocking agent;"
(2) "If the inital estimate at the facility indicates that the thyroid total absorbed doses of 10-30 rad or more are projected, the blocking agent should be adminis-tered immediately to employees at the facility and to other support personnel coming to or working near the facility;"
and (3) "For people beyond the immediate vicinity of the reactor, the decision to administer stable iodide (to the i232 323
27 general public), to instruct them to remain indoors, or to evacuate them would depend on the type of accident, on pre-planned estimates of release, on wind direction and, later, on monitoring data as they become available."
Potassium iodide (U. S. Dharmacopoeia) is approved for human use.
Because the recommended daily dose of iodide to large numbers of persons would require a considerable amount of the chemical agent, it would have been necessary to develop an appropriate form of the agent -- KI to be stock-piled for emergency use only in the event of release of radioiodines from a nuclear power reactor.
The FDA has reviewed the problem and in December 1978 published, in the Federal Register, a notice to establish requirements for manufacture of potassium iodide to be stockpiled for emergency use.
At the time of the TMI accident, no phar-maceutical firm had responded to this notice for meeting analytical controls and stability requirements for manu-f acture of the drug.
Thus, no com..ercially available thyroid blocking agent for human use was available in large enough quantities to protect the general public at the time of the TMI accident.
4.3. SPECIFIC ISSUES - THREE MILE ISLAND NUCLEAR STATION 4.3.1. Metropolitan Edison Administrative, health physics and personnel policy procedures at Met Ed define the health and safety practices in effect during routine and emergency operations of the TMI nuclear power plant.
1.
Routine environmental monitorinc of radioactivity at TMI f7llows NRC regulations.
At the time of the accident at TMI, thermoluminescent dosime:ars were in place at 20 locations around the site.
Environmental sampling of air, soil, river and rain water is conducted routinely.
Met Ed reports a summary of all environmental monitoring through General Public Utilities (GPUs) to the NRC annually.
2.
The personnel radiation dosimetry program at Met Ed follows NRC regulations.
Procedures for medical evaluation at Met Ed, however, contain features which exceed those required by NRC.
For example, Met Ed health physics procedures requires pre-employment and bi-annual medical examinations of all radiation workers -- those in jobs that could result in exposures up to 300 millirems or more in a quarter -- for the detection of radiation-related health effects, and for baseline data to be used in evaluating any potential health effects resulting from accidental over-exposures.
Met Ed does not retrieve past medical records of new employees, and does not request infcrmation on past or present non-occupational radiation exposure such as medical and dental x-rays.
1232 324
28 3.
Met Ed conducts two types of emergency drills during routine operations to prepare for possible plant accidents.
One type, which is designed to test the site emergency plan, is conducted once a year.
Representatives from off-site agencies may observe and critique the on-site drill, but their actual participation is limited to testing the notification system.
A second type is designed to test the on-site emergency medical care procedures.
This annual drill involves simulation of worker in]uries involving contamination what requires on-site emergency treatment, decontamination, and transport to the Hershey Medical Center in Hershey, Pa.
Two community physicians are retained by Met Ed to provide on-site emergency care.
Both these physicians have participated in drills only as observers; neither has administered emergency medical care under simulated or actual contaminated conditions.
NRC regulations for health physics training of nuclear reactor workers leave the curr ulum requirements to the discretion of the utility.
Nc specific criteria or guidance are offered by the NRC on training course content, fre-quency, attendance testing procedures, etc.
Met Ed conducts a series of such health physics training courses; partici-pation at these courses is required for personnel at several different levels.
4.4. RESPONSE TO THE ACCIDENT AT THREE MILE ISLAND 4.4.1. Utility Response to the Accident A number of health-related problems emerged during the accident at TMI.
These included:
(1) the number of functioning protective respirators available was in-adequate -- some workers who were respirator-qualified were required to use respirators for which they had not been fitted or tested and respirators also were used by some workers who were not respirator-qualified; (2) certain essential dor aatry instruments located in the health physics laboratory were inaccessible due to high radiation levels in the area; (3) there was no potassium iodide available at the nuclear plant in the event of radiciodine exposure of workers -- the agent was ot 2ained on the first day of the accident and stored'for possible future use; and (4) Met Ed did not notify its radiation emergency medical services (community physicians and the Hershey Medical Center) of the accident to ensure their readiness to respond to apprise them of the current status, and the potential seriousness of the accident.
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29 4.4.2. State Response to the Accident States have primary responsibility for protection of the public health and safety.
The accident at TMI revealed that the state health and health-related agencies, as well as the TMI-area medical care f acilities, had insuf ficient resources to respond ef fectively to the actual and potential threat to the health and safety of the public and the workers.
A number of problems were evident.
(1) Responsibility for radiological protection in Pennsylvania rests with the Department of Environmental Resources.
At the time of the TMI accident, the Pennsyl-vania Department of Health had no specific authority, or capability, for radiological protection of the public, and no formal liaison existed between the two agencies.
The state Secretary of Health had to appoint a private medical consultant to advise him on radiological health matters thau
, arose during the accident.
(2) The state environmental radiological monitoring capacity at the time of the accident consisted of only a few thermoluminescent dosimeters placed alongside utility dosimeters to verify routine measurements of radiation levels; no emergency response capability for environmental monitoring existed at the state level.
Once off-site exposures were detected during the accident, the state called the DOE / RAP for help in environmental monitoring.
(3) Pennsylvania required emergency planning for areas within 5 miles of a nuclear power plant.
The 5-mile area around TMI did not include any hospitals.
The hospitals within a 10-mile radius did not have emergency plans for radiation accidents at the time of the TMI incident.
Few hospitals were prepared to receive and treat patients with serious radiation injuries or contamination.
Contingency plans for limited patient treatment, and for patient evacuation were developea during the initial days of the emergency.
In addition, there were no directives given by the governor or the secretary of health on protective actions to be taken by health care f acilities during the accident.
For example, decisions on whether and how to evacuate hospitals and nursing homes in the area were lef t to the administrators of those facilities.
Similarly, when the emergency subsided, no directives were given on when and how to terminate the protective actions that had been taken voluntarily by health care institutions and individuals.
(4)
Pennsylvania had no plans for procurement, distribution, or use of potassium iodide as a thyroid-blocking agent for the general public in the event of a radiological emergency.
The state received potassium 1232 326
30 iodide supplies from the HEW during the accident, the state Department of Health chcse to store the drug rather to provide it to distribution points within the community of TMI.
- 4. 4. 3. Federal Response to the Accident Several federal agencies responded to the accident at TMI, each with some responsibility to protect the public health and safety.
The NRC assumed responsibility at the TMI site on Friday mid-day, March 30, 1979, to provide advice to the governor on protection actions -- such as evacuation -- to assist in the reactor accident management, to provide technical assistance and advice, and to attempt to prevent any further radioactive releases into the environ-ment.
The DOE and the EPA provided technical assistance, and advice, on radiological monitoring and surveillance.
HEW provided technical assistance, and advice, on a variety of health matters, including environmental radiological monitoring and protective action -- the provision of 250,000 vials of potassium iodide as a thyroid-blocking agent in the event of large releases of radioactive iodine into the environment.
A second level of response by the HEW took the form of deliberations and recommendations on health-related matters by the Washington-based health of ficials.
During the accident, HEW officials in Washington repeatedly expressed a desire to consult with NRC officials on the public health implications of any NRC decisions relating to large-scale evacuation from the ar6a, and to actions taken to bring the damaged reactor to a safe condition.
Although meetings were held with both HEW and NRC representatives, these were informational briefing sessions rather than consultative on cubstantive health issues.
Although the HEW was a party to the IRAP, the plan was not follcwed and apparently not known to all the Washington-based health officials; because the accident involved an NRC-licensed facility, the DOE did not notify the other federal health agencies, but lef t this responsibility to the NRC.
In general, the initial and continuing notification and involvement of the HEW during the accident was arranged mainly on an ad hoc basis.
The HEW health officials in Washington made two recommendations concerning protection of the public health and safety.
The first was the recommendation to the White House that consideration be given to evacuation of the area of all persons living within 20 miles of the plant, and that residents of the area be notified of a possible evacuation.
This decision was based primarily on the uncertainty of the status of the damaged reactor, and the time that would be available to evacuate the area in the event of further 7'7
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31 releases of radioactivity.
The second decision concerned recommendations for the immediate administration of potassium iodide to the TMI workers, and the distribution of vials of potassium iodide to the general population.
Each of these HEW decisions had been made without consultation with Pennsylvania state officials or the governor.
Further-more, they were made with only limited information on the status of the reactor accident, the emergency response at the state and local levels, and on the concommitant activities of other federal and state health-related agencies.
It remains unclear whether the HEW reconmendation on evacuation was transmitted beyond the White House.
The recommendations concerning distribution and use of potassium iodide, however, were sent to the governor, although they were contrary to the decisions of the Pennsylvania Secretary of health, and his advisor, on the disposition of the potassium iodide.
The HEW recommendations were viewed as directives by the Pennsylvania Secretary of Health; this led to direct conflict with HEW officials.
Direct assistance was also provided by the HEW personnel in the vicinity of TMI.
This involved a variety of activities including:
(a) placement of dosimeters in the TMI area to supplement environmental monitoring of radio-active releases by other agencies; (b) continuous sampling of food, milk and water for radioactive contamination; (c) procurement and delivery of supplies of potassium iodide sufficient for the population living within 20 miles of the damaged plant; (d) training of federal radiation health physicians if needed; and (e) assessment of the personnel dosimetry records for the workers at the TMI plant, in the event that followup epidemiological studies of these workers would be considered.
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- ..a 32 NOTES 1/
A curie is the unit of intensity of radioactivity; it is named after Marie and Pierre Curie who discovered radium in 1989.
2,/
Noble gases, such as helium, neon, krypton, xencn, and radon, are gaseous elements which do not undergo chemical reactions when taken into the body.
At TMI, the amount of radioactivity released into the environ-ment has been estimated to be from 2.4 to 13 million curies, consisting almost entirely of xenon-133.
3/
Some scientists have reported much higher estimates of the population dose, but their estimates were not supported by the investigation of the technical staff of the Commission.
4/
R or roentgen, is the unit of radiation dose in air, and for the types of radiations emitted during the TMI accident, an R is equivalent to a rem; it is named after Wilhelm Conrad Roentgen who discovered x-rays in 1896.
5/
The Committee on the Biological Effects on Ionizing Radiation (BEIR) of the National Academy of Sciences -
National Research Council is presently examining the complex problem of low-level radiation health effects in human populations; the BEIR Committee Report is not yet complete and thus not available for use by the President's Commission.
6/
" Demoralization" is the term used by Dr. Jerome Frank to describe the psychological symptoms and reactions a person is likely to develop "... when he finds that he cannot meet the demands placed on him by his environ-ment, and cannot extricate himself from his predicament" (1973).
Demoralization can coincide with diagnosable psychiatric disorders, but may also occur in the absence of such disorders.
The various sources of the intractable predicaments include, for example, situations of extreme environmental stress such as combat or natural disasters; physical illnesses, especially those that are chronic; and crippling psychiatric symptoms of, for example, the kinds associated with severe psychotic episodes.
- Hence, an elevated score on a scale measuring demoralization is something lixe elevated physical temperature; it tells us that there is something wrong; it does not in itself tell us what is wrong.
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