ML19220C953
| ML19220C953 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/09/1979 |
| From: | Hironori Peterson NRC OFFICE OF STANDARDS DEVELOPMENT |
| To: | NRC OFFICE OF STANDARDS DEVELOPMENT |
| References | |
| NUDOCS 7905160096 | |
| Download: ML19220C953 (8) | |
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Sb -3 2D STATEMENT OF HAROLD T. PETERSON, JR.,*
SENIOR ENVIRONMENTAL HEALTH PHYSICIST, OFFICE OF STANDARDS DEVELOPMENT, U.S. NUCLEAR REGULATORY CCMMISSION My name is Harold Peterson and I am a member of the technical staff of the U.S. Nuclear Regulatory Commission's (NRC) Office of Standards Development.
I am not the senior health official of the NRC or the official spokesman for the Federal radiation protection community.
I do not hold a management or super-visory position in the NRC.
I am a member of an ad hoc interagency group **
which prepared the preliminary assessment of the dose to the most exposed individual and to.the members of the general population within a 50-mile radius of the Three Mile Island Nuclear Station near Middletown, Pennsylvania for the period from the initiation of the accident on March 28, 1979 until April 3, 1979.(I) To the best of my knowledge, the assessment of doses delivered from the Three Mile Island Nuclear Accident from its initiation until approximately noon on April 2, 1979 which was prepared by this ad hoc group was the basis for the estimates of the public health impact delivered in Congressional testimony on April 4, 1979 before the Senate Sub-committee (l) Subsequent s iates of these values were prepared by Dr. Lewis Battist and Mr. John Buc>
of the NRC staff.
}briefresumeofMr.Peterson'sQualificationsispresentedinAttachment1.
The membership of this group is given in Attachment 2.
Disclaimer:
These remarks represent my personal views for which I am solely responsible.
These remarks do not necessarily represent the voices of any other member of the ad hoc dose assessment group and cannot and should not be construed to represent the official position of the Nuclear Regulatory Ca:nmissien, of the senior management of the NRC or of the NRC staff; or the views of any other Federal or State agency.
790516 COY 4 7'f
-7 by Chairman Hendrie of the Nuclear Regulatory Commission, by Secretary Califano and by Surgeon General Richmond of the Department of Health, Education and Welfare and by Administrator Costell of the Environmental Protection Agency.
This ad hoc group was not formed by delih'rae preselection of necessarily the best and most technically qualified
- experts in the area of environmental radiation dosimetry from the various agecies.
Rather, it was formed ad hcc from individuals assigned by their respective agencies to the NRC Incident Response Center on Monday April 2,1979 who recognized a common need for an estimate of the public health consequences of what, in my personal opinion, is the most sericus accident in a commercial nuclear power reactor in the history of the U.S. nuclear power program.
The group had no appointed or elected leader and various membera of the group served in such a capacity by contri-buting ideas, suggestions, and criticisms.
Because of the urgency to prepare estimates of the health impact for presenta-tion at the April 4,1979 Senate hearings, the group was forced to rely upon reference materials that were immediately available in the persaal libraries of the participants and data which was available to as in the NRC Incident Response Center or easily obtained through existing ccmmunication channels to the Federal coordination center adjacent to the Three Mile Island site or to our own agencies.
Time did not permit an extensive review of the scientific literature to determine the best or most appropriate dosimetric parameters for this evaluation.
For this reason, the dose estimates which were prepared by this group are admittedly acknowledged to be preliminary estimates subject to the, increasing availability of additional data and time to prepare more precise
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- estimates of the public heath impact.
The ad hoc group is preparing and will publish for public review as soon as possible a summary of the data and methods used in this assessment.
For estimating doses received during the period from March ' 'th to March 31st, the group relied primarily upon do;es measured by thermoluminescent dosimeters (TLDs) which were in the environment as part of the NRC-required environmental radiation surveillance program conducted by the Metropolitan Edison Company, the operator of the Three Mile Island Nuclear Station.
After March 31st, these data were supplemented by TLD measurements conducted by the Nuclear Regulatory Commission.
The dosimeters were intended to document the lcw radiation levels associated with routine operation of the Three Mile Island reactors.
They were not intended for accident dose assessment.
They do not record dose rates but they do provide an indication of the total dose delivered over a period of time, at their location.
The time-integrated doses from the TLD measurements are generally consistent with available information on offsite dose rate readings which is why they were used Because these TLD dosimeters are encapsulated in glass, they measure only gamma radiation.
These TLDs were not expected to have an appreciable sensi-tivity to beta radiation (electrons). This was known to us when we decided to rely on them.
Samples of these TLDs and other TLDs placed around the Three Mile Island site by other Federal agencies have been taken to the National Bureau of Standards for exposure to a known concentration of xenon-133. This radioactive gas is the principal radionuclide released from the reactor which has been detected in the environment.
This calibration should provide an o?9
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, approximate indication of the sensitivity and accuracy of the response of these TLDs to xcnon-133 radiation.
The estimated doses received by an individual at the location of the highest measured offsite dose rates and the total population within 50-miles of the Three Mile Island plant are whole body gamma doses.
The estimates of the potential health impact did not include the beta skin dose nor the lung inhala-tion dose.
However, calculations I performed over the weekend indicate that inclusion of these two components would not in any way significantly(2) af fect the health impact estimates and the conclusion that the health impact of this accident to date would be insignificant and undetectable ccmpared to either the projected cancers which mignt result annually from natural background radiation or the existing annual cancer death rate in the area I would now like to deal with some of the known criticisms of the health impact assessment:
(2)The estimated lung dose from Nenon-133 to the most exposed individual is less than 1% of the total body dose.
The estimated iatio of the beta and gamma skin dose to the total body gamma dose for xenon-lee is about a factor of 4(3.8).
If all of the population within 50-miles of the site were exposed out-of-doors and without clothing for the entire duration of the accident, the skin dose would increase the total projected health impact of the accident (which includes fatal and non-fatal cancers and genetic effects to all future generations) by approximately 12% (from 1.3 to 1.5 health effects) due to all skin cancers which might occur in the next 70 years.
The total estirr ted cancer fatalities over the lietime of the exposed population woula increase by only about 2% (from 0.45 to 0.45).
The estimated number of cancers that might result from natural background radi-ation (125 millirem / year) is 54 per year.
The estimated existing cancer death rate is 4,500 per year to the 50-mile enclosed population.
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. 1.
The Federal Government is deliberately misleading the public I will state, in sworn testimony under oath, if necessary, that the estimates presented by principal government officials in Senate testimony on April 4,1979 of the public health impact of the Three Mile Island Accident are totally consistent with the dose and health impact assess-ments prtpared by the ad hoc interagency dose assessment group. These estimates represent, in my professional judgment, the best assessment of the potential health impact obtained from the information available ta the ad hoc group at that time.
No e of the Federal agencies nor the State of Pennsylvania has misled the public regarding the estimated health consequences.
2.
The estimates used of the health effects of radiation were not the highest values available.
This statement is technically correct but misleading.
There are two different types of health risk estimates used in the 1972 BEIR report, one of which is approximately( ) 2 to 5 times higher than the other.
The values used represent the geometric mean (a kind of average) of the two risk estimates.
This was not done to understate the health impact.
The average was used in an attempt to reconcile the two types of estimates.
The resulting " average" estimates are, to my knowlege, generally consis-tent with 1 ie radiation health risk estimated used by the Environmental (3) Advisory Committee on the Biological Ef fects of Ionizing Radiation, (BEIR),
"The Effects on Populations of Exposure to Low Levels of Ionizing Radiation," National Academy of Sciences - National Research Council,
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Washington, D.C. November 1972.
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. Protection Agency and the Nuclear Regulatory Commission and which have previously been subjected to scrutiny in public rule making proceedngs of these agencies (4,5)
A "dcse-rate modifying factor" su w was used in the Reactor Safety Study ("Rasmussen" study)(6) was not employed in the estimation of the health effects of the Three Mile Island Accident.
3.
The dose from the accident was delivered at a higher rate than natural background radition and, tnerefore, it is more dancerous.
If there is a dose-rate effect, then, on the basis of the best available estimates, the public health impacts would be over m timated by 200 to 400 percent ( ~0), and perhaps by 1000 per cent The estimates used 2
for the health risk from radiation exposure wer. based upon data from (4)U.S. Atomic Energy Commission Rulemaking to establish " Numerical Guides for Design Objectives and Limiting Conditions of Operat 'On to meet the Criterion "as low as practicable" for Radioactive materials a Light-Water-Cooled Power Reactor Ef fluents".
Docket No. RM-50-2.
(5)U.S. Environmental Protection Agency, Public Hearings on proposed regulation 40 CFR 190 - Environmental Radiation Protection Standard; for Nuclear Power Operations.
March 8-10, 1976.
( )U.S. Nuclear Regulatury Commission, " Reactor Safety Study - An Assessment of the Accident Risks in s.S. Commercial Nuclear Power Plants", WASH-1400, NUREG-75/014 October 1975.
In particular, Appendix G to Volume VI, " Latent Somatic Effects".
( ) United Nationa Scientific Committee on the Ef fects of Atomic Radiation
" Sources and Effects of Ionizing Radiation",1977 Report, United Nations:
New York, (1977) Annex G. " Radiation Carcinogenesis in Man", Section ID.
Suitability of Dose Level and Dose Distribution pp 365-366 paragraph (36).
( ) Scientific Committee 40 of the National Council on Radiation Protection and Measurements, " Influence of Dose Rate and LET on dose Effect Relationships:
Implications for Estimation of Risks of Low-Level Irradiation" Working Draft of April 5, 1976 p. 4
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studies of persons exposed to medical radiation therapy or atomic bombs at doses and dose rates much higher than the doses and dose rates from the accident.
i These risks estimates were derived by assuming thct the effects observed at high doses from high dose rates can be directly and linearly extrapolated to low doses delivered at very much lower dose rates and that there is no absolute safe dose (or threshold) belcw which there is no health risk.
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This assumption is believed by the prominent experts in the field of radiation protection ( ~ 1), to overestimate the health risk from low-level ionizing radiation.
It should also be recognized that to cause cancer, although high doses of radiation are known there is no conclusive scientific evidence that radiation doses in the range of natural backgrcund cause any ill health.
- This is known as a linear, non-threshold, dose-rate-independent dose-effect relationship.
(9) International Conaission on Radiological Protection, " Recommendations of the International Commission on Radiological Protection Adopted January 13, 1977" ICRP Publication 25, Pergoment Press, Oxford (1977) Section D pp 6-7.
(10) Advisory Committee on the Biological Effects of Ionizing Radiation, 1972 BEIR report cited in reference (3) chapter VII,Section IV pp 87-88.
(11) National Council on Radiation Protection and Measurements, "Reviea of the Current State of Radiation Protection Philosophy" NCRP Report No. 43, NCRP:
Washington, D.C. (January 15, 1975) p. 4.
J Attachment 2 Ad Hoc Interagency Group on Dose ^ss'essment for the Three Mile Island Nuclear Station Accident Dr. Marvin Rosenstein, Deputy Director, Division of Electronic Products, Bureau of Radiological Health, FDA, DHEW Dr. Lewis Battist, Health Physicist, Office of Standards Development U.S. NRC Dr. Frank Congel(1)
Acting Chief, Radiolgical Assessment Branch, Office of Nuclear Reactor Regulation, USNRC Mr. Joha Buchanan *, Radiochemist Health Physicist Office of Standards Development USNRC Mr. Mark Nelson Center for Disease Control DHEW Mr. Harold T. Peterson, Jr.*
Senior Environmental Health Physicist Office of Standards Development USNRC Mr. James A. Martin (2)
Health Physicist Accident Analysis Branch Office of Nuclear Reactor Regulation USNRC Mr. Christopher B. Nelson Environment.1 Engineer Division of Environmental snalysis Office of ".adiation Progams USEPA
- denotes fertified Health Physicist by the American Board of Health Physics.
(1)Dr. Cc igel was called to the Three Mile Island Site on 4/3/79 and did not partic ipate in further refinements of the data.
( )Although, Mr. Martin was not directly involved in the group's activity he was. involved in the preparation of the earliest estimates of dose which were presented in a press conference by Mr. Harold Denton of NRC.
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