ML19340F144
| ML19340F144 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 12/22/1980 |
| From: | Snyder B Office of Nuclear Reactor Regulation |
| To: | Minnich J DAUPHIN COUNTY, PA |
| References | |
| NUDOCS 8101190640 | |
| Download: ML19340F144 (5) | |
Text
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,1 Jg UNITED STATES
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g NUCLEAR REGULATORY COMM:SSION
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Docket No. 50-320 r >
y Mr. John E. Minnich, Chairman 7
Dauphin County Com.
P.O. C:r 1295 Harrisburg, Pennsylvania 17108 y
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Dear Mr. Minnich:
This is in response to Dr. Cochran's December 2, 1980 letter in which he raised severai questions regarding the potential health effects of cleanup alternatives indicated in the PEIS.
I have addressed his remarks in detail:
1.
Order of Risk - Although Dr. Cochran may not fully agree, I would like to point out that " order of risk" is considered to be a valid way of expressing risk. The tem comes from the International Commission on Radiological Protection (ICRP Publication 8, p. 3):
" Estimates expressed in this way (e.g., 2 cases per year in a million exposed adults for each rad received) could be readily misinterpreted as implying considerably greater accuracy than the facts justify. A fairer impression might be conveyed by defining orders of risk, a fifth order risk being a risk of death or injury in the range of 1 x 10-3 to 10 x 10-5 and so on, that is to say 10 to 100 injuries would be expected per million persons."
2.
Range of Uncertainties - Dr. Cochran is correct in pointing out the existence of ranges of uncertainties in risk estimates in the BEIR-I report. The staff recognizes this fact and has chosen the best estimate based on reviewing reports from such internationally recognized expertise, e.g., BEIR-I and BEIR-III. Other Federal agencies, EPA and the Bureau of Radiological Health, for example, subscribe essentially to the same approach. Although different models within this context could provide results that vary by factors of 2 or 3, there are r.o fundamental disagreements. Some of the more controversial analyses that would result b variations well outside of this range have been examined closely by internationally recognized and respected groups of experts and have been found to be technically inadequate. A meaningful discussion of these studies is outside the scope of the PEIS. We therefore subscribe to the approach which is recognized by the overwhelming majority of experts in the field.
I believe it is useful to indicate how the risk estimators in the PEIS were derived. The base data used for the fatal cancer risk estimator can be found in Section 9.3.2., " Upper Bound for Latent Cancer Fatalities", in the Reactor Safety, Study, WASH-1400, October 1975.
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Mr. John E. Minnich Specifically, the data on " Upper Bound Risk Coefficients for Latent Cancer Fatalities" Table VI 9-2 for the different age groups were used. Enclosure 1 presents the calculations which, based on dose coefficients, yield the cancer risk estimators of 131 and 135 addi-tional cancers per one-million person-rem for workers ind individual members of the public, respectively. The WASH-1400 coufficients are based on BEIR-I and new data made available since the issuance of BEIR-I. We intend to include a reference on WASH-1400 in the final PEIS.
The statement on possibility of zero 3.
Possibility of Zero Risk risk at the lower dose limit can be found on page 187 of BEIR-III.
Specifically, BEIR-III cites BEIR-I in stating that, "the lower limit, depending on the shape of the dose-incidence curve for low-LET radiation and the efficiency of repair process in counteracting carcinogenic effects, could be appreciably smaller (the possibility of zero is not excluded by data)". The BEIR-III report goes on to state that, "the present Committee endorses this view." The staff.
in the preparation of the PEIS, has presented the potential health l
i risks associated with very low doses and, therefore, has adopted the l
no-threshold approach.
The risk estimator used for occupational exposures 4.
Age Groups includes the consideration of the age group of the cleanup workers (ages 20-65). The estimator for the off-site population is based on the 1970 U.S. population age group distribution.
The risk estimator for genetic effects is obtained 5.
Genetic Risks by summing tne geometric means of the distributions given in the BEIR-I report; in particular, data from Table 4, Chapter V of BEIR-I.
As noted by Dr. Cochran, the 6.
Hanford Study of Mancuso, et al statistical validity of the Hanford study is controversial.
In reference to the Mancuso study, the BEIR-III report states, " Compared with the great majority of studies of irradiated populations, the Hanford study is distinctly lacking in statistical power. That is, assuming the conventional estimates to be representative of the true risks of radiation-induced cancer, the Hanford study could be expected to yield risk estimates that are negative with probability arcund 40%,
positive but statistically nonsignificant estimates with probability of around 50%, and statistically significant but Fighly exaggerated estimates with probability around 10%. Thus, the low statistical power of the Hanford study, according to conventional studies of :!sk estimates, detracts considerably from the challenge posed by the study's results and from the validity of thesQ estimates." For this reason we do not believe inclusion of a discus:61on of Mancuso's study in the PEIS would be constructive, j
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O Mr. John E. Minnich I hope this information will be helpful for Dr. Cochran to understand how the risk estimates on potential health effects in the PEIS were derived.
If you desire, I can arrange for appropriate NRC staff members to attend the first Panel meeting after January 1,1981 and discuss this issue further.
Sincerely, hw A /,
M Bernard J. Sny er, Program Director Three Mile Island Program Office Office of Nuclear Reactor Regulation cc: TMI-2 Advisory Panel Members t
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.l ADVISORY PANEL FOR THE DECONTAsiMATION OF THE THREE MILE ISLAND, UNIT 2 MEMBERS TELEPHONE NUMBERS Dr. H. Arnold Muller 717-787-6436 Pernsylvania Dept. of Health P.O. Box 9 Harrisbur - Pennsylvania 17120 r.
lifford Jones 717-787-2814 Dept. of Environmental Resources P.O. Box 2063 Harrisburg, Pennsylvania 17120 Lt. Gen. Dewitt C. Smith, Jr., USA Retired 717-783-8150 Pennsylvania Emergency Managecent Agency P.O. Box 3321 Harrisburg, Pennsylvania 17105 The Honorable Robert Reid 717-944-4686
!!ayor.of Middletown 60 W. Enaus Street Middletown, Pennsylvania 17057 The Honorable Arthur E. Morris 717-291-4701 Mayor of Lancaster P.O. Box 1559 120 N. Duke Street Lancaster, Pennsylvania 17603 717-255-27d Mr. John Minnich Chairman, Dauphin County Comm.
P.O. Box 1295 Harrisburg, Pennsylvania 17108 l
Nunzio J. Palladino 814-865-7537 Dean, College of Engineering Pennsylvania State University 101 Hammond Building University Park, Pennsylvania 16802 Dr. Henry Wagner 301-955-3350 Room 2001 615 North Wolfe Street Baltimore, Maryland 21205 Dr. Thomas Cochran 202-223-8210 Natural Resources Defense Council Suite 600 1725 I Street, N.W.
Washington, D.C.
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MEMBERS TELEPHONE NUMBERS Mrs. Ann (runk 717-944-6119 143 Race Street Middletown, Pennsylvania 17057 Mr. Joel Roth 717-233-7897 Chairman, TMI Alert 315 Peffer Street Harrisburg, Pennsylvania 17102 Ms. Jean Kohr 717-299-564s 150 East Chestnut Street Lancaster, Pennsylvania 17602 l
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- 949-o049 December 2, 1980 485 4:n-6 6:
5 f) Ib7 Bernard J. Snyder, Program Director i
Three d ie Island Program Office g/ R 7
Office c' Nuclear Reactor Regulation v
U.S. Nuclear Regulatory Commission Washington, D.C.
20555
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Dear Dp M r This is in response to your letter of November 21, 1980 to John E. Minnich regarding my questioning the error limits associated with potential health effects indicated in the 4
draft PEIS on TMI-2.
First, let me address your comments in the third paragraph of your letter where in closing you state:
l For this reason, although it may be desirable to quantify the risk estimates'in the PEIS with error limits, it is not possible to do so in a manner which implies statistical accuracy.
I trust you recognize that it is your PEIS that quotes fatal cancer to three significant figures "131 fatal cancers in the exg =ed workers per one million person-rems" (PEIS, p. 10-8) with no uncertainty limits _or discussion of uncertainties.
Your reference to tne mEIR I discussion of uncertainties is supportive of my argument that you should present in the PEIS the range of risk estimates found in the BEIR reports and other credible references.
With respect to your discussion in paragraph three of the ".. der of risk," this is just a lot of gobbledegook that adds more confusion than enlightenment.
l Turning to your fourth paragraph, you inisread BEIR I.
I Actually you just didn't read far enough.
Your reference to.
1350-3300 deaths from cancer during the 25 years following irradiation due to exposure of the U.S. population to 0.1 rem during one year is taken from BEIL I, p._
fers to extrapola DUPLICATE DOCUMENT the next when taking into cons survivors, Entire document previously of cancer other dat entered into system under:
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