ML20052H039
| ML20052H039 | |
| Person / Time | |
|---|---|
| Issue date: | 04/26/1982 |
| From: | Palladino N NRC COMMISSION (OCM) |
| To: | Starr C ELECTRIC POWER RESEARCH INSTITUTE |
| References | |
| NUDOCS 8205190293 | |
| Download: ML20052H039 (4) | |
Text
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3 April 26, 1982 OFFICE OF THE CHAIRMAN g
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Mr. Chauncey Starr Vice Chairman Electric Power Research Institute Post Office Box 10412 Palo Alto, California 94303 Dear fe d t N $6 This letter is in response to a clopy of your December 21, 1981 letter to
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Mr. Louis 0. Giuffrida, Director, Federal Emergency Management Agency (FEMA), with regard to emergency planning for nuclear power plants which you provided to me.
While I agree with your statement to Mr. Giuffrida that there is mounting evidence to support the reduction of the postulated source terms from nuclear power plant accidents, I believe that the evidence is unclear at the present time as to the degree of reduction that would be realized from many of these mechanistic assumptions.
The best judgment of the NRC staff is that tES existing source terms may be high by a factor of 2 to 10, but that there is insufficient technical justification at this time to state precisely the magnitude of that conservatism. They do believe the uncertainties associated with predicting both the magnitude and the probability of the accident source terms are large.
Your letter referenced recent unpublished German research results as supportive of a substantial reduction in core melt source term releases and a concomitant reduction in the emergency preparedness criteria.
The German research results are preliminary and represent the best estimates of releases for a specific containment design for a German PWR (Biblis B Reactor).
This design is somewhat larger in volume and is stronger than the largest and strongest containments found in plants in the Unitea States.
The research results indicate that this containment design has a higher degree of retention of radioactive material and thus a smaller source term because it is designed to withstand greater pressures. Most U.S. plants do not have containments that approach these attributes and thus cannot be credited with this safety margin.
With regard to possible health effects associated with reduced source terms, we believe that if the source term was reduced by a factor of ten, there would still be potential for early fatalities and injuries out to distances from the plant of 5 and 25 miles, respectively.
With respect to detectable latent cancer fatalities, such releases would generate statistically detectable cancers in the exposed population for distances of about 50 miles. However, latent cancer fatalities have not played a direct role in developing emergency P anning criteria.
l 8205190293 820426 PDR COMMS NRCC CORRESPDFOENCE PDR
i Mr. Chauncey Starr. l In. summary, we believe the on-going research on the source' term could lead to some relaxation of the emergency planning criteria and/or implementation..Thus, the prudent course is-to wait for' additional results from the programs before proposing specific regulatory changes.
Sincerely, Nunzio J. Palladino Chairman i~~
cc: Louis 0. Giuffrida, FEMA I'
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.M M~r. Louis O.
Giuffrida Director' Federal Energy Management Agency 500 C-Street, S.
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Washington, D.
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SUBJECT:
EMERGENCY ' PLANNING FOR NUCLIAR FOWER PLANTS'
Dear Mr. Giuffrida:
Recent experimental and theoretical research in Germany has
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s indicated that in the event of a major nuclear power plant failure resulting in a core meltdown, the amount of radionuclides released into the atmosphere would be drastically reduced from the conventional es't'imates ' hat have been used by the Nuclear-t Regulatory Commission and other's to evaluate public risk.
The significance of these findings is that the appropriate emergency. planning radius around a nuclear plant is very much reduced (probably to one-fifth to one-tenrh [~1/5 - 1/10) of the presently suggested radius); there would be no early health effects from public e xp o's u r e s to radiation;.and any_
latent effects would be so small as not likely to be detectable.
,Further, there are likely to be several days available after the accident before the containment building leaks significantly (4.5 days in the German study), and very little iodine release.
So the present early warning criterion serves'no useful function, and prepar'atory iodine absorptien prevention is unnecessary.
Under these circumstances, the-energency plans being implemented by FEMA in accord with the old criteria wculd be grossly excessiv'e, and mi'ght indeed be the source of an unwarranted public-risk.
Such activities as civilian evacuation exercises.
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distribution of potassium iodide tablets, a.7. d the routine -
testing of 15-minute warning sirens and alarm systems, may not only be unnecessary, but may also result in physical injury.
'and psychological harm from continued public anxiety and stress.
The possibility of a major reduction in the estimates of the release of r'a d io a'c t i v i ty fro'm s u ch^ a c c id e..ts (the " source term," in nuclear parlance) was brought to the attention of the NRC in September 1980 by our staff,
- a. d resulted in NRC hearings on this subject on November 18, 1980.
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Giuffrida Page 2 Director, FEMA December 21, 1981 accident'information ~during th'e past several decades provided-as well as the specialized the basis for these presentations, testimony of experts from our national laboratories and overseas.
The subje6t was again revieged with the NRC on October 26, 1981.
Because of the importance of this topic to public safety, professional attention has been focused on this topic internationally.
The German studies are part of this effort.
As the professional studies and research continue, the mounting evidence appears to support the estimates of a reduced source term.
The NRC staff is being kept abreast of this work, and its sign 3ficance was recognized by its Executive Director for Operations, William J.
Dircks, in his memo to the NRC of June 19, 1981.
While it unay t a.Ke several years to experimentally verify all the analytical details of the source term, it is becoming clearly evident that it should be reduced.
In view of the importance of this matter to estab'lishing public confidence in government _ regulatory agencies and in our many nuclear generating stations, I urge that FEMA-work closely with the NRC in assessing the developing source term situation.
It is very important that FEMA avoid premature and excessively severe public programs which will probably have to be undone klmost as soon as they are fully implemented.
If you,or the FEMA staff would like a detailed technical review of,the source term developments and their implications, we would undertake to arrange it.
Sincerely, A
.Chaun*cey Starr Vice Chairman CS:e,bn f
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Palladino V.
Chairman, NRC e
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