ML20206N719
| ML20206N719 | |
| Person / Time | |
|---|---|
| Issue date: | 08/19/1986 |
| From: | Bernthal F NRC COMMISSION (OCM) |
| To: | Cuomo M NEW YORK, STATE OF |
| Shared Package | |
| ML20206M162 | List: |
| References | |
| NUDOCS 8608260367 | |
| Download: ML20206N719 (3) | |
Text
I
- p ero 4 UNITED STATES 8 i NUCLEAR REGULATORY COMMISSION E WASHINGTON, D. C. 20555
\...../
CHAIRMAN August 19, 1986 ,
The Honorable Mario M. Cuomo i Governor of New York Albany, New York 12224 l
Dear Governor Cuomo:
I am pleased to respond to your letter of June 26, 1986, to former Chairman Palladino. In younletter you requested that the NRC consider changing its regulations or the interpretation thereof so as to require an approved offsite.
emergency evacuation plan as a condition for a low-power operating license j authorizing fuel loading and operations at power levels up to 5% of rated power. In support of your request, you cited the recent Chernobyl accident and reports that the reactor was operating at some six to seven percent of rated power when the accident occurred and you identified four issues that you believe the NRC should consider in the light of Chernobyl. Our response to these issues follows.
- a. Does Chernobyl indicate that low-power testing can pose far greater risks to surrounding populations than previously asserted?
Based upon our current knowledge of the Chernobyl . accident, it does not so indicate. The proximity of the 5% of rated power authorized in low-power operating licenses to the 6% to 7% power level at which the Chernobyl accident is believed to have occurred is not a valid indicator of the relative risks. One of the principal reasons for this is that the reactor operating history of power level (s) that precedes the occurrence of an accident is the key factor in determining the total amount of radioactive material that would physically be present in the reactor core. It is our understanding that the Chernobyl reactor had been operating at or near full power for a significant period of time before the accident. The resulting inventory of radioactive material in the Chernobyl reactor at the time of the accident was therefore substantially greater.than that which would be present in one of our facilities licensed for initial low-power operation and testing. Moreover, the decay heat rate at plants limited to low power operations is substantially lower than that for plants that operate at full power. This means that much more time will be available to take corrective actions during accidents and that the requirements for cooling water are substantially reduced. I would note also that the low-power testing at Shoreham, which is now substantially completed, is similar to that which all licensed plants in the United States have undergone quite safely.
- b. Can a serious accident with widespread geographic effects occur when a nuclear power plant is operating at low-power levels?
l OS'% o 3CD, *yA
- c. Should an offsite emergency evacuation plan be required for low-power testing?
Although it is physically possible for an accident to occur in a nuclear power plant operating at any power level, it has been the Commission's judgment that, if the plant had no previous high power history, the likelihood of occurrence of an accident at low-power levels that would require protective measures outside the boundaries of the plant is negligibly small. As explained above, our current knowledge of the Chernobyl accident does not lead us to alter this judgment. We continue to believe, therefore, that the negligible accident risks do not provide adequate safety basis for changing the NRC's regulations so as to require an offsite emergency evacuation plan as a condition for licensing initial low-power operations and testing. 8
- d. What level of risk, ~if any, is considered acceptable by the NRC, even without an emergency evacuation plan?
Although considerable progress has been made over the years to quantify risk to the public by means of probabilistic risk assessment methodology, the NRC does not rely on a specific " level of risk" to detennine an acceptable basis for licensing. Rather, the NRC primarily. relies on its longstanding defense-in-depth ~ policy, as reflected in its rules and regulatory requirements, to assure that pl. ants licensed to operate do not pose an undue risk to the health and safety of the public. Nevertheless, determination of an acceptable level of risk, independent of emergency evacuation considerations, remains a continuing Comission consideration. That effort is discussed in the Comission's policy statement on Safety Goals, a copy of which is enclosed for your information. As the Policy Statement indicates, a general plant performance guideline now under study by the Comission would limit the~ overall mean frequency of a large release of radioactive materials to the environment from a reactor accident to less than one in a million per year of reactor operation.
A coordinated U.S.-wide effort is currently underway to determine the facts and assess the implications of. the.Chernobyl accident. The effort that is underway includes" participation by the various relevant: Federal agencies, including the Comission, the Department of Energy, the Federal Emergency Management Agency, the Environmental Protection Agency, and the Department of Health and Human ;
Services as well as the Department of State. In addition, it includes participation by noted scientists and engineers from national laboratories, .
academic institutions, and elsewhere, as well as the Electric Power Research Institute and the Institute for Nuclear Power Operations (two industry-based groups). The work will be subjected to wide peer review. l l
The NRC has formed a special task force that is following up on Chernobyl, and l a senior management oversight group to review the findings of the task force.
The target date for the NRC task force report to the Comission is February 1987. The report is expected to identify any areas requiring prompt regulatory action as well as areas needing more detailed study. ,
.. s
_ . . . . . + ...-........mp
f In conclusion, we do not believe that the infomation we have at this time regarding the Chernobyl accident provides adequate basis for the NRC to change ,
its regulations on the issuance of low-power licenses or to halt the conduct of l licensed initial low-power test programs. Should our efforts to determine !
the facts and to assess the implications of the Chernobyl accident provide l significant new information on the risks of initial low-power testing, then the '
Commission will of course reexamine its position. Also, some parties in at least one pending licensing proceeding have argued for denial of a license for low-power testing based on their assessments of the Chernobyl accident and arguments over how NRC's emergency planning regulations ought to be interpreted and applied to the facts of the case. If in the future these adjudicatory ,
issues come before the Comission, they will be judged based on the evidence in ;
the case. This letter does not prejudge those issues.
Sincerely, g k,-
Frederick M. Bernthal Acting Chaiman
Enclosure:
Policy Statement on Safety Goals
,--~-.6=h.-
,,y%,...,oy.
~~-.se---- ,