ML20196B451
| ML20196B451 | |
| Person / Time | |
|---|---|
| Issue date: | 11/18/1998 |
| From: | Collins S NRC (Affiliation Not Assigned) |
| To: | Ralph Beedle NUCLEAR ENERGY INSTITUTE (FORMERLY NUCLEAR MGMT & |
| References | |
| PROJECT-689 NUDOCS 9812010104 | |
| Download: ML20196B451 (1) | |
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UNITED STATES I
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- p November 18, 1998 Mr. Ralph E. Beedle Senior Vice President and Chief Nuclear Officer Nuclear Energy Institute Suite 400 1776 i Street NW Washington, DC 20006-3708
SUBJECT:
Dear Mr. Beedle:
This letter responds to your letter of October 2,1998, informing the NRC of NEl's plans to address the issue of control room habitability. We are encouraged by the formation of the NEl Task Force to address the issues presented by the NRC at the public workshop on August 16,
-1998. We were also encouraged by how quickly the Task Force began its work with a meeting in September and plans for additional meetings in the near future. However, we would like the Task Force to increase emphasis on the issue of unfiltered inleakage.
Unfiltered inteakage into the control room envelope has been measured at ten operating plants using tracer gas tests. The range of the measured leakage rates was approximately 70 - 4,300 cfm. In each case the measured inleakage rate, was greater than the inleakage rate assumed in the plant's design basis dose analyses for the control room, substantially greater in most cases. Some plants concluded that the measured leakage invalidated these analyses to such an extent that the design dose objectives of 10 CFR Part 50, Appendix A, General Design Criterion 19 were no longer met, causing licensees to initiate technical specification changes and/or compensatory measures to allow continued plant operation.
We all agree that control room habitability is important to plant safety. The ability of the operators to safely remain in the control room to monitor and take actions to mitigate an accident is an underlying assumption in both designasis analyses and severe accident risk l
analyses. In addition, it is important for the operatort to be confident of their safety in the control room.
The NRC and the industry are moving towards a performance-based regulatory framework.
l Discrepancies exist between the assumed inleakage in the design basis analyses and the measured inleakages and are inconsistent with such a framework. This was an important issue raised by the NRC at the public workshop. The test results suggest to us that periodic tracer gas tests of the control room envelope would provide a valuable tool for assessing control room integrity. We are willing and ready to participate with the NEl Task Force to address these issues.
Sincerely, IlO oi?O1 Y(0 mue or
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Office of Nuclear Reactor Regulation
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