ML20215E096
| ML20215E096 | |
| Person / Time | |
|---|---|
| Issue date: | 06/09/1987 |
| From: | Kerr W Advisory Committee on Reactor Safeguards |
| To: | Zech L NRC COMMISSION (OCM) |
| References | |
| TASK-A-44, TASK-OR ACRS-R-1249, NUDOCS 8706190252 | |
| Download: ML20215E096 (3) | |
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- [e arcoq'of UNITED STATES h[h[ f)
!"' o NUCLEAR REGULATORY COMMISSION
]s7 $ aE ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 0, WASHINGTON, D. C. 20555 ;
b . , , , , * ',e , June 9, 1987
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The Honorable Lando W. Zech, Jr.
Chairman U.S. Nuclear Regulatory Commission Washington, D.C. 20555
Dear Chairman Zech:
SUBJECT:
ACRS COMMENTS ON THE NRC STAFF PROPOSAL FOR THE RESOLUTION OF USI A-44, " STATION BLACK 0UT" During the 326th meeting of the ACRS, June 4-6, 1987, and in our 325th meeting on May 7-9, 1987, we discussed the resolution of USI A-44,
" Station Blackout," that is being proposed by the NRC Staff. We also discussed the Nuclear Utility Management and Resources Committee (NUMARC) initiatives directed at reducing the risk from " Station Blackout." A Subcommittee meeting was also held to discuss this issue -
with the NRC Staff on May 6, 1987. During these meetings, we had the benefit of presentations by representatives of the NRC Staff and NUMARC. I We also had the benefit of.the documents referenced.
Since March 30, 1982, members of the ACRS have considered and discussed this issue at nine meetings, and offered comments to the Executive Director for Operations in letters dated July 13, 1983 and March 12, 1985. The ACRS has been generally receptive to and supportive of the l Staff's efforts in seeking resolution of the issue.
We consider the proposed resolution of USI A-44, " Station Blackout," to - 4 be workable, and we commend the Staff for its efforts. However. we do 1 not recommend issuance of the final rule at this time. -j We believe that the NUMARC initiatives may be a viable alternative for dealing with this issue on an expeditious schedule and-may require the l 1 east expenditure of resources on the part of the industry. We b lieve '
that the electric utility industry has a strong incentive to deal with 1
" Station Blackout."
One shortcoming of the proposed NUMARC initiatives is the absence of a requirement for any assessment of a plant's ability to cope with station . ,
blackout for a specified length of time. A letter from NUMARC has '
advised us that they are developing a methodology to do this, but that :
industry-wide agreement will have to be obtained. They expect that the development of their initiatives will be substantially completed by September of'this year.' ,
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r The Honorable Lando W. 'Zech, Jr. . June 9, 1987-We recommend that the Staff continue to work with NUMARC on the techni-cal aspects of the NUMARC efforts. If-by September of this year it is determined by the Staff that-the NUMARC initiatives will not be effec-tive or timely in reducing the risk from " Station Blackout" to accept-able levels, or that the NUMARC initiatives will be unduly difficult to evaluate on a plant-to-plant basis, we then recommend issuance of the final rule.
Additional remarks by ACRS Members Glenn A. Reed and Charles J. Wylie are presented below.
Sincerely, William Kerr Chairman Additional Remarks by ACRS Members Glenn A. Reed and Charles J. Wylie We believe the NRC Staff has done a commendable job in bringing A-44 to resolution. However, we continue to support two previous. ACRS letters (July 13, 1983 and March 12, 1985) recommending in part that A-44 implementation should be integrated with A-45, " Shutdown Decay Heat Removal Requirements." Unfortunately A-45 has not arrived at the same status, and the NRC Staff wishes to proceed now with a rule and guide on station blackout which deal with- A-44 only. But, the: root issue is not station blackout but rather decay heat removal .to limit core melt risk to an appropriate level.
We do not consider it in the best interest of nuclear safety to proceed now with an NRC rule and guide on station b*.ackout, which could compro-mise future desirable and more effective action for decay heat removal.
Since it appears that NUMARC-Nuclear Utilities Group on Station Blackout (NUGSB0) has also been moving forward with an industry effort, and since the electric utilities should have premiere capabilities to upgrade vulnerabilities to station electrical blackout, we recommend NUMARC-NUGSB0 carry the ball, with NRC Staff interfacing and monitoring -- but without an NRC rule.- This arrangement would leave the'NRC uncompromised to act appropriately on A-45 when its resolution is completed. In our opinion there may be some outlier units for which it.is more preferable to focus and expend funds. on the root . issue- of decay- heat removal without diverting effort to station blackout; and such focusing may' be more harmonious with the backfit rule.
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I The Honorable Lando W. Zech, Jr. June 9, 1987.
References:
- 1. U.S. Nuclear Regulatory Comission, Federal . Register Notice (51 FR
.9829)'for_the proposed Station Blackout .Rute (10 CFR 50.63),
j p'ablished on March 21, 1986.-
- 2. U.S. Nuclear Regulatory Guide - on. " Station - Blackout," dated March ,
30, 1987. .
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- 3. U.S. Nuclear Regulatory Comission, NUREG 1109, " Regulatory /Backfit , 1 Analysis for the Resolution. of ' Unresolved Safety - Issue A-44," !
submitted March 30, 1987.
-4. U.S. Nuclear, Regulatory Comission NUREG-1032, " Evaluation of Station Blackout Accidents at Nuclear Power' Plants," draft, submit-ted April 16, 1987. l
- 5. U.S. Nuclear Regulatory Comission, NUREG/CR-3226, " Station Black- o '
out Accident Analyses," dated May 1983.
- 6. U.S. Nuclear Regulatory Comission, NUREG/CR-2989, " Reliability' of .
Emergency AC Power Systems at Nuclear Power Plants, dated July-1
'1983. l l
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