ML20126E596
| ML20126E596 | |
| Person / Time | |
|---|---|
| Issue date: | 12/18/1992 |
| From: | Shewmon P Advisory Committee on Reactor Safeguards |
| To: | Selin I, The Chairman NRC COMMISSION (OCM) |
| References | |
| FRN-57FR14514, REF-GTECI-B-56, REF-GTECI-EL, TASK-B-56, TASK-OR ACRS-R-1505, AE06-1-029, AE6-1-29, NUDOCS 9212290210 | |
| Download: ML20126E596 (2) | |
Text
-- . . - - - - - _ _ - - - - - - - - - - - _ - _ , - - - - - - - - - - - - - . - - - - - - - -
l
- 'f* *t Gut,'o
~g
.! N n NUCLEAR REGUL ATORY COMMIS0lON ACR5R-1505
{ A j ADVISOR ( COMM11 TEE ON REACTOR SAFEGUARDS t? .; W ASHINGT ON, D. C. 20555
- , a
/
December 18, 1992 The Honorable Ivan Selin Chairman U.S. Nuclear Regulatory Commission Washington, D.C. 20555
Dear Chairman Selin:
SUBJECT:
RESOLUTION OF CEdERIC SAFETY ISSUE B-56, " DIESEL GENERATOR RELIAUILITY" Dur3ng the 392nd meeting of the Advisory Committee on Reactor Safeguards, December 9-11, 1992, we reviewed the NRC staff's 1*ttest proposals for amendment of the Station niace:out (SBO) Rule, 10 CFR 50.63, and the corresponding revision of Regulatory Guide 1.9, which address resolution of Gencric Safety Issue (GSI) B-56,
" Diesel Generator Reliability." During this review, we had the benefit of discussions with rep:esentatives of the NRC staff and NUMARC. We also had tha benefit of the documents referenced. On several occasions in recent yours we have reviewed the staff's proposals for resolution of GSI B-56, and have of fered our advice.
As stated in our previous reports, we continue to believe that addi'ionc1 regulations and guidance are not warranted to ensure adequate diesel generator reliability. The recent industry-wide diesel generator reliability is better than 98 percent, as measured by f ailure history over the past few years. This is well above the reliability suggested by the relevant regulatory guide as adequate to meet the requiroments of the SBO Rule. It is an improvement over what was being observed five years ago, end the improvement has been achieved through industry and staff Initiatives without the proposed amendment.
A principal argument of the staff for a rule amendment is that a future relaxation in licensee attention to the diesel. generators may occur, and that if it does, the monitoring requirements of the amendment will reveal it. We believe the current NUMARC Initiative SA and implementation of the Maintenance Pule should ensure adequate attention to diesel generators.
In adultion, current regulations require that every diesel generator failure receive a detailed analysis and if a cause of the failure is identified, it must be remedied. This requirement alone 9212290210 921218 PDR
, ACHS \
R-1503 PDR gl l
O >M r v
. . W ---
4 d'
. The linnorable 1 van Selin 2 December 18, 1992 maken it likely that the current high level of rollability will be maintained.
It in not necessary for un to repeat our position on the statistical questions that have plagued the diccol generator reliability accuranco issuo. In addition, the deterministic reliability standards of 0.95 and 0.975, which led to the diesel generator dilemma, are still in place.
In summary, wo believe that existing regulations and industry initiatives will ensure adequato diosol generator reliability, and recommend that the Generic Safety Issuo D-56 be resolved without further regulatory action.
Sincoroly,
'\~)cu.AA0 (+ N4++
Paul Shovmon Chairman 301erf2n.cse:
- 1. . Memorandum dated November 6, 1992, from W. Minnern, Office of Nuclear Regulatory Research, NRC, to R. Fraley, ACRS,
Subject:
Ronolution of GSI D-56, " Emergency Diesel Generator Rollability"
- 2. NUMARC Initiative SA of NUMARC 8700, " Guidelines and Technical Bases fer NUMARC Initiativos Addressing Station Blackout at Light Water reactoro," Revision 1, August 1991
- 3. Letter dated March 5, 1992, from A. Marion, NUMARC, to !!.
Lewis, ACRS, regarding industry-wide data on emergency diesel generator performance
Subject:
Reliability of Emergency AC Power at Nuclear Power Plants
- 5. ACRS report dated December 20, 1991, from David A. Ward, ACRS Chairman, to Chairman Solin, NRC, Srbject: Resolution of Generic Safety Issuo B-56, "Diccol Generator Rollability"
- 6. ACRS reporc dated Auguut 14, 1990, from Carlylo Michelcon.
ACRS Chairman, to Chairman Carr, NRC, Subject; Proposed Resolution of Generic Safety Issue B-56, "Diocol Generator Rollability" l