ML13324A628
| ML13324A628 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 04/29/1985 |
| From: | Medford M Southern California Edison Co |
| To: | Thompson H Office of Nuclear Reactor Regulation |
| References | |
| GL-84-015, TAC-55900 NUDOCS 8505010137 | |
| Download: ML13324A628 (6) | |
Text
Southern California Edison Company P. 0.
BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD. CALIFORNIA 91770 M.O.MEDFORD TELEPHONE MANAGER, NUCLEAR LICENSING (818) 302-1749 April 29, 1985 Director, Office of Nuclear Reactor Regulation Attention: Mr. H. L. Thompson, Jr., Director Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C. 20555 Gentlemen:
Subject:
Docket No. 50-206 NRC Generic Letter 84-15, Proposed Staff Actions to Improve and Maintain Diesel Generator Reliability San Onofre Nuclear Generating Station Unit 1
References:
(A) Letter M. 0. Medford (SCE) to D. G. Eisenhut (NRC),
dated October 26, 1984, NRC Generic Letter 84-15 NRC's Generic Letter 84-15, dated July 2, 1984, contained several recommendations to nuclear utilities for attaining and maintaining high reliability of the emergency diesel generators.
By Reference A, Southern California Edison (SCE) submitted a partial response to these recommendations. Reference A stated that a reliability improvement program for the San Onofre Unit 1 emergency diesel generators would be developed by April 1, 1985, and then a comparison of this program with NRC Generic Letter 84-15 would be prepared and forwarded to the NRC.
This is to inform you that a report describing the features of our reliability improvement program has been developed and issued for implementation. Enclosure I to this letter compares that program with the example provided in Enclosure 3 of NRC Generic Letter 84-15. Effective April 1, 1985, all diesel start attempts and their results are monitored and logged in accordance with Revision 1 of Regulatory Guide 1.108.
This transmittal completes our response to Generic Letter 84-15.
8505010137 850429 PDR ADDOCK o 02Ob P
Mr. J. L. Thompson, Jr.
-2 If you have any questions, please let me know.
Subscribed on this day of
, 1985.
Respectfully submitted, SOUTHERN CALIFORNIA EDISON COMPANY By: P9. 72h46 B. 0. Medford Manager, Nuclear Licensing Subscribed and sworn t before me this day of
/zff OFFICIAL SEAL AGNES CRABTREE NOTARY PUBLUC -
CARWOHNIA Not Pub1 c in and for the County of PE6NCIPAL OrPtUBL IN Los Angeles, State of California LOSANGELESCOUNTY My Commission Expires Aug. 27, 1986 My Commission Expires:
7 /
Enclosure I cc:
USNRC Document Control Desk (Washington, D.C. 20555)
F. R. Huey (USNRC Senior Resident Inspector, Units 1, 2 and 3)
Enclosure I Comparison of San Onofre Unit 1 Reliability Improvement Program With Enclosure 3 of NRC's Generic Letter 84-15 NRC's Example Performance Specification San Onofre Unit 1 Reliability Program
- 1. Reliability Goals The staff would like plants to maintain
Reference:
Letter M.0. Medford (SCE) diesel generator reliability at or above to D.M. Crutchfield (NRC) specified levels, with.95 as the minimum dated June 29, 1984, desired level.
Return to Service Requirements, Enclosure 1 to the referenced letr reported a cumulative achieved reliability of 98.7% and 99.0% for diesel generator #1 and #2 respectively for the period April 1977 to April 1, 1984. However, the method used in calculating these numbers was not developed to conform to the definitions and criteria of Reg. Guide 1.108. Effective April 1, 1985, San Onofre Unit 1 has implemented Reg. Guide 1.108, positions C.2.e. and C.3.a, and will attempt to maintain a reliability level of >.95 on each diesel, as calculated from the last 100 valid tests at any time.
- 2. Reliability Level Reliability (R)
Action
References:
(1) Letter M. 0. Medford Remedial Actions R >.95 31 day surveillance (SCE) to interval.
Increase to J. A. Zwolinski testing to once every (NRC), dated 7 days for 2 failures March 8, 1985, in the past 20 tests.
Revised Maintenance and Surveillance Program
-2 NRC's Example Performance Specification San Onofre Unit 1 Reliability Program
.95 >R >.90 31 day surveillance (2) Letter K. P. Baskin interval.
Increase (SCE) to testing to once every H. R. Denton (NRC),
7 days for 2 failures dated February 14, in the past 20 tests.
1985, Amendment Application No. 126 R <.90 Disqualify diesel generator. Requalify by 14 consecutive starts within 75 days of failure.
By Reference 1, SCE committed to extensive maintenance and surveillance (M&S) program designed to provide highly reliable diesel generator performance during future plant life.
SCE considers that the full implementation of this M&S program, combined with root cause determinations of all observed diesel generator failures and implementation of appropriate corrective actions will assure that the reliability level of > 0.95 is met. Additionally, by Reference (2), SCE submitted proposed Technical Specification changes to the NRC to limit engine loading 4500 kw + 5% (versus 6000 kw nameplate rating) and to restrict the application of fast engine test starts to the refueling interval SISLOP test only.
-3 NRC's Example Performance Specification San Onofre Unit 1 Reliability Proram In the course of work performed by the Transamerica Delaval (TDI) diesel generator owners group to assess the reliability of TDI diesel engines, it has been determined that engine starts (whether fast or slow) and engine coastdowns both subject the diesel crankshaft to undesirable stress concentrations. For this reason, accelerated testing is not preferred as a method of requalifying the diesels after a failed test. However, all diesel generator failures will be 0
evaluated, and corrective actions implemented. Requalification may include accelerated testing, depending on the circumstances of the failures.
- 3. Surveillance Test a.)
Normal surveillance frequency - in The normal surveillance frequency is Frequency accordance with manufacturer's at least once per 31 days.
recommendation, but at least once Accelerated testing frequency will be per 31 days.
as discussed in items 2 and 4.
b.)
Accelerated frequency - with 2 or more failures in last 20 tests, increase frequency to once a week.
- 4. Remedial Action Criteria If the number of failures is greater than Remedial action criteria are as or equal to 3 in 20 or 6 in 100, prepare described in item 2 above.
In and maintain a report on the diesel generator addition, if the reliability level reliability improvement program.
drops to <.95 (as calculated from the last 100 surveillance tests), the subject failures will be evaluated further. Corrective actions will be implemented based on the type and circumstances of the failure and may include accelerated testing.
Additionally, the contents of the existing diesel generator reliability program will be reviewed for possible revision.
-4 NRC's Example Performance Specification San Onofre Unit 1 Reliability Program
- 5. Requalification Criteria With 5 or more failures in 20 tests or 11 Requalification testing is or more failures in 100 tests, the diesel discussed in item 2.
generator is subjected to a requalification program, requiring 14 consecutive tests without failure.
- 6. Failure to requalify diesel The diesel generator is declared inoperable The diesel generator is declared and action statement in the plant inoperable and action statement in Technical Specification is followed.
the plant Technical Specification followed.
- 7.
DG inoperability limits The staff determined that the allowable SCE may in the future submit a out-of-service period for a DG should be proposed Technical Specification greater than the current 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Tech. Spec.
change to increase the allowable limit, while placing a yearly limit on out-of-service period.
cumulative out-of-service hours for planned and unplanned maintenance. Licensees may propose total cumulative outage time along with the basis for time chosen.
- 8.
Valid Demands and Failures Valid demands and failures used in the Valid demands and failures used in above paragraphs should be determined in the above paragraphs will be accordance with Reg. Guide 1.108, determined in accordance with Reg.
position c.2.e.
Guide 1.108, position c.2.e.
- 9.
Reliability Records Maintain records in accordance with Maintain records in accordance Reg. Guide 1.108, position c.3.a.
with Reg. Guide 1.108, position Submit a yearly data report on diesel C.3.a. The reliability records generator reliability to the NRC.
maintained onsite will be available at any time for NRC audit.
IAA:4009F:6092u