ML20198N941
| ML20198N941 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 01/15/1998 |
| From: | Graham P NEBRASKA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 50-298-97-18, NLS980009, NUDOCS 9801210268 | |
| Download: ML20198N941 (5) | |
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> Nebraska Public Power District "f@MC't""
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Januaiy 15,1998
- U.S. Nucien Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001 Gentlemen:
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Subject:
Follow-up Information Relative to Unresolved Items Identified in NRC Inspection Report 97-18 Cooper Nuclear Station, NRC Docket 50-298, DPR-46
Reference:
- 1. Letter to G. R. Horn (NPPD) from A. T. Howell (USNRC) dated December 17, 1997, "NRC Inspection Report 50 298/97,18" By letter dated December 17,1997 (Reference 1), the NRC documented an inspectio: onducted October 20 through November 17,1997, at the Cooper Nuclear Station. Therein the NRC requested Nebraska Public Power District (District) provide follow-up information relative to two unresolved items idemified during the inspection. This letter provides the requested follow-up information as detailed below.
- 1. Request: Provide a schedule for completing the root cause assessment associated with the failure to implement and effective preventive maintenance program on the safety-related breakers.
Response: The root cause assessment for SCAQ 97-1387 has been completed. A copy of the assessment has been forwarded to the NRC inspection team leader Jeffrey Sh>+elford.
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Request: Provide your plans to complete the necessary equipment overhauls.
Response The schedule for the remaining essential and non-esse ~:al 4160V circuit breaker overhauls is provided as Enclosure 1. Note that this schedule is tbr planning purposes only and is subject to change based on plant conditions, parts availability, resources, etc., without follow-up notification to the NRC.
- 3. Request: Provide an explanadon of your plana to revise the 125 Vdc icad and voltage study.
Response: The District plaa to revise the 125 Vdc load and voltage studies by August 31,1998.
These revisions will include the following actions:
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- A representative sample of circuits will be validated to assure a high level of
. confidence in the inputs to be used. This representative sample will be expanded, as appropriate, based on the number and significance of any errors found.
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NLS980009 January 15,1998 Page 2 cf 2 The existing calculations are based on a single scenario that superimposes the loads of Station Black Out (SBO), Appendix R, and Loss of Coolant Accident - Loss of Off-site Power (LOCA-LOOP). This approach has been found te be overly conserve.ive, difficult to maintain, and somewha
'ofusing. Accordingly, this single scenario will be separated into individual scenarios,pecific to the requirements being addressed.
The basis for the sequencing of events in each scenario will be validated and documented.
Once the revisions are approved, the calculated load currents will be used to provide the basis for the battery ser. ice test load profiles In addition, the calculated voltages will'oe used to proside the basis for service test acceptance criteria previously iacking in surveillance procedures.
Should you have any questions concerning this matter, please contact me.
Sincerely, P. D. Graham Vice President of Nuclear Energy
/ctm Enclosure cc: Regional Administrator USNRC - Region IV Senior Project Manager USNRC - NRR Project Directorate IV-1 St.nior Resident Inspector USNRC NPG Distribution l
to NLS980009 Schedule for Remaining 4160V Breaker Overhauls 4
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SCHEDULE FOR 4160V CIRCUIT BREAKERS Breakers to be replaced / refurbished during the Mid-Cycle Outage (Scheduled for 2/28/98)
> 1 AN, Breaker For Feeder To 4160V Bus l A From Normal Transformer
> II3N, Breaker For Feeder To 4160V Bus IB From Normal Transformer
>* SSIG, Breaker For 480V Substation G Breakers to be replaced / refurbished during Refueling Outage 18 (Scheduled for 10/98)
> SSI A, Breaker For 480V Substation A
> SSIB, Breaker For 480V Substation B
> SSIC, Breaker For Normal Feed To Station Senice. nansformer In 345 KV Switchyard
> SSID, Breaker For Backup Feed To Station Senice Transformer In 345 KV Switchyard
> SSIE, Breaker For 480V Substation E
> ICS, Breaker For Feeder To 4160V Bus IC From Startup Transformer
> IDS, Breaker For Feeder To 4160V Bus ID From Startup Transformer
> ICN, Breaker For Feeder To 4160V Bus IC From Normal Transformer
> IDN, Breaker For Feeder To 4160V Bus ID From Normal Transformer
> CPI A, Condensate Pump A
> CPIB, Condensate Pump B
' > CPIC, Condensate Pump C
> CDPI A, Condensate Booster Pump A
> CBPIB, Condensate Booster Pump B
> CBPIC, Condensate Booster Pump C Breakers to be replaced / refurbished during the designated weeks during plant operation
> 1 AS, Breaker For Feeder To 4160V Bus l A From Startup Transformer - Week 9803
> IBS, Breaker For Feeder To 4160V Bus 1C From Startup Transformer - Week 9802
> IBE, Breaker For Tie To 4160V Bus IE - Week 9814
>-1 AE, Breaker For Tie To 4160V Bus IE - Week 9815
> 1 AF, Breaker For Tie To 4160V Bus IF - Week 9823
> 1BG, Breaker For Tie To 4160V Bus 1G-Week 9822
> SCWPlc, Breaker For Screen Wash Pump C - Week 9804
> SCWP1D, Breaker For Screen Wash Pump D - Week 9817
> CWPI A, Breaker For Circ Water Pump A - Week 9848
> CWP1B, Breaker For Cire Water Pump B - Week 9849
> CWPIC, Breaker l'or Circ Water Pump C - Week 9816
> CWPID, Breaker For Cire Water Pump D - Week 9852
>* SWPIB, Breaker For Senice Water Pump B (has already been swapped out with a qualified breaker from Dresden on 11/5/97 which is being replaced with a CNS breaker week 9804)
- denotes essential breakers i
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ATTACHMENT 3 LIST OF NRC COMMITMENTS l
Corresponder.ce No: NLS980009 Th'e following table identifies those a tions conndtted to by the District in this document.
Any other actions discussed in the submittal represent intended or planned acticas by the District. They are described to the NRC for the NRC's information and are not regulatory concatments.
Please notify the Licensing Manager at Cooper Nuclear Station of Tny questiens regarding this document or any associated regulatory commitments.
COMMITTED DATE COMMITMENT OR OUTAGE The District will revise the 125 Vdc load and voltage studies. These revisions will include the following actions:
- A representative sample of circuits will be validated to assure a high level of confidence in the dnputs to be used.
This representative sample will be expanded, August 31, 1998 as appropriate, based on the number and rignificance
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- The single scenario will be separated into individual of any errors found.
scenarios specific to the requirements being addressed.
- The basis for the sequencing of events in each scenario will be validated and documented.
The calculated load currents will be used to provide the RF018 basis for the battery service test load profiles.
The calculated voltages will be used to provide the basis for service test acceptance criteria previously lacking RCO18 in surveillance procedures.
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PROCEDURE NUMBER 0.42 l
REVISION NUMBER S l
PAGE 9 OF 13 l
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