ML20247C719

Forwards Supplemental Response to NRC Bulletin 88-001 Re Westinghouse Series Ds Circuit Breakers.Insp Info Corrected

ML20247C719
Person / Time
Site:	Byron
Issue date:	05/15/1989
From:	Richter M COMMONWEALTH EDISON CO.
To:	Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
IEB-88-001, IEB-88-1, TAC-65955, TAC-65956, NUDOCS 8905250028
Download: ML20247C719 (4)

Text

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/ %ddress Reply to: Post Office [ToTT6T L/ Chicago, Illinois 60690 0767 May 15, 1989 Mr. A. Bert Davis Regional Administrator U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137

Subject:

Byron Station Units 1 and 2 Supplemental Response to NRC Bulletin No. 88-01 NRC Docket Nos. 50-454/455, TACS 65955/65956

References:

(a) NRC Bulletin No. 88-01, dated February 5, 1988.

(b) W.E. Morgan letter to A.B. Davis, dated April 8, 1988.

(c) W.E. Morgan letter to A.B. Davis, dated June 27, 1988.

(d) M.H. Richter letter to A.B. Davis, dated February 9, 1989.

Dear Mr. Davis Reference (a), addressed to all holders of operating licenses or construction permits for nuclear power reactors, provided information on Westinghouse series DS circuit breakers and safety concerns associated with their use. Addressees using these breakers in Cler: 1E service were requested to perform and document inspection of the welds on the pole shafts and inspection of the alignment in the breaker closing mechanism.

This letter corrects the DS circuit breaker inspection information previously reported for Byron Station in Reference (d), and provides the current status of the breaker inspections following the completion of the recent Byron Unit 2 refuel outage.

1 Reference (d), which provided a status of the breaker inspections at the conclusion of the Fall 1988 Refuel Outage for Byron Unit 1, incorrectly reported that the total number of assigned (in-service) breakers was 78 instead of 86. The 8 breakers which were omitted from the total were the reactor trip / bypass breakers (4 breakers per unit). As reported in Reference (b), the reactor trip /bypasr breakers for both units had initially been inspected within the 30 day period requested by Reference (a). These initial inspections revealed the reactor trip / bypass breakers had marginal pole shaft 8905250020 890515 [

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welds requiring reinspection at 200 cycles. The Unit I reactor trip / bypass breakers were reinspected and the pole shafts were replaced during the Unit I refueling outage (Fall 1988), which was the first refueling outage for the unit following the-issuance of Reference (a). The results of the inspections on the Unit I reactor-trip / bypass breakers were. reflected in the breaker inspections reported in Reference (d). In addition, Reference (d) incorrectly reported that the number of assigned breaker inspections was 42 instead of 3 9. E Three (3) of-the reported breaker inspections had been performed on unassigned (spare) breakers. Therefore, Reference (d) should have reported

'that'39 of the 86 assigned circuit breakers had "short-term" and "long-term" inspections performed as defined in Reference (a). These " revised" inspection results have been used to calculate the totals presented in this letter. It should be noted that the listing of the inspected breakers in Reference (d) was accurate.

Byron Unit 2 has recently completed its first refueling outage since the issuance of Reference (a). Twenty-nine (29) assigned breakers (which  !

included the 4 Unit 2 reactor trip / bypass breakers) had "short-term" and "long-term" inspections performed, as defined in Reference-(a), during the refuel outage. The inspections, performed on Westinghouse DS-206 and DS-416 circuit breakers, included the welds for the three main pole levers, the four welds on the pole shaft, and a direct check of the alignment of the breaker closing mechanism. A list of the circuit breakers which were inspected is attached.

The results of the inspections are presented below.

TYPE 411 IYPE 206 No. of breakers inspected 6 23 No. of breakers which had pole shafts 6 23 replaced due to welds No. of breakers requiring corrective action 0 0 for alignment Weld deficiencies included porosity problems and failure to meet the required size criteria. Following maintenance, aliganent was verified to be acceptable for all 29 breakers.

At this time, 68 of the 66 assigned circuit breakers have been inspected. The progress of the inspections is ahead of the schedule previously presented in References (b) and (c). As reported in Reference (c),

l' the unassigned (spare) breakers will have inspections performed prior to being placed in service. Satisfactory completion of all Reference (a) related inspections is tracked by the "480 VAC DS 206/416 Breaker Critical Inspection items Log Book", which is maintained by the Electrical Maintenance Department at Byron Station.

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~ Please address any questions that you or your staff may have -

concerning.this response to this office.

Respectfully, l

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M.H. Richter Nuclear Licensing. Administrator rf/9001k8 ces Document Control Desk Resident Inspector - Byron Subscribe 6 and Suo Lo befq/ me this / dayh 7:::::::: ::::::::::::::,

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l CIRCUIT BREAKERS INSPECTED FOR NRC BULLETIN 88-01 DURING BYRON STATION UNIT 2 REFUELING OUTAGE 1 l

Ereaker Number Description Breaker Type ,

1. 2RD05EA Reactor Trip Breaker DS 416

2. 2RD05EB Reactor Trip Breaker DS 416

3. 2RDOSEC Reactor Trip Breaker DS 416

4. 2RD05ED Reactor Trip Breaker DS 416 5'

5. 2AP26E 231X-2B Manual DS 206 6.. 2AP21E 231X-3A Manual DS 206

7. 2AP25E 231X-3B Manual DS 206

8. 2VD01CA 231X-3D Electrical DS 206

9. 2DC03E 231X-4B Manual DS 206 8-

10. 2AP05E 231Z-2D Electrical DS 416

11. 2AP93E 231Z-3A Manual DS 206 l-

12. OSXO3CC 231Z-3B L.S. DS 206 ' '

13. OSXO3CD 231Z-3C L.S. DS 206

14. OSXO3CC 2312-4B H.S. DS 206

15. OSX03CD 2312-4C H.S. DS 206

16. 2AP24E 232X-2B Manual DS 206

17. 2AP23E 232X-3A Manual DS 206

18. 2AP27E 232X-3B Manual DS 206 i

19. 2VD01CB 232X-3D Electrical DS 206 .

20. 2VA08CA 232X-4A Electrical DS 206 l

21. 2DC04E 232X-4B Manual DS 206

22. 2T006P 232X-5A Electrical DS 206 ,

23, 2AP28E/2AP32E 232X-5B Manual DS 206 II

24. 2AP06E 232Z-2D Electrical DS 416 l

25. 2AP92E 2322-3A Manual DS 206

26. OSX03CG 232Z-3B L.S. DS 206

27. OSX03CH 232Z-3C L.S. DS 206

28. OSX03CG 232Z-4B H.S. DS 206 i.

29. OSXO3CH 232Z-4C H.S. DS 206 (1587z/28z-3)