ML20150B673
| ML20150B673 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 06/27/1988 |
| From: | Morgan W COMMONWEALTH EDISON CO. |
| To: | Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 4857K, 88-001, 88-1, IEB-88-001, IEB-88-1, NUDOCS 8807120114 | |
| Download: ML20150B673 (2) | |
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Chicago, Illinois 60690 0767 June 27, 1988 Mr. 4. Bert Davis Rer'ional Administrator U.S. Nuclear Regulatory Commission Region III 799 Roosb>elt Road Glen Ellyn, IL-60137 P
Subject:
Byron Station Units 1 & 2 Braidwood Station Units 1 & 2 Supplemental Response to NRC Bulletin No. 88-01 NRC Docket Nos. 50-454/455 and 50-456/457
Reference:
(a) NRC Bulletin No. 88-01, dated February 5, 1988 (b) W.E. Morgan Letter to A. Bert Davis dated April 8, 1988 (c) L.N. Olshan letter to H. Bliss dated April 22, 1988
Dear Mr. Davis:
The above referenced NRC Bulletin (a) requested that holders of operating licenses of construction permits for Nuclear Power Reactors provide information on Westinghouse series DS circuit breakers an(' safety concerns associated with their use. Additionally, to request that addresses w ing these breakers in class 1E service, perform and document inspection,of the alignment in the breaker closing mechanism. The following information updates Braidwood Station's response to NRC Bulletin 88-01 as originally transmitted in reference (b).
Braidwood Station has completed the long and short term inspections of the four Unit 2 reactor trip breakers using the acceptancre criteria given in the NRC Bulletin and Westinghouse Technical Bulletin NSID-TB-87-ll.
Three of the reactor trip breakers failed to meet the acceptance criteria.
The results are summarized below:
2RD05E Trip A
- Rejected, Weld #6 size (1/8" for 3/8" total length) 2RD05E Trip B
- Acceptable 2RD05E Bypass A - Rejected, Weld #4 size (1/8" for 3/8" total length) 2RD05E Bypass A - Rejected, Weld #2 Porosity 1/16", cumulative 3/16" size not 1800; Weld #3 length (3/16" size not 180o)
Each cf the breakers with rejected pole shaf ts were corrected by installing new pole shafts. All were satisfactorily tested and subsequently placed in service.
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.e e Additionally clarification is being submitted in regards to the letter transmitted in reference (b), concerning Byron Station's response to Bulletin 88-01.
Reference (b) implied that Byron Station will inspect the DS-type circuit breakers in one entire electrical division in each refueling outage and Reference (c) confirmed the NRC's understanding of this schedule.
In clarification of References (b) and (c), Byron Station proposes to inspect the remaining 62 in service safety-related breakers during their next preventive maintenance surveillance inspe.. tion as scheduled by the Byron station General Surveillance program. The Byron Station General Surveillance program schedules approximately 25% of each Unit's total breakers for preventive maintenance surveillance inspections during each 21 month period, so that at the end of each refueling outage approyimately 25%
of each Unit's breakers have had their preventive maintenance surveillance performed. The 34 unassigned safety-related DS-series breakers will have welas inspected prior to being placed in service. Satisfactory completion of all NRC Bulletin 88-01 related inspections is tracked by the "480 VAC DS 206/416 Breaker Critical Inspection Items Log Book", which is maintatined in the Electrical Maintenance Department. All inspections are scheduled for completion by 1993.
please address any questions that you or your staff may have concerting this response to this office.
Respectfully N
W.E. Mwrgan Nuclear Licensing Administrator rf ec: Document Control Desk Resident Inspector's BY/BW 4b57K