ML20137L684
| ML20137L684 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 11/27/1985 |
| From: | Alexich M, Alexich M INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| AEP:NRC:0962B, AEP:NRC:962B, CAL, NUDOCS 8601280057 | |
| Download: ML20137L684 (3) | |
Text
F b m (S INDIANA & MICHIGAN ELECTRIC COMPANY P.O. BO X 16631 bT"^*
COLUMBUS, OHIO 43216 om"W Css November 27, 1985 AEP:NRC:0962B Donald C. Cook Nuclear Plant Unit Nos. 1 and 2 f
Docket Nos. 50-315 and 50-316 License Nos. DPR-58 and DPR-74
' RESPONSE TO CONFIRMATORY ACTION LETTER REGARDING-RPS TRIP BREAKER Mr. James G. Keppler, Regicnal Adminis'trator U.S. Nuclear Regulatory Commission Office of Inspection and. Enforcement Region III 799 Roosevelt Road Glen Ellyn, IL 60137
Dear Mr. Keppler:
This letter provides response to your Confirmatory Action Letter (CAL) dated October 30, 1985. This CAL pertained to the improper response of the reactor trip breaker "A" which occurred daring a reactor trip event at Donald C. Cook Unit 2 on October 29, 1985. Our previous letter on this matter, AEP:NRC:0962 (dated Novenber 6,1985), provided you an outline of our actions taken subsequent to the Unit 2 reactor trip of October 29, 1985, as well as a request for your concurrence for restart of Donald C.
Cook Units 1 and 2.
That letter discussed all' items except Item 7 of the
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CAL.
This letter responds to Item 7 and thus, based on discussions with your staff, it is our understanding that this Ictter closes all items associated with the CAL.
From November 11 to 15, 1985, personnel from AEPSC and Westinghouse Electric Corporation (and observed by personnel from the NRC - Washington) conducted a series of tests at Westinghouse testing facilities in Monroeville, Pennsylvania designed to evaluate the failure to trip on the
" Train A" undervoltage trip attachment (UVTA) and the failure to pass the Westinghouse Owners Group 20-ounce margin test of the " Train B" UVTA.
Planning and evaluation efforts were begun immediately after initial
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testing in preparation for the next stage of. testing. The attachment to this letter provides additional information on the testing performed in Monroevilla and the conclusions reached to date.
Our findings durirg the investigation at the Donald C. Cook Nuclear Plant immediately following the Unit 2 reactor trip event of October 29, 1985 have already been provided in our submittal AEP:NRC:0962. Following I
completion of all testing, the failed UVTAs will be disassembled for inspection of lubrication and potential wearing and binding points. This l
l 8601280057 851127 PDR ADOCK 05000315 S
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. AEP:NRC:0962B Mr. James G. Keppler procedure is presently under development and is planned to take place during the week of December 2-6, 1985. - A formal report indicating the findings and conclusions of the entire UVTA investigation should be published by Westinghouse Electric Corporation and is expected to be available by January 31, 1986.
This document ha's been' prepared following Corporate procedures which incorporate a reasonable set of controls to insure its accuracy and completeness prior to. signature by the undersigned.
Very truly yours,
/
M. P. Al xich 6k Vice President)
Cm Attachment cc: John E. Dolan W. G. Smith, Jr. - Bridgman R. C. Callen G. Bruchmann G. Charnoff NRC Resident Inspector - Bridgman
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ATTACHMENT TO AEP:NRC 0962B From November 11 to November 15, 1985, personnel from AEPSC and Westinghouse Corporation drafted and subsequently conducted a series of tests designed to evaluate the failure to trip of one UVTA and the failure to pass the Westinghouse owners Group (WOG) 20-ounce margin test of a second UVTA. Tests were conducted at a Westinghouse facility in Monroeville, Pennsylvania.
The testing program involved inspecting and exercising the two failed UVTAs from D. C. Cook, and two new UVTAs obtained directly from Westinghcuse stock.
Inspections were also carried out on two UVTAs of earlier design, supplied as original equipment with the D. C. Cook reactor trip switchgear.
During the inspection of the UVTAs, weld splatter was noted on the base of the UVTA that failed to trip the reactor trip breaker "A" on October 29, 1985. This weld splatter was in a position to interfere with the normal freedom to travel of the UVTA trip spring. Subsequent testing appears to confirm that this was a major contributing-factor to the failure experienced at D. C. Cook.
Inspection identified no abnormalities in the other failed D. C. Cook UVTA, the two UVTAs taken from stock, or the two old-style UVTAs.
The D. C. Cook UVTA that failed the WOG 20-ounce margin test and the two Westinghouse stock UVTAs were placed through repetitive trip-and-recet cycles in an attempt to repeat the failure to meet the WOG 20-ounce margin test. Data obtained from the testing is now under evaluation.
A second battery of tests and inspections is presently being arranged with Westinghouse for the purpose of confirming the results of our earlier testing. As part of these new tests and inspections we will conduct a careful disassembly of the failed UVTAs. This second phase of the testing program is tentatively scheduled for the week of December 2 at Westinghouse facilities in the Pittsburgh area.
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