ML20151T039
| ML20151T039 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 08/08/1988 |
| From: | Shelton D TOLEDO EDISON CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| 1-813, NUDOCS 8808160228 | |
| Download: ML20151T039 (2) | |
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TOLE ^DC
% EDISON A Cerwur Ferg, Cew, DONALD C. SHELTON w, n wn M * ""
Docket No. 50-346 License No. NPF-3 Serial No. 1-813 August 8, 1988 United States Nuclear Regulatory Commission Document Control Desk Vashington, D. C.
20555
Subject:
NRC Open Item 86-32-03:
Inspection of Material Condition of Auxiliary Feedvater (AFV) Valves AF 599 and AF 608 g
1 Gentlemen:
Toledo Edison (TE) planned to inspect the internals of Auxiliary Feedvater Valves AF 599 and AF 608 during the 5th refueling outage to investigate the cause of the higher than expected thrust measurements that vere obtained during MOVATS testing performed in the fall of 1986. This testing was performed in conjun'. tion with Action Plan AP12 of the Davis-Besse Course of Action (C0A) which identified several required actions to correct existing deficiencies and prevent future problems with the Limitorque operators on AFV valves AF-599 and AF-608. These corrective actions included verification that valve data and measurements used for stress and torque calculations were correct based on field reasurements of valve dimensions used in the calculations. NRC Inspection Report No. 50-346/86032 documented the NRC's I
reviev and concurrence with Toledo Edison's completion of this action. The internal inspection and subsequent evaluation of the valve material condition is considered an NRC Open Item (346/86032-03) pending completion and NRC reviev.
i The purpose of the internal inspection was to determine the cause of the higher than expected thrust measured by the MOVATS testing. TE's subsequent evaluation of the MOVATS test results did not indicate any areas of concern over the length of the valve stroke. The problem appears to be due to the valve's design configuration rather than any material degradation.
Since TE believes an internal inspection vould not reveal how the configuration contributed to the increased thrust, a decision was made to replace these valves. The removal vould allow the valves to be shipped to en offsite facility and tested in a more controlled environment.
Velan, the valve manufacturer, had recommended replacement of the valve discs in November, 1986, as a long term fix but this was deemed unnecessary since TE had already decided to replace the valves (with one of a higher pressure design and a longer stroke time),
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THE TOLEDO EDSON COMPANY ED' SON PLAZA 300 MA0! SON AVENUE TCLEDO, OH'O 43652 1
8808160228 880808 PDR ADOCK 05000346 G
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' Docket No. 50-346 License No. NPF-3 r
Setial No. 1-813 Page 2 TE is deferring replacement of these valven until the 6th Refueling Outage (RFO) due to a delay in valve delivery by the vendor.
Presently, both valves are fully operational and meet all their functional requirements. As part of the Davis-Besse C0A corrective action, the automatic closure signal from the Steam and Feedvater Rupture Control System (SFRCS) is being removed during the current refueling outage. These valves vill be normally aligned open thereby i
enhancing the most frequently needed safety function, delivery of auxiliary No mechanism exists to cause automatic feedvater to the steam generators.
closure of these valves. The only action that vill close the valves is direct operetor action. Thus continued use of the existing valves until the 6th RF0 j
has no adverse effect on continued safe operation of Davis-Besse.
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..l Very tr 1 yours, D
j EBS/ sag i
v cci A. B. Davis, Regional Administrator DB-1 Resident Inspector i
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