ML20247B376
| ML20247B376 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 05/04/1989 |
| From: | Greenman E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Reed C COMMONWEALTH EDISON CO. |
| References | |
| CAL-RIII-87-26, NUDOCS 8905240105 | |
| Download: ML20247B376 (2) | |
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MAY '4 1999 Docket No 50-Docket No.
-374 Commonwealth Edison Company ATTN: Mr. Cordell Reed Senior Vice President Post Office Box 767 Chicago, IL 60690 Gentlemen:
By letters dated July. 13, 1988, and February 10, 1989, Commonwealth Edison Company-(CECO), requested NRC approval to revise the frequency (LaSalle) from for main. steam-isolation valve (MSIV) cycling for the LaSalle County Station E
monthly to quarterly.
In December 1987, one of the MSIVs at LaSalle failed to close properly due' to solenoid valve problems. This event was similar to two events which occurred at the Perry facility in the fall of 1987. Region III issued.a Confirmatory Action Letter (CAL-RIII-87-026) to LaSalle on December 21, 1987, which required increased MSIV cycle. testing.
The solenoid valve failures appeared to be temperature induced. Accordingly, a test program was developed by Cleveland Electric Illuminating Company (CEI),
the licensee for the Perry plant to fully investigate the failure mechanisms.
Solenoid valves were subjected to different temperatures for a range of times.
The results of the test program were submitted to NRC in a letter from CEI dated May 2, 1988.
The test results showed no functional anomalies for ASCO solenoid valves with viton seals (such as LSalle has) after 92 days at a temperature of 225'F. At higher temperatures, the testing was able to duplicate the observed condition of the failed valve at LaSalle, that is, an amber film in the valve body. This supports the licensee's ' suspected failure mechanism of degradation of the lubricant, exposed to elevated temperature over time.
In addition, Sargent and Lundy (the LaSalle architect engineer) performed calculations for CECO which established a quantitative relationship between.
temperature and the rate at which the lubricant degrades. The data were
-then used 'to establish a service life for the lubricant of 2.09 years at the i"
ambient conditions for its application in the MSIV solenoid valves at LaSalle
(~ 154 F).
8905240105 890504 PDR ADOCK 05000373 P
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I Commonwealth Edison Company 2 g 4 gggg Based upon these results, it is our understanding that CECO committed to rebuild or replace the ASCO solenoids at LaSalle every refueling outage (approximately every 18 months).
Based upon review of the condition of the LaSalle solenoid valves, the investigation performed by CECO, the special tests performed for CEI, and CECO's commitment to rebuild or replace the ASCO solenoid valves every refueling outage, we approve your request to return the MSIV test frequency to quarterly. Should you experience elevated temperatures, we expect you to adjust your testing frequency accordingly.
Sincerely, Edward G. Greenman, Director Division of Reactor Projects cc:
T. Kovach, Nuclear Licensing Manager G. J. Diederich, Station Manager DCD/DCB (RIDS)
Licensing Fee Management Branch Resident Inspector, RIII Richard Hubbard J. W. McCaffrey, Chief Public Utilities Division David Rosenblatt, Governor's Office of Consumer Services P. Shemanski, NRR h
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