ML17252A938
| ML17252A938 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 12/06/1973 |
| From: | Worden W Commonwealth Edison Co |
| To: | O'Leary J US Atomic Energy Commission (AEC) |
| References | |
| WPW Ltr.#891-73 | |
| Download: ML17252A938 (2) | |
Text
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_c,; Dresden Nuclear Power Stationt...**?.::t:~~h
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- Regulatory Docket File orris, Illinois ecember 6, 1973
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Mr. J. F. 0 Leary, Director Directorate of Licensing
- u. s. Atomic Energy C011111ission Washington, D. c.
20545
SUBJECT:
LICENSE DPR*25 1 DRESDEN NUCLEAR POWER STATION, UNIT #3, REPORT dF ABNORMAL OCCURRENCE PBR SECTION 6.6.B.l OF TRB TECHNICAL SPECIFICATIONS.
FAILURE OF REACTOR CLEAN UP SYSTEM yALVB M0-3-1201*2 TO OPERATBi;
References:
- 1) Notificat~on of Region Ill of ABC Regulatory Operations Telephone: F. Maura, 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br /> on November 28, 1973 Telegram:
Keppler9 1620 hours0.0188 days <br />0.45 hours <br />0.00268 weeks <br />6.1641e-4 months <br /> 0n November 28, 1973
- 2) DWGS:. P & ID. M-361
Dear Mr. O'Leary:
This le.tter is to report a condition relating to the operation of the unit at about 2011 hours0.0233 days <br />0.559 hours <br />0.00333 weeks <br />7.651855e-4 months <br />. on November 27. At. this time M0-3-1201-2 failed to isolate on a reactor *t*ow water level scram.
This malfunction is contrary to section 3.7.D.l of the Technical Specifications which requires that the isolation valve be operable during reac~or power operating conditions.
PROBI.Ell At 2011 hours0.0233 days <br />0.559 hours <br />0.00333 weeks <br />7.651855e-4 months <br />, Unit :3: was operating at* 2178 MWt and 729 MWe.
The cleanup system was in service and operating.
The reactor scrammed on low water level. As a result of the scram, the clean-up valve, M0-3-1201-2, failed to isolate. This valve is.the second isolation valve in the system.
The first isolation valve, M0-3*1201-1, operated as: designed.
INVESTIGATION While investigating this incident, it was !found that the breaker auxiliary contacts for the "M coil were tarnished. : Thia condition preVented the proper operation of the contacts which thus prevented the valve motor from operating.
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Kr. J. F. O'Leary December 6, 1973
- CORRECTIVB-:ACTION -
The tarnished contacts were cleaned and the valve was tested. It operated satisfactorily.
In light of this incident, the station is initiating a program to inspect all breakers for DC motor operated isolation valves. These inspec-tions will include cleaning contacts and adjusting the contact pressure as necessary. Valve breakers will be inspected as the valves become available during outages.
EVALUATIONS This valve malfunction did not jeopardize the safety of the public or plant personnel because the redUlldant valve in this line functioned properly. Consequently, startup of the unit was considered safe.
A similar problem has been experienced recently on motor operated valve 2*220*2 on Unit 2. However, these two malfunctions do not constitute an unsafe trend and the corrective action being initiated_ will prevent such a trend from being established.
Sincerely, W. (J t()~lft<...
- w. P. Worden Superintendent Dresden Nuclear Power Station WPW:do