ML20084R748
| ML20084R748 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 09/19/1974 |
| From: | Stephenson B COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| Shared Package | |
| ML20084R750 | List: |
| References | |
| 656-74, RO-50-249-74-54, NUDOCS 8306150532 | |
| Download: ML20084R748 (2) | |
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Address Reply to: Post O!hco Box 767 a
r Chicago, I'linois 60690 BBS Ltr.#656-74 Dresden Nuclear Power Station R. R. #1 Morris, Illinoio 60450 September 19, 1974 Mr. Jameo G. Keppler, Regional Director Directorato of Regulatory Operationc-Region III U. S. Atomic Energy Coc:siccion 799 Roooovelt Road Glen Ellyn, Illinois 60137
SUBJECT:
REPORT OF U'! USUAL EVEt?P PER SECTION 6.6.0 0F THE TECRTICAL SPEEIFICATIC !S.
References:
- 1) Regulatory Guide 1.16 Rev.1 Appendix A
- 2) Drecden Station Dravingo 5 358
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Report Number 50-249/1974-54 i
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Report Dato: September 19, 1974
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.y Occurrenco Dates August 27, 1974 7
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Facility: Dresden Nuclear Power Otation, Morrio, Illinois
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g ED7fIPICATION OP OCCURRE!!CE Core opray valve 3-1402-3Ri failure to cloco.
8 C0:7DITIONS PRIOR TO OCURRC:CE Coro spray valve and pump operability curveillance was being performed as required prior to removing an Emergency Diesel Generator from service. At the time of the occurrence, the unit was in the "Run" modo and themal power was about 1430 megawatts. The unit was operating at an electrical load of 443 megawatts.
c DESCRIPPION OP OCCURRENCE While conducting the core spray valve operability checks, prior to removing an emergency diecel generator from service, E0 valve 3-1402-38A failed to cloco. The valve failed on the initial attrapt at operation when the valvo control switch was placed in the closed pocition.
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WPY ENT REGION
4 Mro JameJ G. K;ppl S:ptemb:r 19, 1974 DESIGNATION OP APPARTP CAUSE OF OCCURRENCE The thermal overloads for motor operated valve 3-1402-3SA n'ad tripped.
ANALYSIS OP OCCURRENCE During the failure of the 3-1402-38A valve to cicco, the cafety of the plant and public was not in jeopardy. Although the "A" loop of the core spray cyctem would have lost sc=e flou during operation, it would not havo been enough to mako it inoperable. In addition, all other core cooling systems ucre operational during the occurrence.
CORRECTIVE ACTION The inmediato corrective action taken was to manually close the 3-1402-38A valvo. After the thermal overloads auto react, the valve van operated three times ou:cessfully from the control room. The valve limit owitches and torque switches were checked and found to bo operating correctly, llowever, during the check it was discovered that the valvo did not auto open on a low flow signal. The cupply breaker for the 3-1402-38A valvo vaa improperly mounted in the motor control center. The breaker housing has three connectors which mate with three cannectors on the motor control center, and supply three phaco power to the valve motor. One phase connector was not making contact.
The motor vould operate with two of the requir'ed three phase connections.
!!owever, the motors operating temperature and running current would be incrossed to the point where the thermal overloado would open. The breaker housing was pocitioned properly and then occured to the motor control center.
Since this in the first timo the breaker housing was removed from the motor control center, it 10 concluded that it was initially installed improperly. No problem with this type of breaker connector has occurred in the pact and the corrective action taken at this time 10 considered to be sufficient.
FAILURE DATA The core opray valve }-1402-38A has failed only once in the last two years.
A previoun failure occurred on October 16, 1973 as reported to Region III in a letter to Mr. A. Giambusco dated November 15, 1973 from Mr. F. Morris of Dresden Station. The cause of that failure was due to an inoperablo flow t; witch DP 1464A.
Sincerely, O
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- . B. Stephenson B
0 Superintendent BBStTELtdo O
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