ML20132A348
| ML20132A348 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 09/06/1985 |
| From: | Opeka J NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| F0831A, F831A, SD-86, NUDOCS 8509250317 | |
| Download: ML20132A348 (1) | |
Text
NORTDr.AST UTILITIES con r.i On.c... s.io.n sir i. e.riin. connecticut EI,7$IviY c$w P.O BOX 270 m m.ama.caraa- ~
HARTFORD, CONNECTICUT 06141-0270 L
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(203) 685-5000 September 6,1985 Docket No. 50-423 F0831A Dr. Thomas E. Murley Regional Administrator U. S. Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406
Dear Dr. Murley:
Millstone Nuclear Power Station, Unit No. 3 Reporting of Potential Significant Deficiencies in Accordance with 10CFR50.55(e):
Differential Relays GE Type PVD21 (SD-86)
In an August 8,1985 telephone conversation between your Mr. T. Rebelowski and our Mr. R. 3. Young, Northeast Nuclear Energy Company (NNECO) reported a potential significant deficiency in the construction of Millstone Unit No. 3 in accordance with 10CFR50.55(e). The potential significant deficiency involves the General Electric Type PVD21 Differential Relays located in the Class IE 4160 volt switchgear. Mechanical impacts to the switchgear doors containing the PVD21 relays have caused tripping of the switchgear circuit breakers.
NNECO has met with General Electric to discuss this issue. The apparent sensitivity to shock of the PVD21 relays raises concern that a potential common mode failure of both 4160 volt busses would occur at a seismic loading not as yet determined. Analysis alone is not able to accurately determine this seismic loading. Therefore, a retest of the PVD21 relays will be performed.
Until the retest is performed, a final report cannot be provided. We will provide an update on this matter by October 18,1985.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY b b d _.
- 3. F. Opdka/
U Senior Vice President cc:
Mr. 3. M. Taylor, Director Division of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555 8509250317 850906 PDR ADOCK 05000423 S
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