ML20116P195
| ML20116P195 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/15/1985 |
| From: | Counsil W NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| (SD-71), F0700A, NUDOCS 8505070550 | |
| Download: ML20116P195 (2) | |
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April 15,1985 Docket No. 50-423 F0700A Dr. Thomas E. Murley Regional Administrator U.S. Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406
Reference:
(1)
W.
G.
Counsit to T.
E.
- Murley, F0675A, dated February 15,1985.
Dear Dr. Murley:
Millstone Nuclear Power Station, Unit No. 3 Reporting of Potential Significant Deficiencies in Accordance with 10CFR50.55(e):
Emergency Generator Load Sequencers (SD-71)
In a January 17, 1985 telephone conversation between your Mr. T. Rebelowski and our Mr. R. K. McCarthy, 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 deficiency involved the improper operation of the emergency generator load sequencers supplied by Vitro Laboratories.
While performing an automatic test verification utilizing the external auto-test box, it was discovered that the loss-of-power relays on the output of the load sequencers would actuate. The purpose of the test is to verify the critical electrical path within the sequencer logic. This test verification should not activate the output relays of the sequencer. This actuation would result in the de-energization of all affected loads on the subject bus. We have determined that this condition represents a significant deficiency in the final design of Millstone Unit No. 3.
Vitro Laboratories has developed a corrective design package which was reviewed and approved by our engineering staff. With the assistance of Vitro Laboratories, we have implemented the actions necessary to correct this significant deficiency. The sequencers have been successfully retested and the critical electrical path within the logic verified.
8505070550 850415 PDR ADOCK 05000423 S
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, We consider this to be.our final report for SD-71. We trust that the above information satisfactorily responds to your concerns.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY BTbt' W. G. Counsil Senior Vice President cc:
Mr. 3. M. Taylor, Director.
Division of Inspection and Enforcement U.S. Nuclear Regulatory Commission Phillips Building 7920 Norfolk Avenue Bethesda, MD 20814 4
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