TXX-6782, Interim Deficiency Rept CP-87-80 Re Inconsistencies Observed in Design & Installation of Fuses.Initially Reported on 870831.Evaluation of Safety Significance Continuing.Next Rept to Be Submitted by 880129
| ML20235K779 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 09/30/1987 |
| From: | Counsil W, Keeley G TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| CP-87-80, TXX-6782, NUDOCS 8710050228 | |
| Download: ML20235K779 (2) | |
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M Log # TXX-6782 2
File # 10110
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908.3 Ref #10CFR50.55(e) 7UELECTRIC William G. Coumil e m n,, n,em sem September 30, 1987 l
V. S. Nuclear Regulatory Commission Attention:
Document Control Desk Washington, D. C. 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50-445 AND 50-446 i
FUSE SIZING l
SDAR: CP-87-80 (INTERIM REPORT)
Gentlemen:
On August 31, 1987, we verbally notified your Mr. H. S. Phillips of a deficiency involving inconsistencies which have been observed in the design and installation of fuses. This deficiency was discovered during third-party investigations addressed in Corrective Action Request (CAR)87-037. This is an interim report of a potentially reportable item under the provisions of 10CFR50.55(e).
Specifically, two instances of installation of improper fuse sizes have been identified.
In both. cases, the current rating of the fuse installed was less than the required current rating.
The two circuits which contained the incorrect fuses are associated with safety related shunt trip devices which are normally de-energized.
However, during a loss of Off-site Power, these circuits are required to "shed" emergency bus loads from service when the emergency diesel generators are starting.
The subject fuses provide short-circuit and overcurrent protection for the cables and devices in the circuits.
Since the fuses' current ratings are smaller than required, passing the maximum design current through the fuses could de-energize the circuit.
8710050228 870930 7
DR ADOCK 050 5
I 40 North Ohve Street LB SI Dallas. Texas 75201
2 TXX-6782 September 30, 1987 Page 2 of 2 Our evaluation of the safety significance of this condition is continuing.
Our next report on this issue will be submitted no later than j
January 29, 1988.
Very truly yours, W. G. Counsil 1
7 By:
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G. S. Keeley Manager, Nucle @ c ing WJH:tgj c-Mr. R. D. Martin,-Region IV Resident inspectors, CPSES (3) l l
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