ML20153E711
| ML20153E711 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 08/31/1988 |
| From: | Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| CP-88-033, CP-88-33, TXX-88656, NUDOCS 8809060396 | |
| Download: ML20153E711 (2) | |
Text
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Log # TXX-88656 P.
File # 10110 i
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Ref.
- 10CFR50.55(e) 1UELECTRIC w n. c.co a August 31, 1988 I
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U. S. Nuclear Regulatory Commission Attn: Document Control Oesk 1
Washington, D.C.
20555 i
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES) i 3
DOCKET N05, 50-445 AND 50-446 EDG VOLTAGE OUTPUT i
SDAR: CP-88-033 (INTERIM REPORT) l 4
Gentlemen:
On August 30, 1988, we verbally notified your Mr. H. S. Phillips of a i
reportable deficiency under the emergency diesel generator (EDG) provisions of 10CFR50.55(e) involving the i
1 static exciter voltage regulation circuitry.
1 The required information follons.
l Description On March 11, 1987, the NRC was notified in accordance with 10CFR50 Part 21 by I
IMO Delaval, Inc., of a potential deficiency with the static exciter voltage j
regulation reset design for the EDGs.
Subsequently, the NRC and TV Electric l
j were notified by letter dated August 17, 1988, that this problem was j
applicable to CP5ES.
lH0 Delaval, Inc., has identified a specific problem with the static exciter voltage regulator (SEVR) reset design inherent in any installation utilizing an SEVR circuit which relies on engine speed to reset, i
The CPSES EDGs are designed to operate at 450 rpm.
Upon initiation of EDG i
3 shutdown, the SEVR is tripped and does not reset until the engine speed decreases to 425 rpm.
If an emergency start signal is received during the coastdonn prior to reaching 425 rpm the engine would accelerate to its synchronous speed of 450 rpm but there would be no generator output, since the
.s j
exciter would not be energized.
This deficiency is the result of a manufacturer design error.
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TXX 88656 August 31, 1988 Page 2 of 2 Safety implications Had this deficiency remained undetected, the operability of the EDGs under all conditions could not be assured, and therefore could have adversely affected the safety of operations over the life of the plant.
Corrective Action Our evaluation of the corrective action required to resolve the deficient condition is continuing. We will address the correctise action and corrective action impl oentation schedule in our next report which will be submitted no later than January 15, 1989.
Very truly yoy,rsg SM
/
W. G. Counsil WJH/mlh c - Mr. R. D. Martin, Region IV Resident inspectors, CPSES (3)