ML20210B353
| ML20210B353 | |
| Person / Time | |
|---|---|
| Site: | Washington Public Power Supply System |
| Issue date: | 04/22/1987 |
| From: | Holmberg B WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| To: | Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| REF-PT21-87, REF-PT21-87-110-000 GOI-87-0041, GOI-87-41, PT21-87-110, PT21-87-110-000, NUDOCS 8705050293 | |
| Download: ML20210B353 (2) | |
Text
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UECEIVED
'- WASHINGTON PUBLIC POWER SUPPLY SYSTEM' P.O. Box 968
- 3000 George \\'ashington 1%'ay
- Richland, abs $g%rpfg REGloi;y73g April 22,1987
'G01-87-0041 Docket No. 50-460 Mr. John B. Martin Regional Administrator, Region V U. S. Nuclear Regulatory Commission 1450 Maria Lane, Suite 210 Walnut Creek, California 94596
Subject:
NUCLEAR PROJECT N0. 1 POTENTIALLY REPORTABLE CONDITION 10CFR50.55(e)
EMERGENCY DIESEL GENERATOR STATIC EXCITER V0LTAGE REGULATOR
Reference:
Telecon, C.R. Edwards (Supply System) to Al Toth (NRC), April 6, 1987, same subject In the reference telecon, the Supply System informed your office of a reportable deficiency under 10CFR50.55(e).
-The attached provides a statement of the identified condition and a brief description of our planned actions to correct the identified deficiency. Based on the current construction status at WNP-1, the Supply System will not be able.
to issue a final report at this time. An update will be provided at construction restart.
.If you have any questions or desire further information, please advise.
r ,
.A.'H6h15k,WNP-1 Program Director (MD 821)
BAH:LCO:pd (PJ3/70)
Attachment i cc: A. D. Edmondson, UE&C (898)
E. C. Haren, UE&C (895) l i E. Revell, BPA (399)
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NRC Document Control Desk, Washington, D. C.
i SDCC l
8705050293 870422 PDR ADOCK 03000460 S PDR i i 1 1
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Attachment DOCKET N0. 50-460 POTENTIALLY REPORTABLE CONDITION PER 10CFR50.55(e)
EMERGENCY DIESEL GENERATOR STATIC EXCITER VOLTAGE REGULATOR DESCRIPTION OF DEFICIENCY The Supply System's WNP-1 Project utilizes two emergency diesel generators from IMO Delaval, formerly Transamerica Delaval (TDI), as its emergency power supply source. IMO recently issued a 10CFR Part 21 report concerning a potential problem with the static exciter voltage regulator (SEVR) reset design.
The SEVR system is designed to de-energize upon receipt of a normal shutdown signal and to reset when the engine speed falls below 200 RPM. If an emergency is received before the engine coasts below this reset speed, the engine will accelerate to its normal operating speed of 450 RPM. However, the exciter would not have been energized, thereby preventing the generator from providing any output voltage.
ANALYSIS OF SAFETY IMPLICATION Loss of generator output voltage would prevent the energization of emergency loads necessary for the safe controlled shutdown of the plant.
CAUSE OF DEFICIENCY Although this circuitry was an intentional design feature to allow an engine / generator shutdown without overheating the generator field, it apparently overlooked the potential for an emergency start during the engine coastdown.
CORRECTIVE ACTION IMO Delaval recommends that the subject control circuits be modified to energize the SEVR upon receipt of an emergency start signal. IMO Delaval is in the process of designing these modifications. Upon completion, information necessary to implement the required changes will be forwarded to the site. Due to the project status, actual rework will be delayed until restart.
ACTION TO PREVENT RECURRENCE Correction of the control circuitry will ensure that the WNP-1 engines are acceptable for providing power to emergency loads. No further action is deemed necessary.