ML20077F805
| ML20077F805 | |
| Person / Time | |
|---|---|
| Site: | Washington Public Power Supply System |
| Issue date: | 07/21/1983 |
| From: | De Lorenzo R WASHINGTON PUBLIC POWER SUPPLY SYSTEM |
| To: | Sternberg D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| REF-PT21-83 10CFR-050.55E, 10CFR-50.55E, GO1-83-0367, GO1-83-367, NUDOCS 8308030051 | |
| Download: ML20077F805 (3) | |
Text
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Washington Public Power Supply SystemSJ g,,
P.O. Box 968 3000GeorgeWashingtonWay Richland, Washington 99352 (509)372.5000
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July 21, 1983 9
G01-83-0367 Nuclear Regulatory Commission Region V 1450 Maria Lane, Suite 210 Walnut Creek, CA 94596 Attention:
D.M. Sternberg, Chief Reactor Projects Branch No. 1
Subject:
NUCLEAR PROJECTS 1 & 4 DOCKET N05. 50-460 and 50-513 REPORTABLE CONDITION 10CFR50.55(e)
EMERGENCY DIESEL GENERATOR POTENTIAL TRANSFORMER TILTOUT SUBASSEMBLIES
Reference:
A) Telecon, CR Edwards, Supply System to Bob Dodds, NRC, same subject, dated June 28, 1983.
In Reference A the Supply System informed your office of a reportable deficiency under 10CFR50.55(e).
Attachment A 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-1/4, 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 furti,er information, please advise.
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R.A. De Lorenzo, Program Director WNP-1 RAD /LC0/cmh Attachment cc:
TA liangelsdorf, BPC (861 )
V Mani,-UE&C (897)
Document Control Desk, NRC G Haren, UE&C (895)
FDCC (899)
ORM (847)
RS Goldstein, UE8C (898) 8309030051 830721 PDR ADOCK 05000460 a
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ATTACHENT A WNP 1/4 DOCKET NOS. 50-460 AND 50-513 REPORTABLE CONDITION PER 10CFR50.55(e)
EERGENCY DIESEL GENERATOR POTENTIAL TRANSFORER TILTOUT SUBASSEMBLIES BACKGROUND The Supply System purchased Emergency Diesel Generators, two per plant from Transamerica Delaval.
RTE Delta Corporation provided the generator control panels under subcontract to Delaval.
RTE Delta has reported under the requirements of 10CFR Part 21, a deficiency associated with the potential transformer tiltout subassembly in the generator control panel.
Following receipt of the 10CFR Part 21 notification from Transamerica Delaval, it was determined that this deficiency was reportable under the requirements of 10CFR50.55(e).
DESCRIPTION OF THE DEFICIENCY RTE Delta manufactured the generator control panels (one per diesel) for WNP-1/4. Each of these panels contains a tiltout subassembly which consists of two or three potential transformers, a set of primary knife type disconnects, and a set of flexible pressure type secondary disconnects.
In April 1982, during post seismic electrical testing, a failure was noted in the primary disconnect clips.
The closed "U"
shaped stationary part of the knife type primary disconnect was spread apart to a degree where good contact was no longer possible.
Investigation of the cause of failure revealed that during seismic testing at Wyle Lab. in Norco, California the seismic simulator table had experienced air in the hydraulic system which caused the unit to receive some very severe jolts which were higher than required for testing.
During this test, no recording instruments were monitoring the clip contacts, therefore, no evidence is available to determine at l
what point the failure occured.
Prior to this incident, other similar l
panels had successfully passed such seismic tests.
i SAFETY IMPLICATIONS Poor contact in the primary disconnect portion of the tiltout subassem-l bly could affect the voltage sensing and render the voltage control l
function of the generator inoperable.
As a result, operation of the associated emergency diesel generator would be inhibited and unavail-able to supply emergency power.
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CORRECTIVE-ACTION The deficiency resulted from a malfunction of the shaker table during testing which caused a more severe test condition than required.
Although the disconnects are apparently adequate, having passed the required testing, the decision was made to modify the clip assembly to increase the safety margin based on worst case, plus conditions.
In September 1982, the modified cup assembly was seismically tested to a test plan prepared by Wyle Laboratories, Norco, California.
The new assembly satisfactorily passed the seismic testing and will be used in retrofitting.
The replacement parts will be furnished by Delaval within the next ye ar.
Due to the construction status at WNP-1/4, installation of the new parts cannot be scheduled.
As a result, the Supply System will provide an update at construction restart for each of the Projects.
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