TXX-4078, Deficiency Rept Re Defective Breaker Support Brackets in 480-volt switchgear.Thirty-six Brackets Contain Suspect Welds.Replacements Tentatively Scheduled for Shipment in Dec 1983
| ML20082E585 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 11/16/1983 |
| From: | Gary R TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, TXX-4078, NUDOCS 8311280243 | |
| Download: ML20082E585 (2) | |
Text
l TENAS UTILITIES GENERATING COMPANY 2001 DHYAN 1 dwelt. DAtl.AN.TEXAM 75201
...ci,~.'j,^".I....~,
November 16, 1983
.~m TXX-4078 Mr. E. H. Johncon, Chief Reactor Project Branch 1 U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement 611 Ryan Plaza Drive, Suite 1000 Docket Nos.:
50-445 Arlington, TX 76012 50-446 7
i, COMANCHE PEAK STEAM ELECTRIC STATIOt DEFECTIVE BREAKER SUPPORT BRACKETS >-
QA FILE:
CP-83-20, SDAR-122 NOV5i88,3 FILE N0.:
10110
-i L. __ _ _
Dear Mr. Johnson:
In accordance with 10CFR50.55(e), we are submitting the enclosed report of actions taken to correct a deficiency regarding defective breaker support brackets.
Supporting documentation is available at the CPSES site for your Inspector's review.
Very truly yours,
)
RJG:ln cc:
NRC Region IV - (0 + 1 copy)
Director, Inspection & Enforcement (15 copies)
U.S. Nuclear Regulatory Commission Washington, DC 20555 8311280243 831116 PDR ADOCK 0500044S S
^
.h
/
f\\
4 TXX-4078 November 16, 1983 ATTACHMENT DEFECTIVE BREAKER SUPPORT BRACKETS DESCRIPTION During routine testing of DS-416 breakers, a tack weld joining the secondary disconnect support bracket to the seismic positioner was observed broken.
Further inspection of the breaker revealed a second broken weld. After confirming the inspection criteria with the supplier (Westinghouse), ten (10) additional breakers were inspected. All breakers examined were found unacceptable.
The DS-416 breakers are used in all 480V switchgear. A 100% inspection by site and supplier personnel has identified thirty-six (36) brackets containing suspect welds. Failure of one or mcre welds on the secondary contact support bracket could result in disengagement of the secondary disconnecting contacts from the corresponding control contacts. Loss of DC control power to the circuit breaker would result.
SAFETY IMPLICATIONS With the loss of DC control power, the circuit breaker could not be opened by an automatic or remote signal. The intended safety function of the breaker would be lost.
4 CORRECTIVE ACTION Replacements for brackets with defective or suspect welds are being secured i
from the supplier. The integrity of the replacement brackets will be confirmed through the quality assurance procurement interface. Replacements will be installed upon receipt.
Replacements are tentatively scheduled for shipment in mid-December,1983.
t
- - -.