United States Nuclear Regulatory Commission - Protecting People and the Environment

LICENSEE: SOUTHERN CALIFORNIA EDISON & SAN DI
SITE: SAN ONOFRE 2 3 EN NUMBER:35685
DOCKET: 05000362 EVENT DATE: 05-05-99
RX TYPE: PWR PWR EVENT TIME:
VENDORS: CE CE NOTIFY DATE: 05-06-99
EMERGENCY CLASS: N/A REGION: 4 STATE: CA TIME: 15:12
OPS OFFICER: CHAUNCEY GOULD
10 CFR SECTION: CCCC UNSPECIFIED PARAGRAPH

UNIT
SCRAM
CODE
RX
CRIT
INIT
PWR
INITIAL
MODE
CURR
PWR
CURRENT
MODE
2 N Y 100 Power Operation 100 Power Operation
3 N N 0 Hot Shutdown 0 Hot Shutdown

THE LICENSEE HAS DETERMINED THAT A MANUFACTURING DEFECT IS PRESENT ON SOME OF THE POTTER AND BRUMFIELD (P&B) RELAYS THEY HAVE AT THE SITE.

SIXTEEN P&B RELAYS, MODEL KUP93-14A32-120, WERE SUPPLIED IN LOT #913501 BY THE VENDOR AS COMMERCIAL GRADE ITEMS AND WERE DEDICATED FOR NUCLEAR SERVICE AT SAN ONOFRE. THE LICENSEE'S LAB ANALYSIS OF FOUR OF THESE RELAYS DETERMINED THE CONTACT PADS WERE INSUFFICIENTLY WELDED TO THEIR CONTACT ARMS AND COULD BECOME DETACHED. BASED ON THEIR REVIEW OF RELAY FAILURE HISTORY, THE LICENSEE CONCLUDED THE INSUFFICIENT CONTACT PAD WELDING IS LIMITED TO LOT #913501.

THESE RELAYS HAVE BEEN REPLACED WITH NEW P&B RELAYS WHICH HAVE THE CONTACT PADS RIVETED TO THEIR CONTACT ARM, THUS PRECLUDING ANY CONTACT DETACHMENT.

Page Last Reviewed/Updated Thursday, March 29, 2012