Part 21 Report - 1995-173
SAN ONOFRE 2 3 29096 07-21-95 POW
LICENSEE: SOUTHERN CALIFORNIA EDISON & SAN DI
SITE: .SAN ONOFRE 2 3 . EN NUMBER:29096
DOCKET: 05000361 05000362 EVENT DATE: 07-21-95
RX TYPE: PWR PWR EVENT TIME: 00:00
VENDORS: CE CE NOTIFY DATE: 07-21-95
EMERGENCY CLASS: N/A REGION: 4 STATE: CA TIME: 20:45
OPS OFFICER: TIM McGINTY
10 CFR SECTION: CCCC 21.21 UNSPECIFIED PARAGRAPH
UNIT SCRAM RX INIT INITIAL MODE CURR CURRENT MODE
CODE CRIT PWR PWR
2 N Y 100 POWER OPERATION 100 POWER OPERATION
3 N Y 83 POWER OPERATION 83 POWER OPERATION
SAN ONOFRE PROVIDED A PART 21 REPORT REGARDING POTTER & BRUMFIELD
(P&B) MODEL-5095 MOTOR-DRIVEN RELAYS (MDR). SAN ONOFRE WAS
NOTIFIED BY P&B OF POSSIBLE IMPROPER RE-ASSEMBLY OF SEVERAL
DIFFERENT MODELS OF P&B RELAYS. THE IMPROPER RE-ASSEMBLY INVOLVES
INTERNALLY DAMAGED (BENT) CONTACT ARMS THAT COULD ADVERSELY
EFFECT RELAY INTERRUPT CAPABILITY, DIELECTRIC CAPABILITY,
RELIABILITY, AND LIFE EXPECTANCY. THE PROBLEM IS POTENTIALLY
APPLICABLE TO ANY MDR RELAY RETURNED TO P&B FOR REWORK OR
DISASSEMBLY BETWEEN MARCH 1993 AND MARCH 1995.
POTTER & BRUMFIELD INC. (A SEIMENS CO.) IS LOCATED IN MARION, KY.
SEVEN OF EIGHTEEN RELAYS RETURNED FROM P&B TO SONGS WERE
SUBSEQUENTLY INSTALLED IN SAFETY-RELATED SYSTEMS OF THE SONGS
PLANTS. THE MOST LIMITING APPLICATION OF THESE SEVEN MDR RELAYS
IS IN THE CONTROL CIRCUITS OF VALCOR SOLENOID VALVES WHICH
ISOLATE CONTAINMENT PRESSURE TRANSMITTER SENSING LINES AT UNITS 2
AND 3. THE SOLENOID VALVES ARE NORMALLY OPEN AND REMAIN OPEN
DURING ACCIDENT CONDITIONS INSIDE THE CONTAINMENT. THESE VALVES
ARE ONLY REQUIRED TO CLOSE IN ORDER TO ISOLATE A SENSING LINE
FAILURE OR LOSS OF PRESSURE BOUNDARY IN THE TRANSMITTER. THE
SEVEN INSTALLED RELAYS WILL BE REPLACED AT THE EARLIEST
OPPORTUNITY FOLLOWING PROCUREMENT OF REPLACEMENTS. THE SEVEN
INSTALLED P&B MDR RELAYS AT SONGS REMAIN OPERABLE AT THIS TIME
BASED ON POSITIVE DEDICATION TESTING RESPONSE, SYSTEM DESIGN USE,
SUCCESSFUL INSTALLATION POST-MAINTENANCE TESTING, AND PAST
OPERATING EXPERIENCE WITH OTHER RELAYS USED IN THIS TYPE
APPLICATION.
THE HOO FORWARDED THE PART 21 NOTIFICATION TO VERN HODGE.
Page Last Reviewed/Updated Wednesday, March 24, 2021