Part 21 Report - 1998-106
LICENSEE: CONSOLIDATED EDISON CO. OF N.Y./NEW
SITE: INDIAN POINT 2 EN NUMBER:34713
DOCKET: 05000247 EVENT DATE: 08-29-98
RX TYPE: PWR EVENT TIME: 00:00
VENDORS: W-4-LP NOTIFY DATE: 08-29-98
EMERGENCY CLASS: N/A REGION: 1 STATE: NY TIME: 17:12
OPS OFFICER: BOB STRANSKY
10 CFR SECTION: CCCC 21.21 UNSPECIFIED PARAGRAPH
UNIT SCRAM RX INIT INITIAL MODE CURR CURRENT MODE
CODE CRIT PWR PWR
2 N N 0 HOT SHUTDOWN 0 HOT SHUTDOWN
10 CFR PART 21 REPORT REGARDING BINDING OF WESTINGHOUSE DB-50
CIRCUIT BREAKERS
"AFTER COMPLETION OF SURVEILLANCE TEST PMT-170 AUXILIARY
FEEDWATER PUMP (AFWP) ACTUATION FUNCTIONAL TEST, OPERATIONS MADE
AN ATTEMPT TO START 21 AFWP FROM CCR CONTROL SWITCH. THE BREAKER
DID NOT CLOSE.
"DURING STEP BY STEP INVESTIGATION AND INSPECTION, IT WAS
DETERMINED THAT:
(1) THE INERTIA LATCH FAILED TO RESET TO ITS NORMAL POSITION
TO ENABLE
THE OPERATING MECHANISM CLOSING THE BREAKER. (THE VISUAL
INSPECTION
FOUND THE INERTIA LATCH TO BE IN A POSITION TO PRECLUDE
THE
OPERATING MECHANISM FROM CLOSING THE BREAKER.)
(2) THE INERTIA LATCH INITIALLY WAS BINDING SEVERELY. AFTER
MANIPULATION OF THE LATCH THE FRICTION DECREASED TO A
POINT WHERE
THE MOVEMENT WAS NORMAL. WHEN THE LATCH WAS MOVED AXIALLY
TOWARD
THE SNAP RING IT WOULD BIND AT THAT POINT.
(3) THE CAUSE OF THE FAILURE WAS SPALLING OR BREAKING-AWAY OF
SURFACE
COATING ON THE PIVOT PIN AND POSSIBLY THE BUSHING (PIVOT
PIN HOLE)
OF THE INERTIA LATCH. THE FRAGMENTS OF THE COATING
ACCUMULATED ON
THE SURFACES OF THE PIN AND THE BUSHING IN DISCREET
LOCATIONS,
REDUCED THE CLEARANCE BETWEEN THE PIVOT PIN AND THE
BUSHING. THE
REDUCTION IN CLEARANCE RESULTED IN BINDING OF THE INERTIA
LATCH.
THE INERTIA LATCH BINDING PREVENTED THE LATCH TO RESET IN
ITS
NORMAL POSITION AND PREVENTED THE BREAKER FROM CLOSING.
THE
DIMENSIONS OF THE 21 AUXILIARY FEED PUMP BREAKER INERTIA
LATCH PIN
AND PIVOT PIN HOLE [BUSHING] WERE FOUND TO BE NOMINAL
0.375" AND
0.376" RESPECTIVELY.)
"THE EXAMINATION OF THE COATING ON THE SHAFT PIN CLEARLY SHOWED
THAT THE COATING WAS BREAKING AWAY FROM THE SURFACE. THE DAMAGE
MAY HAVE BEEN INITIATED DURING TREATMENT WITH THE EMERY CLOTH AS
PART OF THE CUSTOM FITTING PROCESS. HOWEVER IT APPEARS, THAT
DURING SERVICE, MATERIAL WAS DISLODGED FROM THE SURFACES. THE
VISUAL EXAMINATION INDICATES THAT THE QUALITY OF BONDING OF THE
COATING ON THE SHAFT WAS INADEQUATE."
THE NRC RESIDENT INSPECTOR WILL BE INFORMED BY THE LICENSEE.
Page Last Reviewed/Updated Wednesday, March 24, 2021