Part 21 Report - 1997-360

LICENSEE: AUTOMATIC VALVES CORPORATION SITE: AUTOMATIC VALVES CORPORATION EN NUMBER:32253 DOCKET: EVENT DATE: 04-25-97 RX TYPE: EVENT TIME: 00:00 VENDORS: NOTIFY DATE: 05-01-97 EMERGENCY CLASS: N/A REGION: 3 STATE: MI TIME: 16:14 OPS OFFICER: JOHN MacKINNON 10 CFR SECTION: CCCC 21.21 UNSPECIFIED PARAGRAPH PART 21 REPORT REGARDING FAILURE OF SCRAM SOLENOID PILOT VALVES ISSUED BY AUTOMATIC VALVES CORPORATION, NOVI, MICHIGAN. IN SEPTEMBER, 1996, AUTOMATIC VALVES CORPORATION (AVCO) WAS NOTIFIED BY VERMONT YANKEE THAT A SCRAM SOLENOID PILOT VALVE WAS MAKING A BUZZING SOUND (RATHER THAN A HUMMING SOUND) WHEN ENERGIZED. AVCO DISCOUNTED THE REPORT AND TOOK NO ACTION AT THAT TIME BECAUSE ALL AC SOLENOIDS HUM TO SOME EXTENT AND THEY ASSUMED THIS NOISE TO BE A NORMAL AC HUM SINCE NO KNOWN PRODUCT OR CUSTOMER COMPLAINT FAILURE HAD EVER BEEN RECEIVED BY AVCO DUE TO AC HUM OR BUZZ. ON 04/24/97, WHILE VERMONT YANKEE WAS PERFORMING SCRAM TIME TESTING, THE CONTROL ROD ASSOCIATED WITH THE NOISY SCRAM SOLENOID PILOT VALVE #06-11-118 (WHICH HAD BEEN NOISY FOR THE LAST SIX MONTHS) HAD A SCRAM TIME THAT WAS SLOWER THAN THE OTHER CONTROL RODS THAT WERE BEING TESTED, BUT WAS WITHIN THE TECHNICAL SPECIFICATION TIME LIMITS. AVCO HAS DETERMINED THAT THE NOISE WAS DUE TO METALLIC VIBRATION WITHIN THE SCRAM SOLENOID PILOT VALVE WHICH CAUSED THE VALVE PERFORMANCE TO DEGRADE. DURING PAST ACCEPTANCE TESTS, AVCO DID NOT USE AUDIBLE NOISE EMANATING FROM THE SCRAM SOLENOID PILOT VALVES AS AN ACCEPTANCE CRITERION. AVCO HAS CHANGED THEIR PROCEDURES TO USE THIS CRITERION. AVCO HAS SUPPLIED SCRAM SOLENOID PILOT VALVES TO 20 - 25 NUCLEAR POWER PLANTS IN THE UNITED STATES. *** UPDATE AT 1640 ON 05/02/97 BY AVCO TODD HUTCHINS TAKEN BY MacKINNON *** AFTER INTERVIEWS WITH AVCO INSPECTION PERSONNEL, AVCO MANAGEMENT PERSONNEL DETERMINED THAT VALVES AT AVCO HAD BEEN INSPECTED FOR "NOISE" BUT THIS HAD BEEN DONE UNOFFICIALLY WITHOUT ANY CONSISTENT ACCEPTANCE/REJECTION CRITERIA. DIMENSIONAL DIFFERENCES BETWEEN SOLENOIDS THAT BUZZ AND HUM ARE NOT DETECTABLE. THIS WAS CONFIRMED WITH TWO AVCO SOLENOID VALVE COMPETITORS. DEFINITIONS FOR ACCEPTABLE AC HUM AND REJECTABLE BUZZ FOR AC SOLENOIDS HAVE NOW BEEN ADDED TO IN-PROCESS INSPECTION POINTS AND FINAL TEST PROCEDURES AT AVCO. AVCO RECOMMENDATION: EVEN THOUGH THE SOLENOID VALVE FUNCTIONED, IT WAS SIGNIFICANTLY SLOWER DUE TO THE AMOUNT OF METALLIC BY-PRODUCT FROM THE BUZZING SOLENOID PLUNGER. REGARDLESS OF THE MANUFACTURER, SOLENOIDS SHOULD BE CHECKED FOR BUZZING NOISES AS IT COULD DEGRADE THE PERFORMANCE AND POTENTIALLY THE LIFE OF THE VALVE. ANY REBUILDING OF ANY SUPPLIER'S SOLENOID VALVES REQUIRES A 'NOISE" TEST. SINCE 1970, AVCO HAS NOT BEEN ADVISED OF A SINGLE SAFETY RELATED AVCO PRODUCT FAILURE DUE TO THIS CAUSE. VERMONT YANKEE CONFIRMED THIS WITH A CHECK OF THE NUCLEAR PLANT RELIABILITY DATA SYSTEM. AVCO WILL RETEST, RECERTIFY, AND RESHIP AT NO CHARGE ANY SUSPECTED PRODUCT. AVCO WILL REPLACE AND RESHIP AT NO CHARGE ANY COMPONENT FOUND TO BE FIELD DEFECTIVE. THE OPERATIONS OFFICER NOTIFIED R1DO (MICHAEL MODES), R2DO (CHUCK CASTO), R3DO (MARK RING), R4DO (JOE TAPIA) & NRR VERN HODGE. NOTE: SEE EVENT #32263 FOR A RELATED EVENT. LICENSEE: VERMONT YANKEE NUCLEAR POWER CORP. SITE: VERMONT YANKEE 1 EN NUMBER:32263 DOCKET: 05000271 EVENT DATE: 05-02-97 RX TYPE: BWR EVENT TIME: 15:15 VENDORS: GE-4 NOTIFY DATE: 05-02-97 EMERGENCY CLASS: N/A REGION: 1 STATE: VT TIME: 16:36 OPS OFFICER: JOHN MacKINNON 10 CFR SECTION: AINA 50.72(b)(2)(iii)(A) POT UNABLE TO SAFE SD UNIT SCRAM RX INIT INITIAL MODE CURR CURRENT MODE CODE CRIT PWR PWR 1 N N 0 COLD SHUTDOWN 0 COLD SHUTDOWN AUTOMATIC VALVE CORPORATION SCRAM SOLENOID PILOT VALVES FAILED A SCRAM TIME TEST. ON 04/24/97, SCRAM SOLENOID PILOT VALVE (SSPV) #06-11-118 FAILED A SCRAM TIME TEST. PRIOR TO THE SSPV FAILING THE TEST, IT EXHIBITED A BUZZING SOUND. THE LICENSEE REPLACED THE FAILED SSPV AND NINE OTHER SSPVs EXHIBITING NOISE. THE PLANT HAS 93 SSPVs INSTALLED IN THE SCRAM SYSTEM AND 8 SSPVs INSTALLED ON THE MAIN STEAM ISOLATION VALVES (MSIV). THE LICENSEE SHIPPED THE FAILED VALVE TO THE SUPPLIER, AUTOMATIC VALVE CORPORATION, FOR VISUAL INSPECTION, FAILURE ANALYSIS, AND ROOT CAUSE DETERMINATION. THE LICENSEE HAS SUBMITTED A BASIS FOR MAINTAINING OPERATION WHICH INCLUDES ADDITIONAL MONITORING OF SSPVs BY PLANT OPERATORS TO THE NRC RESIDENT INSPECTOR AND NRC REGION 1. THE LICENSEE PLANS TO INSPECT THE MSIV SCRAM SOLENOID PILOT VALVES PRIOR TO PLANT RESTART. THE LICENSEE INFORMED THE NRC RESIDENT INSPECTOR. NOTE: SEE EVENT REPORT #32253 FOR BACKGROUND INFORMATION.

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