United States Nuclear Regulatory Commission - Protecting People and the Environment


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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