Part 21 Report - 1997-300

 
 

LICENSEE: PUBLIC SERVICE ELECTRIC & GAS CO.  

SITE: HOPE CREEK 1                          EN NUMBER:32100

DOCKET: 05000354                         EVENT DATE: 04-07-97

RX TYPE: BWR                             EVENT TIME: 15:11

VENDORS: GE-4                           NOTIFY DATE: 04-07-97

EMERGENCY CLASS: N/A  REGION: 1 STATE: NJ      TIME: 18:48

OPS OFFICER: DICK JOLLIFFE            

10 CFR SECTION: CCCC  21.21               UNSPECIFIED PARAGRAPH

                AIND  50.72(b)(2)(iii)(D) ACCIDENT MITIGATION  

UNIT  SCRAM   RX   INIT  INITIAL MODE     CURR   CURRENT MODE

      CODE   CRIT  PWR                    PWR

 1    N       Y    100   POWER OPERATION  100   POWER OPERATION



THE LICENSEE HAS OBSERVED AN INCREASING NUMBER OF STRUTHERS-DUNN 

219 NE SERIES RELAY FAILURES.                                    

                                                                 

THESE RELAYS ARE INSTALLED IN A VARIETY OF SAFETY-RELATED        

APPLICATIONS. THE FAILURE MECHANISM IS THE THERMAL DEGRADATION OF

THE RELAY BEARING PAD MATERIAL (A 1-MILLIMETER THICK STRIP OF    

MAGNETIC VINYL PLASTIC MATERIAL LOCATED NEAR THE RELAY COIL) DUE 

TO EXPOSURE TO HIGH TEMPERATURES (APPROXIMATELY 175�F) WHEN THE  

COIL IS ENERGIZED.  THIS CAUSES LOSS OF THE ALIGNMENT BETWEEN THE

ARMATURE AND COIL AND CAUSES RAPID MOTION (CHATTERING) OF        

ARMATURE AND CONTACTS.  THE RELAY CAN FAIL WITH AN OPEN CONTACT, 

A CLOSED CONTACT, OR A SHORTED COIL.  THIS FAILURE MECHANISM HAS 

BEEN OBSERVED ONLY FOR RELAYS WITH AC COILS.                     

                                                                 

THE FAILURE MECHANISM AND FAILURE MODES HAVE BEEN CONFIRMED WITH 

THE MANUFACTURER, STRUTHERS-DUNN.  PER THE MANUFACTURER, MAGNETIC

VINYL PLASTIC IS NOT THE PROPER BEARING PAD MATERIAL.  SILICON   

RUBBER, WHICH HAS A HIGH RESISTANCE TO HEAT DEGRADATION, IS THE  

PROPER BEARING PAD MATERIAL.                                     

                                                                 

THE LICENSEE HAS REASONABLE ASSURANCE OF CONTINUED OPERABILITY   

BASED ON THE FOLLOWING:                                          

                                                                 

- PANEL WALKDOWNS ARE PERFORMED WEEKLY TO LISTEN FOR BUZZING     

RELAYS AND                                                       

  TAKE IMMEDIATE ACTION IF ANY BUZZING IS DETECTED.              

- RELAY BUZZING IS AN INDICATION WHICH PRECEDES RELAY FAILURE.   

ADEQUATE                                                         

  TIME EXISTS BETWEEN THE START OF BUZZING AND EVENTUAL RELAY    

FAILURE;                                                         

  THE FAILURE IS NOT IMMEDIATE.                                  

- THERE ARE CURRENTLY NO INDICATIONS OF IMMINENT FAILURE OBSERVED

FOR ANY                                                          

  OF THE AFFECTED RELAYS.                                        

- THE RELAYS ARE SCHEDULED FOR REPLACEMENT BEFORE THE END OF     

THEIR                                                            

  QUALIFIED OR CALCULATED SERVICE LIFE.                          

                                                                 

ALL SAFETY-RELATED SYSTEMS ARE OPERABLE.                         

                                                                 

IF UNDETECTED, THIS CONDITION COULD HAVE PREVENTED THE           

FULFILLMENT OF A SAFETY FUNCTION.  THEREFORE, THIS REPORT IS     

BEING MADE IN ACCORDANCE WITH 10 CFR 50.72(b)(2)(iii)(D).  THIS  

REPORT IS ALSO BEING MADE PURSUANT TO THE REQUIREMENTS OF 10 CFR 

PART 21.                                                         

                                                                 

THE LICENSEE PLANS TO SUBMIT A LICENSEE EVENT REPORT ON THIS     

EVENT.                                                           

                                                                 

THE LICENSEE PLANS TO NOTIFY LOCAL OFFICIALS AND THE NRC RESIDENT

INSPECTOR.