United States Nuclear Regulatory Commission - Protecting People and the Environment


LICENSEE: NIAGARA MOHAWK POWER CORP.         

SITE: NINE MILE POINT 2                     EN NUMBER:31822

DOCKET:  05000410                        EVENT DATE: 02-18-97

RX TYPE:  BWR                            EVENT TIME: 14:30

VENDORS:  GE-5                          NOTIFY DATE: 02-20-97

EMERGENCY CLASS: N/A  REGION: 1 STATE: NY      TIME: 15:13

OPS OFFICER: LEIGH TROCINE            

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



10 CFR PART 21 NOTIFICATION REGARDING THE EXCESSIVE FAILURE RATE 

OF BORG-WARNER (BWIP) PRESSURE SWITCHES USED IN THE GAS          

TREATMENT, SERVICE WATER, AND HEATING AND VENTILATION SYSTEMS    

                                                                 

SEVERAL BWIP PRESSURE SWITCHES FAILED DURING OPERATION AND       

INITIAL CALIBRATION, AND AN EVALUATION CONCLUDED THAT THE        

SWITCHES ARE UNABLE TO MAINTAIN THE CORRECT RESET POINT WHEN THE 

SETPOINT IS ADJUSTED.  ACCORDING TO THE MANUFACTURER, THE SUBJECT

SWITCHES DO NOT HAVE AN ACCURATELY ADJUSTABLE RESET VALUE.  THE  

RELATIONSHIP BETWEEN THE SETPOINT OF THE SWITCHES AND THEIR RESET

POINT IS NOT LINEAR NOR CONSISTENT BETWEEN DIFFERENT SWITCHES OF 

THE SAME MODEL.  THEY ARE DESIGNED TO OPERATE WITH A MAXIMUM     

SETPOINT AND MINIMUM RESET WINDOW ONLY.  AS A RESULT, THE        

SWITCHES ARE NOT CONSISTENTLY ABLE TO BE INITIALLY CALIBRATED TO 

THE DESIRED SETPOINT; AND ONCE INSTALLED AND CALIBRATED, MINOR   

SETPOINT DRIFT MAY PLACE THE SWITCHES OUTSIDE THEIR ACCEPTABLE   

TOLERANCES.                                                      

                                                                 

THERE ARE A TOTAL OF 40 QUESTIONABLE BWIP PRESSURE SWITCHES      

INSTALLED IN THE PLANT (22 IN THE GAS TREATMENT SYSTEM, 6 IN THE 

SERVICE WATER SUPPLY TO COOLERS AND CHILLERS, AND 12 IN THE      

CONTROL BUILDING VENTILATION SYSTEM). EACH OF THE ASSOCIATED     

VALVES HAS TWO OR THREE OF THE SWITCHES WITHIN ITS HYDRAULIC     

CONTROLS.  THE TYPE OF FAILURE ASSOCIATED WITH THE SWITCH DEPENDS

ON WHICH SWITCH HAS FAILED.  THE EFFECTS OF A FAILED SWITCH CAN  

BE A VALVE FAILING TO OPEN AND BEING UNABLE TO CLOSE OR A VALVE  

FAILING CLOSED AND BEING UNABLE TO OPEN.                         

                                                                 

THE LICENSEE PERFORMED AN OPERABILITY DETERMINATION AND CONCLUDED

THAT THERE IS REASONABLE ASSURANCE THAT THE SWITCHES WILL OPERATE

AS REQUIRED. THIS DETERMINATION WAS BASED ON SUCCESSFUL INITIAL  

CALIBRATION TESTING, POSITIVE TEST DATA OF INSTALLED             

CALIBRATIONS, AND IMPLEMENTATION OF ADDITIONAL ADMINISTRATIVE    

CONTROLS TO SHORTEN THE CALIBRATION FREQUENCY.                   

                                                                 

THE LICENSEE HAS BEEN IN CONTACT WITH ENERTECH (THE VENDOR) IN   

CALIFORNIA AND WITH BORG-WARNER (THE MANUFACTURER).  THE LICENSEE

ALSO BELIEVES THAT ENERTECH HAS BEEN IN CONTACT WITH THE NRC.    

                                                                 

THE LICENSEE PLANS TO NOTIFY THE NRC RESIDENT INSPECTOR. (REFER  

TO THE HOO LOG FOR SITE CONTACT TELEPHONE NUMBERS.)              



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