United States Nuclear Regulatory Commission - Protecting People and the Environment


LICENSEE: ILLINOIS POWER CO.                 

SITE: CLINTON 1                             EN NUMBER:32815

DOCKET: 05000461                         EVENT DATE: 08-25-97

RX TYPE: BWR                             EVENT TIME: 00:00

VENDORS: GE-6                           NOTIFY DATE: 08-25-97

EMERGENCY CLASS: N/A  REGION: 3 STATE: IL      TIME: 18:35

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

 1    N       N      0   COLD SHUTDOWN      0   COLD SHUTDOWN  



10 CFR PART 21 NOTIFICATION - CONTROL CIRCUIT FOR DIVISION 1     

EMERGENCY DIESEL GENERATOR (EDG) FEED BREAKER DOES NOT MEET      

DESIGN BASIS DUE TO DESIGN ERROR AND COULD PREVENT POWER FOR     

DIVISION 1 SAFE SHUTDOWN EQUIPMENT DURING A MAIN CONTROL ROOM    

FIRE WITH A LOSS OF OFFSITE POWER.                               

                                                                 

THIS REPORT INVOLVES THE DESIGN OF THE CONTROL CIRCUIT FOR       

DIVISION 1 EDG 4-KV 1A1 FEED CIRCUIT BREAKER 252-DG1KA.  THE     

CONTROL CIRCUIT DESIGN WAS SUPPLIED BY SARGENT & LUNDY.  IN      

ACCORDANCE WITH THE SAFE SHUTDOWN ANALYSIS AND 10 CFR PART 50,   

APPENDIX R, SECTION III.L, THE CONTROL CIRCUIT FOR THE BREAKER IS

REQUIRED TO BE DESIGNED TO ALLOW ISOLATION OF THE MAIN CONTROL   

ROOM WIRING/CONTROLS AND OPERATION OF THE BREAKER FROM THE

REMOTE

SHUTDOWN PANEL DURING A FIRE IN THE MAIN CONTROL ROOM.           

                                                                 

THE NATURE OF THE DEFICIENCY IS THE ABSENCE OF ISOLATION CONTACTS

IN THE DESIGN OF THE OFFSITE SOURCE PERMISSIVE HAND SWITCH       

CIRCUIT.  SINCE THE CIRCUIT INCLUDES A CABLE IN THE MAIN CONTROL 

ROOM, IT SHOULD BE ISOLATED TO ASSURE OPERABILITY OF THE EDG FEED

BREAKER WHILE PLACING THE PLANT IN SAFE SHUTDOWN FROM THE REMOTE 

SHUTDOWN PANEL.  DURING A POSTULATED FIRE IN THE MAIN CONTROL    

ROOM CONCURRENT WITH A LOSS OF OFFSITE POWER, FIRE COULD DAMAGE  

THE MAIN CONTROL ROOM CABLES.  THIS IN TURN COULD CAUSE MULTIPLE 

GROUND FAULTS, THE LOSS OF CONTROL POWER FOR THE DIVISION 1 EDG  

FEED BREAKER, AND A LOSS OF POWER TO DIVISION 1 EQUIPMENT.  THE  

SAFE SHUTDOWN ANALYSIS RELIES ON DIVISION 1 EQUIPMENT OPERATED   

FROM THE REMOTE SHUTDOWN PANEL IN ORDER TO BRING THE PLANT TO A  

SAFE SHUTDOWN CONDITION IN THE EVENT OF A FIRE IN THE MAIN       

CONTROL ROOM.                                                    

                                                                 

THIS ISSUE POTENTIALLY AFFECTS ALL CIRCUITS ROUTED THROUGH THE   

REMOTE SHUTDOWN PANEL.  THE FOLLOWING TWO CIRCUITS WERE          

IDENTIFIED TO BE DEFICIENT IN DESIGN:  THE CONTROL CIRCUIT FOR   

BREAKER 252-DG1KA AND THE CONTROL CIRCUIT FOR THE DIVISION 1     

ESSENTIAL SWITCHGEAR HEAT REMOVAL SYSTEM FAN DAMPER.             

                                                                 

THE LICENSEE IS NOT AWARE OF OTHER FACILITIES THAT WOULD BE      

AFFECTED BY THIS DEFICIENCY.                                     



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