United States Nuclear Regulatory Commission - Protecting People and the Environment


LICENSEE: COMMONWEALTH EDISON CO.            

SITE: ZION 1 2                              EN NUMBER:32037

DOCKET: 05000295 05000304                EVENT DATE: 03-27-97

RX TYPE: PWR PWR                         EVENT TIME: 13:55

VENDORS: W-4-LP W-4-LP                  NOTIFY DATE: 03-27-97

EMERGENCY CLASS: N/A  REGION: 3 STATE: IL      TIME: 15:55

OPS OFFICER: HENRY BAILEY             

10 CFR SECTION: CDEG  21.21(c)(3)(i)      DEFECTS/NONCOMPLIANCE

UNIT  SCRAM   RX   INIT  INITIAL MODE     CURR   CURRENT MODE

      CODE   CRIT  PWR                    PWR

 1    N       N      0   COLD SHUTDOWN      0   COLD SHUTDOWN  

 2    N       N      0   COLD SHUTDOWN      0   COLD SHUTDOWN  



PART 21 NOTIFICATION BY VENDOR.  COOPER-BESSEMER EMERGENCY       

DIESELS                                                          

                                                                 

ON JANUARY 27, 1997 COMMONWEALTH EDISON COMPANY IDENTIFIED A     

SIGNIFICANT DROP IN CRANKCASE LUBE OIL LEVEL IN ONE OF THE       

COOPER-BESSEMER EMERGENCY DIESEL GENERATORS.  SUBSEQUENT         

INVESTIGATION REVEALED THAT A CRACK HAD DEVELOPED IN THE CYLINDER

LINER WALL ALLOWING JACKET WATER TO ENTER THE COMBUSTION

CHAMBER.

 THIS RESULTED IN A FAILED PISTON.  UPON REVIEW OF THE FAILED    

PISTON IT WAS NOTED THAT THE PISTON CROWN THICKNESS IN THE AREA  

OF FAILURE WAS BELOW DRAWING SPECIFICATIONS.                     

                                                                 

THIS IS THE ONLY KNOWN FAILURE OF SUBJECT LINER.  THIS LINER     

DESIGN IS IN USE ON "EARLY" KSV ENGINES IN USE AT THE ZION       

STATION AND AT THE COOPER NUCLEAR STATION.  FAILURE OF THE PISTON

WAS A DIRECT RESULT OF THE LINER FAILURE. FINITE ELEMENT ANALYSIS

IS BEING CONDUCTED BY COOPER-BESSEMER TO DETERMINE ACCEPTABLE    

MINIMUM THICKNESS FOR THE PISTON CROWN SECTION. THIS PISTON      

EVALUATION COULD AFFECT THE FOLLOWING KSV USERS: PALO VERDE,     

BRAIDWOOD, BYRON, ZION, WATERFORD III, SOUTH TEXAS, COOPER, NINE 

MILE POINT 2, AND SUSQUEHANNA.  IT IS EXPECTED THIS EVALUATION   

WILL BE COMPLETED BEFORE MAY 28, 1997.                           



Page Last Reviewed/Updated Thursday, March 29, 2012