United States Nuclear Regulatory Commission - Protecting People and the Environment

LICENSEE: TENNESSEE VALLEY AUTHORITY         
SITE: BROWNS FERRY 2                        EN NUMBER:30559
DOCKET:  05000260                        EVENT DATE: 05-29-96
RX TYPE:  BWR                            EVENT TIME: 09:15
VENDORS:  GE-4                          NOTIFY DATE: 05-29-96
EMERGENCY CLASS: N/A  REGION: 2 STATE: AL      TIME: 13:37
OPS OFFICER: CHAUNCEY GOULD           
10 CFR SECTION: AIND  50.72(b)(2)(iii)(D) ACCIDENT MITIGATION  
UNIT  SCRAM   RX   INIT  INITIAL MODE     CURR   CURRENT MODE
      CODE   CRIT  PWR                    PWR
 2    N       Y    100   POWER OPERATION  100   POWER OPERATION

THE LICENSEE WAS MADE AWARE OF A NONCONSERVATISM IN THE          
CALCULATED VALUE OF SAFETY LIMIT MINIMUM CRITICAL POWER RATIO    
(SLMCPR) BY GENERAL ELECTRIC.                                    
                                                                 
GE SUBMITTED A PART 21 ON 5/21/96 STATING THAT GENERICALLY SLMCPR
VALUES FOR GE-11 FUEL MAY NOT YIELD THE MOST CONSERVATIVE        
RESULTS. THE LICENSEE WAS OFFICIALLY NOTIFIED BY GE THAT CYCLE   
SPECIFIC ANALYSIS OF THE OPERATING BROWNS FERRY UNITS HAS BEEN   
COMPLETED. FOR UNIT 2, CONTAINING 200 GE-11 FUEL BUNDLES, THE    
SLMCPR HAS BEEN DETERMINED TO BE 1.09. FOR UNIT 3, CONTAINING 32 
GE-11 FUEL BUNDLES, THE SLMCPR HAS BEEN DETERMINED TO BE 1.07.   
THE SLMCPR FOR UNIT 2 IS NONCONSERVATIVE BY 0.02 WITH RESPECT TO 
PLANT TECH SPEC 1.1.A.1, WHICH STATES THAT THE MCPR LESS THAN    
1.07 SHALL CONSTITUTE A VIOLATION OF THE FUEL INTEGRITY LIMIT.   
PRIOR TO STARTUP, AT THE BEGINNING OF UNIT 2 CYCLE 9, THE        
LICENSEE HAD IMPLEMENTED, BASED ON PRELIMINARY INFORMATION, A    
0.03 - 0.04 PENALTY ON THE OPERATING LIMIT MINIMUM CRITICAL POWER
RATIO (OLMCPR) IN ORDER TO BOUND ANY POTENTIAL NONCONSERVATISM IN
THE GENERIC SLMCPR CALCULATION. THE OPERATING LIMIT PENALTY HAS  
ENSURED THAT THE NEW SAFETY LIMIT WOULD NOT HAVE BEEN EXCEEDED   
FOR ANY ANALYZED TRANSIENT DURING THE CURRENT OPERATING CYCLE.   
THE OPERATING LIMIT PENALTY WILL BE ADJUSTED BASED ON THE        
VERIFIED SLMCPR DATA PROVIDED BY GE.                             
                                                                 
THE RI WAS INFORMED.  SEVERAL EVENT REPORTS ON THIS TOPIC WERE   
RECEIVED PREVIOUSLY (e.g. #30407, #30509, #30539).               

Page Last Reviewed/Updated Thursday, March 29, 2012