United States Nuclear Regulatory Commission - Protecting People and the Environment


LICENSEE: SIEMENS POWER CORP-NUCLEAR DIVISION

SITE: SIEMENS POWER CORP-NUCLEAR DIV        EN NUMBER:34119

DOCKET:                                  EVENT DATE: 04-21-98

RX TYPE:                                 EVENT TIME: 12:00

VENDORS:                                NOTIFY DATE: 04-22-98

EMERGENCY CLASS: N/A  REGION: 4 STATE: WA      TIME: 12:40

OPS OFFICER: DICK JOLLIFFE            

10 CFR SECTION: CCCC  21.21               UNSPECIFIED PARAGRAPH



10 CFR PART 21 REPORT - NONCONSERVATIVE PREDICTION OF MONITORED  

CORE MCPR -                                                      

                                                                 

SIEMENS POWER CORPORATION (SPC) PERSONNEL DETERMINED THAT        

ADDITIVE CONSTANTS USED IN THE MINIMUM CRITICAL POWER RATIO      

(MCPR) DETERMINATION FOR SIEMENS ATRIUM-9B FUEL BY THE CORE      

MONITORING SYSTEM WERE FOUND TO BE NON-CONSERVATIVE (UP TO 7.6%  

BASED ON THE ORIGINAL ADDITIVE CONSTANTS).  IN ADDITION, SPC     

PERSONNEL DETERMINED THAT THE UNCERTAINLY IN THE ADDITIVE        

CONSTANT FOR THIS FUEL DESIGN WAS LARGER THAN PREVIOUSLY         

ESTIMATED.  THE REVISED UNCERTAINTY HAS THE POTENTIAL TO AFFECT  

THE MCPR SAFETY LIMIT.                                           

                                                                 

SPC PERSONNEL NOTIFIED ALL SPC CUSTOMERS WITH ATRIUM-9B LEAD TEST

ASSEMBLIES OR RELOAD QUANTITIES OF THE FUEL OF THE POSSIBLE      

NONCONSERVATIVE PREDICTION OF THE MONITORED MCPR AT CONDITIONS   

WHERE A SEVERELY UP-SKEWED AXIAL POWER SHAPE COULD OCCUR.        

                                                                 

PLANTS AFFECTED ARE DRESDEN UNIT 3 (CYCLE 15), QUAD CITIES UNIT 2

                                                                 

(CYCLE 15), AND KUOSHENG UNITS 1 AND 2.                          





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