United States Nuclear Regulatory Commission - Protecting People and the Environment


LICENSEE: ABB-COMBUSTION ENGINEERING         

SITE: ABB-COMBUSTION ENGINEERING            EN NUMBER:31616

DOCKET:                                  EVENT DATE: 12-06-96

RX TYPE:                                 EVENT TIME: 12:00

VENDORS:                                NOTIFY DATE: 01-17-97

EMERGENCY CLASS: N/A  REGION: 1 STATE: CT      TIME: 16:15

OPS OFFICER: DICK JOLLIFFE            

10 CFR SECTION: CCCC  21.21               UNSPECIFIED PARAGRAPH



- ABB-CE 10CFR21 REPORT ON PIPING PRESSURE LOSSES BETWEEN SG AND 

MSSVs -                                                          

                                                                 

ON 12/06/96, ABB-COMBUSTION ENGINEERING IDENTIFIED A DEFECT      

CONCERNING THE PIPING PRESSURE LOSSES (i.e., DIFFERENTIAL        

PRESSURE) BETWEEN THE STEAM GENERATOR (SG) AND THE MAIN STEAM    

SAFETY VALVE (MSSV) INLETS WHEN THE MSSVs ARE ACTIVATED.         

OMISSION OF THE SUBJECT PRESSURE LOSS FROM ANALYSES OF           

OCCURRENCES DURING WHICH MSSVs ACTUATE COULD ADVERSELY AFFECT

THE

RESULTS OF CORRESPONDING LOCA AND NON-LOCA THERMAL HYDRAULIC     

SAFETY ANALYSES,                                                 

MSSV PERFORMANCE, AND PIPING SYSTEM STRUCTURAL ANALYSES.  THE    

MAGNITUDE                                                        

OF THE PIPING PRESSURE LOSSES THAT ABB-CE HAS EXAMINED RANGES    

FROM APPROXIMATELY 10 PSI TO MORE THAN 50 PSI.                   

                                                                 

ABB-CE DETERMINED THAT THIS OMISSION WAS APPLICABLE TO ALL SAFETY

ANALYSES DURING WHICH THE MSSVs ARE ACTIVATED FOR NUCLEAR POWER  

PLANTS FOR WHICH ABB-CE WAS THE NUCLEAR STEAM SUPPLY SYSTEM      

(NSSS) SUPPLIER.                                                 

                                                                 

ON 01/16/97, ABB-CE NOTIFIED EACH LICENSEE FOR WHICH IT WAS THE  

NSSS SUPPLIER OF THIS ISSUE.                                     

                                                                 

ABB-CE CONSIDERS THAT THIS ISSUE MAY BE APPLICABLE TO NUCLEAR    

POWER PLANTS OTHER THAN THOSE FOR WHICH ABB-CE WAS THE NSSS      

SUPPLIER.                                                        



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