United States Nuclear Regulatory Commission - Protecting People and the Environment


Licensee/Facility:                     Notification:

Public Service Electric & Gas Co.      MR Number: 1-95-0009
Hope Creek 1                           Date: 01/25/95
Hancocks Bridge,New Jersey             SRI PC                             
Dockets: 50-354

Subject: ANCHOR-DARLING SWING CHECK VALVES                               
Reportable Event Number: N/A


On November 16, 1994, during a core spray system inservice test, a pump  
discharge check valve stuck open allowing reverse flow through the       
associated pump and causing it to spin in reverse at approximately 1500  
rpm before the flow was stopped. An internal inspection of the valve     
following the event identified deformation in the valve body casting     
caused by contact with the disk hinge arm.  The licensee surmised that   
this was an indication of excessive disk travel that was allowing the    
valve to "stick open."                                                   
On January 19, 1995, during an internal valve inspection resulting from a
generic review following the November 16 event, PSE&G technicians noted  
deformation in the body of a safety auxiliaries cooling system (SACS)    
pump discharge check valve. Previously this system had experienced       
pressure/flow oscillations which may be attributed to check valve        
The valves in question are Anchor-Darling swing check valves. The        
licensee has identified a population of 32 of these valves (of various   
dimensions - 12", 16", 20") in safety related plant systems. The licensee
intends to continue to open and inspect the remainder of these valves    
during upcoming scheduled system outages. The root cause of the failure  
mechanism has not been established, in part because the internals are    
suspended from the cover which must be removed in order to conduct the   
inspection. Consequently, the actual "as found" condition is difficult to
observe and assess. The licensee is considering notification in          
accordance with 10 CFR 21.                                               

Regional Action:

Resident inspectors will continue to monitor the licensee's review of    
this issue and will report any further indications of its generic nature 
and/or significance as it pertains to the operability of safety-related  

Contact:  John White                 (610)337-5114
          Robert Summers             (610)337-5189

Page Last Reviewed/Updated Monday, January 27, 2020