United States Nuclear Regulatory Commission - Protecting People and the Environment

IE Circular No. 78-15 - Checkvalves Fail to Close in Vertical Position



CR78015 

                               UNITED STATES 
                       NUCLEAR REGULATORY COMMISSION 
                          WASHINGTON, D. C. 20555 

                              July 20, 1978 

MEMORANDUM FOR:     B. H. Grier, Director, Region I 
                    J. P. O'Reilly, Director, Region II 
                    J. G. Keppler, Director, Region III 
                    K. V. Seyfrit, Director, Region IV 
                    R. H. Engelken, Director, Region V 

FROM:               H. D. Thornburg, Director, Division of Reactor  
                    Construction Inspection, IE 

SUBJECT:            IE CIRCULAR NO. 78-15 - CHECKVALVES FAIL TO CLOSE 
					IN VERTICAL POSITION 

     The subject circular should be dispatched for action to all power 
reactor licensees with a construction permit and/or operating license no 
later than July 24, 1978. The text of the circular and draft letter to 
licensees are enclosed for this purpose. 


                                   H. D. Thornburg, Director 
                                   Division of Reactor Construction 
                                     Inspection 
                                   Office of Inspection and Enforcement 
Enclosures: 
1.  Draft Transmittal Letter 
2.  IE Circular No. 78-15 

CONTACT:  W. Laudan, IE 
          49-27551 
.

(Draft letter to all power reactor facilities with construction permit 
and/or operating license)  

                                                     IE Circular No. 78-15 
Gentlemen: 

The enclosed Circular 78-15, is forwarded to you for information. If there 
are any questions related to your understanding of the suggested actions, 
please contact this office. 


                                        Signature 
                                        (Regional Director) 

Enclosures: 

1.  IE Circular No. 78-15 
2.  List of IE Circulars 
      Issued in 1978 
.

                             UNITED STATES 
                      NUCLEAR REGULATORY COMMISSION 
                   OFFICE OF INSPECTION AND ENFORCEMENT 
                         WASHINGTON, D. C. 20555 

                              July 20, 1978  

                                                     IE Circular No. 78-15 

TILTING DISK CHECK VALVES FAIL TO CLOSE WITH GRAVITY IN VERTICAL POSITION 

The Anchor/Darling Valve Company reported to the NRC on May 23, 1978 a 
condition at the San Onofre Nuclear Plant where an 8" - 1500# tilting disk 
check valve failed to close with gravity because it was installed in a 
vertical rather than a horizontal pipeline. The valve disc was counter 
weighted to close with the force of gravity when installed in a horizontal 
pipe. The manufacturer did not determine the reverse flow necessary to close
the improperly installed valve. The check valve is located in the Low 
Pressure Safety Injection System as the first valve inside the containment 
and may not have closed as required to maintain the containment integrity. 

Anchor/Darling has notified all purchasers of such valves and indicated to 
them possible implications of vertical installations. 

It should be noted that similar problems may arise with tilting disk check 
valves from other manufacturers. 

Tilting disk checkvalves can be designed for either horizontal or vertical 
piping but not for both. Improperly installed tilting disk check valves will
not function properly. 

All holders of operating licenses or construction permits should be aware of
the potential for malfunction of safety-related systems caused by improperly
positioned tilting disk check valves. Consideration should be given to the 
importance of verifying that all such valves in critical systems are 
installed only in the orientation specified by the manufacturer. 

No written response to this circular is required. 

If you require additional information regarding this matter, contact the 
Director of the Regional office. 

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