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. 1 of 1
Page Last Reviewed/Updated Tuesday, September 01, 2015
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