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Information Notice No. 83-70, Supplement 1: Vibration-Induced Valve Failures
SSINS No.: 6835 IN 83-70, Supplement 1 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 March 4, 1985 Information Notice No. 83-70, SUPPLEMENT 1: VIBRATION-INDUCED VALVE FAILURES Addressees: All nuclear reactor facilities holding an operating license (OL) or construction permit (CP). Purpose: This information notice is provided to supplement Information Notice 83-70 and to alert addressees of additional valve failures and system inoperability as a result of loose valve stem antirotation devices. These additional failures involve valves supplied by companies other than the Anchor Darling Company. It is expected that recipients will review the information for applicability to their facilities. Suggestions contained in this notice do not constitute NRC requirements; therefore, no specific action or written response is required. Background: Information Notice (IN) 83-70 described events at the Shoreham Station Unit 1 and the Zimmer Station where valve stem clamps (antirotation devices) had become loose because of normal system vibration. The loose stem clamps caused the valves to become inoperative. IN 83-70 reported failures of this type only on globe valves supplied by the Anchor Darling Company. Description of Circumstances: A review of licensee event reports (LER) has revealed that failure of the antirotation device is not unique to globe valves manufactured by Anchor Darling. Valves of other manufacturers also have experienced similar failures. These manufacturers were Blaw-Knox, Rockwell-Edward, W-K-M Division (WKM), and Copes-Vulcan. The defective valves found in this review also were used in systems such as the residual heat removal (RHR) heat exchanger discharge, auxiliary feedwater, main steam, containment isolation and main feedwater. The events involving failure of the antirotation device on valves other than those supplied by Anchor Darling occurred at four plants; Quad Cities 1, James A. Fitzpatrick, San Onofre 2, and Surry 1. The event at Quad Cities 1 occurred on April 12, 1983, and was reported in LER 83-018. While starting the 1C RHR service water pump during a minor preventive maintenance on the pumps, the operator observed an excessively high discharge pressure and low flow from the pump. An inspection of the RHR heat exchanger discharge valve revealed that the valve was actually closed although 8502270050 . IN 83-70, Supplement 1 March 4, 1985 Page 2 of 3 it indicated open in the control room; the motor operator was functioning properly, but the valve was not opening. Subsequent licensee investigation revealed that the cause of this event was the failure of the antirotation pin. The antirotation pin in the valve had fallen out; this pin is held in place by a set screw. It was determined that normal system vibration caused the set screw to loosen and allowed the antirotation pin to fall out. The antirotation pin was replaced, the set screw was tightened securely, and the valve was tested satisfactorily. The valve was a 12-inch globe valve, manufactured by Blaw-Knox Company. The event reported in LER 82-047 at James A. Fitzpatrick occurred on October 7, 1982. During normal full-power operation, a reactor scram occurred as the result of a blockage of the "D" main steam line. Subsequent investigation revealed that the "D" inboard main steam isolation valve (MSIV) had its disc separated from the stem, allowing the main disc to drop to the closed position. The valve disassembly showed that the antirotation pin in the MSIV disc was sheared allowing the disc to unscrew. The MSIVs were Rockwell-Edward flow balanced stop valves, Type 1612Y. A new stem and disc assembly was installed with two antirotation, pins 90 degrees apart. Specific attention was paid to ensuring an interference fit of the pins. The valve was reassembled and leak tested satisfactorily. Seven previous failures of Rockwell-Edward Main steam isolation valves in boiling water reactors were reported in Information Notice No. 81-28, dated September 3, 1981. These failures all resulted in the main disc becoming disconnected from the valve stem. LER 82-066, dated August 18, 1982, provides a description of an event involving failure of an antirotation device, which occurred at San Onofre 2 on July 19, 1982. While in Mode 3, one auxiliary feedwater (AFW) system train was rendered inoperable because of the inability of the AFW control valve to open fully. An action of limiting condition for operation was initiated. Inspection of the valve revealed that the antirotation plate/mechanical indicator was bent and jammed against the yoke guide with the valve in the closed position. The damaged antirotation plate was replaced. The valve was manufactured by WKM. The event at Surry 1 is described in LER 83-043. On September 14, 1983, following a reactor trip from 100% power, it was observed that two main feedwater regulation valves did not fully close when they received a feedwater isolation signal from the reactor protection system. Subsequent licensee investigation indicated that one of these valves did not fully close because of failure of the stem antirotation device. The second valve failed for an unrelated reason. The antirotation device was replaced and the valve stroke was reset. This valve was manufactured by Copes-Vulcan, Inc. . IN 83-70, Supplement 1 March 4, 1985 Page 3 of 3 No specific action or written response to this notice is required. If you have any questions regarding this matter, please contract the Regional Administrator of the appropriate NRC regional office or this office. Edward L. Jordan Director Division of Emergency Preparedness and Engineering Response Office of Inspection and Enforcement Technical Contact: H. Bailey, IE (301) 492-9006 Attachment: List of Recently Issued IE Information Notices .
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