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IEB 80-21 Valve Yokes Supplied by Malcolm Foundry Company, Inc. (Generic Letter 80-92)
GL80092 SSINS No.: 6820 Accession No.: 3008220246 IEB 80-21 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 November 6, 1980 IE BULLETIN NO. 80-21: VALVE YOKES SUPPLIED BY MALCOLM FOUNDRY COMPANY, INC. Description of Circumstances: On June 17, 1980, Pennsylvania Power and Light Company notified IE Region I that cracks had been discovered in the yokes of a number of valves in the residual heat removal (RHR) system at their Susquehanna Steam Electric Station. The potential for common-mode failure of the yokes on several valves in redundant, safety-related trains of the RHR system constitutes a failure mode whereby all RHR functions could be simultaneously lost. Specifically, the cracks were located in the radii at the yoke mounting flange-to-yoke vertical section interface. An analysis and evaluation of the most severely cracked value yoke was performed by the valve manufacturer, Anchor Darling Valve Company. They concluded that the cracking was not due to casting defects, but rather was due to the yoke material not having the proper mechanical properties. Purchased as ASTM A-216, Grade WCB material, the actual valve yoke material had tensile and yield strengths below the minimum values listed in the ASTM material specification. The cracked valve yokes were all cast by Malcolm Foundry Company, Inc., of Newark, New Jersey. The foundry is no longer in business. Anchor Darling has begun a program of verifying the tensile strengths of the other valve yokes cast by Malcolm and used on Anchor Darling valves at Susquehanna. To date, approximately half of the yokes have been tested. Of those tested, over 25 percent of the valve yokes have revealed Brinell hardness values significantly below the appropriate value obtained from the approximate relationship of Brinell hardness to tensile strength included in ASTM Specification A-370. These additional valve yokes are on a wide range of valve sizes and are from a number of different purchase orders placed with Malcolm over a period of at least ten months during 1974 and 1975. Thus, it appears that the problem is not isolated to one heat of material or to one short time period. Anchor Darling intends to replace the defective valve yokes at Susquehanna and to begin a testing program at other nuclear power plants under construction where valves with valve yokes cast by Malcolm have been provided. Since Malcolm Foundry Company, Inc., is no longer in business, the NRC staff cannot determine directly if Malcolm has provided valve parts to other valve manufacturers for use in nuclear power plants. . IEB 80-21 November 6, 1980 Page 2 of 3 Actions To Be Taken by Addressees: For all power reactor licensees or holders of construction permits the following actions are required: 1. Determine if any of the active valves in use or planned for use in safety-related systems at your facility have valve parts cast by Malcolm Foundry Company, Inc. If no valves are identified as having potentially faulty material, indicate that this is the case and ignore the remaining questions. 2. Licensees having active safety-related valves with potentially faulty material shall immediately visually inspect for cracks all normally accessible valve parts (i.e., those which can be inspected during reactor operation). 3. Licensees or permit holders having active safety-related valves with potentially faulty material shall identify the manufacturer(s) of these valves and either: a. Verify that all valve parts cast by Malcolm have mechanical properties in accordance with the ASTM material specification if such is not the case, then comply with either b or c below also. b. Replace the defective materials and/or valves. c. Identify any other corrective actions that may be exercised and the basis for such actions. For plants with an operating license, the results of your initial determination (item 1), visual inspection results (item 2), a list of affected valve manufacturers, your planned action (item 3), and the schedule for accomplishing this action shall be reported within thirty days of the date of this bulletin to the Director of the appropriate NRC Regional Office with a copy sent to the NRC Office of Inspection and Enforcement, Division of Reactor Construction Inspection, Washington, DC 20555. For plants with a construction permit, the results of you initial determination (item 1), a list of affected valve manufacturer(s), your planned action (item 3) and the schedule for accomplishing this action shall be reported within sixty days of the date of this bulletin to the Director of Reactor Construction Inspection, Washington, DC 20555. Compliance with this bulletin by the licensees does not relieve the affected valve manufacturers from the reporting requirements of 10 CFR Part 21. If you desire additional information regarding this matter, please contact the appropriate IE Regional Office. . IEB 80-21 November 6, 1980 Page 3 of 3 Approved by GAO, B180225 (R0072); clearance expires November 30, 1980. Approval was given under a blanket clearance specifically for identified generic problems.
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