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Information Notice No. 83-71: Defects in Load-bearing Welds on Lifting Devices for Vessel Head and Internals
SSINS No.: 6835 IN 83-71 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 October 27, 1983 Information Notice No. 83-71: DEFECTS IN LOAD-BEARING WELDS ON LIFTING DEVICES FOR VESSEL HEAD AND INTERNALS Addressees: All holders of nuclear power reactor operating licenses (OL) or construction permits (CP). Purpose: This information notice provides notification of the potential for failure of reactor vessel head and internals lifting devices manufactured by Babcock and Wilcox Company. It is expected that addressees will review the information provided here for applicability to their facilities. No specific response or action is required. Description of Circumstances: A lifting device for the vessel head and internals supplied to Florida Power Corporation by Babcock and Wilcox was found to have weld defects in load-bearing welds. If the welding defects were to go uncorrected, they could jeopardize the capability of the lifting system to safely handle safety-related components within reactor compartments. The subject lifting device was fabricated to industry standards. However, a subsequent regulatory requirement, NUREG-0612 requires that the lifting device be tested in accordance with ANSI N14.6 on the basis that it is to carry heavy loads over safety-related systems. Florida Power Corporation committed to perform appropriate non-destructive examination (NDE) on the device as required. Results of the NDE (magnetic particle) revealed four indications in welds on the tripod, one on the turnbuckle, and one on the latchblock. In addition, a visual examination revealed that several welds showed undercut, porosity, and cold lapping. Defects found were considered potential safety hazards if not repaired and suggest that the industry standards used were inadequate to meet the service intended. As a remedy, the welds on the tripod and the latchblock were repaired and the turnbuckles were replaced with a solid unwelded model. Subsequent to repairs, the lifting device was qualified for use as designated by performance of NDE and load testing in accordance with ANSI N14.6 as required by NUREG-0612. Although . IN 83-71 October 27, 1983 Page 2 of 2 load testing in accordance with ANSI N14.6 satisfies the letter of NRC requirements, prudence would indicate the desirability, of rigorous NDE, to improve confidence that lifting and handling systems, when tested, will not fail. The example cited was furnished by Babcock and Wilcox, but the NRC concern applies to both standard and custom elements of heavy-load-handling systems. If you have any questions regarding this matter, please contact 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: J. B. Henderson, IE (301) 492-9654 Attachment: List of Recently Issued IE Information Notices .
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