Bulletin 78-12A: Atypical Weld Material in Reactor Pressure Vessel Welds
UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 November 24, 1978 IE Bulletin No. 78-12A ATYPICAL WELD MATERIAL IN REACTOR PRESSURE VESSEL WELDS Description of Circumstances: This Bulletin is a supplement to IE Bulletin 78-12, issued on September 29, 1978, and the two documents should be considered together. Bulletin 78-12 described the use of weld wire that failed to meet all specified chemical properties in welds of twelve identified reactor pressure vessels. Use of the atypical weld material in vessel weldments causes them to have higher than normal nil-ductility transition temperature characteristics which in turn requires more conservative pressure/temperature operating limits. Bulletin 78-12 was issued for the purpose of verifying that similar atypical weld material was not also supplied to other vessel manufacturers and used in reactor pressure vessel fabrication. Recognizing that the scope of the record review required is extensive and time consuming, and to assure that responses provided are meaningful, the requirements of Bulletin 78-12 are being modified. Action To Be Taken By Licensees and Permit Holders: For all power reactor facilities with an operating license or a construction permit, except those already identified as possibly having atypical weld material (1): (1) The twelve nuclear units identified as having possible atypical pressure vessel weldments are: Three Mile Island Unit Nos. 1 and 2, Crystal River Unit No. 3, Arkansas Nuclear One Unit No. 1, Oconee Unit No. 3, Rancho Seco Unit No. 1, Midland Unit No. 1, Quad Cities Unit No. 2, Browns Ferry Unit No. 1, Turkey Point Unit No. 4 and Zion Unit Nos. 1 and 2. 1 of 2 . IE Bulletin No. 78-12A November 24, 1978 1. Provide all information available on weld materials used for each reactor vessel primary boundary ferritic weldment. (2) (Items 1c, 1d, 2a, 2b, first sentence of 2c, 3 and 4 of Bulletin 78-12.) This information may be provided to NRC through the vessel manufacturers or suppliers as appropriate to prevent duplication of data. 2. Correlation of specific heat, lot or batch to specific weldments in specific vessels is not required at this time. (Last sentence of Item 2c, Bulletin 78-12 .) However, each licensee is required to verify that the weld materials information provided to the NRC under Item 1 does in fact cover each reactor vessel for which the licensee is responsible. 3. Responses to item 1 above shall be submitted in writing within 120 days of the date of this Bulletin supplement. Reports should be submitted to the Director of the appropriate NRC Regional Office and a copy should be forwarded to the U.S. Nuclear Regulatory Commission, Office of Inspection and Enforcement, Division of Reactor Construction Inspection, Washington, D.C. 20555. Approved by GAO, B180225 (R0072); clearance expires 7/31/80. Approval was given under a blanket clearance specifically for identified generic problems. (2) Weld material information submitted will be evaluated by NRC. Requests for further information will be dependent upon results of these evaluations. Additional requests or instructions will be issued following these evaluations. 2 of 2
Page Last Reviewed/Updated Tuesday, March 09, 2021
Page Last Reviewed/Updated Tuesday, March 09, 2021