United States Nuclear Regulatory Commission - Protecting People and the Environment

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. 



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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. 



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