Bulletin 78-12A: Atypical Weld Material in Reactor Pressure Vessel Welds
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
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
(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
(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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