Bulletin 78-12: Atypical Weld Material in Reactor Pressure Vessel Welds
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
September 26, 1978
IE Bulletin No. 78-12
ATYPICAL WELD MATERIAL IN REACTOR PRESSURE VESSEL WELDS
Description of Circumstances
On August 4, 1978, the NRC was informed by the Duke Power Company and the
Babcock and Wilcox Company (B&W) that the weld wire used in some of the
reactor vessel welds in Oconee Unit No. 3 may have differed from that
specified. A chemical analysis of one sample of archive material by B&W
disclosed that the nickel content was measured to,be 0.1 percent (versus
0.45 to 0.8 percent nominal specified) and the silicon content was measured
to be 1.0 percent (versus 0.3 to 0.6 percent nominal specified). The heat of
weld metal in question was supplied by the Page Company, a Division of the
American Chain & Cable Co., Bowling Green, Kentucky to B&W, the manufacturer
of the Oconee, Unit 3 vessel. Further checks by B&W of its records have
identified eleven additional vessels in which the incorrect weld material
may have been used. Owners of these vessels have been notified.
The NRC staff has made a determination of the possible effects on reactor
vessel integrity of the use, or possible use, of the improper weld material.
Weldments containing the atypical material are likely to have higher than
normal nil-ductility transition temperature characteristics. Therefore to
maintain reactor vessel safety margins, implementation of new conservative
pressure/temperature operating limits may be required.
While the specific problem has been identified as possibly affecting twelve
vessels manufactured by B&W, it is not possible to conclude in the absence
of specific information that similar atypical weld material was not also
supplied to other vessel manufacturers and used in reactor pressure vessel
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. 78-12 September 26, 1978
1. Conduct a record search (2) of all primary reactor pressure vessel
weldments (excluding partial penetration welds) and submit the
following information (3):
a. The principal vessel manufacturer. If other manufacturers were
utilized, identify those companies and the weldments completed by
b. The type and form of weld materials and the identifying heat and
lot numbers used in each weldment.
c. The weld material manufacturer(s) and the types and form of
d. The specified properties of the weld materials and the completed
weldments (Chemistry, tensile and impact properties, as
2. Describe the procedures utilized during fabrication to verify
conformance to the specifications. Specifically provide the following:
a. Describe the type, number and dates of tests performed on welding
materials to satisfy the material conformance testing requirements
for each heat, lot or combination of heat and batch, etc., of
welding materials used in the construction or repair of the
reactor pressure vessel in your facility. Indicate whether each
heat, lot or batch subdivision (coil or spool) was tested and the
extent of such testing, i.e., were both ends of a coil or spool of
wire tested for each sub-arc flux-wire combination or heat-flux
b. Describe the type, number and dates of other tests such as
procedure qualification, welder performance tests, in-process
checks on post-weld tests which were performed.
(2) The record search may be performed by the vessel manufacturer and the
requested information reviewed as appropriate by each licensee prior to
forwarding to the NRC. It is not the intent of this Bulletin to require
each licensee to individually examine manufacturing records of a
generic nature. Records of nonconforming conditions that may be
identified by the manufacturer and are uniquely applicable to a
specific vessel should however be carefully examined by the owner.
(3) Some of the information requested by this Bulletin may have been
previously supplied to the NRC under the Surveillance Program.
Information previously submitted may be referenced in lieu of
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IE Bulletin No. 78-12 September 26, 1978
c. For each of the tests described in 2(a) and 2(b) above, describe
the parameters of each test and provide the results obtained.
Identify the applicability to specific weldments by correlation of
heat, lot or batch as appropriate.
3. Identify those cases of weld filler material which did not meet
procurement specifications based on verification tests, i.e. mechanical
or chemical properties. Describe the disposition action taken or the
acceptance basis for utilization in vessel fabrication. In such cases,
discuss the effect that the atypical weld composition has on the
fracture toughness of the weld metal.
4. Provide information on the availability of archive weld materials which
might be used for verification purposes.
5. Please provide your response in writing within 60 days. 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 (ROO72); clearance expires 7/31/80. Approval was
given under a blanket clearance specifically for identified generic
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