Part 21 Report - 1996-390
ACCESSION #: 9604090154
Integrated Nuclear Services April 5, 1996
Document Control Desk
U. S. Nuclear Regulatory Commission
Washington, DC 20555-0001
Subject: Interim Report of Potential Safety Concern on Material Used for
Fabrication of Permanent Canal Seal Plate
The purpose of this letter is to provide you with preliminary information
on a Potential Safety Concern. The concern relates to the use of
material constructed with welded angles that are not allowed by ASME
A479, for a safety related component, the permanent canal seal plate.
Use of the welded angles is thought to not adversely affect safety during
normal power operation. Reliance on the welded angles may be of concern
when the permanent canal seal plate fulfills its function of retaining
water in the reactor canal during refueling activities. This latter
concern is the basis for the Preliminary Safety Concern. In addition,
our preliminary evaluation indicates that the highest load on the weld
would occur during a core flood line rupture; the concern here being that
the structure might become a missile.
The subcontractor for fabrication of the seal plates, currently in use at
Arkansas Nuclear One and Crystal River-3, purchased commercial grade
materials with Certified Materials Test Reports (CMTR's). FTI (then
BWNT) upgraded this material to "safety related" and certified as such
based on laboratory tests and alloy analyses on sample pieces from each
angle. Examination of recently purchased identical material revealed the
presence of welds, which is not allowed by ASME A479. Documentation
received from the material vendor, upon questioning by Framatome
Technologies, verified that the material used for the permanent canal
seal plates currently in use was also welded. There are no questions
about other materials used in the fabrication of the seal plates.
The seal plates currently in use have been cycled through normal
operation and a refueling. The plates have been visually inspected and
show no signs of degradation. The two affected plants have been notified
of the need to revise the material certification and of the need to
augment visual inspection prior to each canal flooding.
3315 Old Forest Road, P.O. Box 10935, Lynchburg, VA 24506-0935
Telephone: 804-832-3000 Fax: 804-832-3663
FTI has not completed its evaluation of the welds. This letter is not a
notification of a substantial safety hazard under 10CFR21.
FTI will provide a final report to the NRC in approximately six months
upon completion of the evaluation of the welds and final resolution of
the Preliminary Safety Concern.
If you have any questions concerning this matter, please contact the
undersigned at 804-832-2817 or Robert Schomaker at 804-832-2917.
Very truly yours,
J. H. Taylor, Manager
c: B. W. Sheron/NRC
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