Part 21 Report - 1997-851
ACCESSION #: 9803160061
Duquesne Light Company Beaver Valley Power Station
P.O. BOX 4
Shippingport, PA 15077-0004
SUSHIL C. JAIN (412) 393-5512
Division Vice President Fax (412) 643-8069
Nuclear Services
Nuclear Power Division
March 9, 1998
L-98-041
U. S. Nuclear Regulatory Commission
Attention: Document Control Desk
Washington, DC 20555-0001
Subject: Beaver Valley Power Station, Unit No. 2
Docket No. 50-412, License No. NPF-73
10 CFR 21 Evaluation Report (Status Update): Senior Flexonics
Expansion Joints
On November 14, 1997, Duquesne Light Company (DLC) provided a 10 CFR
21 interim report to the NRC via letter L-97-059 regarding the subject
Part 21 notification to DLC through Stone & Webster Corporation. DLC is
providing a status update report of our 10 CFR Part 21 evaluation of the
subject expansion joints utilized at Beaver Valley Power Station Unit 2.
The Senior Flexonics expansion joints, which are installed in the
Unit 2 service water system, were evaluated for the effects of increased
stiffness due to expansion joint tie rods and determined that the current
applications of the subject expansion joints are acceptable.
The Stone & Webster notification identified that the original
modeling techniques for Senior Flexonics metal tied expansion joints may
have produced unconservative loading on the expansion joint assembly
itself as well as adjacent equipment (i.e., pumps, heat exchangers,
etc.). The expansion Joints were computer modeled to accurately account
for the expansion joint stiffness for lateral and torsional movement.
The axial stiffness of the tie-rods, which governs the joint stiffness
was also correctly modeled. Although the bending stiffness of the joint
incorporated the expansion joint assembly itself, and not the tie-rods, a
review of the displacements under all loading conditions, shows that the
movements are sufficiently low such that additional bending will not be
induced in or across the joints. The system is well supported and
operates at a low temperature such that piping system displacements are
well controlled and limited.
DELIVERING
QUALITY
ENERGY
Beaver Valley Power Station, Unit No. 2
10 CFR 21 Evaluation Report (Status Update):
Senior Flexonics Expansion Joints
Page 2
The review of the existing calculation, including a review and field
walkdowns of the subject expansion joints which are located on the Unit 2
Service Water System, shows that the expansion joints will perform their
required function and that the system remains within design compliance.
Sincerely,
Sushil C. Jain
c: Mr. D. S. Brinkman, Sr. Project Manager
Mr. D. M. Kern, Sr. Resident Inspector
Mr. H. J. Miller, NRC Region I Administrator
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