Part 21 Report - 1998-172
ACCESSION #: 9803310028
Illinois Power Company
Clinton Power Station
P.O. Box 678
Clinton, IL 61727
Tel 217 935-5623
Fax 217 935-4632
Walter G. MacFarland IV
Chief Nuclear Officer
ILLINOIS
POWER U-602968
An Illinova Company 4F.140
March 24, 1998
Docket No. 50-461 10CFR21.21
Document Control Desk
Nuclear Regulatory Commission
Washington, D. C. 20555
Subject: 10CFR21 Interim Report 21-97-055: Westinghouse DHP Circuit
Breaker Auxiliary Switch Operating Assembly Anomalies
Dear Madam or Sir:
On January 16, 1998, Illinois Power (IP) issued 10CFR21 Interim
Report 21-97-055 in letter U-602910 to notify the NRC that an evaluation
under the provisions of 10CFR, Part 21 was not complete for deviations
discovered in safety-related Westinghouse DHP circuit breaker auxiliary
switch operating assemblies. The following information is a follow-up to
the, January 16, 1998 letter.
On November 20, 1997, IP identified an adverse trend in auxiliary
switch operating assembly anomalies in Westinghouse DHP circuit breakers.
The anomalies were found in Clinton Power Station (CPS) circuit breakers
during maintenance activities performed at both CPS and a circuit breaker
refurbishment services supplier.
The auxiliary switch operating assembly includes the auxiliary
switches, the operating link, and the operating cam (if applicable).
Anomalies found included four cases of bent auxiliary switch links
including two links exhibiting cracks, and two cases of missing "E" clips
(auxiliary switch link pin retaining clip). The bent auxiliary switch
links appeared to be caused by the length of the link. The "E" clips
appeared to have come off the link pins as a result of excessive force
occurring as the links bowed. A broken auxiliary switch link pin and two
cases of lower auxiliary switch cracking due to apparent binding were
also found. In all cases, the weakest component in the auxiliary switch
operating assembly appears to have been the part that failed.
U-602968
Page 2
Condition report 1-97-11-388 was initiated to track an investigation
and resolution of this adverse trend issue. IP determined this issue was
potentially reportable under the provisions of 10CFR21 on November 20,
1997. IP's evaluation of this issue under the provisions of 10CFR21 has
not been completed. CPS has been evaluating these anomalies with the
supplier in an attempt to determine the cause for them and actions to
prevent recurrence. The supplier has been provided one of the bent and
cracked auxiliary switch CPS links.
IP is currently evaluating the supplier's response to several
questions regarding this issue. The supplier's response does not support
that this issue is reportable under 10CFR21; however, IP has determined
that the evaluation of this issue requires additional engineering review.
In addition, an independent circuit breaker services supplier is
performing an evaluation of this issue. IP will continue to evaluate
this issue for reportability under 10CFR21, and communicate with
Westinghouse to obtain a resolution. IP will complete the evaluation of
this issue by May 28, 1998.
Additional information about this issue may be obtained by
contacting D. G. Lukach, Plant Engineer, at (217) 935-8881, extension
3952.
Sincerely yours,
Walter G. MacFarland, IV
Senior Vice President
RSF/krk
cc: NRC Clinton Licensing Project Manager
NRC Resident Office V-690
Regional Administrator, Region III, USNRC
Illinois Department of Nuclear Safety
Westinghouse
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