Part 21 Report - 1998-175
ACCESSION #: 9806010284
Illinois Power Company
Clinton Power Station
P. O. Box 578
Clinton, IL 61727
Tel 217 935-5623
Fax 217 935-4632
Walter G. MacFarland IV
Senior Vice President
and Chief Nuclear Officer
ILLINOIS U-603007
POWER 4F.140
An Illinova Company
May 26, 1998
Docket No- 50461
10CFR21.21
Document Control Desk
Nuclear Regulatory Commission
Washington, D. C. 20555
Subject: 10CFR21 Final 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 21-97055 in letter U-6029 10 to notify the NRC that an evaluation
under the provisions of 10CFR, Part 21 was not complete for anomalies in
safety-related Westinghouse DHP circuit breaker auxiliary switch
operating assemblies. IP provided an update to the NRC on the continuing
evaluation of this issue in IP letter U-602968, dated March 24, 1999. IP
has now completed the evaluation of this issue and concludes that it
should be it reported under the provisions of 10CFR21. The basis for
this conclusion is that the anomalies could cause a failure of the
auxiliary switch operating assembly during breaker operation, resulting
in loss of the breaker safety function.
On November 20, 1997, IP identified an adverse trend of 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 came 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-603007
Page 2
Condition report 1-97-11-388 was initiated to track an
investigation and resolution of this adverse trend, issue. On November
20, 1997, IP determined this issue was potentially reportable under the
provisions of 10CFR21.
IP is providing the following information in accordance with
10CFR21.21(d)(4). Initial notification of this matter will be provided
by facsimile of this letter to the NRC Operations Center in accordance
with 10CFR21.21(d)(3), within two days of the date the responsible
officer signs this letter.
(i) Walter G. MacFarland, IV, Senior Vice President and Chief
Nuclear Officer of IP, Clinton Power Station, Highway 54, 6
Miles East, Clinton, Illinois, 61727, is informing the Nuclear
Regulatory Commission of a condition reportable under the
provisions of 10CFR, Part 21.
(ii) The basic component involved in this condition is the auxiliary
switch operating assembly, including the auxiliary switches,
the operating link, and the operating cam (if applicable), for
Westinghouse Model DHP 4160-volt and 6900-volt circuit
breakers.
(iii) The auxiliary switch operating assembly, including the
auxiliary switches, the operating link, and the operating cam
(if applicable), were supplied to Clinton Power Station by
Westinghouse, Pittsburgh PA, as part of Model DHP circuit
breakers.
(iv) The deviations identified include 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 anomalies appear to be caused by stacked
manufacturing tolerances associated with the auxiliary switch
operating assembly. The bent auxiliary switch links appear to
be caused by the length of the link. The "E" clips appear 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.
IP has concluded that this issue should be reported under the
provisions of 10CFR21. The basis for this conclusion is that
the deviations could cause a failure of the auxiliary switch
operating assembly during breaker operation and result in loss
of the breaker safety function and loss of safety function of
associated equipment loads.
The circuit breaker could fail to trip or could fail to close.
The closing and/or tripping function can be adversely impacted
depending on when the auxiliary switch operating assembly fails
during the operating cycle and the position of the auxiliary
switch during or after the failure.
(v) The auxiliary switch operating assembly condition was
identified and determined to be potentially reportable under
the provisions of 10CFR21 on November 20, 1997.
U-603007
Page 3
IP notified the NRC in letters dated January 16, 1998, and
March 24, 1998, that the evaluation of the issue was not
complete, and additional time was needed for completing the
evaluation,
(vi) CPS has 43 DHP breakers installed in safety-related
applications and 2 spare safety-related DHP circuit breakers
potentially affected by the auxiliary switch operating assembly
deficiencies. Other facilities using DHP circuit breakers
could be affected by this deficiency.
(vii) DHP circuit breakers will be inspected and reworked/refurbished
as necessary prior to startup from the current outage. These
activities include inspecting and correcting any auxiliary
switch operating assembly deficiencies identified. Currently,
IP personnel are performing the inspection and rework
activities, and a vendor is performing the refurbishment
activity. In addition, DHP circuit breakers are currently
inspected and reworked on a 3-year periodicity and refurbished
on a 6-year periodicity under the preventive maintenance
program.
(viii) IP has no advice about this issue for other purchasers or
licensees.
Additional information about this issue may be obtained by
contacting R. A. Philipps, Plant Engineer, at (217) 935-8881, extension
3464.
Sincerely yours,
Walter.G. MacFarland, IV
Senior Vice President and
Chief Nuclear Officer
RSF/mlh
cc: NRC Clinton Licensing Project Manager
NRC Resident Office, V-690
Regional Administrator, Region III, USNRC
Illinois Department of Nuclear Safety
INPO Records Center
Westinghouse
POWER REACTOR EVENT NUMBER:
FACILITY: CLINTON REGION: 3 NOTIFICATION DATE: 05/28/98
UNIT: [1] [ ] [ ] STATE: IL NOTIFICATION TIME: 12:15 [ET]
RX TYPE: [1] GE-6 EVENT DATE: 05/28/98
EVENT TIME: 10:00[CDT]
NRC NOTIFIED BY: R.S. FRANTZ LAST UPDATE DATE: 05/28/98
HQ OPS OFFICER: FANGIE JONES
NOTIFICATIONS
EMERGENCY CLASS: NOT APPLICABLE
10 CFR SECTION: JOHN MADERA RDO
CDEG 21.21(c)(3)(i) DEFECTS/NONCOMPLIANCE
VERN HODGE NRR
UNIT SCRAM CODE RX CRIT INIT PWR INIT RX MODE CURR PWR CURR RX
MODE
1 N N 0 COLD SHUTDOWN 0 COLD SHUTDOWN
EVENT TEXT
10 CFR PART 21 FINAL REPORT REGARDING WESTINGHOUSE DHP CIRCUIT
BREAKER
AUXILIARY SWITCH OPERATING ASSEMBLY ANOMALIES
ON JANUARY 16, 1998, ILLINOIS POWER (IP) ISSUED 10CFR21 INTERIM REPORT
21-97-055 IN LETTER U-602910. THIS NOTIFIED THE NRC THAT AN EVALUATION
UNDER THE PROVISIONS OF PART 21 OF 10CFR WAS NOT COMPLETE FOR
ANOMALIES
IN SAFETY-RELATED WESTINGHOUSE DHP CIRCUIT BREAKER AUXILIARY
SWITCH
OPERATING ASSEMBLIES. IP PROVIDED AN UPDATE IN LETTER U-602968 ON
MARCH
24, 1998 TO THE NRC. IP HAS COMPLETED THE EVALUATION OF THIS ISSUE AND
CONCLUDES THAT IT SHOULD BE REPORTED UNDER THE PROVISIONS OF
10CFR21.
THE BASIS FOR THIS CONCLUSION IS THAT THE ANOMALIES COULD CAUSE A
FAILURE
OF THE AUXILIARY SWITCH OPERATING ASSEMBLY DURING BREAKER
OPERATION,
RESULTING IN LOSS OF THE BREAKER SAFETY FUNCTION.
THE ANOMALIES INCLUDED FOUR CASES OF BENT AUXILIARY SWITCH LINK
AND TWO
CASES OF MISSING "El' CLIPS. THE BASIC COMPONENT INVOLVED IN THIS
CONDITION IS THE AUXILIARY SWITCH OPERATING ASSEMBLY, INCLUDING THE
AUXILIARY SWITCHES, THE OPERATING LINK, AND THE OPERATING CAM (IF
APPLICABLE), FOR WESTINGHOUSE MODEL DHP 4160-VOLT AND 6900-VOLT
CIRCUIT
BREAKERS. THE ASSEMBLY WAS SUPPLIED BY WESTINGHOUSE, PITTSBURGH,
PA, AS
PART OF MODEL DHP CIRCUIT BREAKERS.
CLINTON POWER STATION HAS 43 DHP BREAKERS INSTALLED IN
SAFETY-RELATED
APPLICATIONS AND 2 SPARE SAFETY-RELATED DHP BREAKERS POTENTIALLY
AFFECTED
BY THE AUXILIARY SWITCH OPERATING ASSEMBLY DEFICIENCIES. DHP CIRCUIT
BREAKERS WILL BE INSPECTED AND REWORKED/REFURBISHED AS NECESSARY
PRIOR TO
STARTUP FROM THE CURRENT OUTAGE.
*** END OF DOCUMENT ***
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