United States Nuclear Regulatory Commission - Protecting People and the Environment


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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