United States Nuclear Regulatory Commission - Protecting People and the Environment

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


  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.


                                                  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


                              Sincerely yours,

                              Walter G. MacFarland, IV

                              Senior Vice President


cc:  NRC Clinton Licensing Project Manager

     NRC Resident Office V-690

     Regional Administrator, Region III, USNRC

     Illinois Department of Nuclear Safety



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