United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9510110230

                                                  Illinois Power Company
                                                  Clinton Power Station
                                                  P.O. Box 678
                                                  Clinton, IL 61727
                                                  Tel 217 935-5623
                                                  Fax 217 935-4632

                                                  John G. Cook
                                                  Vice President
ILLINOIS                                            U-602502
     POWER                                          L16-95(10 -06 )LP

                                                    4F.140
                                                  JGC-403-95
                                                  October 6, 1995

Docket No. 50-461                                 10CFR21.21

Document Control Desk
Nuclear Regulatory Commission
Washington, D.C. 20555

Subject: 10CFR21 Interim Report 21-95-018: Asea Brown Boveri
         ITE Gould Type SS-13 Solid State Trip Device Failure

Dear Sir:

     On August 7, 1995, during an attempt to shift the Control Room
Heating, Ventilating, and Air Conditioning (VC) system operation from the
A train to the B train, the B train return air fan would not start.  An
investigation of the failure to start found the fan's circuit breaker,
0AP06E5D, in a tripped condition.  Illinois Power (IP) staff reset the
circuit breaker and attempted to start the fan but the breaker tripped
again.  The breaker was replaced with a spare breaker, and the fan
started and operated satisfactorily.  Testing of the deficient breaker on
August 8, 1995, identified that its solid state trip device was causing
the breaker to trip.  IP does not know why the solid state trip device
caused the breaker to trip, but has returned the device to the supplier
for testing.

     On August 10, 1995, IP determined that the potentially deficient
type SS-13 solid state trip device was a condition potentially reportable
under the provisions of 10CFR21. IP's investigation of this issue and
evaluation for reportability are restrained by the results of supplier
testing of the potentially deficient solid state trip device.

     On August 21, 1995, IP identified another potentially deficient type
SS-13 solid state trip device.  This device was installed in the circuit
breaker for the B Switchgear Heat Removal (VX) system condensing unit
motor.

     IP provides the following information in accordance with
10CFR21.21(c)(4).  Initial notification of this matter will be provided
by facsimile of this letter to the NRC Operations Center in accordance
with 10CFR21.21(c)(3) on the date this letter is signed by the
responsible officer.


                                                                 U-602502
                                                                 Page 2

(i)       J. G. Cook, Vice President of IP, Clinton Power Station, Post
          Office Box 678, Clinton, Illinois, 61727, is the responsible
          officer informing the Nuclear Regulatory Commission (NRC) of a
          condition potentially reportable under the provisions of 10CFR
          Part 21, by means of this report.

(ii)      The Basic components involved in this condition are solid state
          trip devices, type SS-13, manufacturer part number 609901-T012,
          serial numbers 45779 and 45778.  One trip device was installed
          in the circuit breaker for VC system B train return air fan
          0VC04CB, and the other trip device was installed in the circuit
          breaker for the VX system B train condensing unit motor
          1VX06CB.  The trip device provides electrical overcurrent
          protection of the connected circuit breaker load.

(iii)     The solid state trip devices were manufactured by Gould/ITE
          (now ABB, Asea Brown Boveri).

(iv)      During an attempt to transfer VC system operation from the A
          train to the B train, the B train return air fan would not
          start.  An investigation found the return air fads circuit
          breaker in a tripped condition.  T-P reset the circuit breaker
          and attempted to start the return air fan but the breaker
          tripped again.  The breaker was replaced with a spare breaker
          and the fan started and operated satisfactorily.  Testing of
          the VC system breaker identified that its solid state trip
          device was causing the breaker to trip.  The trip device in the
          VX system exhibited similar symptoms as the VC system trip
          device.  IP does not know why the solid state trip device
          caused the breaker to trip but is continuing the investigation
          of this issue.

          The failure of the VC system B train return air fan prevents
          the B train from performing its intended safety function which
          is to maintain a habitable environment and ensure the
          operability of all components in the main control room under
          all operating and accident conditions.

(v)       The potentially deficient solid state trip device in the VC
          system was identified on August 8, 1995.  On August 10, 1995,
          IP determined that the trip device was potentially reportable
          under the provisions of 10CFR, Part 21.

(vi)      A model SS-13 solid state trip device is typically installed on
          auxiliary power 480-volt circuit breakers used for motor
          control at CPS.


(vii)     IP replaced the VC system breaker (having the potentially
          deficient device) with a spare breaker and the fan started and
          operated satisfactorily.  Testing of the device by IP at CPS
          was inconclusive.  IP has returned the VC system solid state
          trip device to the supplier for testing.  Initial testing by
          the supplier at its Fenton, Missouri location was also
          inconclusive.  The supplier is currently planning to test


                                                            U-602502
                                                            Page 3

          the device at its Allentown, Pennsylvania location.  IP is
          awaiting the results of the supplier testing to determine
          further actions.  The supplier has not provided a schedule for
          completing the testing.

          IP replaced the VX system trip device with a new unit and plans
          to return the potentially deficient device to the supplier for
          testing.  IP is tracking the solid state trip device issue in
          accordance with condition report 1-95-08-012.

(viii)    IP has no advice to offer other purchasers or licensees about
          this issue at this time.  Additional information about this
          issue may be obtained by contacting D. G. Lukach, system
          engineer, at (217) 935-8881, extension 3952.

          IP will provide an update on the status of the investigation of
this issue by December 20, 1995.

                                        Sincerely yours,


                                        J. G. Cook
                                        Vice President

RSF/csm

cc:   NRC Clinton Licensing Project Manager
      NRC Resident Office, V-690
      Regional Administrator, Region III, USNRC
      Illinois Department of Nuclear Safety
      INPO Records Center
      Asea Brown Boveri


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