United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9509080034

                                   ABB

                                        August 30, 1995
                                        LD-95-039

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

Subject:  Report of a Defect Pursuant to 10 CFR 21 in Palisades Nuclear
          Power Plant Reactor Protection System

Dear Sir:

The purpose of this letter is to notify the Nuclear Regulatory Commission
of a "defect", as defined in 10 CFR 21 - "Reporting of Defects and
Noncompliance", in a Reactor Protection System (RPS) sub-component
provided by Combustion Engineering, Inc.  (CE) to Consumers Power Company
for the Palisades Nuclear Power Plant.  The defect was the presence of a
hardwired connection (i.e., a "jumper") in each of the four (4)
Containment High Pressure (CHP) trip logic circuits.  This causes the RPS
to be unable to trip the reactor on a valid high containment pressure
signal.

An evaluation performed by CE has determined that this condition
represents a major degradation of safety-related equipment and a loss of
safety function necessary to mitigate the consequences of certain
accidents since all four (4) trip channels were disabled.  In addition,
the conditions surrounding an initiating accident could be exacerbated
since the CHP trip signal, while failing to initiate a reactor trip,
would initiate several Engineered Safety Features (ESF) actions.

This condition was identified by CPCo, who in turn notified CE.  CE
assisted CPCo personnel in correcting the identified problem and
returning the RPS, and specifically the CHP trip channels, to an operable
status.  Having examined the nature of the problem, CE has no reason to
believe that this reportable condition applies to any other plant for
which CE designed the Nuclear Steam Supply System (NSSS).

                ABB Combustion Engineering Nuclear Power

Combustion Engineering, Inc.  P.O. Box 500     Telephone (203) 688-1911
                              1000 Prospect    Fax (203) 285-5203
                              Hill Rd.
                              Windsor, CT 06095

Document Control Desk                                           LD-95-039
August 30, 1995                                                    Page 2

The Enclosure summarizes the information available to us at this time.
If you have any questions, please feel free to contact me or Mr.  Chuck
Molnar of my staff at (203) 285-5205.

                                        Very truly yours,
                                        COMBUSTION ENGINEERING, INC.

                                        Dr. Ian C. Rickard, Director
                                        Operations Licensing

Enclosure: As stated

cc:  K.  Powers (CPCo)
     R.  S.  Siudek (CE)
     J.  W.  Davis (ABB Electro Mechanics)

                                                   Enclosure to LD-95-039
                                                              Page 1 of 2

              ABB Combustion Engineering Nuclear Operations
            10 CFR 21 Report of a Defect or Failure to Comply

The following information is provided pursuant to the requirements
identified in 10 CFR 21.21 (c)(4):

(i)       Name and address of the individuals informing the Commission:

                    Dr.  I. C. Rickard, Director
                    Operations Licensing
                    Combustion Engineering, Inc.
                    1000 Prospect Hill Road
                    Windsor, CT 06095-0500

(ii)      Identification of the facility the activity or the basic
          component supplied or such facility or such activity within the
          United States which fails to comply or contains a defect.

               The facility affected by this defect is the Consumers
               Power Company (CPCo) Palisades Nuclear Power Plant

               The basic component which is the subject of this report is
               a sub-component of the Reactor Protection System (RPS) and
               is identified as ABB Electro Mechanics Part No. 11247-
               47003 Rev. A, "Trip Unit Bin & Interconnection Module
               Assembly".  The Trip Unit Interconnection Module Assembly
               is located immediately behind the individual bistable and
               auxiliary trip units, and serves as the interconnection
               point for trip unit inputs and outputs.  It is in this
               assembly that trip unit inputs and outputs are routed to
               the proper connectors to form the two (2) out of four (4)
               trip logic, as well as providing trip annunciation,
               sequence of events recording, and trip unit bypass and
               test capability.

(iii)     Identification of the firm constructing the facility or
          supplying the basic component which fails to comply or contains
          a defect.

               Combustion Engineering, Inc. (CE) supplied the Trip Unit
               Bin & Interconnection Module Assembly.

(iv)      Nature of the defect or failure to comply and the safety hazard
          which is created or could be created by such defect or failure
          to comply:

               The defect identified is a hardwired connection (i.e., a
               "jumper") across the Slot 11 Containment High Pressure
               (CHP) trip contacts.  The presence of this jumper
               precludes initiation of a reactor trip when a valid CHP
               trip signal is received.

               CE has determined that this "jumpered" condition
               represents a major degradation of safety-related equipment
               and a loss of safety function necessary to mitigate the
               consequences of certain accidents since all four (4) trip
               channels were disabled.  In addition, the conditions
               surrounding an initiating accident could be exacerbated
               since the CHP trip signal, while failing to initiate a
               reactor trip, would initiate several Engineered Safety
               Features (ESF) actions.  For example, on high containment
               pressure the High and Low Pressure Safety Injection Pumps
               receive start signals, Charging Pumps are started, and
               Containment Isolation is initiated.  The potential exists,
               therefore, for ESF actions to take place without reactor
               trip occurring while still operating at full power.
               Moreover, the reactor operator will receive conflicting
               reactor trip inputs.  Specifically, receipt of a valid
               containment high pressure trip signal will result in
               annunciation of reactor trip on

                                                   Enclosure to LD-95-039
                                                              Page 2 of 2

               that signal; however, power to the Control Rod Drive
               Mechanisms (CRDMs) will not be interrupted and a reactor
               trip will not occur.  Consequently, the control rod "on-
               bottom" light indication will not light.  The reactor
               operator would have to decide which trip input indication
               being received is valid; resulting in the potential for
               taking inappropriate corrective action(s).

(v)       The date on which the information of such defect or failure to
          comply was obtained:

               The presence of a jumper across the Slot 11 CHP trip
               contacts was identified by CPCo Palisades Nuclear Power
               Plant personnel on or about July 28, 1995.  CE was
               informed of the situation by CPCo on July 30, 1995. CE
               completed the 10 CFR 21 discovery phase of its internal
               reporting procedure on August 3, 1995.  The decision that
               the deviation represented a defect which is reportable
               under the provisions of 10CFR21 was finalized by the
               Nuclear Safety Committee on August 28, 1995.

(vi)      In the case of a basic component which contains a defect or
          fails to comply, the number and location of all such components
          in use at, supplied for, or being supplied for one or more
          facilities or activities subject to the regulations in this
          part.

               CE provided new Interconnection Module Assemblies to CPCo
               for the Palisades Nuclear Power Plant in 1992.  To the
               best of CE's knowledge, based on a poll of other CE
               plants, the defect described above is only applicable to
               these specific Interconnection Module Assemblies supplied
               to the Palisades Nuclear Power Plant.

(vii)     The corrective action which has been, is being, or will be
          taken; the name of the individual or organization responsible
          for the action; and the length of time that has been or will be
          taken to complete the action:

               The corrective action, which has been taken was to remove
               the jumpers (by cutting through the circuit board
               connections) in Slot 11 of the Interconnection Module
               Assemblies in all four (4) RPS channels.  Once the problem
               was identified, the jumper connection on the
               Interconnection Module was readily identified on both the
               wire list and on the physical layout of the
               Interconnection Module Turret Board Assembly.  The
               corrective action was supervised by CPCo personnel and
               performed by ABB Electro Mechanics personnel at the
               Palisades site in the presence of an engineer from CE
               Instrumentation and Controls Engineering.  CPCo personnel
               performed post-correction action verification of jumper
               removal.  The matrix test procedure, which had originally
               failed to detect the jumper, was modified to provide a
               valid test.  This modified procedure was run on all four
               (4) RPS channels to verify that the jumper was no longer
               present, and that the CHP trip function was operable
               (i.e., that a reactor trip would be initiated, if
               required).

               A comprehensive test program was developed and conducted
               to verify that all Interconnect Module inputs and outputs
               were functional.  This test program was further extended
               to include verification of all RPS functions, whether
               associated with the Trip Unit Interconnect Module or not.
               This enhanced test program was performed by Palisades
               personnel prior to plant startup.  CE and Palisades
               personnel worked together to derive the list of procedures
               which must be performed to verify operability.

(viii)    Any advice related to the defect or failure to comply about the
          facility, activity, or basic component that has been, is being,
          or will be given to purchasers or licensees:

               CE plans to issue an Infobulletin to licensees of CE
               designed NSSSs discussing the defect reported above.

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