ML18064A884

Part 21 Rept Re Presence of Hardwired Connection in Each of Four Containment High Pressure Trip Logic Circuits.Jumpers Removed in Slot 11 of Interconnection Module Assemblies in All Four Channels

ML18064A884
Person / Time
Site:	Palisades
Issue date:	08/30/1995
From:	Rickard I ABB COMBUSTION ENGINEERING NUCLEAR FUEL (FORMERLY, ASEA BROWN BOVERI, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-PT21-95 LD-95-039, LD-95-39, NUDOCS 9509080034
Download: ML18064A884 (4)

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II II 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 thatthis .condition represents a major '.,', .* ; **., ..

degradation of..safety-;-related. equipment' and.a'loss of .safety*functior.r necessary, to* mitigate:the:;P: :* :;. -'"c .

• consequences of certain accidents since all four (4) trip channels were disabled. In addition, the conditiorfs*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, Irie. P.O. Box 500 Telephone (203) 688-1911 1000 Prospect Hill Rd. Fax (203) 285-5203

( 9509080034 950830 \

I Windsor, CT 06095 I PDR ADOCK 05000255 I

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• Document Control Desk e 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.

~~

. Rickard, Director Operations Licensing

Enclosure:

As stated cc: K. Powers (CPCo)

R. S. Siudek (CE)

J. W. Davis (ABB Electro Mechanics)

ABB Combustion Engineering Nuclear Operations

• Enclosure to LD-95-039 Page 1 of 2 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 t_he 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/or, or being supplied/or 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 GE'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 detectthe.

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 lnfobulletin to licensees of CE designed NSSSs discussing the defect reported above.