ML20054E851

Technical Evaluation of Electrical Instrumentation & Control Design Aspects of Overside of Containment Purge Valve Isolation & Other Engineered Safety Feature Signals for Cooper Nuclear Power Station

ML20054E851
Person / Time
Site:	Cooper
Issue date:	06/30/1982
From:	Cooper J EG&G, INC.
To:	NRC
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ML20054E848	List: ML20054E847 ML20054E851
References
EGG-1183-4149, NUDOCS 8206140341
Download: ML20054E851 (18)

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P 1-GE O S 1183-4149 4

- JUNE 1980 Energy Measurements Group

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s TECHNICAL EVALUATION OFsTHE ELECTRICAL, 1

INSTRUMENTATION, AND CONTROL DESIGN ASPECTS OF THE g

OVERRIDE OF CONTAINMENT PURGE VALVE ISOLATION AND OTHER ENGINEERED SAFETY FEATURE SIGNALS FOR THE COOPER NUCLEAR POWLR STATION N

5 (DOCKET NO. 50-298)

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g.{ DESIGNATED 031GI!1L brtifiedEy_B.'L.Me9el Work Performed for Lawrence Livermore National Laboratory under U.S. Department of Energy Contract No. DE-ACO B-76 NVO 1183.

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e v4i DISCLAIMER i

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This report was prepared as an ' account' of work sponsored y the United n

States Government.

Neither the United States nor the United States Department of Energy, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for i

the accuracy, completeness or usefulness of any information, apparatus, R

product or process disclosed, or represents that its use would not infringe J j on privately owned rights.

Reference herein to any specific commercial t

product, process, or service by trade name, mark, manufacturer, or other-

-i wise, does not necessarily constitute or imply its endorsement, recomend-ation, or favoring by the United States Government or any agency thereof.

l The views and opinions of authors expressed herein do not necessarily state

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I or reflect those of the United States Government or any agency thereof.

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)mEGcG caern ece ur.m:xis croup s:n nemen ep.retiene EGG 1183-4149 June 1980 E

TECHNICAL EVALUATION OF THE ELECTRICAL,

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INSTRUMENTATION, AND CONTROL DESIGN ASPECTS OF THE f

OVERRIDE OF CONTAINMENT PURGE VALVE ! SOLATION

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AND OTHER ENGINEERED SAFETY FEATURE SIGNAL 5 FOR THE COOPER NUCLEAR POWER STATION (DOCKET NO. 50-298) by J. H. Cooper Approved for Publication hhh&,1

'J. 'R'. Radosevic Department Manager This Document is UNCLASSIFIED

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Nicholas f. Broderick Department Manager Work Performed forLawrence Livermore Nationallaboratory under U.S. Department of Energy Contract No. DE.ACC 8-76 NVQ 1183.

SAN RAMON OPERATIONS d

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ABSTRACT This report documents the technical evaluation of. the electrical, instrumentation, and control design aspects of the override of containment

.orge valve isolation and other engineered safety feature signals for the l

Cooper Nuclear Power Station.

The review criteria are based on IEEE Std-279-1971 requirements for the safety signals to all purge and venti-lation isolation valves.

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'A FOREWORD 1

This report is supplied as part of the Selseted Electrical.

Instrumentation, and Control Systems Issues (SEICSI) Program being con-ducted for the U.

S.

Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, Division of Operating Reactors, by Lawrence Livermore Labora tory, Field Test Systems Division of the Electronics Engineering Department.

The U. S. Nuclear Regulatory Commission funded the work under an authorization entitled " Electrical, Instrumenta tion and Control System Support," B&R 20 19 04 031, FIN A-0231.

The work was perfonned by EG&G, Inc., Energy Measurements Group, San Ramon Operations, for Lawrence Livermore Laboratory under U. S. Depart-ment of Energy contract number DE-AC08-76NV01183.

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I li TABLE OF CONTENTS

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1.

INTRODUCTION.

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EVALUATION OF COOPER NUCLEAR POWER STATION 2.1 Review Criteria 3

i 2.2 Containment Ventilation Isolation Circuits 3

I Design Description 2.3 Containc.ent Ventilation Isolation System Design 4

Evaluati on.

2.4 5

Other Engineered Safety Feature System Circuits 7

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3.

CONCLUSIONS.

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REFERENCES.

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TECHNICAL EVALUATION OF THE ELECTRICAL, INSTRUMENTATION, AND CONTROL DESIGN ASPECTS OF THE OVERRIDE OF CONTAINMENT PURGE VALVE ISOLATION AND OTHER ENGINEERED SAFETY FEATURE SIGNALS

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FOR

,e THE COOPER NUCLEAR POWER STATION (Docket No. 50-298)

J. H. Cooper EG8G, Inc., Energy Measurements Group, San Ramon Operations 1.

INTRODUCTION Several instances have been reported where automatic closure of the containment ventilation / purge valves would not have o: curred because the safety actuation signals were either manually overridden or blocked during normal plant operations.

These events resulted from procedural inadequacies, design deficiencies, and lack of ~ proper management controls.

These events also brought into question the mechanical operability of the l

containment isolation valves themselves.

These events were determined by the U. S. Nuclear Regulatory Comission (NRC) to be an Abnomal Occurrence

(#78-5) and were, accordingly, reported to the U. S. Congress.

As a follow-up on this Abnomal Occurrence, the NRC staff is reviewing the electrical override aspects and the mechanical operability l

aspects of containment purging for all operating power reactors.

On November 28, 1978, the NRC issued a letter entitled " Containment Purging l

During Nomal Plant Operation" [Ref.13 to all boiling water reactor (BWR) and pressurized water reactor (PWR) licensees.

In a letter [Ref. 2] dated l

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January 4,1979, the Nebraska Public Power District (NPPD), licensee for

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the Cooper Nuclear Power Station, replied to the NRC generic letter.

A meeting was held on September 12, 1979 by the NRC staff and EG8G, Inc. (San Ramon Operations) personnel.

In the meeting of September 12, 1979, and during a conference call, the licensee described the purge valve isolatjon system design changes made to the Cooper Nuclear Powe,r Station as described later in this report.

This document addresses only the electrical, instrumentation, and control (EI&C) design aspects of the containnent ventilation isolation (CVI) and other engineered safety features (ESFs).

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2.

EVALUATION OF THE COOPER NUCLEAR POWER STATION K

2.1 REVIEW CRITERIA

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I The primary intent of this evaluation is to determine that the following requirements are met for the safety signals to all ESF equipment.

l (1)

Criterion no.1--In keeping with the requirements of GDC 55 and 56 [Ref. 33, the overriding

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one type of safety actuation signal (e.g., radia-l tion) should not cause the blocking of any other type of safety actuation signal (e.g., pressure)

.R for those valves that have no function besides I

containment isolation.

.N (2)

Criterion no. 2--Sufficient physical features N

(e.g., keylock switches) are to be provided to l

facilitate adequate administrative controls.

(3)

Criterion no. 3--The system-level annunciation of i

the overridden status should be provided for i

every safety system im active (see R.G.1.47)pacted when any override is I

Incidental to this review, the following additional NRC staff N

design criteria were used in the evaluation:

(1)

Criterion no. 4--Diverse signals should be pro-l vided to initiate isolation of the containment i

ventilation system.

Specifically, containment N

high radiation, safety injection actuation, and containment high pressure (where containment high pressure is not c portion of safety injection actuation) should automatically ini tiate CVI.

(2)

Criterion no. 5--The instrumentation and control systems provided to initiate ESF should be de-N signed and qualified as safety-grade equipment.

• The following definition is given for clarity of use in this evaluation C

Override:

The signal is still present, and'it is blocked in order to perform a function contrary to the signal.

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(3).

Criterion no. 6--The overriding or resetting of the ESF actuation signal should not cause any valve or damper to change position.

Criterion 6 in this review applies primarily to related ESF systems because implementation of this criterion for containment isolation

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systems will be reviewed by the Lessons Learned Task Force, based on the reconsnenda ions in NUREG 0578, Section 2.1.4 [Ref. 4].

Automatic valve repositioning upon re. set may be acceptable when containment isolation is not involved; consideration will be given on a case-by-case bas.f s.

Accept-ability would be dependent upon system function, design intent, and suit-able operating procedures.

2.2 CONTAINMENT VENTILATION ISOLATION CIRCUITS DESIGN DESCRIPTION Cooper Nuclear Power Station has two ESF trains which can cause isolation of the containment ventilation system.

The initiating or per-missive contacts of each train are combined as series inputs to form an "0R" gate. These contacts are described below:

1.

Automatic Contacts (a) Containment 'high radiation (one radiation monitor in each train, with contacts and cross-coupling in both trains)

(b) Drywell high pressure or reactor vessel low

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water level 2.

Manual Contacts

.(a) Keylock manual valve control (open/close)

(b) ACAD postaccident override

• The following definition is given for clarity of use in this evaluati.'i Reset:

The signal has come and gone, and the circuit is being c1 cared in order to return it to the normal condition. l

When containment high radiation calls for containment isolation, K13 in the trip auxiliary unit opens and de-energizes the RMA-X and RMB-X relays.

These relays, or the drywell high pressure or reactor low water ESF signals, de-energize isolation relays ISO-1AX, 2AX, IBX, arid 2BX, which are located in the isolation relay cabinet.

The isolation relays fu'nction in the valve control circuits causing the closure of the ventilation Rl' valves.

l In the case of the motor-operated valves, there is an open cir-cuit and a close circuit.

The control has a seal-in that causes the valve to close completely after initiation by a mcmentary signal.

The. isolation signal of the isolation relay will cause the valve to close.

Limit switches in the control circuit automatically coordinate the opening and closing functions of the valve, and limit lights in the control room in-dicate the status of the valve.

An override keylock switch is employed in the valve-open control circuit of the inner valves (230 MV and 231 MV) and is associated with the Atmospheric Containment Dilution System (ACAD) for postaccident venting and with the Standby Gas Treatment System (SBGT).

l In the case of air-operated valves, the isolation signal and the manual switch signal are the only closing signals that de-energize the solenoid-operated air pilot valves to remove air from the ventilation valve.

The ventilation valve closes by spring force.

When the solenoid air valve is energized, air goes to 'the ventilation valve to open it l

against the spring force.

The air-operated valve also has limit switches to energize the limit lights which indicate the valve status in the control room.

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2.3 CONTAINMENT VENTILATION ISOLATION SYSTEM DESIGN EVALUATION l

In response to this issue, the Cooper Nuclear Power St'ation is currently operating on an unlimited purging basis that they fe~el is necessary to meet the requirements of the plant.

Due to the inerting and de-inerting requirements for operation, approximately 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br /> of purging b

W is required for each shutdown, which means that hours per year is practically impossible.

limiting purging to 90 would be held to a minimun.

The licensee stated that purging The individual CVI valves have manual open/close switches system level re. set or override control.

There is an override on the control of the two inboard valves for postaccident venting to the ACAD

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flarrrnabla gas recombiner and to the Standby Gas Treatment System (SBG Unlike other'BWRs, t' e SBGT system cannot be used during C h

postaccident override.

The bypass system has a keylock switch with the capability for administrative control of the key.

It is stated in the NPPD letter of January 4,1979 [Ref. 23, that there is no annunciator on postaccident CVI override switch; however, as the system is not licen for operation and will not be used, none should be required.If a system-level annunciator is required, it should be a part of the ACAD license change.

The NRC staff criteria nos.1, 2, and 3 are satisfied.

The containment isolation automatic actuation signal is initiated by one or more of three safety signals as described in section 2.2.

We conclude that NRC staff criterion no. 4 is satisfied.

Based on the information provided by the licensee during the September 12, 1979 meeting with the NRC and by the NPPD letter of December 18,1979 [Ref. 53, the radiation monitoring equipment at the Cooper N Power Station is designed and qualified as safety-grade (Class ment.

We conclude that NRC staff criterion no. 5 is satisfied.

The valve control switch for the air-operated valves is a two-position switch that will be modified so that the valves will not re-open when the isolating signal is reset.

This modification satisfies NRC criterion no. 6.

2.4 OTHER ENGINEERED SAFETY FEATURE SYSTEM C As stated in the NPPD letter of December 18, 1979 [Ref. 53, the licensee submitted an evaluation of other ESF systems in Bulletin 79-D8 [Ref. 63 o IE We audited several of these other ESF systems for compliance with the criteria regarding overrides, safety grad and automatic valve reopening.

The ESF systems audited were high pressure core injection, residual heat removal, and core spray.

We conclude that the ESF systems audited satisfy the NRC I

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CONCLUSIONS The El&C design aspects of containment purge valve isolation and other ESF signals for Cooper Nuclear Power Station were evaluated using those design criteria stated in Section 2.1 of this report.

l We conclude that the CVI system design meets the NRC staff criteria.

We also conclude that the other ESF circuit designs audited meet l

the NRC staff criteria.

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REFERENCES 1.

NRC/ DOR letter (A. Schwencer) to NPPD, " Containment Normal Plant Operation," dated November 28, 1978.

2.

NPPD letter (J.M. Pflant) to NRC (H. Denton, A'ttn: T.

Ippolito),

" Docket 50-298 Containment Cooper Nuclear Plant," dated January 4,1979. Purging' During Normal Pl 3.

U.S. Nuclear Regulatory Commission, Standard Review Plan Isolation System," NUREG 75/087, Rev.1, section b.2.4." Containment 4.

U.S.

Nuclear Regulatory Commission, "TMI Short-term Implementatio Action," NUREG-0578.

5.

Vent Valve Operability,NPPD letter (J.M. Pilant) to NRC (T. Ippo Cooper Nuclear Station," dated December 18, n

1979.

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NPPD letter (J.M. Pilant) to NRC (K. Seyfrit), "IE Bulletin 79-08 Events Relevant to Boiling Water Reactors Identified During Thre Island Incident," dated April 25, 1979.

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DISTRIBUTION LIST i

LLNL/Livermore EG8G/SR0 Lawrence Livennore National Laboratory P. O. Box Livermore,808 EG8G-Inc.

California 94550 P. O. Box 204 M. H. Dittmore, L-97 (2 copies)

San Ramon, California 94583 3g Author (2 copies)

C. E. Brown (4 copies)

B. G. Mayn M. W. Nishimura LLNL/ Nevada a

Lawrence Livennore National Laboratory

{

P. O. Box 45 U. S. Nuclear Regulatory Commission Mercury, Nevada 89023 Washington, D. C. 20555 Y

{

W. E. Reeves, L-577 (2 copies)

D. G. Eisenhut, MS-528 P. C. Shemanski, MS-416 (3 copies) r USDOE/NY00 USDOE/ TIC 4

U. S. Department of Energy Nevada Operations Office U. S. Department of Energy P. O. Box 14100 Technical Information Center r

Las Vegas, Nevada 89114 P. O. Box 62 J. A. Koch Dak Ridge, Tennessee 37830 R. R. Loux T. Abernathy (2 copies)

R. B. Purcell e

j CEB/amr/ Cathy #1 13 I

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