ML17341A535

Technical Evaluation of Electrical,Instrumentation & Control Design Aspects of Override of Containment Purge Valve Isolation & Other Engineered Safety Features Signals

ML17341A535
Person / Time
Site:	Turkey Point
Issue date:	01/31/1981
From:	Cooper J EG&G, INC.
To:
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ML17341A532	List: ML17341A533 ML17341A534 ML17341A535 ML17341A537
References
1183-4160, NUDOCS 8109180209
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Energy 'Measurements Group San Remen Operations 1183-4160 January 1987 TECHNICAL EVALUATIONOF'THE ELECTRICAL, INSTRUMENTATION,AND: CONTROL DESIGN ASPECTS'F THE OVERRIDE, OF CONTAINMENTPURGE VALVEISOLATION AND OTHER ENGINEERED SAFETY FEATURE'SIGNALS FOR THE TURKEY POINT NUCLEAR PORKIER STATION, UNITS'3 and 4 by J:.

H. Cooper Approved for Publication J.

R. Radosevic Department Manager This:. document is, UNCLASSIFIED g

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Derivative.

C1:assifier:

N>cho as' ro eric Department. Manager Work P'erformed'for LawrenceiLivermore.National Laboratory,u'nder U;S. Department'of Energy,'ontract'No.

DE-ACOB-'76'NVO'1183.

,8109180209 810831

,PDR ADOCK 05000250 P

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ABSTRACT This report. documents the. technical evaluation of the electrical, instrumentation, and control design aspects of the:override of containment purge valve isolation and other engineered safety feature signals for the Turkey Point Huclear,power Station, Units 3 and 4.

The review cri:teria are based on IEEE Std-279-1971:

requirements for the safety signals. to all purge and ventilation isolation valves.

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FOREMORD This

report, is supplied as part of the Selected 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 National Laboratory, Field Test Systems Division of the Electronics Engineering Department.

The U.S.

Nuclear Regulatory Commission, funded the work under an authorization entitled "Electrical, Instrumentation and Control System Support,"

B&R 20 19 04 031, FIN A-0231.

The work was performed by EG&G, Inc., Energy Measurements

Group, San Ramon Operations,, for Lawrence Livermore National Laboratory under U.S.

Department of Energy contract number DE-AC08-76HV01183.

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TABLE OF CONTENTS

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INTRODUCTION.

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EVALUATION OF TURKEY POINT HUCLEAR POWER STATION, UNITS 3 AND 4

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2.1 Review Criteria 2.2 Containment Ventilation Isolation Circuits Design Description 2.3 Containment Ventilation Isolation System Design Evaluationo

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2.4 Other Engineered, Safety Feature System Circuits

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6 3'ONCLUSIONS..............,..

7 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 FOR THE TURKEY POINT NUCLEAR POWER STATION, UNITS 3 AND 4 (Docket Nos.

50-250 and 50-251)

J.

H.. Cooper EG&G,. Inc., Energy Measurements

Group, San Ramon Operations l.

INTRODUCTION Several instances have been reported where automatic closure of the containment ventilation/purge valves

.would not have occurred because the safety actuation signals were. either manually overridden or blocked during'ormal plant operations.

These events resul'ted'rom procedural inadequacies, design deficiencies, and lack of proper management. controls.

These events'lso brought into question the mechanical'perability of the containment isolation valves themselves.

These events were determined by the U'.S.

Nuclear Regulatory Commission (NRC) to.be an Abnormal Occurrence

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

As a follow-up on this.

Abnormal Occurrence, the NRC staff is reviewing the. electrical override aspects and:

the, mechanical operability aspects-of containment purging for all operating-power reactors.

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

Purging, During: Normal Plant'peration" (Ref'.. 1] to all boi ling water reactor (BMR) and pressurized water reactor (PHR), licensees.

In a letter (Ref. 2] dated January 5, 1979, the Florida Power and. Light. Company (FPLC),, licensee for the Turkey Point Nuclear Power Station,, Units

3. and 4, replied to the NRC generic, letter.,

A'eeting was held on. May, 30,. 1979 by, the NRC. staff and EG&G',, Inc.

(San Ramon; Operations),

personnel.

In the meeting 'of May 30, 1979;. during: a: conference: cal,l, and. in letters of June 8,, 1979'Ref.,

3]', and December 13, 1979 [Ref;, 4],, the: licensee.

described

.the, purge valve isola-.

ti'on system design of the. Turkey Point, Nucl'ear'ower Station. as discussed later in this: report.

This: document'. addresses only'he: electrical',

i'nstrumentation,.

and.

control (EI&C) design aspects of'he: containment.

ventilation isolation (CVI) and. other engineered, safety features:

(ESFs).

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EVALUATION OF TURKEY POIHT HUCLEAR POWER STATIOH, UHITS 3 ANO 4 2.1 REVIEW CRITERIA The primary intent of this evaluation is to determine if the following HRC staff criteria are met for the safety signals to all purge and ventilation isolation valves:

(1)

Criterion no.. 1--In keeping with the requirements of GOC 55 and 56 (Ref. Sj, the overriding* of one type of safety actuation signal'e.g.,

radiation) should not cause the blocking of any other type of safety actuation signal (e.g

, pressure) for those valves that have no function besides containment isolation.

(2)

Criterion no. 2--Sufficient, physical features (e.g.,

keylock switches) are to be, provided to facilitate adequate administrative controls.

(3)

Criterion no-.

3--The system-level annunciation of the overridden status should be provided. for every safety system.impacted when any override is active (see R.G. 1'.47).

Incidental to this review,.

the following additional HRC staff design criteria were used in the evaluation:

(1)

Criterion no.

4--Diverse signals should be pro-vided to initiate isolation of the containment ventilation system..

Specifically,.

containment.

high radiation, safety injection actuation,,

and containment high pressure (where containment high pressure is not a.portion of'afety injection actuation) should automatically initiate CVI.

(2)

C'riterion: no.

5The instrumentation and control systems.

provided:

to, initiate

ESF, should be, de-signed: and. qualified. as. safety-grade:

equipment.

~y.1ygyyg..':y::y:1gy:f g.gg:

Override'.

The. signal is: still: present,.

and it is: bl'ocked, in order. to; perform.

a~ function contrary: to, the: s'ignal..

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(3)

Criterion no. 6--The overriding or'esetting* of the isolation actuati'on signal should not cause any valve or damper to change position.

Criterion.

'6: in this review applies primarily to related ESF systems because implementati'on of this criterion for containment isolation systems, will be reviewed by the Lessons Learned Task Force,.

based on the

,recomnendations in NUREG

0578, Section

2. 1.4 (Ref. 6].

Automatic valve reposi.tioning upon reset may be acceptabl'e when. containment isolation is not involved; consideration will be, given on a case-by-case

.basi's.

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

OESIGN OESCR IP TION'ach of the Turkey. Point. units has two ESF trains which cause isolation of the containment ventilation, system.,

The initiating, signals for each train, which are listed below, are combined as parallel inputs to form an "OR" gate.

2.2 (1)

Automatic Si'al s (a')

High radiation (particulate or gas)

(b)

Safety injection, actuation (2)

Hanual'i nals a

Containment isolation; phase:

A' pushbotton (b)

Containment isolation; phase.

B: - pushbutton Each train includes the automatic and manual;input "OR" gates, a,

retentive:

memory element.,

which is.

a: lock-out,relay with a

manual reset,,

and a'ontainment ventilati'on isolation control circuit'.

The retentive memory is a device. which retains the condition of the, output. that.

corresponds, to the. last.

input.,

'This retentive memory element is not capabl'e of overriding; containment:

ventil'at'ion i'solation signal's.

and: will not; latch. an override on the. CVI.. If a, manual

.reset; is; attempted when,a, trip-signal's.present,.

the device wi.ll'eturn to: a trip-ped, condition..

When; either

a. monitored: plant; condition. or.

a. manual input. calls.

.for isolation,. the si.'gnal goes'hrough~

the. "OR"'ate and trips: the: reten-tive memory el'ement. to. the 'isolation state..

The isolation'alve: control circuit, operates:

to: cl'ose; the. ventil'ation valve,, and. remains: in: that, state, unti:1 the retentive; memory, el'ement. is: manual-ly reset..

'Thhf1 ig:dfIi.i.i':gi'f I'.l.y. f Reset::;

The: signal has'ome and. gone,.

and the: circuit; is being.

cleared'. in order to: return; it'o the. normal'ondition.

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I'j Cg Ag F9 2.3 DES IGH.. EYALUATIOH In their letter of Oecember 13 1979: LRef. '43, the licensee for Turkey Point Nuclear Power Station, Units 3

and 4

has, committed to 1'imit containment.

purging during power operation

()2$ power),'o a total of 200 hours0.00231 days <br />0.0556 hours <br />3.306878e-4 weeks <br />7.61e-5 months <br /> per year for.the site, which'ncludes purging of 'both units.

.An. override of the safety injection signal'oes not block or.

overri'de the radiation. or manual isolation signals.

We conclude,,

there-fore, that HRC'riterion no..

1. is satisfied.

There is no override.

in the..CV;I circuit; therefore, special pliysical features are not required.

We conclude that criterion no.

2. is not applicable.,

There.are annunciators on the safety injection actuation signal:,,

the containment hi.gh pressure si'gnal,.

and the.high radiation and contain-ment vent'ilation isolation signals.

When asked if SI. override.

was annun-ciatedI on the CVI panel',, the licensee.

stated,.in the litter. of October 27, 1'980 L'Ref'.

75 that there is an annunciator for the override.. of safety injection targeted as "SI Bl'ocked",

and that "Containment, Ventilation Isolation"- override annunciation would be inappropriate.

We conclude, that with the "SI Bl'ocked"'nnunciator clearly visible. from the containment ventilation control panel, HRC'riterion Ho.. 3 will be met.,

Containment ventilation isolation is initiated: by safety injec-tion (i'ncluding a, high containment. pressure.signal) as:.well's'y either of two high containment radiation signals.

Hence, the:

CVI, system design incl'udes diverse, actuation. signa'1's and: satisfies'RC'ri.terion no., 4'.,

\\'oththe CVI. system and'. the. equipment; providing signals for it'.

are part of the pl'ant: safeguards.

actuation system; The. 1'.icensee states in their le'tter-of. October 27:,

1980':Ref;.

7]', that. the: safeguards':

system: is designed; and: qual'ified.

as: safety-grade..

and'. that: the CVI. system.

al.so, is,

. safety-grade; We: conclude,. therefore, that'RC'riterion no..

5 is satis.-

fiedd.,

Fol.lowing manual

reset, the retentive memory, element'emains in the reset condition until' subsequent trip signal (automatic or manual) occuls

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The trip condition

,of the CYI is annunciated on the control'anel; valve-position lights (full open/full closed) are provided.

Resetting; the: safety.injecti'on'ignal. cannot. cause: the.

CY~I:

system'o reset,.

nor. will it; cause: automatic reopening of the. containment', ventila-tion; val,ves;..

Cl'earing; the, CVI; isol'ation'ignal: requires: manual'peration of the: reset'.,

'Reopening; the. val'ves also; requires:

manual'. operation of: the.

indi,vidual'entilation valve switches..

We: concl'ude;, therefore;. that:

HRC:

criterion Ho.. 6 is; sati'sfied.

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2.'4 OTHER ENGINEERED SAFETY FEATURES (ESF)

SYSTEM CIRCUITS The other engineered safety features (ESF) audited were contain-ment isolation Phase.

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The other.

ESF system circuits are the same as the containment venti lat:ion isolation (CYI) circuits with respect tcf overrides, and valve reopening on reset.

Me conclude that the HRC criteria're met.

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CONCL'US IONS The EI8C -design aspects of containment purge, valve isolation and other ESF signals for the Turkey Point Nuclear Power Stati'on, Units 3 and 4 were evaluated using those design criteria stated in Section 2.1 of this report.

Me determine that the CVI'ystem design and the design of other

-ESF circuits meet, the NRC staff criteria stated in Section.

2.1. of this report.

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REFERENCES 1.

NRC/DOR 1 etter (A.

Schwencer) to

HPPO, "Containment Purging During Normal Plant Operation,,"

dated November 28, 1978.

2.

NPPD letter (R.

E. Uhrig) to HRC (A. Schwencer),

'"Docket 50-250,

251, Containment Purging During Hormal Plant Operations, Turkey Point Nuclear Plant," dated January 5, 1979.

3.

FPL'.'letter (R.

E. Uhrig) to. NRC (A. Schwencer),

"Containment Purging, Turkey Point Nuclear Station, Units 3 and 4," dated, June 8, 1979.

4; FPL letter (R.

E. Uhrig) to NRC (A. Schwencer),

"Containment Purge,"

dated December 13, 1979..

5.

U.S. Nuclear Regulatory Commission, Standard Review Plan, "Containment Isolation System" HUREG 76/087,. Rev.

ection 6.

U.S.

Hucl ear Regulatory Comnission,,

"TMI Short-term Implementation Action,"

NUREG-0578..

7.

FPL letter. (R.

E. Uhrig) to NRC (T. Novak), "Turkey Point', Units 3 and O', Docket Nos.

50-250 and 50-251, Containment Ventilation Isolation",

dated'ctober 27, 1980.

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