ML19336A595

Electrical,Instrumentation & Control Aspects of Override of Containment Purge Valve Isolation & Other Safety Feature Signals, Interim Rept

ML19336A595
Person / Time
Site:	FitzPatrick
Issue date:	09/30/1980
From:	Udy A EG&G IDAHO, INC.
To:	Shemanski P Office of Nuclear Reactor Regulation
References
CON-FIN-A-6256 EGG-EA-5249, NUDOCS 8010300186
Download: ML19336A595 (13)

Text

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wu ectam en u re INTERIM REPORT Accession No.

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Report No. EGG-EA-5249 C:ntract Program or Project

Title:

Electrical, Instrumentation and Control System Support Subject of this Document Electrical, Instrumentation and Centrol Aspects of the Override of Containment Purge Valve Isolation and Other Safety Feature Signals, James A. FitzPatrick Nuclear Power Plant, Docket No. 50-333, TAC No. 42576 Type of Document:

Informal Report Author (s):

A. C. Udy Dite of Document:

September 1980 Rssponsible NRC Individual and NRC Office or Division:

Paul C. Shemanski, Division of Licensing This document was prepared primarily for preliminary or internal use. it has not received full review and approval. Since there may be substantive changes, this document should not be considered final.

. EG&G ldaho, Inc.

. Idaho Falls, Idaho 83415 Prepared for the U.S. Nuclear Regulatory Commission Washington, D.C.

Under DOE Contract No. DE AC07-76lD01570 NRC FIN No. A6256 lNTERIM REPORT hp i5 't v'

1205F

. TECHNICAL EVALUATION REPORT ELECTRICAL, INSTRUMENTATION, AND CONTROL ASPECTS OF THE OVERRIDE OF' CONTAINMENT PURGE VALVE ISOLATION AND OTHER SAFETY FEAIURE SIGNALS JAMES A. FITZPATRICK NUCLEAR POWER PLANT

. Docket No. 50-333 September 1980 A. C. Udy EG&G Idaho, Inc.

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TAC No. 42576 I

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ABSIRACT .

Several instances have been reported where the automatic closure

- of the' containment ventilation or purge isolation valves would not have occurred becsese the safety actuation signals were manually overridden or blocked during normal plant operations. This report a'ddresses elec-trical, instrumentation, and control design aspects for these valves, and the ability of the' unit containment ventilatic~isystem to isolate-on several dive'rse paramete's.

r 'Other related safety systems were audited to the same guidelines.

-While the-licensee has responded to NRC requests for information,- .

the information presently availtble is insufficient to complete this .

! review. The licensee also needs to commit to circuit modifications to -

remove an identified design ' deficiency.-

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CONTENES l

1.0 IRIRODUCIION . . . . . . . . . . . . . . . . . . . . . . . . . . 1 I 2.0 EVALUATION OF JAMES A. FITZPATRICK NUCLEAR POWER PLANT . . . . . 2 2.1 Review Guidelines . . . . . . . . . . . . . . . . . . . . . 2 i 2.2 Containment Ventilation Isolation Circuits Design Description . . . . . . . . . . . . . . . . . . . . . . . . 3 l

2.3 Containment Ventilation Isolation System Design i

Evaluation . . . . . . . . . . . . . . . . . . . . . . . . 4 2.4 Other Related Engineered Safety Feature System Circuits . . 5 l 3.0

SUMMARY

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4.0 REFEREscES . . . . . . . . . . . . . . .. . . . . . . . . . . . 7 l

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TECHNICAL EVALUATION REPORT ELECTRICAL, INSTRUMENTATION, AND CONTROL ASPECTS OF THE OVERRRIDE OF CONTAINMENT PURGE VALVE ISOLATION

' AND OTHER SAFETY FEATURE SIGNALS

,' JAMES A. FITZPATRICK NUCLEAR POWER PLANT 1.0 IKIRODUCTION 4

Based on the information supplied by the Power Authority of the State of New York (PASNY), this report addresses the electrical,

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instrumentation, and control system design aspects of the Containment 4

Ventilation Isolation (CVI) subsystem of the Primary Containment Isolation (PCI) system and other related Engineered Safety Feature (ESF) functions for the FitzPatrick plant.  ;

. Several instances have been reported where the automatic closure l . of the containment ventilation or purge isolation valves would not have

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• occurred because the safety actuation signals were manually overridden or blocked during normal plant operations. These events resulted.from procedural inadequacies, design deficiencies, and a lack of proper management controls. These. events also brought into question the mech-anical operability of the valves themselves. These events were deter-mined by the Nuclear Regulatory Commission (NRC) to be an Abnormal Occurrence (#78-05) and accordingly, were reported to Ccagress.

. As a follow-up of this Abnormal Occurrence, tha NRC is reviewing the electrical override aspects and the mechanical operability aspects of containment purging for all operating reactors. On November 28, i 1978, the NRC issued a letter, " Containment Purging During Normal Plant

', Operation"l to all Boiling Water Reactor.(BWR) and Pressurized Water i Reactor (PWR) licensees. The PASNY responded to the letter and a later 3

i request for information2 in letters of January 9, 1979 , March 2, 6

19794 , August 15, 1979.,

5 and March 19, 1980 . Conversations between the NRC project manager and the licensee have been unsuccessful 1

'in clarifying the information submitted . Subsequently, on June 19, 1980, we requested written clarification of information and a commit-tment to correct a design deficiency.I A 30-day response was requested; no reply has been recieved. ,

2.0 EVALUATION OF FITZPATRICK NUCLEAR POWER PLANT 2.1. Review Guidelines The intent of this evaluation is to determine if the following NRC requirements are met for the safety signals to all ESF equipment:

1. Guideline No.1--In keeping with the requirements of General Design' criteria 55 and 56, the over-ridinga 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. Guideline No. 2--Sufficient physical features (e.g.,

-key lock switches) are to be provided to facilitate adequate' administrative controls.

3. Guideline No.13--A system level annunciation of the overridden status should be provided for every safety system impacted when any override is active.

Incidental to this review, the following additional NRC design criteria were used in the evaluation:

1. Guideline No. 4--Diverse signals should be provided to initiate isolation of the containment ventilation ,

s ys t em.' Specifically, containment high radiation, .

safety injection actuation, and containment high pressure (where containment.high pressure is not a

• portion of safety injection actuation) should auto- -

matica11y' initiate CVI.

a. Tha following definition is given for clarity of use _ in this

- evaluation:

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~ Override

~ the signal is still present, and it is blocked in order to perform a function contrary to the signal. l 2 -

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2. Guideline No. 5--The instrumentation and control systems provided to initiate the ESF should be designed and qualified as safety grade equipment.

- 3. Guideline No. 6--the overriding or resettinga og the ESF actuation signal should not cause any valve or damper to change position.

Guideline 6 in this review applies primarily to other related ESF systems because implementation of this guideline for containment isola-tion will be reviewed by the Lessons Learned Task Force, based on the recocnnendations in NUREG-0578, Section 2.1.4. When containment isola-tion is not involved, consideration on a case-by-case basis of automatic valve repositioning upon reset may be considered acceptable. Accept-ability would be dependent upon system function, design intent, and suitable operating procedures.

2.2 Containment Ventilation Isolation Circuits Design Description

. The FitzPatrick plant has two ESF trains which close independently and separately the inboard and outboard PCI valves.6 The valves can only be opened by manual control. Each CVI valve has a single spring-return-to-neutral switch that controls the valve position. The isola-tion signal for the CVI valves is derived from the following automatic 0

signals :

1. Drywell pressure high ( 2.7 psig)

. 2. Reactor water level low ( 12.5 in.)

3. Reactor building common ventilation exhaust radi-ation high (900 cpm)

4. Both radiation monitors for reactor building common ventilation exhaust (17 RIS-452A & B) failed,

a. The following definition is given for clarity of use in this evaluation:

Reset: the signal has come and gone, and the circuit is being cleared in order to return it to the normal coadition.

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I' There is. no indication from the PASNY submittals that a system-level switch is provided to close all the CVI valves; only the. individual control switches are provided to close the valves manually. ,

For those CVI valves that are solenoid operated, loss of power to -

the control system or loss of air to the solenoid valve closes the isolation valves. For thase that are motor-operated, the last position of the valve is maintained on loss of power. Valve position lights, open and closed, are provided on the control panel.

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Each train CVI isolation signal can be reset and overridden by separate keylocked switches on the Primary Containment Purge and I Inerting Panel to allow manual opening of the CVI valves.0 The unit Final Safety Analysis Report indicates that the drywell pressure high and reactor water level low signals are the same signals used to actu-ate high pressure coolant injection.

• Because of the operating characteristics of the valve position control switches, operator action'is required to open the CVI valves

, after a system level reset of the valve logic.

l 2.3 Containment Ventilation Isolation System Design Evaluation l

Guideline 1 requires that no signal override can prevent another sat'ety actuation signal from functioning. Use of a keylocked emergency manual override switch bypasses the composite (of all initiating sig- -

nals) signal for the Containment Ventilation Isolation valves for that train. In violation of guideline 1, any further initiating signal is ,

then ineffective. When this switch is in the bypass mode, it is annun- ,

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ciated in conformance with guideline 3. .

Guideline 2 requires that reset and override switches have physical provisions to aid in administrative control of the switches. the over-ride switches are keylocked. The momentary contact reset switches have not been shown tc be protected; however, where a reset switch does not 4

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override a signal, physical protection may not be needed. Therefore, complete compliance with this guideline is questioned.

Guideline 3 requires that system level annunciation be provided for whenever an override affects the performance of a safety system. -

The FitzPatrick plant conforma to this guideline, as mentioned above. -  !

Guidel.ne 4 requires that isolation of the CVI system be actuated by several diverse signals. The FitzPatrick plant meets this require-i ment in that (a) the same signals that init ste safety' injection also 1 initiate the PCI system, (b) the reactor containment (i.e., drywell) ,

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pressure is a portion of this signal, and (c) radiecion trips of the reactor building exhaust monitor will cause isolation.

Guideline 5 requires that isolation actuation signals be derived

. from safety grade aquipment. The FitzPatrick signals used for CVI conform to this guideline.6 l

I Guideline 6 requires that no resetting of isolation logic will, of itself, automatically open the isolation valves. The FitzPatrick plant

! conforms to this guideline.

i 2.4 Other Related Engineered Safety Feature System Circuits

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Guideline 2 requires that reset and override switches have physi-l ., cal . provisions to aid in the administrative control of these switches.

While those override. controls that use keylocked switches meet this j

• guideline, those that use pushbutton switches have not been demonstra-j ted to have such provisions. The NRC should require that PASNY install any additional provisions needed to conform to guideline 2.

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Reference 5 reviews the safety systems that have override'capabil-i sty. -It is stated that "none of these everrides or bypasses deviate

from the NRC requirements of Reg. Guide 1.47 r, elative to administrative

! control and annunciation." 'However, PASNY has not made clear that they 5

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r are in compliance with guideline 3 for other related ESF circuits. The NRC should determine whether each ESF override is annunciated.

Incidental to this review, it is noted that the PASNY indicated

" improper suction valve alignment will prevent the residual heat removal ,'

pumps from starting." The NRC should require the PASNY to provide annunciation when these valves are improperly aligned.

No other manual overrides have been identified in the review of the material submitted for this audit.

3.0

SUMMARY

The electrical, instrumentation, and control design aspects of the containment ventilation isolation valves for the FitzPatrick unit were evaluated using the design guidelines stated in Section 2.1 of this .

report, ,

The keylocked bypass switches for the containment ventilation isolation valves have been shown to be annunciated. Isolation is actu-ared by safety-grade signals derived from safety injection (including

,< actor containment pressure) and high radiation levels in the reactor building exhaust. It is not clear from the licensee submittals that this monitors the containment exhaust. The licensee has shown that no reset of the actuation logic will cause the isolation valves to change position. KRC guidelines 4, 5, and 6 are fully complied with. ,

Based on the information available at this time, I have determined -

that:

1. Each train of isolation has one override switch that bypasses all automatic CVI actuation signals. This is not in conformance with NRC guideline 1.

2. The logic reset switches of the James A. FitzPatrick ESF system (including these for the CVI system) have not been shown to have yhysical features to prevent inadvertant operation (NRC guideline 2).

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3. It is not clear that all ESF overrides are annunciated

in conformance with guideline 3,'rather than tagged as permitted by RG 1.47 for infrequently-used bypasses.

The CVI override switches are annunciated.

. Therefore, it is recommended.that the James A. FitzPatrick Nuclear Power Plant'be required tot 4

1. Make the design changes necessary so that one keylacked switch will not override all isolation signals to a j train of the CVI valves.

2. Determine what physical provisions are provided for all

' ESF (including CVI) system level reset switches. Where i provisions are not provided to aid in the administra-tive control of these switches, they should be provided j by the PASNY.

! 3. Supply, as needed, annunciation for each manual over-i ride with'n the ESF system, when the override is active.

!' i Additionally, wnile not directly related to this review, the NRC

} should also determine if an improper. suction valve alignment preventing i the start of the residual heat removal pumps requires annunciation or-I some interlocks to prevent the condition from occurring.

4 4.0 L ?ERENCES

1. NRC/ DOR letter (A. Schwencer) to all BWR and PWR licensees, " Con-

< tainment Purging During Normal Plant Operation," dated November ;28, 1978.

. 2. EC&G Idaho, Inc., letter, A.C. Udy, to J. T. Beard, U.S. NRC,

" James A. FitzPatrick--Containment Purging, Preliminary Review,"

September 13, 1979.

3.- .PASNY letter, Paul J. Early, to Director of Nuclear Regulatory

Commission, " Containment Purging During Normal Plant Operation",

. James A. FitzPatrick Nuclear-Power Plant, Docket 50-333, January 9, 1979, JPN-79-3.

4. PASNY letter, Joseph R. Schnieder, to Director of Nuclear Regula-tory Commission, " Containment Purging During Normal Plant Opera-

. tion", James A. FitzPatrick Nuclear Power Plant, Docket 30-333, March 2, 1979, JPN-79-10.

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5. PASNY letter, Paul ?. Early, to Director of Nuclear Reguictory Commision, " Justification for Continued Containment Purging During Normal Plant Operation," August 15, 1979, JPN-79-50.

6. PASNY letter, Paul J. Early, to Director of Nuclear Reactor Regu- ,

lation, " Response to NRC Request for Additional Information for the Containment Purge and Vent System," March 19, 1980, JPN-80-16. -

7. EG&G Idaho, Inc., telecopy, A. C. Udy to P. Polk, U.S. NRC, " Ques-tions on the Override cf ESF Signals," June 19, 1980.

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