ML20003C261

Technical Evaluation of Electrical,Instrumentation & Control Design Aspects of Override of Containment Purge Valve Isolation & Other Engineered Safety Feature Signals for Indian Point 3 Nuclear Power Plant.

ML20003C261
Person / Time
Site:	Indian Point, Turkey Point
Issue date:	01/31/1981
From:	Jacoby K EG&G, INC.
To:	Shemanski P Office of Nuclear Reactor Regulation
Shared Package
ML17340A763	List: ML17340A762 ML20003C255 ML20003C258 ML20003C261
References
CON-FIN-A-0231, CON-FIN-A-231 EGG-1183-4165, NUDOCS 8102270405
Download: ML20003C261 (14)

Text

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l ENERGY MEASUREMENTS GROl]P l

lI II TECHNICAL EVALUATION OF THE ELECTRICAL, l INSTRUMENTATION, ANP CONTROL DESIGN ASPECTS OF THE g OVERRIDE OF CONTAINMENT PURGE VALVE ISOLATION AND OTHER ENGINEERED SAFETY FEATURE SIGNALS l INDIAN POINT 3 NUCLEAR POWER PLANT FOR THE I (DOCKET No.60-286)

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DISCLAIMER I

This report was prepared as an account of work sponsored by the United 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 the accuracy, completeness or usefulness of any information, apparatus, product or process disclosed, or represents that its use v]uld not infringe on privately owned rightc. Reference herein to any specific commercial l product, process, or service by trade nane, mark, manufacturer, or other- E wis3, does not necessarily constitute or imply its endorsement, recocrend-ation, or favoring by the United States Govern ent or any agency thereof. as The views and opinions of authors expressed herein do not necessarily state g or reflect those of the United States Government or any agency thereof.

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1 I INTERIM REPORT l I n'q 1E::GzG T.?*!*o0l:TO*."'**

Accession No.

Report No. EGG 1183-4165 Contract Program or Project

Title:

Electrical. Instrumentation, and Control System Support I

Subject of this Document:

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 Indian Point 3 Nuclear Power Plant Type of Document:

Informal Report I Author (s):

K. D. Jacoby I Date of Document:

January 1981 Responsible NRC Individual and NRC Of fice or Division:

Paul Shemanski, Division of Operating Reactors This document was prepared primarily for preliminary or internal use. It has not received fu.ll review and approval. Since there may be substantive changes, this document should not be conside.'ed final.

EG&G Energy Measuremr;1ts Group San Ramon Operations San Hamon, CA 94583 Prepared for the U.S. Nuclear Regulatory Comission I Washington, D.C.

Under 00E Contract No.B&R 201904031 NRC FIN No.

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lNTERIM REPORT I

I U ESsG 1183-416s January 1981 I Energy Measurements Group San Ramon Operations I

TECHNICAL EVALUATION OF THE ELECTRICAL, INSTRUMENTA.':".,N, AND CONTROL DESIGN ASPECTS l OFTHE OVMRIDE OF CONTAINMENT PURGE VALVE ISOLATION ANb OTHER ENGINEERED SAFETY FEATURE SIGNALS FOR THE INDIAN POINT 3 NUCLEAR POWER FLANT (DOCKET No 50-286)

I by I K. D. Jacoby Approved for Publication I /

6 htN. h ^ 41.85 J. If.~Radosevic Department Manager l This document is UtlCLASSIFIED ass er: ,

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'Nicnolas E. 4roderick l Department Manager I

l Work Performed for Lawrence Livermore NationalLaboratory under U.S. Department of Energy l$ Contract No. DE.ACO8-76 NVO 1183.

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ABSTRACT I This report documents the technical evaluation of the electrical, instrumentation, and control design aspects of the override of containment I purge valve isolation and other engineered safety feature signals for the Indian Point 3 Nuclear Power Plant. 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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i FOREWORD This report is supplied as part of the Selected Elc'trical, 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 I

g authorization entitled " Electrical, Instrumentation and Control System g Support," B&R 20 19 04 031, FIN A-0231.

The work was performed by EG&G, Inc., Energy Measurements GNip, i lI San Ramon Operations, for Lawrence Livermore National Laboratory under U.S.

Department of Energy contract nuziber DE-AC08-76NV01183. {

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!I TABLE OF CotifENTS lE3 Pdge i

! i iI j 1. INTR 000Cfl0N. . . . . . . . . . . . . 1 l

! 2. EVALUATION OF INDIAN POINT 3 NUCLEAR POWER PLANI. . . . 3 2.1 Review Criteria . . . . . . . . . . 4 2.2 Containment Ventilation Isolation Circuits  !

t Design Oescription . . . . . . . . . 4

! 2.3 Containment Ventilation Isolation System Design

( Evaluation. . . . . . . . . . . . 5 I 2.4 Other Engineered Safety Feature System Circuits . . 6 l

3. CONCLUSIONS . . . . . . . . . . . . . t)

I l References. . . . . . . . . . . . . . . 11 I

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TECHNICAL EVALUATION OF THE ELECTRICAL, I INSTRUMENTATION, AND CONTROL DESIGN ASPECTS OF THE OVERRIDE OF CONTAINMENT PURGE VALVE ISOLATION AND OTHER ENGINEERED SAFETY FEATURE SIGNALS I FOR THE INDIAN POINT 3 NUCLEAR POWEP, PLANT (Docket No. 50-286)

K. D. Jacoby I EG&G, Inc., Energy Measurements Group, San Ramon Operatione I

1. INTRODUCTIOM 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 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 containment isolation valves thanselves. These events were determined by I the U. S. Nuclear Regulatory Commission (NRC) to be an Abnonnal 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 fur all operating power reactors. On I November 28, 1978, the NRC issued a letter entitled " Containment Puroing During Normal Plant Operation" [Ref.1] to all boiling water reactor (BWR) and pressurized water reactor (PWR) licensees. In a letter [Ref. 2] dated I January 3, 1979, and a letter [ Pef. 3] dated March 2, 1979, the Power Authority of the State of New York, the licensee for the Indian Point '

Nuclear Power Plant, replied to the NRC generic letter.

References 4 through 14 list the additional correspondence between the NRC and the licensee on this subject. Reference 15 sucinarizes a meeting held with the licensee and Westinghouse in which Westinghouse I described the design of the ESF control circuits used at Indian Point 3 Nuclear Power Plant.

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

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2. EVALUATION OF INDI AN POINT 3 NUCLEAR POWER PLANT I 2.1 REVIEW CRITERIA I The primary intent of this evaluation is to determine that the following requirements are met for the safety signals to all ESF equipaent.

(1) Criterion no. 1--In keeping with the requiremmts of GDC 55 arid 56 [Ref. 16], the overriding

• of e type of safety actuation signai (e.g., radiation) should I not cause the blocking of any other type of safety actuation signal (e.g., pressure) for those valves that have no function besides c intainment 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 overriden status should be provided for every safety I system impacted when any override is active (see R.G.

1.47).

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

(1) Criterion no. 4--Diverse signals should be provided to I initiate isolation of the containment ventilation system. Specifically, containment high radiation, safety i nj ect ion actuation, and containment high I pressure (where containment high pressure is not a portion of safety injection actuation) should auto-matically initiate CVI.

(2) Criterion no. 5--The instrumentation and control I systems provided to initiate the ESF should be de-signed and qualified as safety-grade equipment.

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

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

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I (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 E systems because implementation of this criterion for containment isolation 3 systems have been reviewed by the Lessons Learned Task Force, based on the reconnendations in NUREG 0578, 'sc'. ion 2.1.4 [Ref. 17]. Automatic valve repositioning upon reset may be acci.,' table when containment isolation is not involved; consideration will be given on a case-by-case basis. Accept-ability would be dependent upon system function, design intent, and suit-able operating procedures.

2.2 CONTAINMENT VENTILATION ISOLATION CIRCUITS DESIGN DESCRIPTION Indian Point 3 Nuclear Power Plant has two ESF trains which can cause isolation of the containment ventilation system. The initating contacts for each train are combined as parallel inputs to form an "0R" circuit. These contacts are described below:

(1) Automatic Contacts (a) Containment stack high gaseous radiation and high particulate radiation (two nonnally-open contacts in parallel from the radiation moni-tors). These radiation monitors indicate the radiation level of the containment atmosphere.

(b) Containment spray actuation (a normally-open contact). The containment spray actuation signal derives its input from containment high pressure signals.

(c) Containment isolation phase A actuation (a normally-open contact). The containment isola-tion phase A actuation signal derives its input from the safety injection actuation signal ,

which is a result of several diverse signals, E including containment high pressure. 3 (2) Manual Contacts (a) Containment isolation phase A system-level I manual actuation will autoaatically cause CVI actuation.

(b) Containment spray system-level manual initia-tion will automatically cause CVI actuation.

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

Reset: The signal has come and gone, and circuit is being cleared in order to return it to the nonnal condition.

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lI Each train includes the automatic input "0R" circuit, a latching l i

I miay, and a slave relay with contacts in the control circuits for the solenoid valves of the CVI valves. A " reset" switch and a " reset" seal-in rehy work in conjunction with the latching relays. The " reset" switch and -

its :al-in relay are connected downstream of all the automatic initiating I

contacts. The " reset" switch for each train is an unprotected, simple, spring-loaded , pushbutton switch.

When a monitored plant condition calls for isolation, electric power is provided to caerate the latchinq relay (type MG-6 relay) which, in turn, energizes its slave relay (e.g., VI-lX). Contacts of the slave relay open to remove electric power fran the solenoid valves causing the isola-I tion valves to ciose.

When the " reset" switch is operated , the " operate" coil of the I latching relay is de-energized, the " reset" coil of the latching relay is energized, and the " reset" seal-in relay is energized. With the latching relay in the reset condition, the slave relay is de-energized making elec-l tric power available to the solenoid-val ve circuits. The seal-in relay will stay energized by power obtained through the contacts of the initiat-l ing condition (e.g., high radiation, containment spray, containment isola-tion phase A).

Once the CVI reset pushbutton has been depressed, the CVI actua-tion signal acts as a pennissive for the CVI valves to be opened. To open these valves once the circuitry has been reset, three-position, spring-return-to-center switches must be manentarily switched to the "open" posi-tion. l The circuit design does not include provisions to annunciate the

" reset" or overridden status. Valve position lights (i.e., full-open/ full-closed) are provided.

l 2.3 CONTAINMENT VENTILATION ISOLATION SYSTEM DESIGN EVALUATION 1 '

The CVI signal has a " reset" that is more properly termed an l override, as defined in this review. This override, containing a seal-in 3 relay, constitutes a system-level override which prevents reactivation of l5 CVI by either manual or automatic input signals as long as an isolation signal continues uninterrupted. While in this override condition, neither the automatic safety signal s nor trianual ictuation can cause the containment I

ventilation / purge valves to close. When the last isolation signal is interrupted or cleared, the seal-in relay will drop out and allow a subse-quent isolation input signal to generate a CVI actuation signal and reclose the valves.

In response to NRC Interim Requirements [Ref. 4], the licensee recently modified their system design by moving the containment stack high I

l gaseous radiation and high particulate radiation contacts from the latching relay circuit to the slave relay circuit, allowing the radiation signal to I I

I close the containment ventilation / purge valves, even though a system-level override exists. This change improved the system, but did not satisfy the ,

interim requirements. As a result of this review, the licensee has comnit-

'g ted to modify the CVI circuitry by removing the reset relay [Ref. 14].

This change will eliminate the bypass or override function of the CVI circuit. We conclude that this change is acceptable and that NRC staff g criterion 1 will be satisfied. 3 The existing CVI s i g na'. override (" reset") function uses a simple, unprotected, spring-loaded pushbutton switch. The comnitted change to the CVI circuitry will eliminate the override function, leaving the

" reset" pushbutton to perform only a simple reset function. NRC staff criterion no. 2 regarding physical features that facilitate administrative controls applies to overrides and therefore will not apply to the CVI circuit as modified. Similarly, NRC staff criterion no. 3 regarding annun-ciation of override status will not apply to the CVI circuit as modified.

The CVI system design includes diverse actuation signals, and we conclude that NRC staff criterion no. 4 is satisfied.

Resetting the safety injection signal cannot cause the CVI system to reset nor will it cause the automatic reopening of the containment ventilation / purge valves. It appears that NRC staff criterion no. 6 is E satisfied; however, that eval uation has been performed by the Lessons 3 Learned Task Force as discussed in Section 2.1.

2.4 OTHER ENGINEERED SAFETY FEATURE SYSTEM CIRCUITS During this review, it was determined that the containment spray I and containment isolation (fo- fl uid systems) have a " reset" override E circuit similar to that of the CVI.

Each of the containment isolation phase A and containment spray systems has both an automatic and a manual trip input. If either system had a system-level override in effect, the manual input could not initiate the safety action. As a result of this review, the licensee has cocmitted to nodify the containment isolation Phase A and containment spray systems to allow manual actuation of the system at any time [Ref.14]. On its own initiative, the licensee has decided that the containment isolation phase B system will also be modified by adding a manual actuation pushbutton which is capable of initiating the safety action at any time. These modifica-tions will prevent the overriding of one type of safety actuation signal from blocking another type of safety actuation signal . We conclude that these changes are acceptable and that NRC staff criterion 1 will be satis-fied.

The " reset" switches for both trains of the containment spray, containment isolation, phase A and phase B, and safety injection systems are simple, unprotected, spring-loaded pushbutton switches. This design is judged to be inadequate to preclude an inadvertent " reset." As a resuit of this review, the licensee has committed to protect the " reset" pushbuttons I

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I I with hinged safety ccvers that require deliberate action by the operators to actuate the buttons [Ref. 14 ] . With the pushbuttons protected by hinged safety covers, we conclude that NRC staff criterion no. 2 is satisfied.

The presence of an everride (" reset") of the contairrnent spray, or containment isolation is not annunciated. As a result of this review, I the licensee has comnitted to provide containment spray, containment isola-tion phase A and containment isolation phase B with indicating lights that will provide the operator with an indication that the autoaa t ic safety signal that actuated the system is overridden.

The function of the indicating lights that are being i nst al led for the referenced engineered safety features will be incorporated into the I appropriate existing operating procedures. In addition to the revision of the existing operating procedures, the status of these indicating lights will be incorporated into the shift turnover status. However, since an I ir.dicator light on a status panel is not an annunciator and does not have an associated audible al a nn, we concl ude that NRC staff criterion no. 3 will not be satisfied. We recommend the installation of the appropriate system-level annunciation of the overridden system and of every safety system impacted.

Initiation of SI will cause the closing of the Cl phase A valves I and, consequently, the CV! valves. Af ter 120 seconds, the circuit design allows the Si actuation signal to be overridden (" reset"). Thus, the SI actuation input signal to these systems can be removed. While none of the I CVI or CI valves will automatically reopen, these systems could be reset and the valves returned to an open position.

staff criteria used in this evaluation.

This design meets the NRC Any further evaluation of this situation will be conducted by the NRC staff outside this report.

The ESF equipment, other than the radiation monitors previously disc ussed, has been found to be safety grade equipnent which meets the I intent of IEEE 279-1968.

is satisfied.

Thus, we conclude that NRC staff criterion no. S I When the containment spray system is reset, the val ves will automatically reclose. As a result of this review the licensee has com-mitted to modify the circuitry such that, upon reset, these valves will remain in their emergency positions [Ref. 14 ] . We conclude that NRC cri-terion no. 6 is satisfied.

During the evaluation of these ESFs, it was noted that contain-I ment spray is initiated by the coincidence of containment HIGH-HIGH pres-sure and the SI signal. Because the SI signal may have been " reset" by the time that containment pressure reaches the HIGH-HIGH setpoint for certain I postulated accidents, automatic actuation of the containment spray system may not occur when required. As a result of this review, the licensee has committed to modify the containment spray system such that it is actuated only by containment HIGH-HIGH pressure [Ref. 14 ]. This modification will I allow autunatic actuation of this system whenever .aquired, and is accept-able.

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3. CONCLUSIONS  !

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l The El&C design aspects of containment purge valve isolation and j i other ESF signals for the Indian Point 3 Nuclear Power Plant were evaluated  !

using those design criteria stated in Section 2.1 of this report.

f We concl ude that, with the modifications described, the CVI i system will meet all but one of the six NRC staff criteria, and that the t other ESFs reviewed will meet all but one of the five NRC staff criteria f applicable to them.

The following changes are reconinended for the CVI and other ESF 1

(1) For CVI, qualify the existing radiation monitoring i i instrumentation which inputs the CV! system, or pur- ,

i chase new instrumentation which is already qualified I

g envirorsnentally and seismically for the conditions l3 3

that could be expected to exist at the point of in-stallation during postulated accidents.

(2) For the other ESFs, provide system-level annunciation j of the overriden status for each system which may be

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overriden.

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REFERENCES

1. NRC letter ( A. Schwencer) to Power Authority of the State of New York ,

" Containment Purging During Nonnal Plrt Operation," dated November 28, 1978.

2. PASNY letter (P. J. Early) to NRC ( A. Schwencer) " Docket 50-286, Con-tainne't Purging During Nonnal Plant Operations," dated January 3, 1979.

3. PASNY letter (J. R. Schmieder) to NRC ( A. Schwencer) " Docket 50-286, I Containment Purging During Normal Plant Operation," dated March 2, 1979.

4. NRC letter (S. A. Varga) to PASNY (G. T. Berry), Docket No. 50-286 (no title), dated October 23, 1979.

5. PASNY letter (P. J. Early) to NRC ( A. Schwencer) " Docket 50-286, Con-tainment Isolation System," dated December 13, 1979.

6. PASNY letter (P. J. Early) to NRC ( A. Schwencer) " Docket 50-286, Con-tainment Purging and Venting During Normal Operation," dated December 28, 1979.

7. PASN" letter (P. J. Early) to NRC ( A. Schwencer), " Docket No. 50-286 Containment Isolation System," dated March 6, 1980.

8. NRC letter ( A. Schwencer) to PASNY (G. T. Berry), Docket iio. 50-286 (no I title), dated April 11, 1980.

Varga), " Docket No. 50-286,

9. PASNY letter (P. J. Early) to NRC (S. A.

Request for Additional Infonnation," dated June 2,1980.

10. NRC letter (S. A. Varga) to PASNY (G. T. Berry), Docket No. 50-286 (no title), dated August 20, 1980.

11. NRC letter (S. A. Varga) to PASNY (G. T. Berry), Docket No. 50-286 (no title), dated August 29, 1980.

12. PASNY letter (J. P. Bayne) to NRC (S. A. Varga), " Docket No. 50-286, Electrical Override / Bypass of ESF Actuation Signals," dated September 11, 1980.

13. PASNY letter (J. P. Bayne) to NRC (S. A. Varga), " Docket No. 50-286, Electrical Override / Bypass," dated October 2, 1980.

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i REFERENCES (continued)

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14. PASNY letter (J. P. Bayne) to NRC (S. A. Varga), " Docket No. 50-286, E Electrical Override / Bypass Aspects of ESFs," dated October 23, 1980. E

15. NRC memo (L. Olshan) to distribution, " Summary of Meeting," dated September 12, 1980.

16. 10 CFR 50, Appendix A, General Design Criterion.

17. U.S. NRC, "TMI-2 Lessons Learned Task Force Status Report and Short-Term Reconnendations", NUREG-0578, published July,1979.

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DISTRidVT10N LIST LLNL/Livermore EGAG/SRO l

l Lawrence Livermore National Laboratory EG&G, Inc. '

P. O. Box 808 P. 0. Box 204 Livermore, California 94550 San Ramon, California 94583 M. H. Dittmore, L-97 (2 copies) Author (2 copies)

C. E. Brown (4 copies)

B. G. Mayn l M. W. Nishicura LLNL/ Nevada NRC ,

Lawrence Livermore National Laboratory V. S. Nuclear Regulatory Cocutission I P. O. Box 45 Mercury, Nevada 89023 Washington, D.C. 20555 W. E. Reeves, L-577 (2 copies) J. T. Beard, MS-416 D. G. Eisenhut, MS-528 G. Lainas, MS-416 P. C. Shemanski, MS-416 i

USDOE/NV00 US00E/T1C U. S. Department of Energy V. S. Department of Energy Nevada Operations Office Technical information Center i I P. O. Box 14100 Las Vegas, Nevada 89114 P. O. Box 62 Dak Ridge, Tennessee 37830 J. A. Koch I. Abernathy (2 copies)

R. R. Loux R. B. Purcell l

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