ML20031B361
| ML20031B361 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 09/21/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| References | |
| REF-GTECI-B-24, REF-GTECI-EL, TASK-06-04, TASK-6-4, TASK-B-24, TASK-OR, TASK-RR LSO5-81-09-054, LSO5-81-9-54, NUDOCS 8110010277 | |
| Download: ML20031B361 (10) | |
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f Septenber 21, 1981 Docket No. 50-213 o,
LS05-81-09-054 T R[
Mr. W. G. Counsil, Vice President 8
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Post Offic Jox 270 Hartford, Connecticut 06101 j'
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liaar Mr. Counsil:
SUBJECT:
SEP TOPIC VI-4, CONTAINMENT ISOLATION SYSTEM (ELECTRICAL)
HADDAM NECK The staff has determined that the scope of rev% and evaluation perfarned for multi-plant generic activity B-24 includes C e electrical aspects of SEP Topic VI-4.
Miitional review and evaluation is, therefore, not re-qu i"3d.
Enclosed is a copy of our current avalua. tion of the electrical portion of reneric activity B-24 for Haddam Neck. This assessment compares your facility, as described in Docket No. 50-213, with the criteria currently used by the regulatory staff for licensing new facilities. Please inform us if your as-built facility differs from the licensing basis assumed in our escessment within 30 days upon receipt of this letter.
This evaluation will be a basic it.put to the integrated safety. assessment j
for your facility unless you identify changes needed to reflect the as-l built conditions at your faciltty. This assessment ir.ay be revised in the l
future if your facility desic is changed or if NRC criteria relating to l
this subject are modified before the integrated assessment is completed.
i This evaluation is the staff's position regarding design of your facility in the subject area. With regard to be referenced topic, the staff has concluded your facility meets current licensing criteria, p hf ha.
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%I m,ckds G i, t Dennis M. Crutchfield, Chief l
Operating Reactors Branch No. 5
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M. W. G. Counsil
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cc Day, Berry & Howarc Counselors at Law One Constitution Plaza Hartford, Connectirst 06103 Superintendent Haddam Neck Plant RFD #1 Post Office Box 127E East Hampton, Connecticut 06424 Mr. Jaaes R. Hinnelwright Northeast Utilities Service Company P. O. Box 270 Hartford, Connecticut 06101 Russell Library 119 Broad Street Middletown, Connecticut 06457 Board of Selectaen Town Hall Haddam, Connecticut 06103 Connecticut Energy Agency ATTN: Assistant Director Research and Policy Development Department of Planning and Energy Poliqy 20 Grand Street Hartford, Connecticut 06106 U. S. Environmental Protection Agency Region 1 Office ATTN: EIS C0ORDINATOR JFK Federal Building Boston, Massachusetts 02203 Resident Inspector Haddam Neck Nuclear Power Station v
c/o U. S. NRC East Haddam Post Office East Haddam, Connecticut 06423 e
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i SAFETY EVALUATION FEPORT HADDAM NECK PLANT OVERRIDE OF CONTAINMENT PURGE ISOLATION INTRODUCTION Instances have been reported at nuclear puser plants where the intended automatic closurt :,f the containm4nt purge / ventilation valves during a postulated accident would not haee occurred because the safety actuation signals were inadvertently overridden and/or blocked, due to design deficiencies. These instances were determined to constitute an Abnormal Occurrence (#78-5). As a follow-up action:, NRR issued a generic letter requesting each licensee to take certain actions _
EVALUATION The enclosed report " Electrical, Instrumentation and Control Aspects of the Override of Containme6t Purge Valve Isolation," (1609F) was prepared for us by EG&G, Idaho as part of our technical assistance contract program.
The report provides their technical evaluation of the design compliance with NRC-provided criteria.
Because the Haddam Neck containment ventilation valves are locked shut as required by Technical Specifications, and have no automatic isolation rignals or overrides, the NRC guidelines do not apply.
CONCLUSION Based upon our review of the contractor's technical report, we conclude that the electrical portion of this topic does not apply to this plant.
The mechanical operability of the contait-ent purge valves is being analyzed separately.
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Enclcsure 2 1609F I
SEP TECHNICAL EVALUATIOli TOPIC VI-4 ELECTRICAL, INSTRlh1ENTATION, AND CONTROL ASPECTS OF THE OVERRIDE OF CONTAINMENT PURGE VALVE ISOLATION FIN DRAFT HADDAM NECK PLANT Docket No. 50-213 September 1980 f
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CONTENTS 1
1.0 INTRODUCTION
2.0 EVALUATION OF HADDAM NECK NUCLEAR PLANT 2
2.1 Review Guidelines.
2 2.2 Containment Ventilation Isolation Circuits Design Description.
3 2.3 Containment Ventilation Isolation System Design Evaluation 3
3.0
SUMMARY
4 1
4.0 REFERENCES
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SEP TECHNICAL EVALUATION TOPIC VI-4 ELECTRICAL, INSTRUMENTATION, AND CONTROL ASPECTS OF fHE OVERRRIDE OF CONTAINMENT PURGE VALVE ISOLATION llADDAM NEL4 PLANT 1.0, INTRODUCTION Based on the information supplisd by Connecticut Ynnkee Atomic Power Company (CYAPCo) and Northeast Utilities (NU), this report s3 dresses the electrical, instrumentation, and control aspects of Containment Ventilation Isolation (CVI).
Instances have been reported where automatic closure of contain-o ment ventilation (purge isolation)' valves would not accur, if teded, because the actuation signals were manually overridden (blocked) during normal plant operation.
Lack of proper management controls, proced-ural inadequacies, and circuit design deficiencies contributed to these instances. These events also brought into question the mechanical
" operability of the valves. These events were determined by the Nuclear Regulatory Commission (NRC) to be an Abnormal Occurrence (#78-05) and were reported to Congress.
The NRC is now reviewing the electrical override aspects and the mechanical operability aspects of containment purging for all o'perating reactort. On November 28, 1978, the NRC issued a letter, " Containment Purging During Normal Plant Operation" to all Boiling Water Reactor and Pressurized Water Reactor licensees tc initiate a review of these systems.
CYAPCo responded to this request for information in a letter 2
dated January 3, 1979. The NRC supplied information specifically for this review on March 4, 1980.3 e
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2.0 EVALUATION OF HADDAM NECK NUCLEAR PLANT 2.1 Review Guidelines Tho intent of this evaluation in to determine if the actuation signals for the CVI systes meet the following NRC criteria:
1.
Guideline No. 1--In keeping with the requirements of General Design Criteria.55 ar.d 56, the i
of one type of safety actuation a
ove. r toir.s signal (e.g., mediation) 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 isola?. ion.
2.
Guideline No. 2--Sufficient physical featurcs (e.g.,
key lock switches) are to be provided to facilitate adequate administrative controls.
3.
Guideline No. 3--A 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.)
Additionally, this review uses the following NRC design guidelines:
1.
Guideline No. 4--Diverst signals should be provided to initiate isolation of the containment ventilation system. Specifically, containment high radiation, safety injection actuation, and containment high pressure (where cos.cainment high pressure is not a portion of safety injection actuation) should auto-matica11y init. ate CVI.
2.
Guideline No. 5--The instrumentation and control systems provided to initiate the CVI should be designed and qualified as safety grade equipment.
s The following definition
'.s given for clarity of use in this a.
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evaluation:
Override: The signal is still present, and it is blocked in order to
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perform a function contrary to the signal.'
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Guideline No. 6--the overriding or resetting the CVI actuation signal should not cause any valve or damper to chante position.
2.2 Containment Ventilatioa Isolation Circuits Design Description The Haddam New. plant has manual containment purge valves.
These valves are not a part of the automatic containment isolation system. Sections 3.11 and 1.8 of the Haddam Neck Technical Specifica-tions require containment integrity wheneve,r the plant is in'an oper-ating mode or the reactor coolant system is greater or equal to 300 psig and 200 F.
Since the containment purge valves are part of the containment boundary, these valves are locked closed when containment integrity is required by Technical Specification 1.8.2.2 N
2.3 Containment Ventilation Isolation System Design Evaluation Guideline 1 allows no signal override to prevent another safety actuatica signal from functioning. Because there are no signals which initiate closure of the C71 valves,' this guideline does not apply to the Haddam Neck plant.
Guideline 2 requires reset and override switches to have physical provisions to aid in administrative control of reset and overrise switches. This guideline does not apply to the Haddam Neck CVI' system.
Guideline 3 requires system level annunciation wherever an over-ride affects the performance of a safety system. This guideline does not apply to the Haddam Neck CVI system.
f The following definition is given for clarity of use in this a.
evaluation:
.y Reset The signal has come and gone, anl the circuit is being cleared in order to return it to the normal condition.
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i Guideline 4 requires that isolation of the CVI system be actuated by several diverse signals. The Haddam Neck plant has only manual valves that are locked closed when the unit is in an operating mode.
The NRC has no requirement that these valves be automatically operated; therefore, the Haddam Neck plant need not conform to this guideline.
t Guideline 5 requires isolation actuation signals to be derived from safety grade equipment. The Haddam Neck plant has no present need to adhere to this guideline, as there are no isolacion actuat, ion signals.
Guideline 6 requires that resetting of isolation logic will not, i
of itself, automatically open the isolation valves. This guideline is not applicable as the Haddam Neck CVI system uses manual valves that are required by Technical Specification to be locked closed when the unit is in an operating condition.
t 3.0
SUMMARY
(
The electrical, instrumentation, and control design aspects of the containment ventilation isolation valves for the Haddam Neck plant were evaluated using the design guidelines stated in Section 2.1 of this
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report. P.ause the Haddam Neck containmsnt ventilation valves are locked shut as required by Technical Specifications, a ;d have no auto-matic isolation signals or overrides, the NRC guidelir.es do not apply.
SEP Topic VII-2 will review related engineered safety feature systems to insure that control logic and design is in accordance with i
IEEE Standard 279. The mechanical operability ofithe containment purge f
valves is being analyzed separately from this report.
4.0 REFERENCTS 1.
NRC/ DOR letter, A. Schwencer, to all BWR and PWR licensees, Con-
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tainment Purging During Normal Plant Operation," dated November 28,,7 l
1978.
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2.
CYAPCo letter, W. G. Counsil, to Dirsctor of Nuclect Rasetor Rigu-lation, NRC, "Haddam Neck Plant Coat:iinnent Purgi.ng," January 3, 1979.
3.
NRC letter, J. E. Knight, to Wayne Roberts, EG&G Idaho, Inc.,
"Information for Containment Purge Review for Haddam Neck,"
March 4, 1980.,
4.
Letter, CYAPCo (Counsil) to NRR (Crutchfield), dated September 4, 1980.
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