ML19345C963
| ML19345C963 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 10/24/1980 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| References | |
| TASK-06-04, TASK-6-4, TASK-RR NUDOCS 8012080672 | |
| Download: ML19345C963 (9) | |
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UNITED STATES g
NUCLEAR REGULATORY COMMISSION O
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October 24, 1980 c3 Docket No. 50-213 g
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ha Mr. W. G. Counsil, Vice President Nuclear Engineering and Operations
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Connecticut Yankee Atomic Power Company c)
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Post Office Box 270 O
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Dear Mr. Counsil:
RE: SEP TOPIC VI-4, ELECTRICAL, INSTRUMENTATION, AND CONTROL ASPECTS OF THE OVERRIDE OF CONTAINMENT PURGE VALVE ISOLATION (HADDAMNECK)
Enclosed is a copy of our evaluation of Systematic Evaluation Program Topic VI-4, Electrical, Instrumentation, and Control Aspects of the Override of Containment Purge Valve Isolation. 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 assessment within 60 days of receipt of this letter.
This evaluation will be a basic input to the integrated safety assess-ment for your facility unless you identify changes needed to reflect the as-built conditions at your facility. This topic assessment may be revised in the future if your facility design is changed or if NRC criteria relating to this topic is modified before the integrated assessment is completed.
Sin erely, g
y1 Dennis
. Crutchfie d, C ' f Operating Reactors Branch #5 Division of Licensing
Enclosure:
Completed SEP Topic VI-4 cc w/ enclosure:
See next page R0 12080
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Mr. W. G. Counsil October 24, 1980 cc Dayi Berry & Howard U. S. Environmental Protection Counselors at Law Agency One Constitution Plaza Region I Office Hartford, Connecticut 06103 ATIN: EIS COORDINATOR JFK Federal Building Superintendent Boston, Massachusetts 02203 Haddam Neck Plant RFD #1 Resident Inspector Post' Office Box 127E Haddam Neck Nuclear Power Station East Hagton, Connecticut 06424 c/o U. S. NRC East Haddam Post Office Mr. James R. Himelwright East Haddam, Connecticut 06423 Northeast Utilities Service Cogany P. O. Box 270 Hartford, Connecticut 06101 Russell Library 119 Broad Street Middletown, Connecticut 06457
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Board of Selectmen Town Hall Haddam, Connecticut 06103 Connecticut Energy Agency ATTN: Assistant Director Research and Policy Development Department of Planning and Energy Policy 20 Grand Street Hartford, Connecticut 06106 Director, Technical Assessment Division Office of Radiation Programs (AW-459)
U. S. Environmental Protection -
Agency Crystal Mall #2 Arlington, Virginia. 20460
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I SEP TECHNICAL EVALUATION TOPIC VI-4 ELECTRICAL, INSTRUMENTATION, AND CONTROL ASPECTS OF THE OVERRIDE OF CONTAINMENT PURGE VALVE ISOIATION HADDAM NECK PLANT Docket No. 50-213 s
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CONTENTS l.0 INTRODUCTION.
1 2.0 EVALUATION OF HADDAM NECK NUCLEAR PLANT 2-2.1 Review Cuidelines.
..2 2.2 Containment Ventilation Isolation Circuits Design Description.
3 2.3 Containment Ventilation Isolation System Design Evaluation 3
3.0
SUMMARY
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4.0 REFERENCES
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SEP TECHNICAL EVALUATION TOPIC VI-4 ELECTRICAL, INSTRUMENTATION, AND CONTROL ASPECTS OF THE OVERRRIDE OF CONTAINMENT PURGE VALVE ISOIATION HADDAM NECK PLANT
1.0 INTRODUCTION
Based on the information supplied by Connecticut Yankee Atomic Power Company (CYAPCo) and Northeast Utilities (NU), this report addresses the electrical, instrumentation, and control aspects of Containment Ventilation Isolation (CVI).
s Instances have been reported where automatic closure of contain-ment ventilation (purge isolation) valves would not occur, if needed, because the actuation signals were manually overridden (blecked) during normal plant operation.
Lack of proper management controls, proced-ural inadequacies, and circuit design de ficiencies 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 operating reactors.
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 to 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.
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2.0. EVALUATION OF HADDAM NECK NUCLEAR Pl. ANT 2.1 Review Guidelines The intent of this evaluation is. to determine if the actuation signals fcr the CVI system meet the following NRC requirements:
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Guideline No. 1--In keeping with the requirements of General Design Criteria 55 and 56, the overriding of one type of safety actuation a
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
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no function besides containment isolation.
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Guideline No. 2--Suf ficient physical features (e.g.,
key. lock switches) are to be provided to facilitate adegoate administrative controls.
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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--Diverse signals should be provided to initiate isolation of the containment ventilation l
sys tem.
Specifically, containment high radiation, safety injection actuation, and containment high pressure- (where containment high pre ssure is not a portion of ' safety injection actuation) should auto-matica11y initiate CVI.
2.
Guideline No. 5--The instrumentation and control systems provided to initiate the CVI should be
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designed and qualified as safety grade equipment.
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The following definition is given for - clarity of use in this evaluation:
Override: The signal. is still pre sent, and it is blocked in order to perform a function contrary to the signal.
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Guideline No. 6--the overriding or rosettinga og the CVI actuation signal should not cause cny valve or damper to change position.
2.2 Containment Ventilation Isolation Circuits Design Description The Haddam Neck 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 whenever the plant is in an oper-ating mode or the reactor coolant system is greater or equal to 300 psig and 200 F.2 - 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.
2.3 Containment Vent. lation Isolation System Design Evaluation Guideline 1 allows no signal override to prevent another safety actuation signal from functioning. Because there are no signals which initiate closure of the CVI 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 override 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.
9 The following definition is given for clarity of use in this a.
evaluation:
J Re se t: The signal has come and gone, and the circuit is being cleared in order to return it to the normal condition.
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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 requiremhnt that these valves be automatically operated; therefore, the Haddas Neck plant need not conform to this guideline.
Guideline 5 requires isolation actuation signals to be derived
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from safety grade equipment.
U.e Haddam Neck plant has no present need to adhere to this guideline, as there are no isolation actuation signals.
i Guideline 6 requires that -resetting of isolation logic will not, 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.
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 report. Because the Haddam Neck containment ventilation valves are locked shut as required by Technical Specifications, and have no auto-matic isolation signals or overrides, the NRC guidelines do not apply.
SEP Topic VII-2 will review related engineered safety feature systeau to insure that control logic and design is in accordance with IEEE Standard 279. The mechanical operability of the containment purge valves is being analyzed separately from this report.
4.0 REFERENCES
1.
NRC/ DOR letter, A. Schwencer, to all BWR and PWR licensees, " Con-tainment Purging During Normal Plant Operation," dated November 28, 1978.
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CYAPCo letter, W. G. Counsil, to Director of Nuclear Reactor Regu-lation, NRC, "Haddam Neck Plant Containment Purging," January 3, 1
1979.
3.
NRC letter, J. E. Knight, to Wyne Roberts, EG&G Idaho, Inc.,
"Inf ormation f or Containment Purge Review for Haddam Neck,"
March 4, 1980.
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