ML20010F437

Forwards Supplemental Evaluation of SEP Topic V-II-A, Requirements for Isolation of High & Low Pressure Sys. Mods to Chemical & Vol Control Sys & Safety Injection Valve Control Circuitry Proposed

ML20010F437
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	09/01/1981
From:	Crutchfield D Office of Nuclear Reactor Regulation
To:	Counsil W CONNECTICUT YANKEE ATOMIC POWER CO.
References
TASK-05-02, TASK-5-2, TASK-RR LSO5-81-09-005, LSO5-81-9-5, NUDOCS 8109100182
Download: ML20010F437 (4)

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September 1,1981 ff.U ' %

79 Docket No. 50-213 LS05 09-005

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Mr. W. G. Counsil, Vice President

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1. melear Engineering and Operatfor.s connecticut Yankee Atomic Power Company

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Post Office Box 270 Q,yh Hartford, Connecticut 06101

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SUBJECT:

SEP TOPIt. V-ll.A REQUIREMENTSSFOR ISOLATION OF HIGH AND LOW PRESSURE SYSTEMS SAFETY EVALUATION FOR HADDAM NECK The enclosed staff safety evaluation supplanents our contractor's evaluation that has been made available to you previously. As a result of our safety evaluation of Topic V-ll.A. we art also proposing modifications to the CVCS and SI valve control circuitry.

The need to actually implement these changes will be determined during the integrated plant safety assessment. This topic assessment may be revised to the futura if your facility desigin is changed or if NRC criteria relating to this topic are modified Nfore the integrated assessment is completed.

Sincerely, Dennis M. Crutchfield, Chief Operating Reactors Branch No. 5 Divis16a of Licensing

Enclosure:

As stated gf cc w/encleeure:

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e Mr. W. G. Counsil cc Day, Berry & Howard Counselors at Law One Constitution Plaza Hartford, Connecticut 06103 Superintendent Haddam Neck Plaat RFD #1 Post Office Box 127E East Hampton, Connecticut 06424 Mr. Richard F:. Laudenat Manager, Generation Facilities Licensing Northeast Utilities Service Company P. O. Box 270 Hartford, Connecticut 06101 Russell Library 119 Broad Street Middletown, Connecticut 06457 Board of Selectmen Town Hall Haddam, Connecticut 06103 Connecticut Energy Agency ATTN: Assistant Director Research and Policy Development Departnent of Planning and Energy Policy 20 Grand Street Hartford, Connecticut 06106 U. S. Environmental Protection Agency Region I Office ATTN: EIS C0ORDINATOR 4

JFK Federal Building Boston, Massachusetts 02203 Resident Inspector Haddam Neck Nuclear Power Station c/o U. S. NRC

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East Haddam Post Office East Haddam, Connecticut 06423 4

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TOPIC: V-ll.A REQUIREMENTS FOR ISOLATION OF HIGH AND LOW PRESSURE SYSTEMS I.

INTRODUCTION Several systems that have a relatively low design pressure are connected to the reactor coolant pressure boundary. The valves that fom the interface between the high and low pressure systems must have sufficient redundancy and interlocks to assure that the low pressure systems are not subjected to coolant pressures that exceed design limits. The pro-blem is complicated since under certain operating modes (e.g., shutdown cooling and ECCS injection) these valves must open to assure adequate reactor safety.

II. REVIEW CRITERIA The review criteria are presented in Section 2 of EG&G Report 1340F,

" Electrical; Instrumentation and Control Features for Isolation af High and Low Pressure Systems" III. RELATED SAFETY TOPICS AND INTERFACES The scope of review for this tnpic was limited to avoid duplication of effort since some aspects of the review were performed under related topics. The related topics and the subject matter are identified below.

Each of the related topic reports contain the criteria and review guid-ance for its subject matter.

V-3 Overpressurization Protection V-10.B RHR Rellability VI-4 Containment Isolation Topic V-ll.B is dependent on the present topic infomation for completion.

VI. REVIEW GUIDELINES The review guidelines are presented in Section 7.3 of the Standard Review Pla n.

V.

EVALUATION As noted ir, EG&G P1 port 1340F, Haddam Neck has three systems directly connected to the RCS that have a lower design pressure rating than the RCS. The RHR system. SI system, and CVC5 are not in compliance with cur-rent licensing criteria for isolation of high and low pressure systems as noted below.

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1) The RHR system inboard isolation valves do not h' ave diserse and in-dependent interlocks to prevent opening when RCS pressure exceeds RHR system design pressure as required by BTP. RSB-5-1

2) The RHR cystem outboard isolation valves have no: pressure-related interlocks as required by BTP RSB-5-1 4

3) No interlocks are provided to automatically close any RHR system isolation valves if RCS pressure increases above RHR system design pressure during RHR system operation as required by BTP RSB-5-1

4) The SI system isolation valves have no interlocks to prevent open-ir.; if RCS pressure exceeds SI system design pressure as required by SRP 6.3

5) The isolation valves for the CVCS do not havt interlocks to prevent CVCS overpressurization and the check valva used for isolation do not have position Indication in the control room.

VI. ~ CONCLUSIONS.

The deviation for lack of isolation valve diverse interlocks is accept-able because in addition to the single interlock pressure signal on the valves closer to the RCS, the other two valves are key-lock type and are under. administrative controls to prevent opening prior to the inter-lock-pennissive pressure. By procedure, none of these valves are opened unless RCS pressure is below 400 psig.

The deviation for lack of automatic suction valve closuce on increasing RCS pressure is acceptable because, in addition to the administrative and procedural controls on these valves, an alarm is provided at 400 psig to warn the operator that RCS pressure is increasing towards RHR design pressure whenever the Overpressure Protection System (OPS) is enabled.

Upon receipt of an alarm, the control room operator would be able to ter-minate the pressure increase or to perform the required procedural steps to isolate the RHR.

Because ofthe severe consequences of a LOCA outside of containment the staff proposes that:

1) The SI system isolation valve control be modified to prevent opening if RCS pressure exceeds SI system design pressure as required by SRP 6.3.

2)^~ The indication and control of the CVCS valves should be modified to satisfy th~e interlock provisions of SRP Section 6.3 und BTP RSB-5-1.

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