ML20032C095
| ML20032C095 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 11/03/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| References | |
| TASK-05-11.A, TASK-5-11.A, TASK-RR LSO5-81-11-002, LSO5-81-11-2, NUDOCS 8111060691 | |
| Download: ML20032C095 (5) | |
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November 3, 1981 Docket No. 50-213 LS05-81 ll-002 Mr. W. G. Counsil, Vice President Nuclear Engineering and Operations Connecticut Yankee Atonic Power Company Post Office Box 270 Hartford, Connecticut 06101
Dear Mr. Counsil:
SUBJECT:
SEP TOPIC V-11.A, REQUIREMENTS FOR ISOLATI0tl 0F HIGH AND LOW PRESSURE SYSTEMS, REVISED SAFETY EVALUATION FOR HADDAM NECK The enclosed staff safety evaluation hashbeen revised to reflect plant modif' cations made as a result of the TMI Lessons Learned project. As a result of our safety evaluation of Topic V-11.A, we are proposing modifications to the 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 in the future if your facility design is changed or if NRC criteria relating to this topic are modified before the integrated assess-ment is completed.
Sincerely, Dennis M. Crutchfield, Chief
(
rating Reactors Branch No. 5
)
/p gfon of Licensing 56ol N
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6 Mr. W. G. Counsil l
l CC Day, Berry & Howard Counselors at Law One Constitution Plaza Hartford, Connecticut 06103 Superintendent Haddam Neck Plant RFD #1 Post Office Box 127E East Hampton, Connecticut 06424 Mr. Richard R. Laudenat Manacer, Generation Facilities Licensing Northeast Utilities Service Company P. O. Bnx 270 Hartford, Connecticut 06101 Russell Library 119 Broad Street Middletown, Connecticut 06457 Board of Selectmen Tcan Hall Haddam, Connecticut 06103 Connecticut Energy Agency ATTN: Assistant Director Research and Policy Development Department of Planning and Energy Policy 20 Grand Street
, Hartford, Connect cut 06106 i
U. S. Environmental Protection Agency Region 1 Office ATTN: Regional Radiation Representative JFK Federal Building Boston, Massachusetts 02203 Resident Inspector Haddam Neck Nuclear Power Station c/o U. S. NRC East Haddam Post Office i
East Haddam, Connecticut 06423 l
e SYSTEMATIC EVALUATION PROGRAM TOPIC V-11.A HADDAM NECK TOPIC: V-ll.A REQUIREMENTS FOR ISOLATION OF HIGH AND LOW PRESSURE SYSTEMS 1.
INTRODUCTION Several systens'that have a relatively low design pressure are connected to the reactor coo'lant pressure boundary. The valves that form 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 of High and Low Pressure Systems" III. RELATED SAFETY TOPICS AND INTERFACE.
The scope of review fur this topic was simited to avoid duplication of effort since sane aspects of the review were performed under related topics. The related 6] pics and the subject matter are identified below.
Each of the related topic reports contain the criteria and review guid-ance for its subject matter.
l V-3 Overpressurization Protection V-10.B RHR Reliability l
VI-4 Containment Isolation f
Topic V-ll.B is dependent on the present topic information for completion.
l
' VI. REVIEW GUIDELINES The review guidelines are presented in Section 7.3 of the Standard Review Plan.
i V.
EVALUATION As noted in EG&G Report 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 CVCS are not in compliance with cur-rent licensing criteria for isolation of high and low pressure systems as l
noted below.
l f
I
,.- 1) The RHR system inboard isolation valves do not have diverse 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 system outboard isolation valves have no pressure-related interlocks as required by BTP RSB-5-1
- 3) No interlocks are provided to automatically clos $ 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-ing if RCS pressure exceeds SI system design pressure as required by SRP 6.3
- 5) The isolation valves for the CVCS do not have interlocks-to prevent CVCS overpressurization and the check valves 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 singls interlock pressure signal on the valves closer to the RCS, the other two valves are key-lock type and are under administrative controls to preveat opening prior to the inter-lock pemissive pressure. By procedure, none of these valves are opened unless RCS pressure is below 400 psig.
The deviatior for lack of automatic suction valve closure 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 of the severe consequences of a LOCA outside of containment the staff proposes that 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.
The CVCS letdown line valve controls have been modified as a result of TMI Lessons Learned so that the three inch inboard and outboard isolatinn valves will close on High Containment Pressure or Low Pressurizer Pressure or Level.
This modification was evaluated under SEP Topic XV-16 and found acceptable.
,a
. The charging pump discharge valves do not satisfy the applicable criteria and modifications to these valves will be pursued under SEP Topic VI-4.