ML13330A208
| ML13330A208 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 01/07/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Dietch R SOUTHERN CALIFORNIA EDISON CO. |
| References | |
| TASK-05-02, TASK-5-2, TASK-RR 10107, LSO5-81-1-007, LSO5-81-1-7, NUDOCS 8102130092 | |
| Download: ML13330A208 (10) | |
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DISTR~iUTION Docket No 50-206 Mr.
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RHermann NRRB reading SEP file DocketNo. 50-206 SEPgDEisenhut OELD RPurple.
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GLainas NC R R.Tedesco Mr. R. Dietch, Vice President ADen6ko Nuclear Engineering and Operati-ons WRussell T~iovak Southern California Edison Company-DCrutchfield JRoe.
2244 Walnut Grove Avenue H~ihJWetmore Post Office Box 800 RSc holl SNowicki NSRC, JB.uchanan Rosemead, California 91770e
Dear Mr. Dietch:
RE: REVISED TECHNICAL ASSESSMENT OF SEP TOPIC V-*II.A; ELECTRICAL, INSTRUMENTATION AND CONTROL FEATURES FOR ISOLATION OF HIGH ANDTLOW PRESSURE SYSTEMSE 166losed is a copy of our revised evaluation of Systematic Evaluation Program Topic V-II.A; Electrical, Instrumentation, and Control Features.
for Isolation ofHigh and Low Pressure Systems. This assessment compares your facility, as described in Docket No. 50-206, with the.----
criteria currently used by the regulatory staff for licens-ing-new facilities. Please0inform us if your as-built faciity differs from the licensing basis assumed In our assessmint within 90,days of receipt of this letter.
This evaluation will'be a basic input to the integrated safety assessment for your facility unless you identify changes needed to reflect the as built conditions at your facility. This topic assessment may be revised in theAfuture if your facility design is changed or if NRC criteria relating to this topic is modified before the integrated assessment, is completed.
Sincerely, S 0)
Dennis M. Crutchfield, Chi Operating Reactors Branch DivisionSof Licensing
Enclosure:
Revised Draft SEPt Topic V-II.A cc w/enclosure:
See next page 8 102 13 0 09 OFFICEO SEPB:DL......SL/.SEP.B:DL.. C/SE.PB:.DL
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SURNAME for ol ao fH and Low e s
Syses Thisasemt DATE 0i~t~.fy
_I NRCcFORM 318y110/80) NRCM as r
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UNITED STATES NUC AR REGULATORY COMMISSION WASHINGTON, D. C. 20555 JAN 0 7 1980 Docket No. 50-206 LS05-81-1-007 Mr. R. Dietch, Vice President Nuclear Engineering and Operations Southern California Edison Company 2244 Walnut Grove Avenue Post Office Box 800 Rosemead, California 91770
Dear Mr. Dietch:
RE:
REVISED TECHNICAL ASSESSMENT OF SEP TOPIC V-II.A; ELECTRICAL, INSTRUMENTATION AND CONTROL FEATURES FOR ISOLATION OF HIGH AND LOW PRESSURE SYSTEMS Enclosed is a copy of our revised evaluation.of Systematic Evaluation Program Topic V-II.A; Electrical, Instrumentation, and Control Features for Isolation of High and Low Pressure Systems. This assessment compares your facility, as described in Docket No. 50-206, 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 90 days of receipt of this letter.
This evaluation will be a basic input to the integrated safety assessment 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.
Sincerely, ennTs M. CrutchfieldVief Operating Reactors Branch #5 Division of Licensing
Enclosure:
Revised Draft SEP Topic V-II.A cc w/enclosure:
See next page
Mr. - tember 16, 1980 cc w/enclosure:
Charles R. Kocher, Assistant Director, Technical Assessment General Counsel Division Southern California Edison Company Office of Radiation Programs Post Office Box 800 (AW-459)
Rosemead, California 91770 U. S. Environmental Protection Agency David R. Pigott Crystal Mall #2 SSarmuel B. Casey Arlington, Virginia 20460 Chickering & Gregory Three Embarcadero Center U. S. Environmental Protection Twenty-Third Floor Agency San-Francisco, California 94111 Region IX Office ATTN: EIS COORDINATOR Jack E. Thomas 215 Freemont Street Harry B. Stoehr San Francisco, California 94111 San Diego Gas & Electric CompanyR P. 0. Box 1831 San Diego, California 92112 KMC, Incorporated 1747 Pennsylvania Avenue, N. W.
Resident Inspector Washington, D. C. 20006 c/o U. S. NRC P. 0. Box AA Oceanside, California 92054 DMission Viejo Branch Library 248." Chrisanta Drive Mission Viejo, California 92676 Mayor City of San Clemente San Clemente, California 92672
- Chairmn Board of Supervisors
- County of San Diego San Diego, California 92101 California Department of Health U.ATTN:
Chief, Environmental Radiation Control 'Unit Radiological Health Section 714 P Street, Room 498 Sacramento, California 95814
t0 1345F SEP TECHNICAL EVALUATION REPORT ELECTRICAL, INSTRUMENTATION, AND CONTROL FEATURES FOR ISOLATION OF HIGH AND LOW PRESSURE SYSTEMS SAN ONOFRE NUCLEAR STATION, UNIT 1 Southern California Edison Docket No. 50-206 December 1979 12-10-80 Revision 1
CONTENTS
1.0 INTRODUCTION
1 2.0 CRITERIA 1
2.1 Residual Heat Removal (RHR) System.......
1 2.2 Emergency Core Cooling System...........
2 2.3 Other Systems...............
2 3.0 DISCUSSION AND EVALUATION........
3 3.1 Residual Heat Removal (RHR) System....
3 3.2 Emergency Core Cooling System.........
3 3.3 Chemical and Volume Control System.......
4 4.0
SUMMARY
5
5.0 REFERENCES
5 11~
SEP TECHNICAL EVALUATION REPORT ELECTRICAL, INSTRUMENTATION, AND CONTROL FEATURES FOR ISOLATION OF HIGH AND LOW PRESSURE SYSTEMS SAN ONOFRE NUCLEAR STATION, UNIT 1
1.0 INTRODUCTION
The purpose of this review is to determine if the electrical, instrumentation, and control (EI&C) features used to isolate systems with a lower pressure rating than the reactor coolant primary system are in compliance with currentlicensing requirements as outlined in SEP Topic V-11A. Current guidance for isolation of high and low pres sure systems is contained in Branch Technical Position (BTP) EICSB-3, BTP RSB-5-1, and the Standard Review Plant (SRP), Section 6.3.
2.0 CRITERIA 2.1 Residual Heat Removal (RHR) Systems.
Isolation requirements for RHR systems contained in BTP RSB-5-1 are:
(1) The suction side must be provided with the following isolation features:.
(a) Two power-operated valves in series with posi tion indicated in the control room.
(b) The valves must have independent and diverse interlocks to prevent opening if the reactor coolant system (RCS) pressure is above the design pressure of the RHR system.
(c) The valves must have independent and diverse interlocks to ensure at least one valve closes upon an increase in RCS pressure above the design pressure of the RHR system.
(2) The discharge side must be provided with one of the following features:
(a) The valves, position indicators, and interlocks described in (1)(a) through (1)(c) above.
(b) One or more check valves in.series with a normally-closed power-operated valve which has
its position indicated in the control room.
If this valve is used for an Emergency Core Cooling System (ECCS) function, the valve must open upon receipt of a safety injection signal (SIS) when RCS pressure has decreased below RHR system.design pressure.
(c) Three check valves in series.
(d) Two check valves in series, provided that both may be periodically checked for leak tightness and are checked at least annually.
2.2 Emergency Core Cooling System. Isolation requirements for ECCS are contained in SRP 6.3. Isolation of ECCS to prevent overpres surization must meet one of the following features:
(1) One or more check valves in series with a normally closed motor-operated valve (MOV) which is to be opened uponotreceipt of a SIS when RCS pressure is less than the ECCS design pressure (2) Three check valves in series (3) Two check valves in series, provided that both may be periodically checked for leak tightness and are checked at least annually.
2.3 Other Systems. All other low pressure systems interfacing with the RCS must meet the following isolation requirements from BTP EICSB-3:
(1) At least two valves in series must be provided to isolate the system when RCS pressure is above the system design pressure and valve position should be provided in the control room (2) For systems with two MOVs, each MOV should have independent and diverse interlocks to prevent opening until RCS pressure is below the system design pressure and should automatically close when RCS pressure increases above system design pressure (3) For systems with one check valve and a MOV, the MOV should be interlocked to prevent opening if RCS pressure is above system design pressure and.should automatically close whenever RCS pressure exceeds system design pressure.
2
3.0 DISCUSSION AND EVALUATION There are three systems at San Onofre Unit 1 which have a direct interface with the RCS pressure boundary and have a design pressure rating of all or part of the system which is less than that of the RCS. These systems are the Chemical and Volume Control System (CVCS),
the Emergency Core Cooling System (ECCS), and the Residual Heat Removal (RHR) system.
3.1 Residual Heat Removal System. The RHR system takes a suction ontthe RCS loop C hot leg, circulates the water through the RHR system heat exchanger, and discharges to the RCS loop A cold leg.
Two motor operated valves in series provide isolation capabilities in both the suction and discharge lines.
Each of these MOVs has position indica tion in the control room. The inboard (closest to the RCS) valves are interlocked to prevent opening if RCS pressure is above RHR system design pressure. However, both valves use the same pressure switch and relay to provide this interlock. The outboard valves have no pressure interlocks. None of the valves will automatically close if RCS pres sure increases above RHR system design pressure during RHR system operation.
The RHR system is not in compliance with the current licensing requirements of BTP RSB-5-l since none of the isolation valves will automatically close if RCS pressure exceeds RHR design pressure. Also, the outboard isolation valves have no interlocks to prevent RHR over pressurization, and the inboard valve interlocks are neither diverse nor independent.
- 3.2 Emergency Core Cooling System. The Safety Injection System (SIS) consists of two loops, each supplied by a safety injection pump and a feed pump. Each loop discharges through a common header to the cold legs of each RCS loop.
Isolation is provided by a check valve in series with a MOV for each branch going to the RCS cold legs.
The motor-operated isolation valves have position indication in the control room and open upon receipt of a safety injection signal, but have no 3
interlocks preventing opening when RCS pressure is above SIS design pressure.
The long-term recirculation system uses the refueling water pumps or charging pumps to provide water from the refueling water storage tank or containment sumps to each RCS cold leg.
Isolation is provided by a MOV in series with a check valve for the three branches. The MOVs are opened using a manual switch and have no interlocks to prevent opening when RCS pressure is above SIS design pressure.
The SIS and long-term recirculation system are not in compliance with the current licensing requirements of SRP 6.3 since the MOVs in the discharge lines have no interlocks to prevent opening when RCS pressure exceeds system design pressure.
3.3 Chemical and Volume. Control System. The CVCS takes water from the RCS and passes it through a regenerative heat exchanger, an orifice to reduce its pressure, and a nonregenerative heat exchanger before reducing its pressure further by the use of a pressure control valve. After filtering and cleanup, the water may be returned to the RCS by the use of the charging pumps, which increase the water pressure and pass it through the regenerative heat exchanger to either the RCS loop A cold leg or to the pressurizer auxiliary spray line.
The CVCS suction line isolation is provided by an air-operated valve in series with three parallel solenoid-operated valves. Each of the solenoid valves is operated from the control room and has valve position indicated. The air-operated valve is operated by the pres surizer level control system. None of the valves have interlocks to prevent opening or to automatically close.if the pressure exceeds the design rating of the low pressure portions of the system.
The CVCS discharge line isolation is provided by a check valve in series with an air-operated valve in each of the branches.
The air operated isolation valves in each discharge line branch have position 4
e 0
indication in the control room, but these valves have no interlocks to prevent system overpressurization.
The CVCS is not in compliance with current licensing requirements for isolation of high and low pressure systems contained in BTP EICSB-3 since the suction and discharge line isolation valves have no inter locks to prevent system overpressurization.
4.0
SUMMARY
The San Onofre Unit 1 has three systems with a lower design pres sure rating than the RCS, which are directly connected to the RCS. The CVCS, SIS, and RHR system do not meet current licensing requirements for isolation of high and low pressure systems as specified below.
(1) The CVCS isolation valves have no pressure-related interlocks as required by BTP EICSB-3 (2) The SIS and long-term recirculation system motor operated isolation valves have no pressure-related interlocks required by SRP 6.3 (3) None of the RHR system isolation valves automati callyclose if RCS pressure increases above RHR system design pressure during RHR system operation, and the outboard isolation valves have no pressure related interlocks as required by BTP RSB-5-1. The interlocks for the inboard isolation valves are neither diverse nor independent.
5.0 REFERENCES
- 1.
NUREG-075/087, Branch Technical Positions EICSB-3, RSB-5-1; Standard Review Plan 6.3.
- 2.
Final Safety Analysis Report, San Onofre Nuclear Generating Station, Unit 1.
- 3.
San Onofre drawings (P&ID) 568766, 568767, 568768, and 568769.
- 4.
San Onofre electrical drawings 455368, 455371, 455516, and 5151796.
5