ML19320D014
| ML19320D014 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 07/01/1980 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Peoples D COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8007180436 | |
| Download: ML19320D014 (5) | |
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8 UNITED STATES 8
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July 1, 1980 4
Docket No. 50-10 Mr. D. Louis Peoples Director of Nuclear Licensing Comonwealth Edison Conpany Post Office Box 767 Chicago, Illinois 60690
Dear Mr. Peoples:
RE: SEP TOPIC V-11. A, REQUIREMENTS FOR ISOLATION OF HIGH AND LOW PRESSURE SYSTEMS Enclosed is a copy of our evaluation of Systematic Evaluation Program Topic V-11. A, Requirements for Isolation of High and Low Pressure Systems. This assessment compares your facility, as described in Docket No. 50-10 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.
We have discussed this assessment with your staff and believe the facts concerning your plant are correct. Therefore, our review of this topic is conplete and 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 assess-ment 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 assessment is conpleted.
Sincerely, g
ennis M. Crutchfield, ief Operating Reactors Branch #5 Division of Licensing
Enclosure:
Completed SEP Topic V-ll. A cc w/ enclosure:
See next page 8007180hl3g
e-Mr. D. Louis Peoples July 1, 1980 i
i cc w/ enclosure:
Isham, Lincoln & Beale Director, Technical Assessment f
Counselors at Law Division One First National Plaza, 42nd Floor Office of Radiation Programs f
Chicago, Illinois 60603 (AW-459)
U. S. Environmental Protection J
Mr. B. B. Stephenson Agency Plant Superintendent Crystal Mall #2 Dresden Nuclear Power Station Arlington, Virginia 20460 Rural Route il Morris, Illinois 60450 U. S. Environmental Protection Agency U. S. Nuclear Regulatory Commission Federal Activities Branch Resident Inspectors Office Region V Office Dresden Station ATTN: EIS COORDINATOR RR #1 230 South Dearborn Street Morris, Illinois 60450 Chicago, Illinois 60604 Susan N. Sekuler f
Mr. Richard E. Schaffstall Assistant Attorney General KMC, Incorporated Environmental Control Division 1747 Pennsylvania Avenue, NW 188 W. Randolph Street Washington, D. C.
20006 Suite 2315 Chicago, Illinois 60601 Morris Public Library 604 Liberty Street Morris, Illinois 60451 Chairman Board of Supervisors of Grundy County Grundy County Courthouse Morris, Illinois 60450 Department of Public Health ATTN: Chief, Division of Nuclear Safety 535 West Jefferson Springfield, Illinois 62761 t- -
w,5-SEP TOPIC V-ll.A
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l SEP TECHNICAL EVALUATION REPORT REQUIREMENTS FOR ISOLATION OF HICE AND LOW PRESSURE SYSTEMS DRESDEN 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 current licensing 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 (SCt), Section 6.3.
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2.0 CRITERIA 2.i Residual Heat Removal (RHR) Systems. Isolation requirements for RHR systems contained in BIP RSB-5-1 are:
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(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 independe.: and diverse interlocks to prevent opening if the reactor coolant system (RCS) pressure is above the design pressure of the RER 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 l
design pressure of the RHR system.
(2) The discharge side must be provided with one of the following features:
l (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-cicaed power-operated valve which has 1
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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 RER 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 FCCS 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 upon receipt 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 than both may i
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 E1CSB-33 (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
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design _ pressure,and should automatically close when j
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.
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- i 3.0 DISCUSSION AND EVALUATION There is one system at Dresden 1 which has a direct interface with the RCf and has a lower design pressure rating for all or part of the system than RCS design pressure.
This system is the Core Spray (CS) system.
3.1 Core Spray System. The CS system consists of three pumps providing water to a single header via two parallel piping branches.
Isolation of the two branches is provided by two MOVs in series with a check valve in each branch.
i The HOVs open upon receipt of a CS system start signal when the
' l RCS pressure has decreased to within the CS system design pressure (determined by AP indicator). The valves will not close if RCS pres-sure increases above system design pressure. Closure is accomplished only by operator action. There are no interlocks to prevent the opera-tor from opening the CS system isolation valves from the control room or the local control station when RCS pressure exceeds CS system design pressure.
The CS system does not meet current licensing requirements for isolation of high and low pressure systems, contained in SRP 6.3, since there are no interlocks to prevent the operator from opening the isola-tion valves when RCS pressure exceeds system design pressure.
4.0
SUMMARY
The Dresden Nuclear Station, Unit I hss one system with lower design pressure rating than the RCS which is directly connected to the RCS. The CS system does not meet current licensing criteria contained in SRP 6.3 for isolation of high and low pressure systems since there are no interlocks to prevent the operator from opening the isolation valves when RCS pressure exceeds CS system design pressure.
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5.0 REFERENCES
1.
NUREG-075/087, Branch Technical Positions EICSB-3, RSB-5-1; Stan-dard Review Plan 6.3.
2.
Dresden 1 Drawings M-600, 12E1001-9, -10, -11, and -12, 3.
Final Hazard Sununary Report, Dresden Nuclear Station, Unit 1.
4.
License No. DPR-2, Supplement A to proposed change no. 17, Dresden Nuclear St.ation, Unit 1.
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