ML20246Q073
| ML20246Q073 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 05/08/1989 |
| From: | Olshan L, Sands S Office of Nuclear Reactor Regulation |
| To: | Kovach T COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8905220358 | |
| Download: ML20246Q073 (6) | |
Text
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UNITED STATES
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- NUCLEAR REGULATORY COMMISSION' fg '"
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WASHINGTON, D. C. 20555 In 3
May 8,.1989-l
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Docket Nos' : _ 50-454,.50-455, 50-456, anu 50-457 Mr. Thomas J. Kovach
- NuclearLicensingManager Connonwealth Edison Company
' Post Office Box 767 Chicago, Illinois 60690
Dear Hr. Kovach:
SUBJECT:
CHANGE TO BASES OF TECHNICAL SPECIFICATIONS DEALING WITH OPERABILITY 0F POWER-0PERATED RELIEF VALVES.(PORVs) - BYRON AND BRAIDWOOD By letter dated December 12, 1988, you requested a change to the bases of the-Byron /Braidwood Technical Specifications (TS). The chan Operability for the power-operated relief valves (PORVs)ge clarifies
-by stating that the-PORVs are considered OPERABLE in Modes 1, 2 and 3 in either the manual or automatic mode.. Because r.o credit for PORY operation is taken'in the FSAR analyses for Modes 1, 2, and 3 transients, we conclude that the..equested change is acceptable.
Enclosed is t'he revised TS page B 3/4 4-2 for both Byron and Braidwood.
Sincerely,
. Stephen P. Sands, Project Manager Leonord N. 01shan, Project Manager Project Directorate III-2 Project Directorate III-2 Division of Reactor Projects - III, Division of Reactor Projects - III, IV, V, and Special Projects IV, V, and Special Projects
Enclosure:
As stated cc w/ enclosure:
See next page 8905220358 890508 h
gDR ADOCK 05000454 I
I,
.q
- Mr. Thomas J. Kovach '
. Byron /Braidwood Power Station-Commonwealth Edison Company Units 1 and 2 cc:
Mr. Jack Tain Dr. Bruce von Zellen Atomic Power Distribution Department of Biological Sciences Westinghouse Electric Corporation Northern Illinois University-Post Office Box 355 DeKalb, Illinois 61107 Pittsburgh,_ Pennsylvania 15230 U. S. Nuclear Regulatory Commission -
Joseph Gallo Esq.
Byron / Resident Inspectors Office Hopkins and Sutter 4448 North. German Church Road 1050 Connecticut-Ave., N.W.
Byron, Illinois 61010 Suite 1250 Washington, D.C. 20036 Ms. Lorraine Creek Rt. 1, Box'182.
C. Allen Bock, Esquire Manteno Illinois 60950 Post Office Box 342.
Urbana, Illinois 61801 Mrs. Phillip B. Johnson 1907 Stratford Lane Regional Administrator Rockford, Illinois 61107
- U..S.:NRC, Region III-799 Roosevelt Road, Bldg. #4
.Douglass Cassel, Esq.
Glen Ellyn... Illinois 60137 109 N. Dearborn Street.
Suite 1300
~ Ms. Bridget Little Rorem Chicago, Illinois 60602 Appleseed Coordinator 117 North Linden Street-Ms. Pat Morrison
- Essex,: Illinois 60935 913 N Main Street #707 Rockford, Illinois 61103-7058 Mr. Edward R.' Crass Nuclear Safeguards 'and Licensing David C. Thomas, Esq.
Division' 77 S. Wacker Drive Sargent.& Lundy Engineers Chicago, Illinois 60601 55 East Monroe Street Chicago, Illinois 60603 Mr. Charles D. Jones, Director Illinois Emergency Services U. S. Nuclear Regulatory Ccmmission and Disaster Agency l
Resident Inspectors'0ffice 110 East Adams Street RRf1, Box 79 Springfield, Illinois 62706 Braceville, Illinois 60407
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'~
. Mr. Thomas J. Kovach Byron /Braidwood Commonwealth Edison Company i
CC:
j Mr. Michael C. Parker, Chief Division of Engineering
)
1111no 4 Department of Nucle Safety 1035 Oi...r Park Drive Springfield, Illinois 62704 Michael Miller, Esq.
j Sidley and Austin
)
One First Hatton41 Plaza Chicago, Illinois 60603
' George L. Edgar Newman & Holtzinger, P.C.
3 1615 L Street, N.W.
Washington, D.C. 20036 Commonwealth Edison Company Byron Station Manager j
4450 North German Church Road Byron, Illinois 61010 i
l fi
BASES 3/4.4.2 SAFETY VALVES The pressurizer Code safety valves operate to prevent the RCS from being pressurized above its Safety Limit of 2735 psig.
Each safety valve is designed to relieve 420,000 lbs per hour of saturated steam at the valve Setpoint.
The relief capacity of a single safety valve is adequate to relieve any overpressure condition which could occur during shutdown.
In the event that no safety valves are OPERABLE, an operating RHR loop, connected to the RCS, provides overpressure relief capability and will prevent RCS overpressurization.
In addition, the Overpressure Protection System provides a diverse means of protection against RCS ove. pressurization at low temperatures.
During operation, all pressurizer Code safety valves must be OPERABLE to prevent the RCS from being pressurized above its Safety Limit of 2735 psig.
The combined relief capacity of all of these valves is greater than the maximum surge rate resulting from a complete loss-of-load assuming no Reactor trip and also assuming no operation of the power-operated relief valves or steam dump valves.
Demonstration of the safety valves' lift settings will occur only during shutdown and will be performed in accordance with the provisions of Section XI of the ASME Boiler and Pressure Code.
3/4.4.3 PRES $URIZER The limit on the maximum water volume (1656 cubic feet) in the pressurizer l
assures that the parameter is maintained within the normal steady-state envelope of operation assumed in the SAR.
The limit is consistent with the initial SAR assumptions.
The 12-hour periodic surveillance is sufficient to ensure that the parameter is restored to within its limit following expected transient operation.
The maximum water volume also ensures that a steam bubble is formed and thus the RCS is not a hydraulically solid system.
The requirement that a minimum number of pressurizer heaters be OPERABLE enhances the capability of the plant to control Reactor Coolant System pressure and establish natural circulation.
3/4.4.4 RELIEF VALVES The power-operated relief valves (PORVs) and steam bubble function to relieve RCS pressure during all design transients up to and including the design step load decrease with steam dump.
Operation of the PORVs minimizes the undesirable opening of the spring-loaded pressurizer Code safety valves.
Each PORV has a remotely operated block valve to provide a positive shutoff capability should a relief valve become inoperable.
The PORVs are equipped with automatic actuation circuitry and manual control capability.
Because no credit for PORV operation is taken in the FSAR analyses for Modes 1, 2 and 3 transients, the PORVs are considered OPERABLE in either the manual or automatic mode.
It should be noted that the automatic mode is the preferred configuration, as this provides pressure relieving capability without reliance on operator action.
BYRON - UNITS 1 & 2 B 3/4 4-2 CHANGED BY LETTER DATED May 5, 1989
REACTOR COOLANT SYSTEM BASES 3/4.4.2 SAFETY VALVES The pressurizer Code safety valves operate to prevent the RCS from being pressurized above its Safety Limit of 2735 psig.
Each safety valve is designed to relieve 420,000 lbs per hour of saturated steam at the valve Setpoint.
The relief capacity of a single safety valve is adequate to relieve any overpressure condition which could. occur during shutdown.
In the ever,t that no safety valves are OPERABLE, an operating RHR loop, connected to the RCS, provides overpressure relief capability and will prevent RCS overpressurization.
In addition, the Overpressure Protection System provides a diverse means of protection against RCS overpressurization at low temperatures.
During operation, all pressurizer Code safety valves must be OPERABLE to prevent the RCS from being pressurized above its Safety Limit ~of 2735 psig.
The combined relief capacity of all of these valves is greater than the maximum surge rate resulting from a complete loss-of-load assuming no Reactor trip and also assuming no operation of the power-operated relief valves or steam dump valves.
Demonstration of the safety valves' lift settings will occur only during shutdown and will be performed in accordance with the provisions of Section XI of the ASME Boiler and Pressure Code.
3/4.4.3 PRESSURIZER The limit on the maximum water volume (1656 cubic feet) in the pressurizer assures that the parameter is maintained within the normal steady-state envelope of operation assumed in the SAR.
The limit is consistent with the initial SAR assumptions.
The 12-hour periodic surveillance is sufficient to ensure that the parameter is restored to within its limit following expected transient operation.
'The maximum water volume also ensures that a steam bubble is formed and thus the RCS is not a hydraulically solid system.
The requirement that a minimum number of pressurizer heaters be OPERABLE enhances the capability of the plant to control Reactor Coolant System pressure and establish natural circulation.
3/4.4.4 RELIEF VALVES The power-operated relief valves (PORVs) and steam bubble function to relieve RCS pressure during all design transients up to and including the design step load decrease with steam dump.
Operation of the PORVs minimizes the undesirable opening of the spring-loaded pressurizer Code safety valves.
Each PORV has a remotely operated block valve to provide a positive shutoff capability should a relief valve become inoperable.
The PORVs are equipped with automatic actuation circuitry and manual control capability.
Because no credit for PORV operation is taken in the FSAR analyses for Mode 1, 2 & 3 transients, the PORVs are considered OPERABLE in either the manual or automatic mode.
It should be noted that the automatic mode is the preferred configuration, as this provides pressure relieving capability without reliance on operator action.
BRAIDWOOD - UNITS 1 & 2 B 3/4 4-2 CHANGED BY LETTE9 DATED May 8, 1989
- s..
o l
s, Nay~8, 1989
~
. Docket Nos.: 50-454, 50-455, 50-456. and 50-457-L
.Mr. Thomas J. Kovach L
Nuclear. Licensing Manager =
Commonwealth Edison Company 1
Post OfficeJBox 767
' Chicago,' Illinois 60690
Dear Mr. Kovach:
SUBJECT:
CHANGE TO BASES OF TECHNICAL SPECIFICATIONS DEALING WITH' OPERABILITY
.OF POWER-OPERATED RELIEF VALVES (PORVs) - BYRON AND BRAIDWOOD H
By letter' dated December 12, 1988, you requested a change to the bases of the-Byron /Braidwood Technical Specifications--(. TS). The chan
. operability for the power-operated relief valves (PORVs)ge clarifies by stating.that the E
PORVs are considered OPERABLE in Modes'1, 2 and 3 in either the' manual or automatic mode. Because' no: credit for PORV operation is taken in the FSAR analyses for Modes 1,-2, and 3Ltransients, we conclude that the requested
' change is~ acceptable.
Enclosed is the. revised TS page B 3/4 4-2 for both Byron and Braidwood.
Sincerely, Stephen P.' Sands, Project Manager Leonard N. Olshan, Project Manager Project Directorate III-2
-Project Directorate III-2 Division of Reactor Projects - III, Division of Reactor Projects - III, IV, V, and Special Projects.
IV, V, and Special Projects
^
Enclosure:
As stated cc w/ enclosure:
See next page
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