ML20079P912
| ML20079P912 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 11/07/1991 |
| From: | VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | |
| Shared Package | |
| ML20079P909 | List: |
| References | |
| NUDOCS 9111140149 | |
| Download: ML20079P912 (15) | |
Text
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Attachment 2 Proposed Technical Specificatlots Change North Anna Unit 1 Virginia Electric and Power Company
' 9111140149 913107 PDR ADOCK 03000338 P PDR
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PLANT SYSTDAS 3'4.7.3 COMPONENT COOLING WATER SYSTEM 3/4.7.3.1 COMPONENT COOLING WATER SUBSYSTEM OPERATlNG UMITING CONDITION FOR OPERATION 3.7.3.1 Throo componont cooling water subsystems (shared with Unit 2) shall be OPERABLE' with each subsystem consisting of:
- a. One OPERABLE cornponent cooling water pump and,
- b. Ono OPERABLE component cooling water boat exchanger.
APPLICABILITY: Either Unit in MODES 1,2,3, or 4.
ACIlON: a With one required component cooling water subsystem inoporable, return the component cooling subsystem to OPERABLE status within the next 7 days, or place both units in HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
- b. With two required component cooling water subtystems inoperable, placo both units in HOT SHUTDOWN within the ncxt 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, and within the next hour, initiato actions to place both units in COLD SHUTDOWN and continue until COLD SHUTDOWN is achloved.
- c. With no component cooling water avaltable to supply the residual heat removal heat exchangers to cool the units, place both units in HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and remain in HOT SHUTDOWN until attornato means of docay boat removal can be implomonted. Continue cctions untd both units are in COLD SHUTDOWN.
SURVEILLANCE REQUIREMENTS
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4.7.3.1 Three component cooling water subsystems sball be demonstrated OPERABLE:
a At least onco por 31 days by verifying ti,at each valvo (manurJ, power operated or automatic) servicing in the flow path of the residual heat removal system that l is not locked, scaled, or otherwise secured in position, is in its correct position.
- b. Each component cooling water pump shall be tested in accordance with Specification 4.0.5.
For the purpose of this Technical Specification, each subsystem is considorod OPERABLE if it is operating or if it can be placed in service from a standby condition by manually unisolating a standby heat exchanger and/or manually starting a standby pump.
NORTH ANNA UNIT 1 3/4 7 17
PLANT SYSTEMS 3/4.7.3 COMPONENT COOLING WATER SYSTEM 3/4.7.3 2 COMPONENT COOUNG WATER SUBSYSTEM - SHUTDOWN I
UMITING CONDmON FOR OPERATON l
3.7.3.2 T + .:rmponent cooling water subsystems (shared with Unit 2) shall be OPERABLE *
. 4h M.,h subsystem consisting of:
- a. One OPERABLE component cooling water pump and,
- b. One OPERABLE component cooling water heat exchanger.
APPLICABILITY: Both Units in MODES 5 or 6.
ACTION: With one required component cooling water subsystem inoperable, immediately suspend all operations involving an increase in the reactor decay heat load or a reduction in boron concentration of the Reactor Coolant System.
SURVEILLANCE REQUIREMENTS 4.7.3.2 At least two component cooling vwter subsystems shall be demonstrated OPERABLE:
- a. A? 'sst once per 31 days by vvifying that each valve (manual, power operated or automatic) the flow path of the residual heat removal system that is not locked, sealed, or otherwise secured in position, is in its correct position,
- b. Each component cooling water pump shall be tested in accordance with Specification 4.0.5.
For the purposes of this Technical Specification, each subsystem is considered OPERABLE if it is operating or if it can be placed in service from a standby condition by manually unisolating a standby heat exchanger and/or manually starting a standby pump, w
NORTH ANNA - UNIT 1 3/4 7-17a
PLANT SYSTEMS BASES 3/4.7.1.6 and 3'4.7.7.1.7 STEAM TURBINE and OVERSPEED PROTECTION The turbine generator at the North Anna facility is arranged in a nonpeninsular orientation. Analysis has shown that this arrangement is such that if a turbine failure occurs as a result of destructive overspeed, potentially damaging missles could impact the auxiliary building, containment, control room and other structures housing safety related equipment. The requirements of these two specifications provide additional assurance that the facility will not be operated with degraded valve parormance and/or flawed turbine material which are the major contributors to turbine failum 3/47.2 STEAM GENERATOR PRESSURE / TEMPERATURE LIMITATION The limitation on steam generator pressure and temperature ensures that the pressure induced stresses in the steam generators do not exceed the maximum allowable fracture toughness stress limits. The limita'hns of 70'F and 200 psig are based on average steam generator impact values at 10'F and are sufficient to prevent brit'le fracture.
3/4.7.3.1 COMPONENT COOLING WATER SUBSYSTEM - OPERATING The component cooling water system normally operates continuously to remove heat from various plant components and to transfer the heat to the service water system. The system consists of four subsystems shared between units, with each subsystem containing one pump and one heat exchanger.
The current design basis for the component cooling water system is a fast cooldown of one unit while maintaining normal loads on the other anit. Three component cooling water subsystems need to be OPERABLE to accomplish this function. The fourth subsystem is a spare and may be out af service indefinitely. With only two component cooling water subsystems a slow cooldown on one unit while maintaining normalloads on the opposite unit can be accomplished.
The component cooling water system is designed to reduce the temperature of the reactor coolant system from 350*F to 140'F within 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> during plant cooldown, based on a service water ternperature of 95 F and on having two component cooling water pumps and two heat exchangers in service for the unit being cooled down. Therefore, to ensure cooldown of one unit within 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> and maintain the olhar unit in normal full power operation three of the four subsystems must be OPERABLE.
Because subsystems are placed in standby by shutting down pumps and isolating heat exchangers and this system serves no accident mitigation functions, the subsystem is considered OPERABLE in the standby conditions since it can be easily placed in service quickly t y manual operator actions.
3/4.7.3.2 COMPONENT COOLING WATER SUBSYSTEM - SHUTDOWN The OPERABILITY of the component cooling water system when both units a.1 in COLD SHUTDOWN or REFUELING ensures that an udequate heat sink is maintained fm the residual heat removal system.
NORTH ANNA - UNIT 1 B 3/4 7-4 I
PLANT SYSTEMG EMSES l
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3/4.7.4 SERVICE WATER SYSTEM l
l The OPERABILITY of the service water system ensures that sufficient cooling capacity is available for continued operation of safety related equipment during normal and accident ;
Mnditlois. The redundant cooling capacity of this system, assuming a single failure, is <
consistent with the assumptions used in the isrident conditions within acceptable limits. '
i NORTH ANNA - UNIT 1 B 3/4 7-4a
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Attachment 3 Proposed Technical Specification Change Ncrth Anna Unit 2 Virginia Electric and Power Company
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PLINT SYSTEMS ,
3/4.7.3 COMPONENT COOLING WATER SYSTEM 314.7.3.1 COMPONENT COOLING WATER SUBSYSTEM - OPERATING t:
- l. UMITING CONDmON FOR OPERATION L
, 3.7.3.1 .. Three component cooling water subsystems (shared with Unit 1) shall be
- OPERABLE
- with each subsystem consisting of: j a One OPERABLE component cooling water pump and, l l b. One OPERABLE component cooling water heat exchanger.
APPLICABILITY: Elther Unit in MODES 1,2,3, or 4. l ACTION- c. With one required component cooling water subsystem inoperable, return the component cooling subsystem to OPERABLE status within the next 7 days, or place both units in HOT STANDBY within the n6xt 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD ,
l SHUTDOWN withir the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. l l
- b. With two required component cooling water subsystems inoperable, place both units in HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, and within the next hour, !
initiate actions to place both units in COLD SHUTDOWN and continue until COLD SHUTDOWN is achieved.
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- c. With no component cooling water svallable to supply the residual heat removal heat exchangers to cool the units, place both units in HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and remain in HOT SHUTDOWN until alternate means of decay heat removal can be implemented. Continue actions until both units are in COLD SHUTDOWN.
-SURVEILLANCE REQUIREMENTS 4.7'3.1
. Three component cooling water subsystems shall be demonstrated OPERABLE:
a At least once per 31 days by verifying that each valve (manual, power operated or automatic) servicing in the f!ow path of the residual heat removal system that l' Is not locked, sealed, or otherwise secured in position, is in its correct position.
- b. Each component cooling water pump shall be tested in accordance with Specification 4.0.5.
, For the purpose of this Technical Specification, each subsystem is considered OPERABLE if it i is operating or if it can be placed in serse from a standby condition by manually unisolating a standby heat exchanger and/or manually starting a standby pump.
NORTH ANNA - UNIT 2 3/4 7-14
PLANT SYSTEMS 3/4.7.3 COMPONENT COOLING WATER SYSTEM 3/4.7.3.2 COMPONENT COOLING WATER SUBSYSTEM - SHUTDOWN UMITING CONDITION FOR OPERATION 3.7.3.2 Two component cooling water subsystems (shared with Unit 1) shall be OPERABLE
- with each subsystem consisting of:
- a. One OPERABLE component cooling water pump and,
- b. One OPERABLE component cooling water heat exchanger.
APPLICABILITY: Both Units in MODES 5 or 6.
ACTION: With one required component cooling water subsystem inoperable, immediately suspend all operations involving an increase in the reactor decay heat load or a reduction in boron concentration of the Reactor Coolant System.
SURVEILLANCE REQUIREMENTS 4.7.3.2 At least two component coolitig water subsystems shall be demonstrated OPERABLE:
- a. At least once per 31 days by verifying that each valve (manual, power operated or automatic) servicing in the flow path of the residual heat removal system that is not locked, sealed, or otherwise secured in position, is in its correct position.
- b. Each component cooling water pump shall be tested in accordance with Specification 4.0.5.
For the purposes of this Technical Specification, each subsystem is considered OPERABLE if it is operating or if it can be placed in service from a standby condition by manually unisolating a standby heat exchanger and/or manually starting a standby pump.
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NORTH ANNA - UNIT 2 3/4 7-14a
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f PLANT SYSTEMS IRSES 3/4.7.1.0 and 3/4.7.7.1.7 STEAM TURBINE and OVERSPEED PROTECTION The turbine generator at the North Anna facility is arranged in e nonpeninsular orientation. Analysis has shown that this arrangement is such that if a turbine failure occurs as a result of destructive overspeed, potentially damaging missles could impact the auxiliary building, containment, control room and other structures housing safety related equipment. The requirements of these two specifications provide additional assurance that the facility will not be operated with degraded valve performance and/or flawed turbine material which are the major contributors to turbine failures.
3/4.72 STEAM GENERATOR PRESSURE / TEMPERATURE LIMITATION The limitation on steam gcnerator pressure and temperature ensures that the pressure induced stresses in the stea"' generators do not exceed the maximum allowable fracture toughness stress limits. The limitations of 70'F and 200 psig are based on average steam generator impact values at 10*F and are sufficient to prevent brittle fracture.
I 3/4.7.3.1 COMPONENT COOLING WATER SUBSYSTEM - OPERATING The component cooling water system normally operates continuously to remove heat from various plant components and to transfer the hect to the service water system. The system consists of four subsystems shared between units, with each subsystem containing one pump and one heat exchanger.
The current design basis for the component cooling water system is a fast cooldown of one unit while maintaining normal loads on the other unit. Three component cooling water subsysiems need to be OPERABLE to accomplish this function. The fourth subsystem is a spare and may be out of service indefinitely. With only two component cooling water subsys' ems a slow cooldown on one unit while maintaining normalloads on the opposite unit can be accomplished.
The component cooling water system is designed to reduce the temperature of the reactor coolant system from 350 F to 140"F within 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> during plant cooldown, based on a service water temperature of 95 F and on having two component cooling water pumps and two heat exchangers in service for the unit being cooled down. Therefore, to ensure cooldown of one unit within 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> and maintain the other unit in normal full power operation three of the four subsystems must be OPERABLE.
Because subsystems are placed in standby by shutting down pumps and isolating heat exchangers and this system serves no accident mitigation functions, the subsystem is considered OPERABLE in the standby conditions since it can be easily placed in service quickly by manual operator actions.
3/4.7.3.2 COMPONENT COOLING WATER SUBSYSTEM . SHUTDOWN r The OPERASILITY of the component cooling water system when both units are in COLD SHUTDOWN or REFUELING ensures that an adequate heat sink is maintained for the residual heat removal system.
NORTH ANNA - UNIT 2 B 3/4 74 i
PLNH SYSTEMS ERSES
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3/4.7.4 SERVICE WATER SYSTEM The OPERABILITY of the service water system ensures that sufficient cooling capacity is available for continued operation of safety related equipment during normal and accident conditions.' The redundant eceling capacity of this system, assuming a single failure, is consistent with the assumptions used in the accident conditions within acceptable limits.
d NORTH ANNA - UNIT 2 8 3/4 7-4 a
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i Attachment 4 1
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10 CFR 50.92 Evaluation I North Anna Units 1 and 2 1.
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Virginia Electric and Power Company y
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4 10 CFR 50.92 Significant Hazards Considerations Analysis The proposed changes are being made as a result of an NRC violation re0arding the service water system. Technical Specification changes for the service water system have been submitted 'o the NRC as a recult of the violation. However, in the cover letter transmitting the service water Notification of Violation (dated February 1,1991) the NRC observed that the operation of the component cooling system was different than that described in the UFSAR.
In addition, no formal safety evaluations were done to address this difference.
The proposed Technical Specification change will ensure that operation of the component cooling water system is consistent with its design basis.
The proposed changes enhance the availability of the component cooling water system and ensure that sufficient cooling capacity is available for continued operation of various equipment during normal unit cooldown is available for both units. The proposed changes further ensure the availability of a heat s nk for the residual heat removal system to remove decay heat from the reactor core by requiring that two of the four component cooling water subsystems be OPERABLE when both units are in Modes 5 or 6.
The Limiting Condition for Operation is changed to require three subsystems (shared between both units) to be operable and to define what an operable component cooling water subsystem consists of. Two component cooling water subsystems provide the minimum heat remova' capability to accomplish a slow cooldown on one unit while maintaming normalloads on the opposite unit. To ensure the design basis requirement of a fast cooldown on one unit and normal operational loads on the opposite unit is met, three subt,mtems of component coolin-) water must be OPERABLE. In addition, a footnote was added to further clarity when a subsystem is considered OPERABLE.
The Applicability statement is changed to c!arify that this Technical Specification applies if either or both units are in modes 1 through 4. This change will snsure that sufficient cooling capacity is available for both units.
Action statement 3.7.3.1.a is added to require that it one of the three required subsystems becomes inoperable, that the subsystem be returned to an operable status within seven days.
Action statement 3.7.3.1.a also specifies that if the required component cooling water system subsystem cannot be restored in the required completion time, both units must be placed in a mode in which the risk to the unit is minimized. '
This is done by placing both units in HOT STANDBY in six hours and in COLD SHUTDOWN in the next 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Action statement 3.7.3.1.b is added to require that if two of the three required subsystems become inoperabie, that both units shall be placed in HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and that E.ctions be initiated to place both units in COLD SHUTDOWN within the next hour and continue to COLD SHUTDOWN if component cooling water is available to supply the residual heat
t removal heat exchangers to further cool the units. The units are first placed in a condition where decay heat can be removed by the steam generators. This can be achieved in HOT SHUTDOWN.
Action statement 3.7.3.1.c is added to require that with no component cooling water available to supply the residual heat removal heat exchangers to further cool the units, both units must be placed in HOT SHUTDOWN within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> The units may remain in HOT SHUTDOWN until alternate means of decay heat removal can be implemented. If component cooling is available and a heat sink to further cool the units is available, unit cooldown shall continue until COLD i
- SHUTDOWN is achieved under Action statement 3.7.3.1.b.
Surveillance Requirement 4.7.3.1.a was modified to replace " safety related equipment" with "in the flow path of the residual heat removal system."
Surveillance Requirement 4.7.3.1.b was added to specify surveillance testing I for OPERABILITY determination of the component cooling water pumps in !
accordance with Specification 4.0.5, the ASME Section XI prograin. j Technical Specification 3.7.3.2 was added to support our current UFSAR ;
design bases when both units are in Modes 5 or 6. When both units are in COLD SHUTDOWN or REFUELING the design basis requires that the l component cooling water system be OPERABLE. This is to ensure an adequate heat sink is maintained for the residual heat removal system.
A new Limiting Condition for Operation is established for modes 5 and 6. This new Limiting Condition differs from Specification 3.7.3.1 by requiring that two of the four component cooling water subsystems be OPERABLE. Component cooling water is required to provide a heat sink for the residual heat removal system to remove decay heat from the reactor core. However, there is a significant reduction in potential heat loading on component cooling water with the reduced operational reauirements of the other systems that are cooled by component coo'ing water. The major reduction in heat loads is due to the fact that by mode 5 reactor decay heat has already dropped off significantly and that reactor coolant pumps and control rod drive mechanisms are not required to be operating in modes 5 and 6. Therefore, only two component cooling water subsystems are required to be OPERABLE.
If only one of the two required component cooling water subsystems is
' OPERABLE, Action Statement 3.7.3.2 remiires all operations involving an increase in the reactor decay heat load or a . eduction in baron concentration of the Reactor Coolant System must be immediately suspended. This is consistent with the action requirements for a total loss of residual heat removal l capability during shutdown conditions.
i The Surveillance Requirements are the same as those of Specification 3.7.3.1.
The existing bases section (3/4.7.3) was expanded to provide a more detailed description of the component cooling water system. This bases section was
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also split to provide a description for operating W shutdown conditions (3/4.7.3.1 and 3/4.7.3.2, respectively).
It has a been determined that the proposed changes do not involve a significant hazards consideration as defined in 10 CFR $0.92. This determination was based on the following points.
- 1. Accident Probability or Consequence increase. The proposed changes have no adverse impact upon potential accident probability or consequence. The proposed changes enhance the availability of the component cooling water system and ensure that sufficient cooling capacity is available for continued operation of various equipment during normal unit cooldown 10 available for both units. The proposed changes further ensure the availability of a heat sink for the residual heat removal system to remove decay neat from the reactor core by requiring that two of the four component cooling water subsystems be OPERABLE.when both units are in Modes 5 or 6. No new or unique accident precursors are introduced by these changes to the Technical Specification requirements.
In fact, the clarification of the Technical Specifications to accurately portray the current design basis for the component cooling water system will decrease any potential accident probability or consequence that mcy occur as a result of inaccurate or incomplete information that may be cmrently in the Technical Specifications.
Likewise, the consequences of the accidents will not increase as a result of the proposed Technical Specification changes.
Therefore, the proposed chances do not involve a significant increase in the probability or consequences of an accident previously evaluated.
- 2. Accident Probability Creation. The proposed changes to the Technical Specifications constitutes additional limitations not presently included in the Technical Specificatioris thereby making our Technical Specifications more strinoent. The proposed changes enhance the availability of the component cooling water system and ensure that sufficient cooling capacity is available for continued operation of various equipment during normal unit cooldown is available for both unite The proposed changes further ensure the availability of a heat sink for the residual heat remcval system to remove decay heat from the reactor core by requiring that two of the four component ccoling water subsystems be OPERABLE.when both units are in Modes 5 or 6. Operation with these changes does not create probability for any accident which has not already been evaluated in the Updated Final Safety Analysis Report ('.tFSAR) In fact, these changes are to modify the Technical Specifications to oe consistsnt with the UFSAR design basis. Therefore, the proposed changes will not create the posstility of a new or different kind of accident from any accident previously evaluated.
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Si Safety Margin Reduction. The' results- of the UFSAR accident i
= analyses continue to bound operation under the proposed changes. The proposed changes enhance the availabliity of the~ component cooling water system and ensure that sufficient cooling capacity is available for continued operation of various equipment during normal unit cooldown is t available for both ur!ts. - The proposed changes further ensure. the -
. availability of a heat s!nk for the residual heat removal system to remove decay heat from the reactor-core by requiring that t.vo of the four component cooling wat" subsystems be OPERABLE.when both units are in Modes 5 or 6. The ., posed changes to the Technical Specifications o ensure. consistency with the UFSAR design basis and result in additional
' limitations not currently included in the Technical Specifications, Therefore, the proposed changes do not involve a reduction in the margin to safety.
Based on the above significant hazardt, consideration evaluation,- Virginia Electric and Power Company concludes that the activities associated with this proposod Technical Specification change satisfies the no significant hazards consideration standards of 10 CFR 50.92(c) anj, accordingly, a no significant hazards consideration finding is justified.
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