ML100550637

Developmental Revision B - Technical Requirements Manual Bases B 3.1 - Reactivity Control Systems

ML100550637
Person / Time
Site:	Watts Bar
Issue date:	02/02/2010
From:	Tennessee Valley Authority
To:	Office of Nuclear Reactor Regulation
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Download: ML100550637 (26)

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Boration Systems Flow Paths, Shutdown B 3.1.1 B 3.1 REACTIVITY CONTROL SYSTEMS B 3.1.1 Boration Systems Flow Paths, Shutdown BASES BACKGROUND The boration injection system is a subsystem of the Chemical and Volume Control System (CVCS). The CVCS regulates the concentration of chemical neutron absorber (boron) in the reactor coolant to control reactivity changes. The boration system ensures that negative reactivity control is available during each mode of facility operation. The amount of boric acid stored in the borated water sources always exceeds the amount required to borate the Reactor Coolant System (RCS) to cold shutdown concentration assuming that the control assembly with the highest reactivity worth is stuck in its fully withdrawn position. This amount of boric acid also exceeds the amount required to bring the reactor to hot shutdown and to compensate for subsequent xenon decay.

The components required to perform this function include: (1) borated water sources, (2) charging pumps, (3) separate flow paths, (4) boric acid transfer pumps, and (5) an emergency power supply from OPERABLE diesel generators. The boration system Technical Requirements place limitations on the contained water volume, boron concentration, and temperature of both the Refueling Water Storage Tank (RWST) and Boric Acid Storage System. For MODES 4, 5 and 6, the boron capability is necessary to provide a sufficient SDM to compensate for xenon decay and cooldown from 350°F to 140°F. For MODES 1, 2, and 3, the boron capability is necessary to provide a sufficient SDM to compensate for xenon decay and cooldown to 200°F.

During reactor operation, changes are made in the reactor coolant boron concentration for the following conditions:

1. Reactor Startup - boron concentration must be decreased from shutdown concentration to achieve criticality.

2. Load Follow - boron concentration must be either increased or decreased to compensate for the xenon transient following a change in load.

(continued)

Watts Bar - Unit 2 B 3.1-1 Technical Requirements (developmental) A

Boration Systems Flow Paths, Shutdown B 3.1.1 BASES BACKGROUND 3. Fuel Burnup - boron concentration must be decreased to (continued) compensate for fuel burnup and the buildup of fission products in the fuel.

4. Cold Shutdown - boron concentration must be increased to the cold shutdown concentration.

Boric acid is stored in three boric acid tanks. Two boric acid transfer pumps are provided for each unit with one pump normally aligned with one boric acid tank and continuously running at low speed to provide recirculation for the boric acid system and the boric acid tank. On a demand signal by the reactor makeup control system, the boric acid transfer pumps are shifted to high speed and the pump aligned to the makeup system delivers boric acid to the suction header of the charging pumps (Ref. 1).

APPLICABLE The boration subsystem is not assumed to be OPERABLE to mitigate the SAFETY consequences of a DBA or transient. In the case of a malfunction of the ANALYSES CVCS, which causes a boron dilution event, the response required by the operator is to close the appropriate valves in the reactor makeup system and/or stop the primary water pumps. This action is required before the shutdown margin is lost. Operation of the boration subsystem is not assumed to mitigate this event (Ref. 2). OPERABILITY of the charging pumps, the RWST, and the appropriate flow paths is required as part of the Emergency Core Cooling System (ECCS). The Technical Specifications for the ECCS address the requirements of these components.

TR TR 3.1.1 requires at least one boron injection flow path to be OPERABLE and capable of being powered from an OPERABLE emergency power source during MODES 4, 5, and 6 in order to provide a path to accomplish (1) normal makeup, (2) chemical shim reactivity control, and (3) miscellaneous fill and transfer operations. This requirement may be achieved by meeting one of the following two conditions:

a. A flow path from an OPERABLE boric acid storage tank, through the boric acid transfer pump, through a charging pump to the RCS, or

b. A flow path from an OPERABLE RWST through a charging pump to the RCS.

(continued)

Watts Bar - Unit 2 B 3.1-2 Technical Requirements (developmental) A

Boration Systems Flow Paths, Shutdown B 3.1.1 BASES (continued)

APPLICABILITY The OPERABILITY of one boron injection flow path ensures that this system is available for reactivity control while in MODES 4, 5, and 6. The APPLICABILITY statement is modified by the following Note to ensure the restrictions imposed by Technical Specification LCO 3.0.4.b are considered:

For Mode 4, Technical Specification LCO 3.0.4.b is not applicable to ECCS high head (centrifugal charging) subsystem.

Boron injection flow paths for MODES 1, 2, and 3 are covered in Technical Requirement 3.1.2, Boration Systems Flow Paths, Operating.

ACTIONS A.1 and A.2 With the Boration Systems flow path OPERABILITY requirements not met, or the Boration Systems flow path not capable of being powered by an OPERABLE emergency power source, the plant must be placed in a condition where negative reactivity addition is not required. This is accomplished by suspending all CORE ALTERATIONS and positive reactivity additions immediately. One boron injection flow path is required to meet the TR and to ensure that negative reactivity control is available during MODES 4, 5, and 6. Suspension of these activities shall not preclude completion of actions to establish a safe conservative condition.

The immediate Completion Time is consistent with the required times for actions to be performed without delay and in a controlled manner.

TECHNICAL TSR 3.1.1.1 SURVEILLANCE REQUIREMENTS This surveillance verifies the temperature of the areas containing portions of the flow path from the boric acid tanks is > 63°F (value does not account for instrument error). This ensures that the high concentration of boric acid in the storage tanks is not allowed to precipitate due to cooling.

The Surveillance is modified by a note stating that the surveillance is required only if a flow path from the boric acid storage tanks is required OPERABLE. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Frequency is based on engineering experience and is reasonable considering the time required for performing the surveillance and the probability for changes in the area temperatures.

(continued)

Watts Bar - Unit 2 B 3.1-3 Technical Requirements (developmental) A

Boration Systems Flow Paths, Shutdown B 3.1.1 BASES TECHNICAL TSR 3.1.1.2 SURVEILLANCE REQUIREMENTS Verifying the correct alignment for manual, power operated, and (continued) automatic valves in the Boration System flow path provides assurance that the proper flow paths exist for Boration System operation. This TSR does not apply to valves that are locked, sealed, or otherwise secured in position, since they are verified to be in the correct position prior to being locked, sealed, or secured. This TSR does not require any testing or valve manipulation; rather, it involves verification that those valves capable of being mispositioned are in the correct position. This TSR does not apply to valves that cannot be inadvertently misaligned, such as check valves.

The 31 day Frequency is based on engineering judgment, is consistent with the procedural controls governing valve operation, and ensures correct valve positions.

REFERENCES 1. Watts Bar FSAR, Section 9.3.4, Chemical and Volume Control System.

2. WCAP-11618, MERITS Program-Phase II, Task 5, Criteria Application, including Addendum 1 dated April, 1989.

Watts Bar - Unit 2 B 3.1-4 Technical Requirements (developmental) B

Boration Systems Flow Paths, Operating B 3.1.2 B 3.1 REACTIVITY CONTROL SYSTEMS B 3.1.2 Boration Systems Flow Paths, Operating BASES BACKGROUND A description of the Boration Systems Flow Paths is provided in the Bases for Technical Requirement 3.1.1, "Boration Systems Flow Paths, Shutdown."

APPLICABLE The boration subsystem is not assumed to be OPERABLE to mitigate the SAFETY consequences of a DBA or Transient. In the case of a malfunction of the ANALYSES Chemical and Volume Control System, which causes a boron dilution event, the response required by the operator is to close the appropriate valves in the reactor makeup system and/or stop the primary water pumps. This action is required before the shutdown margin is lost.

Operation of the boration subsystem is not assumed to mitigate this event (Ref. 1). OPERABILITY of the charging pumps, the Refueling Water Storage Tank (RWST), and the appropriate flow paths is required as part of the Emergency Core Cooling System (ECCS). The Technical Specifications for the ECCS address the requirements of these components.

TR TR 3.1.2 requires at least two boron injection flow paths to be OPERABLE during MODES 1, 2, and 3, in order to provide two redundant paths to accomplish (1) normal makeup, (2) chemical shim reactivity control, and (3) miscellaneous fill and transfer operations. This requirement may be achieved by having two of the following three flow paths OPERABLE:

a. One flow path from the boric acid storage tanks, through a boric acid transfer pump, through a charging pump to the Reactor Coolant System (RCS).

b. Two flow paths from the RWST, through a charging pump to the RCS.

(continued)

Watts Bar - Unit 2 B 3.1-5 Technical Requirements (developmental) A

Boration Systems Flow Paths, Operating B 3.1.2 BASES (continued)

APPLICABILITY The OPERABILITY of two boron injection flow paths ensures that this system is available for reactivity control while in MODES 1, 2, and 3.

Two flow paths are required to ensure single functional capability in the event an assumed failure renders one of the flow paths inoperable.

Boron injection flow paths for MODES 4, 5, and 6 are covered in Technical Requirement 3.1.1, "Boration Systems Flow Paths, Shutdown.

ACTIONS A.1 If one of the required boron injection flow paths is inoperable, action must be taken to restore the required flow path to OPERABLE status. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time was developed taking into account the redundant capabilities afforded by the OPERABLE flow path and reasonable time for repairs. The Completion Time is consistent with the time allowed to restore an ECCS train to OPERABLE status (See Technical Specification 3.5.2, "ECCS - Operating.).

A.2.1, A.2.2, and A.2.3 An alternative to Required Action A.1 is to place the plant in MODE 3 and borate to a SDM equivalent to 1% k/k at 200°F within 78 hours9.027778e-4 days <br />0.0217 hours <br />1.289683e-4 weeks <br />2.9679e-5 months <br />, and restore the required flow path to OPERABLE status within 246 hours0.00285 days <br />0.0683 hours <br />4.06746e-4 weeks <br />9.3603e-5 months <br />.

This precludes the need for a flow path for load follow and fuel burnup compensation, allowing the additional 7 days to restore two flow paths to OPERABLE status. An additional 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> (78 hours9.027778e-4 days <br />0.0217 hours <br />1.289683e-4 weeks <br />2.9679e-5 months <br /> total) are allowed to reach MODE 3 from full power in an orderly manner and without challenging plant systems. The allowed Completion Time to reach MODE 3 is reasonable, based on operating experience.

B.1 If the required flow path cannot be restored to OPERABLE status or the Required Actions of Condition A are not met within the associated Completion Times, the unit must be placed in a MODE in which the TR does not apply. This is done by placing the unit in at least MODE 4 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. The allowed Completion Time is reasonable, based on operating experience, to reach required plant conditions in an orderly manner and without challenging plant systems.

(continued)

Watts Bar - Unit 2 B 3.1-6 Technical Requirements (developmental) A

Boration Systems Flow Paths, Operating B 3.1.2 BASES (continued)

TECHNICAL TSR 3.1.2.1 SURVEILLANCE REQUIREMENTS This surveillance verifies the temperature of the required flow path from the boric acid tanks to be at least 63°F (value does not account for instrument error). This ensures that the high concentration of boric acid in the storage tanks is not allowed to precipitate due to cooling.

The surveillance is modified by a note stating that the surveillance is required only if the flow path from the boric acid storage tanks is used as one of the two required flow paths. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Frequency is based on engineering experience and is reasonable considering the time required for performing the surveillance and the probability for changes in the area temperatures.

TSR 3.1.2.2 Verifying the correct alignment for manual, power operated, and automatic valves in the Boration System flow path provides assurance that the proper flow paths exist for Boration System operation. This TSR does not apply to valves that are locked, sealed, or otherwise secured in position, since they are verified to be in the correct position prior to being locked, sealed, or secured. This TSR does not require any testing or valve manipulation; rather, it involves verification that those valves capable of being mispositioned are in the correct position. This TSR does not apply to valves that cannot be inadvertently misaligned, such as check valves.

The 31 day Frequency is based on engineering judgment, is consistent with the procedural controls governing valve operation, and ensures correct valve positions.

TSR 3.1.2.3 This surveillance demonstrates that each automatic valve in the flow path actuates to its required position on an actual or simulated actuation signal. The 18 month Frequency was developed considering it is prudent that this surveillance only be performed during a plant outage. This is due to the plant conditions needed to perform the TSR and the potential for unplanned plant transients if the TSR is performed with the reactor at power.

(continued)

Watts Bar - Unit 2 B 3.1-7 Technical Requirements (developmental) A

Boration Systems Flow Paths, Operating B 3.1.2 BASES TECHNICAL TSR 3.1.2.4 SURVEILLANCE REQUIREMENTS Verification that the flow path from the boric acid tanks delivers at least (continued) 35 gpm (value does not account for instrument error) to the RCS demonstrates that gross degradation of the boric acid transfer pumps, crystallization of boric acid in the system, and other hydraulic component problems have not occurred.

The 18 month Frequency was developed considering it is prudent that this surveillance only be performed during a plant outage. This is due to the plant conditions needed to perform the TSR and the potential for unplanned plant transients if the TSR is performed with the reactor at power.

REFERENCES 1. WCAP-11618, "MERITS Program-Phase II, Task 5, Criteria Application," including Addendum 1 dated April, 1989.

Watts Bar - Unit 2 B 3.1-8 Technical Requirements (developmental) B

Charging Pump, Shutdown B 3.1.3 B 3.1 REACTIVITY CONTROL SYSTEMS B 3.1.3 Charging Pump, Shutdown BASES BACKGROUND A description of the Boration Systems Flow Paths, which include charging pumps, is provided in the Bases for Technical Requirement 3.1.1, "Boration Systems Flow Paths, Shutdown."

APPLICABLE The boration subsystem is not assumed to be OPERABLE to mitigate the SAFETY consequences of a DBA or Transient. In the case of a malfunction of the ANALYSES Chemical and Volume Control System, which causes a boron dilution event, the response required by the operator is to close the appropriate valves in the reactor makeup system and/or stop the primary water pumps. This action is required before the SDM is lost. Operation of the boration subsystem is not assumed to mitigate this event (Ref. 1).

OPERABILITY of the charging pumps, the refueling water storage tank, and the appropriate flow paths is required as part of the Emergency Core Cooling System (ECCS). The Technical Specifications for the ECCS address the requirements of these components. Technical Specification 3.4.12, "Cold Overpressure Mitigation System, places restrictions on maximum number of charging pumps allowed OPERABLE for overpressure concerns.

TR TR 3.1.3 requires one charging pump in the required boron injection flow path to be OPERABLE and capable of being powered from an OPERABLE emergency power source during MODES 4, 5, and 6 in order to provide the driving force to accomplish (1) normal makeup, (2) chemical shim reactivity control, and (3) miscellaneous fill and transfer operations.

(continued)

Watts Bar - Unit 2 B 3.1-9 Technical Requirements (developmental) A

Charging Pump, Shutdown B 3.1.3 BASES (continued)

APPLICABILITY The OPERABILITY of one charging pump in the required boron injection flow path ensures that this system is available for reactivity control while in MODES 4, 5, and 6. The APPLICABILITY statement is modified by the following Note to ensure the restrictions imposed by Technical Specification LCO 3.0.4.b are considered:

For Mode 4, Technical Specification LCO 3.0.4.b is not applicable to ECCS high head (centrifugal charging) subsystem.

Charging pump OPERABILITY requirements for MODES 1, 2, and 3 are covered in Technical Requirement 3.1.4, "Charging Pumps, Operating."

ACTIONS A.1 and A.2 With the required charging pump inoperable or not capable of being powered by an OPERABLE emergency power source, the plant must be placed in a condition where negative reactivity addition is not required.

This is accomplished by suspending all CORE ALTERATIONS and positive reactivity additions immediately. One OPERABLE charging pump in the required boron injection flow path is required to meet the TR and to ensure that negative reactivity control is available during Modes 4, 5, and 6. Suspension of these activities shall not preclude completion of actions to establish a safe conservative condition.

TECHNICAL TSR 3.1.3.1 SURVEILLANCE REQUIREMENTS Periodic surveillance testing of charging pumps to detect gross degradation caused by impeller structural damage or other hydraulic component problems is performed in accordance with the American Society of Mechanical Engineers (ASME) OM Code. This type of testing may be accomplished by measuring the pump developed head at only one point of the pump characteristic curve. This verifies both that the measured performance is within an acceptable tolerance of the original pump baseline performance and that the performance at the test flow is greater than or equal to the performance assumed in the plant safety analysis. SRs are specified in the Inservice Testing Program, which encompasses the ASME OM Code. The ASME OM Code provides the activities and Frequencies necessary to satisfy the requirements.

(continued)

Watts Bar - Unit 2 B 3.1-10 Technical Requirements (developmental) A

Charging Pump, Shutdown B 3.1.3 BASES (continued)

REFERENCES 1. WCAP-11618, "MERITS Program-Phase II, Task 5, Criteria Application," including Addendum 1 dated April, 1989.

Watts Bar - Unit 2 B 3.1-11 Technical Requirements (developmental) A

Charging Pumps, Operating B 3.1.4 B 3.1 REACTIVITY CONTROL SYSTEMS B 3.1.4 Charging Pumps, Operating BASES BACKGROUND A description of the Boration Systems Flow Paths is provided in the Bases for Technical Requirement 3.1.1, "Boration Systems Flow Paths, Shutdown."

APPLICABLE The boration subsystem is not assumed to be OPERABLE to mitigate the SAFETY consequences of a DBA or transient. In the case of a malfunction of the ANALYSES Chemical and Volume Control System (CVCS), which causes a boron dilution event, the response required by the operator is to close the appropriate valves in the reactor makeup system and/or stop the primary water pumps. This action is required before the shutdown margin is lost.

Operation of the boration subsystem is not assumed to mitigate this event (Ref. 1). OPERABILITY of the charging pumps, the refueling water storage tank, and the appropriate flow paths is required as part of the Emergency Core Cooling System (ECCS). The Technical Specifications for the ECCS address the requirements of these components.

TR TR 3.1.4 requires at least two charging pumps to be OPERABLE during MODES 1, 2, and 3 in order to assure redundant pumps to the two redundant flow paths to accomplish (1) normal makeup, (2) chemical shim reactivity control, and (3) miscellaneous fill and transfer operations.

APPLICABILITY The OPERABILITY of two charging pumps ensures that the CVCS system is available for reactivity control while in MODES 1, 2, and 3.

Two charging pumps are required to ensure single functional capability in the event an assumed failure renders one of the pumps inoperable.

Charging pump OPERABILITY requirements for MODES 4, 5, and 6 are covered in Technical Requirement 3.1.3, "Charging Pumps, Shutdown".

(continued)

Watts Bar - Unit 2 B 3.1-12 Technical Requirements (developmental) A

Charging Pumps, Operating B 3.1.4 BASES (continued)

ACTIONS A.1 If one of the required charging pumps is inoperable, action must be taken to restore a required charging pump to OPERABLE status. The 72-hour Completion Time was developed taking into account the redundant capabilities afforded by the OPERABLE charging pump and reasonable time for repairs. The Completion Time is consistent with the time allowed to restore an ECCS train or to restore a boron injection flow path to OPERABLE status (See Technical Specification 3.5.2, "ECCS -

Operating" and Technical Requirement 3.1.2, "Boration Systems Flow Paths, Operating.").

A.2.1, A.2.2, and A.2.3 An alternative to Required Action A.1 is to place the plant in MODE 3 and borate to a SDM equivalent to 1% k/k at 200°F within 78 hours9.027778e-4 days <br />0.0217 hours <br />1.289683e-4 weeks <br />2.9679e-5 months <br />, and restore the required charging pump to OPERABLE status within 246 hours0.00285 days <br />0.0683 hours <br />4.06746e-4 weeks <br />9.3603e-5 months <br />. This precludes the need for a flow path/charging pump for load follow and fuel burnup compensation, allowing the additional 7 days to restore two charging pumps to OPERABLE status. An additional 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> (78 hours9.027778e-4 days <br />0.0217 hours <br />1.289683e-4 weeks <br />2.9679e-5 months <br /> total) are allowed to reach MODE 3 from full power in an orderly manner and without challenging plant systems. The allowed Completion Time to reach MODE 3 is reasonable, based on operating experience.

B.1 If two charging pumps cannot be restored to OPERABLE status or the Required Actions of Condition A are not met within the associated Completion Times, the plant must be placed in a MODE in which the TR does not apply. This is done by placing the plant in at least MODE 4 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. The allowed Completion Time is reasonable, based on operating experience, to reach the required plant conditions in an orderly manner and without challenging plant systems.

(continued)

Watts Bar - Unit 2 B 3.1-13 Technical Requirements (developmental) A

Charging Pumps, Operating B 3.1.4 BASES (continued)

TECHNICAL TSR 3.1.4.1 SURVEILLANCE REQUIREMENTS Periodic surveillance testing of charging pumps to detect gross degradation caused by impeller structural damage or other hydraulic component problems is performed in accordance with the American Society of Mechanical Engineers (ASME) OM Code. This type of testing may be accomplished by measuring the pump developed head at only one point of the pump characteristic curve. This verifies both that the measured performance is within an acceptable tolerance of the original pump baseline performance and that the performance at the test flow is greater than or equal to the performance assumed in the plant safety analysis. SRs are specified in the Inservice Testing Program, which encompasses the ASME OM Code. The ASME OM Code provides the activities and Frequencies necessary to satisfy the requirements.

REFERENCES 1. WCAP-11618, "MERITS Program-Phase II, Task 5, Criteria Application," including Addendum 1 dated April, 1989.

Watts Bar - Unit 2 B 3.1-14 Technical Requirements (developmental) A

Borated Water Sources, Shutdown B 3.1.5 B 3.1 REACTIVITY CONTROL SYSTEMS B 3.1.5 Borated Water Sources, Shutdown BASES BACKGROUND A description of the Boration System Flow Paths, which include borated water sources is provided in the Bases for Technical Requirement 3.1.1, "Boration System Flow Paths, Shutdown."

APPLICABLE The boration subsystem is not assumed to be OPERABLE to mitigate the SAFETY consequences of a DBA or transient. In the case of a malfunction of the ANALYSES Chemical and Volume Control System which causes a boron dilution event, the response required by the operator is to close the appropriate valves in the reactor makeup system and/or stop the primary water pumps. This action is required before the SDM is lost. Operation of the boration subsystem is not assumed to mitigate this event (Ref. 1).

OPERABILITY of the charging pumps, the Refueling Water Storage Tank (RWST), and the appropriate flow paths is required as part of the Emergency Core Cooling System (ECCS). The Technical Specifications for the ECCS address the requirements of these components.

TR TR 3.1.5 requires at least one borated water source to be OPERABLE during MODES 4, 5, and 6 to accomplish (1) normal makeup, (2) chemical shim reactivity control, and (3) miscellaneous fill and transfer operations. This requirement may be achieved by one of the following being OPERABLE as required by TR 3.1.1:

a. A Boric Acid Storage System (BASS); or

b. The RWST.

(continued)

Watts Bar - Unit 2 B 3.1-15 Technical Requirements (developmental) A

Borated Water Sources, Shutdown B 3.1.5 BASES (continued)

APPLICABILITY The OPERABILITY of one borated water source in the required boron injection flow path ensures that this system is available for reactivity control while in MODES 4, 5, and 6.

Borated water source OPERABILITY requirements for MODES 1, 2, and 3 are covered in Technical Requirement 3.1.6, "Borated Water Sources, Operating."

ACTIONS A.1 and A.2 If the required borated water source is inoperable, the plant must be placed in a condition where negative reactivity addition is not required.

This is accomplished by suspending all CORE ALTERATIONS and positive reactivity additions immediately. One borated water source is required to meet the TR and to ensure that negative reactivity control is available during MODES 4, 5, and 6. Suspension of these activities shall not preclude completion of actions to establish a safe conservative condition.

The immediate Completion Time is consistent with the required times for actions requiring prompt attention.

TECHNICAL The Notes in the Technical Surveillance Requirements state that SURVEILLANCE TSR 3.1.5.1, TSR 3.1.5.2, and TSR 3.1.5.3 are only required to be REQUIREMENTS performed if the RWST is the required borated water source, and TSR 3.1.5.4, TSR 3.1.5.5, and TSR 3.1.5.6 are only required to be performed if the BASS is the required borated water source.

TSR 3.1.5.1 This surveillance requires verification every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> that the RWST temperature is greater than or equal to 60°F (value does not account for instrument error). The Frequency of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for performance of the surveillance is frequent enough to identify a temperature change that would approach the 60°F temperature limit and has been shown to be acceptable through operating experience. The TSR is modified by a Note which eliminates the requirement to perform this surveillance when ambient air temperature is greater than or equal to 60°F. With ambient air temperature greater than 60°F, the RWST solution temperature should not decrease below this limit, therefore, monitoring is not required.

(continued)

Watts Bar - Unit 2 B 3.1-16 Technical Requirements (developmental) A

Borated Water Sources, Shutdown B 3.1.5 BASES TECHNICAL TSR 3.1.5.2 SURVEILLANCE REQUIREMENTS This surveillance requires verification every 7 days that the boron (continued) concentration of the RWST is 3,100 ppm. This boron concentration is sufficient to provide an adequate SDM and also ensure a pH value between 7.5 and 10.0. This pH band minimizes the evolution of iodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components. Since the RWST volume is normally stable, a 7-day Frequency to verify boron concentration is appropriate and has been shown to be acceptable through operating experience.

TSR 3.1.5.3 This surveillance requires verification every 7 days that the RWST borated water volume is 62,900 gallons (value does not account for instrument error). This borated water volume is sufficient to provide an adequate SDM and also ensure a pH value between 7.5 and 10.0. This pH band minimizes the evolution of iodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components. Since the RWST volume is normally stable, a 7-day Frequency to verify borated water volume is appropriate and has been shown to be acceptable through operating experience. The 62,900 gallon volume requirement includes 11,400 gallons for shutdown margin and adjustments for minimum safety limit level in the RWST.

TSR 3.1.5.4 This surveillance requires verification every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> that the Boric Acid Tank (BAT) solution temperature is 63°F (value does not account for instrument error). This ensures that the concentration of boric acid in the BAT is not allowed to precipitate due to cooling. The frequency of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for performance of the surveillance is frequent enough to identify a temperature change that would approach the 63°F temperature limit.

(continued)

Watts Bar - Unit 2 B 3.1-17 Technical Requirements (developmental) A

Borated Water Sources, Shutdown B 3.1.5 BASES TECHNICAL TSR 3.1.5.5 SURVEILLANCE REQUIREMENTS This surveillance requires verification every 7 days that the boron (continued) concentration of the BAT is between 6,120 ppm and 6,990 ppm. This boron concentration is sufficient to provide an adequate SDM and also ensure a pH value between 7.5 and 10.0. This pH band minimizes the evolution of iodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components. Since the BAT volume is normally stable, a 7-day Frequency to verify boron concentration is appropriate and has been shown to be acceptable through operating experience.

TSR 3.1.5.6 This surveillance requires verification every 7 days that the BAT borated water volume is 5,300 gallons (value does account for instrument error).

This borated water volume is sufficient to provide an adequate SDM and also ensure a pH value between 7.5 and 10.0. This pH band minimizes the evolution of iodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components. Since the BAT volume is normally stable, a 7-day Frequency to verify borated water volume is appropriate and has been shown to be acceptable through operating experience.

REFERENCES 1. WCAP-11618, "MERITS Program-Phase II, Task 5, Criteria Application," including Addendum 1 dated April, 1989.

2. TVA Calculation, EPM-PDM-071197, Revision 6, Boric Acid Concentration Analysis for BAT and RWST.

Watts Bar - Unit 2 B 3.1-18 Technical Requirements (developmental) B

Borated Water Sources, Operating B 3.1.6 B 3.1 REACTIVITY CONTROL SYSTEMS B 3.1.6 Borated Water Sources, Operating BASES BACKGROUND A description of the Boration System Flow Paths, which include borated water sources is provided in the Bases for Technical Requirement 3.1.1, Boration System Flow Paths, Shutdown.

APPLICABLE The boration subsystem is not assumed to be OPERABLE to mitigate the SAFETY consequences of a DBA or transient. In the case of a malfunction of the ANALYSES Chemical and Volume Control System, which causes a boron dilution event, the automatic response, or that required by the operator, is to close the appropriate valves in the reactor makeup system. This action is required before the SDM is lost. Operation of the boration subsystem is not assumed to mitigate this event (Ref. 1). OPERABILITY of the charging pumps, the RWST, and the appropriate flow paths is required as part of the Emergency Core Cooling System (ECCS). The Technical Specifications for the ECCS address the requirements of these components.

TR TR 3.1.6 requires a Boric Acid Storage System (BASS) and the Refueling Water Storage Tank (RWST) to be OPERABLE as required by TR 3.1.2.

This is a requirement during MODES 1, 2, and 3 to accomplish (1) normal makeup, (2) chemical shim reactivity control, and (3) miscellaneous fill and transfer operations.

APPLICABILITY The OPERABILITY of borated water sources (as required by TR 3.1.2) in the required boron injection flow paths ensures that this system is available for reactivity control while in MODES 1, 2, and 3.

Borated water source OPERABILITY requirements for MODES 4, 5 and 6 are covered in Technical Requirement 3.1.5, Borated Water Sources, Shutdown.

(continued)

Watts Bar - Unit 2 B 3.1-19 Technical Requirements (developmental) A

Borated Water Sources, Operating B 3.1.6 BASES (continued)

ACTIONS A.1, A.2.1, A.2.2, and A.2.3 With the BASS inoperable, action must be taken to restore the BASS to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The Completion Time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to perform Required Action A.1 is reasonable based upon the typical time necessary to effect repairs and the redundant capabilities afforded by the OPERABLE borated water source.

If the BASS cannot be restored to OPERABLE status the plant must be placed in a MODE in which the requirement does not apply. This is done by placing the plant in at least MODE 3 and by borating to a SDM equivalent to at least 1% k/k at 200°F in 6 additional hours (78 hours9.027778e-4 days <br />0.0217 hours <br />1.289683e-4 weeks <br />2.9679e-5 months <br /> total time). It is also required that the BASS be restored to OPERABLE status in an additional 7 days (246 hours0.00285 days <br />0.0683 hours <br />4.06746e-4 weeks <br />9.3603e-5 months <br /> total time).

The 6 additional hours to perform Required Actions A.2.1 and A.2.2 are reasonable and based on operating experience to reach MODE 3 and the required SDM from full power operation in an orderly manner and without challenging plant systems. The 7 day Completion Time per Required Action A.2.3 is based on the low probability of an event occurring during this time period, and the consideration that the remaining borated water sources can provide the required capability.

B.1 If the Required Actions and associated Completion Times of Condition A are not met, the plant must be placed in a MODE in which the TR does not apply. This is done by placing the plant in MODE 4 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

The allowed Completion Time is reasonable and based on operating experience to reach required plant conditions in an orderly manner and without challenging plant systems.

C.1 With the RWST boron concentration or borated water temperature not within limits, action must be taken within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to restore the RWST to OPERABLE status. This 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> limit was developed considering the time required to change either the boron concentration or water temperature.

The Completion Time is consistent with Technical Specification 3.5.4, Refueling Water Storage Tank.

(continued)

Watts Bar - Unit 2 B 3.1-20 Technical Requirements (developmental) A

Borated Water Sources, Operating B 3.1.6 BASES ACTIONS D.1 (continued)

With the RWST inoperable for reasons other than Condition C (e.g., water volume), it must be restored to OPERABLE status within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. The short time limit of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to restore the RWST to OPERABLE status is based on this condition simultaneously affecting two of the boration system flow paths. The Completion Time is consistent with Technical Specification 3.5.4, Refueling Water Storage Tank.

E.1 and E.2 If the Required Actions and associated Completion Times of Condition C or D are not met, the plant must be placed in a MODE in which the TR does not apply. This is done by placing the plant in MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in MODE 4 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The allowed Completion Time is reasonable and based on operating experience to reach required plant conditions in an orderly manner and without challenging plant systems.

TECHNICAL TSR 3.1.6.1 SURVEILLANCE REQUIREMENTS The limits assumed in the accident analysis band for the RWST borated water temperature are 60°F and 105°F (values do not account for instrument error). This surveillance requires verification of the water temperature limits every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This is frequent enough to identify a temperature change that would approach either temperature limit and has been shown to be acceptable through operating experience.

The TSR is modified by a Note which eliminates the requirement to perform this surveillance when ambient air temperatures are within the operating limits of the RWST. With ambient air temperatures within the band, the RWST solution temperature should not exceed the limits.

TSR 3.1.6.2 This surveillance requires verification every 7 days that the boron concentration of the RWST is within the required band. This ensures the reactor will remain subcritical following a LOCA. Further, it assures that the resulting sump pH will be maintained in an acceptable range so that boron precipitation in the core will not occur and the effect of chloride and caustic stress corrosion on mechanical systems and components will be (continued)

Watts Bar - Unit 2 B 3.1-21 Technical Requirements (developmental) A

Borated Water Sources, Operating B 3.1.6 BASES TECHNICAL TSR 3.1.6.2 (continued)

SURVEILLANCE REQUIREMENTS minimized. Since the RWST volume is normally stable, a 7 day Frequency to verify boron concentration is appropriate and has been shown to be acceptable through operating experience.

TSR 3.1.6.3 This surveillance requires verification every 7 days that the RWST borated water volume is within the required limit of 370,000 gallons (value does not account for instrument error). This will ensure that a sufficient initial supply is available for injection and to support continued ECCS and Containment Spray System pump operation on recirculation.

Since the RWST volume is normally stable, a 7 day Frequency to verify borated water volume is appropriate and has been shown to be acceptable through operating experience.

TSR 3.1.6.4 This surveillance requires verification every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> that the Boric Acid Tank (BAT) solution temperature is 63°F (value does not account for instrument error). This ensures that the concentration of boric acid in the BAT is not allowed to precipitate due to cooling. The Frequency of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for performance of the surveillance is frequent enough to identify a temperature change that would approach the 63°F temperature limit and has been shown to be acceptable through operating experience.

This surveillance has been modified by a NOTE stating that the surveillance is only required if the BAT is used as one of the required borated water sources for TR 3.1.2.

TSR 3.1.6.5 This surveillance requires verification every 7 days that the boron concentration of the BAT is in accordance with Figures 3.1.6A, 3.1.6B, and 3.1.6.C of TR 3.1.6. This boron concentration is sufficient to provide an adequate SDM and also ensure a pH value between 7.5 and 10.0.

This pH band minimizes the evolution of iodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components. Since the BAT volume is normally stable, a 7 day sampling Frequency to verify boron concentration is appropriate and has been shown to be acceptable through operating experience.

(continued)

Watts Bar - Unit 2 B 3.1-22 Technical Requirements (developmental) B

Borated Water Sources, Operating B 3.1.6 BASES TECHNICAL TSR 3.1.6.5 (continued)

SURVEILLANCE REQUIREMENTS This surveillance has been modified by a NOTE stating that the surveillance is only required if the BAT is used as one of the required borated water sources for TR 3.1.2.

TSR 3.1.6.6 This surveillance requires verification every 7 days that the BAT borated water volume is in accordance with Figures 3.1.6A, 3.1.6B, and 3.1.6C (the values listed on the figure do not account for instrument error). This borated water volume at the boron concentration specified in TSR 3.1.6.5 is sufficient to provide an adequate SDM. Since the BAT volume is normally stable, a 7 day Frequency to verify borated water volume is appropriate and has been shown to be acceptable through operating experience.

This surveillance has been modified by a NOTE stating that the surveillance is only required if the BAT is used as one of the required borated water sources for TR 3.1.2.

The maximum expected boration capability requirement occurs near EOL from full power peak xenon conditions and requires borated water from a boric acid tank in accordance with Figures 3.1.6A, 3.1.6B, and 3.1.6C, and additional makeup from either (1) the common boric acid tank and/or batching tank, or (2) a maximum of 23,000 gallons of 3,100 ppm borated water from the refueling water storage tank. With the refueling water storage tank as the only borated water source, a maximum of 62,000 gallons of 3,100 ppm borated water is required.

REFERENCES 1. WCAP-11618, MERITS Program-Phase II, Task 5, Criteria Application, including Addendum 1 dated April, 1989.

2. TVA Calculation, EPM-PDM-071197, Revision 6, Boric Acid Concentration Analysis For BAT and RWST.

Watts Bar - Unit 2 B 3.1-23 Technical Requirements (developmental) B

Position Indication System, Shutdown B 3.1.7 B 3.1 REACTIVITY CONTROL SYSTEMS B 3.1.7 Position Indication System, Shutdown BASES BACKGROUND Instrumentation to monitor variables and systems over their operating ranges during normal operation, anticipated operational occurrences, and accident conditions must be OPERABLE. TR 3.1.7 is required to ensure OPERABILITY of the control rod group demand position indicators to determine control rod positions of rod groups not fully inserted with the Reactor Trip System breakers in the closed position.

The OPERABILITY, including group demand position indication, of the shutdown and control rods are initial assumptions in all safety analyses that assume rod insertion upon reactor trip. Rod position indication is required to assess OPERABILITY and misalignment. These safety analyses are not applicable to shutdown conditions. Rod Drop Times and other tests requiring control rod operability, however, are performed at shutdown. Additionally, positive reactivity addition due to rod withdrawal must be compensated for by boron addition. Rod positions are monitored and controlled when withdrawn during shutdown conditions to ensure shutdown margin is maintained. The axial position of shutdown rods and control rods is determined by the group demand position indicators.

The group demand position indicators count the pulses generated in the Rod Control System to provide a readout of the demand bank position (Ref. 1). There is one step counter for each group of rods. Individual rods in a group all receive the same signal to move and should, therefore, all be at the same position indicated by the group step counter for that group. The group demand position indicators are considered highly precise (+/- 1 step or +/- 5/8 inch). If a rod does not move 1 step for each demand pulse, the step counter will still count the pulse and incorrectly reflect the position of the rod.

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Watts Bar - Unit 2 B 3.1-24 Technical Requirements (developmental) A

Position Indication System, Shutdown B 3.1.7 BASES (continued)

APPLICABLE The rod Position Indication System is a system which provides SAFETY information to the operator which could be used to initiate operator action.

ANALYSES However, no DBA or transient assumes operator action to manually trip the reactor, or to take some alternative action if an automatic reactor trip does not occur (Ref. 2). Hence, the shutdown and control rods, including position indication, are not assumed to be OPERABLE to mitigate the consequences of a DBA or transient during shutdown conditions.

Positive reactivity addition due to withdrawal of control rods is compensated for by boron concentration.

TR TR 3.1.7 specifies that the group demand position indicators be OPERABLE and capable of determining within +/- 2 steps the demand position for each shutdown or control rod not fully inserted. For the control rod position indicators to be OPERABLE requires meeting the surveillance requirement of the TR. This requirement provides adequate assurance that control rod position indication during shutdown conditions and rod testing is accurate, and that design assumptions are not challenged. OPERABILITY of the required position indicators ensures that inoperable, misaligned, or mispositioned control rods can be detected.

APPLICABILITY This TR covers only the requirements on Rod Position Indication during MODES 3, 4, and 5 with the reactor trip breakers closed. Rod Position Indication during MODES 1 and 2 are covered by Technical Specification 3.1.8. In MODE 6 and in MODES 3, 4, and 5 with trip breakers open or all rods on the bottom, Rod Position Indication is not required to be OPERABLE. Rod Position Indication OPERABILITY is required only when rods are withdrawn from fully inserted.

ACTIONS A.1 With one or more group demand position indicators inoperable, the plant must be placed in a condition where the demand position indicators are not required. This is accomplished by opening the reactor trip breakers immediately.

The immediate Completion Time is consistent with the required time for actions to be pursued without delay and in a controlled manner.

(continued)

Watts Bar - Unit 2 B 3.1-25 Technical Requirements (developmental) A

Position Indication System, Shutdown B 3.1.7 BASES (continued)

TECHNICAL TSR 3.1.7.1 SURVEILLANCE REQUIREMENTS Exercising rods at a Frequency of 31 days allows the operator to determine that all withdrawn rods, including the group step counter demand position indicator, continue to be OPERABLE. A movement of 10 steps is adequate to demonstrate motion and verify a corresponding step change in the group step counter demand position indicator.

Four hours is provided to perform the first surveillance after closing the reactor trip breakers if the surveillance has not been performed within the previous 31 days. The 31-day Frequency takes into consideration other information available to the operator in the control room and the remote likelihood that rods would be withdrawn from fully inserted for extended periods of time during shutdown conditions.

REFERENCES 1. Watts Bar FSAR, Section 4.2.3 "Reactivity Control System."

2. WCAP-11618, "MERITS Program-Phase II, Task 5, Criteria Application," including Addendum 1 dated April, 1989.

Watts Bar - Unit 2 B 3.1-26 Technical Requirements (developmental) A