Text

Proposed Tech Specs,Increasing Refueling Water Storage Tank & Accumulator Boron Concentration Limits
	ML20206T583
Person / Time
Site:	Farley
Issue date:	07/03/1986
From:	; ALABAMA POWER CO.
To:	;
Shared Package
ML20206T572	List: ML20206T567; ML20206T583;
References
	TAC-61876, TAC-61877, NUDOCS 8607080185
	Download: ML20206T583 (23)
	v • d • e

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REACTIVITY CONTROL SYSTEMS BORATED WATER SOURCES - SHUTDOWN LIMITING CONDITION FOR OPERATION 3.1.2.5 As a minimum, one of the following borated water sources shall be OPERABLE:

a. A boric acid storage system with:

1. A minimum contained borated water volume of 2000 gallons,

2. Between 7000 and 7700 ppm of boron, and

3. A minimum solution temperature of 65*F.

b. The refueling water storage tank with:

1. A minimum contained borated water volume of 30,'0'00 gallons,

2. A minimum boron concentration of 2300 ppm, and

3. A minimum solution temperature of 35'F.

APPLICABILITY: MODES 5 and 6.

ACTION:

With no borated water source OPERABLE, suspend all operations involving CORE ALTERATIONS or positive reactivity changes.

SURVEILLANCE REQUIREMENTS 4.1.2.5 The above required borated water source shall be demonstrated OPERABLE:

a. At least once per 7 days by:

1. Verifying the boron concentration of the water,

2. Verifying the contained borated water volume, and

3. Verifying the boric acid storage tank solution temperature when it is the source of borated water.

b. At least once per 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months by verifying the RWST temperature when it is the source of borated water and the outside air temperature is less than 35*F.

l FARLEY-UNIT 1 3/4 1-11 AMENDMENT NO.

8607090185 860703 -

PDR ADOCK 05000348?

P_ PDR ;

4 REACTIVITY CONTROL SYSTEMS

B0 RATED WATER SOURCES - OPERATING LIMITING CONDITION FOR OPERATION 3.1.2.6 As a minimum,- the following borated water source (s) shall be OPERABLE as required by Specification 3.1.2.2:

a. A boric acid storage system with:

1. A minimum contained borated water. volume of 11,336 gallons, l

2. Between 7000 and 7700 ppm of boron, and

3. A minimum solution temperature of 65 F.

l b. The refueling water storage tank with:

1. A minimum contained borated water volume of 471,000 gallons,

2. Between 2300 and 2500 ppm of boron, and

3. A minimum solution temperature of 35'F.

APPLICABILITY: MODES 1, 2, 3 and 4.

ACTION:

a. With the boric acid storage system inoperable and being used as one of the above required borated water sources, restore the storage system to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months or be in at least H0T STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and borated to a SHUTDOWN MARGIN equivalent to at least 1% delta k/k at 200*F; restore the boric acid storage system to OPERABLE status within the next 7 days or be in COLD SHUTDOWN within the next 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months ,

b. With the refueling water storage tank inoperable, restore the tank to OPERABLE status within one hour or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

1 FARLEY-UNIT 1- 3/4 1-12 AMENDMENT NO.

~ _ _- .. . _ __. . _.. . _ _ . . . ._ - _ _-

3/4.5 EMERGENCY CORE COOLING SYSTEMS (ECCS)-

3/4.5.1 ACCUMULATORS LIMITING CONDITION FOR OPERATION 3.5.1 Each reactor coolant system accumulator shall be OPERABLE with:

a. The isolation valve open,

b. A contained borated water volume of between 7,555 (31.4%) and 7,780' (58.4%) gallons, 5

c. A boron concentration of between 2200 and 2500 ppm, and

d. A nitrogen cover-pressure of between 601 and 649 psig.

APPLICABILITY: MODES 1, 2 and 3.*

ACTION:

a. With one accumulator inoperable, except as a result of a closed isolation valve, restore the inoperable accumulator to OPERABLE status within one hour or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in H0T SHUTDOWN within the following 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months .

b. With one accumulator inoperable due to the isolation valve being closed, either immediately open the isolation valve or be in at least HOT STANDBY within one hour and in HOT SHUTDOWN within the following 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

SURVEILLANCE REQUIREMENTS

=-

==

4.5.1.1 Each accumulator shall be demonstrated OPERABLE:

a. At least once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months by:

1. Verifying the contained borated water volume and nitrogen cover-pressure in the tanks, and

2. Verifying that each accumulator isolation valve is open.

Pressurizer Pressure above the P-11 setpoint.

i FARLEY-UNIT-1 3/4 5-1 AMENDMENT N0.

EMERGENCY CORE COOLING SYSTEMS 3/4.5.5 REFUELING WATER STORAGE TANK LIMITING CONDITION FOR OPERATION 3.5.5 The refueling water storage tank (RWST) shall be OPERABLE with:

a. A minimum contained borated water volume of 471,000 gallons,

b. A boron concentration of between 2300 and 2500 ppm of boron, and

c. A minimum water temperature of 35*F.

APPLICABILITY: MODES 1, 2, 3 and 4.

ACTION:

With the refueling water storage tank inoperable, restore the tank to OPERABLE status within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months or be in at least HOT STANDBY within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

SURVEILLANCE REQUIREMENTS 4.5.5 The RWST shall be demonstrated OPERABLE:

a. At least once per 7 days by:

1. Verifying the contained borated water volume in the tank, and

2. Verifying the boron concentration of the wat60.

b. At least once per 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months by verjfying the RWST temperature when the outside air temperature is less than 35'F.

FARLEY-UNIT 1 3/4 5-11 AMENDMENT N0.

REACTIVITY CONTROL SYSTEMS BASES BORATION SYSTEMS (Continued)

MARGIN from expected operating conditions of 1.77% delta k/k after' xenon decay

.and cooldown to 200*F. . The maximum expected boration capability requirement '

occurs at E0L from full power equilibrium xenon conditions and requires 11,336 gallons of 7000 ppm borated water from the boric acid storage tanks or 44,826. l gallons of 2300 ppm borated water from the refueling water storage tank. l With the RCS temperature below 200*F, one injection system is acceptable without single failure consideration on the basis of the stable reactivity condition of the reactor and the additional restrictions prohibiting CORE-ALTERATIONS and positive reactivity changes in the event the single injection system becomes inoperable.

The limitation for a maximum of one centrifugal charging pump to be OPERABLE and the Surveillance Requirement to verify all charging pumps except the required OPERABLE pump to be inoperable below 180 F provides assurance that a mass addition pressure transient can be relieved by the operation of a single RHR relief valve.

The boron capability required below 200"F is sufficient to provide a SHUTDOWN MARGIN of 1% delta k/k after xenon decay and cooldown from 200 F to 140 F. This condition requires either 2,000 gallons of 7000 ppm borated water from the boric acid storage tanks or 7,750 gallons of 2300 ppm borated water from the refueling water storage tank.

The contained water volume limits include allowance for water not available because-of discharge line location and other physical characteristics.

The limits on contained water volume and boron concentration of the RWST also ensure a pH value of between 8.5 and 11.0 for the solution recirculated .

within containment after a LOCA. This pH band minimizes the evolution of iodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components.

The OPERABILITY of one boron injection system during REFUELING ensures that this system is.available for reactivity control while in MODE 6.

3/4.1.3 MOVABLE CONTROL ASSEMBLIES The specifications of this section ensure that (1) acceptable power 1 distribution . limits are maintained, (2) the minimum SHUTDOWN MARGIN 'is 'l maintained, and (3) limit the potential ~ effects of rod misalignment on associated accident analyses. OPERABILITY of -the control rod position-indicatorsL is required to determine control rod positions and thereby ensure compliance with'the control . rod alignment. and insertion limits.

'FARLEY-UNIT 1 B 3/4 1-3 AMENDMENT NO.

t i

l EMERGENCY CORE COOLING SYSTEMS BASES The Surveillance Requirements provided to ensure OPERABILITY of each component ensures that at a minimum the assumptions used in the safety analyses are met and that subsystem OPERABILITY is maintained. Surveillance requirements for throttle valve position stops and flow balance testing provide assurance that proper ECCS flows will be maintained in the event of a LOCA.

Maintenance of proper flow resistance and pressure drop in the piping system to each injection point is necessary to: (1) prevent total pump flow from exceeding runout conditions when the system is in its minimum resistance configuration, (2) provide the proper flow split between injection points in accordance with the assumptions used in the ECCS-LOCA analyses, and (3) provide an acceptable level of total ECCS flow to all injection points equal to or above that assumed in the ECCS-LOCA analyses.

3/4.5.4 BORON INJECTION SYSTEM THIS SPECIFICATION DELETED.

3/4.5.5 REFUELING WATER STORAGE TANK The OPERABILITY of the Refueling Water Storage Tank (RWST) as part of the ECCS ensures that sufficient negative reactivity is injected into the core to counteract any positive increase in reactivity caused by RCS system cooldown.

RCS cooldown can be caused by inadvertent depressurization, a loss-of-coolant accident or a steam line rupture.

The OPERABILITY of the RWST as part of the ECCS also ensures that a sufficient supply of borated water is avnilable for injection by the ECCS in the event of a LOCA. The limits on RWST minimum volume and boron concentration ensure that

1) sufficient water is available within containment to permit recirculation cooling flow to the core, and 2) the reactor will remain subcritical in the cold condition following mixing of the RWST and the RCS water volumes with all control rods inserted except for the most reactive control assembly in the event of a small break LOCA and with no control rods inserted in the event of a large break LOCA. These assumptions are consistent with the LOCA analyses.

The contained water volume limit includes an allowance for water not usable because of tank discharge line location or other physical characteristics.

'FARLEY-UNIT 1 B 3/4 5-2 AMENDMENT N0.

L

REACTIVITY CONTROL SYSTEMS BORATED WATER SOURCES - SHUTDOWN LIMITING CONDITION FOR OPERATION

=

3.1.2.5 As a minimum, one of the following borated water sources shall be OPERABLE:

a. A boric acid storage system with:

1. A minimum contained borated water volume of 2000 gallons,

2. Between 7000 and 7700 ppm of boron, and

3. A minimum solution temperature of 65'F.

b. The refueling water storage tank with:

1. A minimum contained borated water volume of 30,000 gallons,

2. A minimum boron concentration of 2300 ppm, and

3. A minimum solution temperature of 35'F.

APPLICABILITY: MODES 5 and 6.

ACTION:

With no borated water source OPERABLE, suspend all operations involving CORE ALTERATIONS or positive reactivity changes.

SURVEILLANCE REQUIREMENTS 4.1.2.5 The above required borated water -source shall be demonstrated OPERABLE:

a. At least once per 7 days by:

1. Verifying the boron concentration of the water,

2. Verifying the contained borated water volume, and

3. Verifying the boric acid storage tank solution temperature when it is the source of borated water.

b. At least once per 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months by verifying the RWST temperature when it is the source of borated water and the outside air temperature is less than 35 F.

FARLEY-UNIT 2 3/4 1-11 AMENDMENT NO.-

c. .

, -REAC'TIVITY CONTR0L' SYSTEMS S

.B0 RATED WATER SOURCES - OPERATING LIMITING CONDITION FOR OPERATION 1

1 3.1.2.6 As a minimum, the following borated water source (s) shall be OPERABLE as required by Specification 3.1.2.2:

a. A boric acid storage system with:

-1. A minimum contained borated water volume of 11,336 gallons, i

i 2. Between 7000 and 7700 ppm of boron, and i

3. A minimum solution temperature of 65 F. I 1

b. The refueling water storage tank with:

1. A minimum contained borated water volume of 471,000 gallons,

2. Between 2300 and 2500 ppm of boron, and i 3. A minimum solution temperature of 35 F.

APPLICABILITY: MODES 1, 2, 3 and 4.

ACTION:

i a. With the boric acid storage system inoperable and being used as one of i the above required borated water sources, restore the storage system to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months or be in at' least HOT STANDBY within

! the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and borated to a SHUTDOWN MARGIN equivalent to at i least 1% delta k/k at 200*F; restore the boric acid. storage system to OPERABLE status within the next 7 days or be in COLD SHUTDOWN within the next 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

b. With the refueling water storage tank inoperable, restore the tank to OPERABLE status within one hour or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

i i

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FARLEY-UNIT 2 3/4 1-12 AMEN 0 MENT NO.

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3/4.5 EMERGENCY CORE COOLING SYSTEMS 3/4.5.1 ACCUMULATORS LIMITING CONDITION FOR OPERATION 3.5.1 Each reactor coolant system accumulator shall be OPERABLE with:

a. The isolation valve open,

b. A contained borated water volume of between 7,555 (31.4%) and 7,780 (58.4%) gallons,

c. A boron concentration of between 2200 and 2500 ppm, and

d. A nitrogen cover-pressure of between 601 and 649 psig.

APPLICABILITY: MODES 1, 2 and 3.*

ACTION:

a. With one accumulator inoperable, except as a result of a closed isolation valve, restore the inoperable accumulator to OPERABLE status within one hour or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in HOT SHUTDOWN within the following 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months .

b. With one accumulator inoperable due to the isolation valve being closed, either inmediately open the isolation valve or be in at least HOT STANDBY within one hour and in HOT SHUTDOWN within the following 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

SURVEILLANCE REQUIREMENTS -=,

4.5.1.1 Each accumulator shall be demonstrated OPERABLE:

a. At least once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months by:

1. Verifying the contained borated water volume and nitrogen cover-pressure in the tanks, and

2. Verifying that each accumulator isolation valve is open.

I

Pressurizer Pressure above the P-11 setpoint.

I l

FARLEY-UNIT 2 3/4 5-1 AMENDMENT NO.

1 i

E________________.________.___ ._ _ _ . . . _ _ _ _ . _ _ . _ _ ._ _

_j

l l

EMERGENCY CORE COOLING SYSTEMS 3/4.5.5 REFUElfNG WATER STORAGE TANK

. LIMITING CONDITION FOR OPERATION 3.5.5 The refueling water storage tank (RWST) shall be OPERABLE with:

a. A minimum contained borated water volume of 471,000 gallons,

b. A boron concentration of between 2300 and 2500 ppm of boron, and

c. A minimum water temperature of 35 F.

APPLICABILITY: MODES 1, 2, 3 and 4.

ACTION:

With the refueling water storage tank inoperable, restore the tank to OPERABLE status within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months or be in at least HOT STANDBY within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

SURVEILLANCE REQUIREMENTS E 4.5.5 The RWST shall be demonstrated OPERABLE:

a. At least once per 7 days by:

1. Verifying the contained borated water volume in the tank, and

2. Verifying the boron concentration of the water.

b. At least once per 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months by verifving the RWST temperature when the outside air temperature is less than 35*F.

t AMENDMENT NO.

FARLEY-UNIT 2 3/4 5-11 l

L

REACTIVITY CONTROL SYSTEMS BASES 2

80 RATION SYSTEMS (Continued)

MARGIN from expected operating conditions of 1.77% delta k/k after xenon decay and cooldown to 200 F. The maximum expected boration capability requirement occurs at E0L from full power equilibrium xenon conditions and requires 11,336 gallons of 7000 ppm borated water from the boric acid storage tanks or 44,826 gallons of 2300 ppm borated water from the refueling water storage tank.

With the RCS temperature below 200*F, one injection system is acceptable without single failure consideration on the basis of the stable reactivity condition of the reactor and the additional restrictions prohibiting CORE ALTERATIONS and positive reactivity changes in the event the single injection system becomes inoperable.

The limitation for a maximum of one centrifugal charging pump to be OPERABLE and the Surveillance Requirement to verify all charging pumps except the required OPERABLE pump to be inoperable below 180*F provides assurance that a mass addition pressure transient can be relieved by the operation of a single RHR relief valve.

The boron capability required below 200 F is sufficient to provide a SHUTDOWN MARGIN of 1% delta k/k after xenon decay and cooldown from 200 F to 140*F. This condition requires either 2,000 gallons of 7000 ppm borated water from the boric acid storage tanks or 7,750 gallons of 2300 ppm borated water from the refueling water storage tank.

The contained water volume limits include allowance for water not available because of discharge line location and other physical characteristics.

The limits on contained water volume and boron concentration of the RWST also ensure a pH value of between 8.5 and 11.0 for the solution recirculated within containment after a LOCA. This pH band minimizes the evolution of iodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components.

The OPERABILITY of one boron injection system during REFUELING ensures that this system is available for reactivity control while in MODE 6.

3/4.1.3 MOVABLE CONTROL ASSEMBLIES The specifications of this section ensure that (1) acceptable power distribution limits are maintained, (2) the minimum SHUTDOWN MARGIN is maintained, and (3) limit the potential effects of rod misalignment on associated accident analyses. OPERABILITY of the control rod position indicators is required to determine control rod positions and thereby ensure compliance with the control rod alignment and insertion limits.

FARLEY-UNIT 2 B 3/4 1-3 AMENDMENT N0.

EMERGENCY CORE COOLING SYSTEMS BASES The Surveillance Requirements provided to ensure OPERABILITY of each component ensures that at a minimum the assumptions used in the safety analyses are met and that subsystem OPERABILITY is maintained. Surveillance requirements for throttle valve position stops and flow balance testing provide assurance that proper ECCS flows will be maintained in the event of a LOCA.

Maintenance of proper flow resistance and pressure drop in the piping system to each injection point is necessary to: (1) prevent total pump flow from exceeding runout conditions when the system is in its minimum resistance configuration, (2) provide the proper flow split between injection points in accordance with the assumptions used in the ECCS-LOCA analysrs, and (3) provide j an acceptable level of total ECCS flow to all injection points equal to or l I

above that assumed in the ECCS-LOCA analyses.

3/4.5.4 BORON INJECTION SYSTEM THIS SPECIFICATION DELETED.

3/4.5.5 REFUELING WATER STORAGE TANK The OPERABILITY of the Refueling Water Storage Tank (RWST) as part of the ECCS ensures that sufficient negative reactivity is injected into the core to counteract any positive increase in reactivity caused by RCS system cooldown.

RCS cooldown can be caused by inadvertent depressurization, a loss-of-coolant accident or a steam line rupture.

The OPERABILITY of the RWST as part of the ECCS also ensures that a sufficient supply of borated water is available for injection by the ECCS in the event of a LOCA. The limits on RWST minimum volume and boron concentration ensure that

1) sufficient water is available within containment to permit recirculation cooling flow to the core, and 2) the reactor will remain subcritical in the cold condition following mixing of the RWST and the RCS water volumes with all control rods inserted except for the most reactive control assembly in the event of a small break LOCA and with no control rods inserted in the event of a large break LOCA. These assumptions are consistent with the LOCA analyses.

The contained water volume limit includes an allowance for water not usable because of tank discharge line location or other physical characteristics.

B 3/4 5-2 AMENDMENT N0.

FARLEY-0, NIT 2

.4 ATTACHENT 2 I

l Significant Hazards Evaluation Pursuant to 10CFR50.92 For the Proposed Increase in RWST and Accumulator Boron Concentration Limits l Proposed Changes:

Increase the boron concentration limits for the refueling water storage tank (RWST) from 2000-2200 ppm to 2300-2500 ppm and increase the boron concentration limits for the accumulators from 1900-2200 ppm to 2200-2500 ppm. Each individual change is proposed as follows:

(1) Revise Specification 3.1.2.5 to require a minimum boron concentration of 2300 ppm in the RWST, (2) Revise Specifications 3.1.2.6 and 3.5.5 to require the RWST to have a boron concentration between 2300 and 2500 ppa, (3) Revise Specification 3.5.1 to require the reactor coolant system accumulators to have a boron concentration between 2200 and 2500 ppm, (4) Revise Bases 3/4.1.2 to require 44,826 gallons of 2300 ppm borated water from the RWST to provide a shutdown margin of 1.77% delta k/k above 200 F and 7,750 gallons of 2300 ppm borated water to provide a shutdown margin of 1% delta k/k below 200 F, and (5) Revise Bases 3/4.5.5 to reflect the criteria for subcriticality for both the large and small break LOCA analyses.

Background:

The Farley Nuclear Plant emergency core cooling system (ECCS) boration capabilities are supplied by the refueling water storage tank (RWST) and accumulators. The boron supplied by these sources provides negative reactivity to shutdown the core for LOCA and non-LOCA accidents. The Farley Nuclear Plant Technical Specifications currently require that the RWST boron concentration be maintained between 2000 ppm and 2200 ppm, while the accumulators boron concentration must be maintained between 1900 ppm and 2200 ppm. In order to provide the aecessary shutdown requirements for future reload cycle designs without the addition of excessive numbers of burnable absorbers, Alabama Power Company proposes a technical specification change to increase the RWST i aron concentration limits to 2300-2500 ppm and to increase the accumulator Mron concentration limits to 2200-2500 ppm.

l l

t Attachment 2 Significant Hazards Evaluation Pursuant to 10CFR50.92 For the Proposed Increase in RWST and Accumulator Boron Concentration Limits Page 2 Farley Nuclear Plant is currently operating on 18-month cycles which are designed with capacity factors in excess of 90%. As a result of designing these high energy cycles, the calculated critical boron concentrations for the low end of the previous cycle burnup window are becoming increasingly higher. This reduces the available margin for ensuring subcriticality with only ECCS injection. For example, the recent Unit 2 Cycle 5 reload core had to be redesigned with an increase in the number of burnable absorbers from 592 to 1120 to reduce the post-LOCA critical boron concentration and thus ensure that sufficient margin existed between the post-LOCA critical boron concentration and the mixed-mean baron concentration available in the containment sump following the LOCA. With the proposed increase in the RWST and accumulator boron concentration limits, sufficient margin will exist for the necessary shutdown I requirements of the ECCS without the addition of an excessive number of burnable absorbers as was required for the Unit 2 Cycle 5 design. These changes will allow more economical reload core designs and provide added assurance for maintaining reactor subcriticality at all times under the most conservative assumptions for all accident analyses.

To support these proposed changes to the RWST and accumulator boron concentration technical specification limits, an evaluation of the impact of the increased boron concentration on LOCA and non-LOCA accident analyses, the post-LOCA boron precipitation analysis, the post-accident sump pH and equipment qualification, the RWST solubility limits, and plant chemistry has been performed. This evaluation, which is provided in Attachment 3, concludes that the proposed increase in boron concentration limits is acceptable and provides additional safety margin with respect to the accident analyses while accommodating more economical fuel designs.

The proposed change to Bases 3/4.5.5 is strictly a clarification which was identified concurrently with the need to increase the RWST boron concentration.

The Bases, as currently written, state that the RWST boron concentration limits ensure the reactor will remain subcritical following mixing of the RWST and RCS water volumes with all control rods inserted except for the most reactive control assembly. The Bases also state that this assumption is consistent with the LOCA analyses. However, this assumption is only true for the small break LOCA analysis because the large break LOCA analysis assumes the core must remain subcritical with no credit taken for insertion of control rods (which is a more conservative assumption). Therefore, this proposed change corrects the discrepancy identified in the RWST ECCS Bases.

Analysis:

Alabama Power Company has reviewed the requirements of 10CFR50.92 as they relate to the proposed increase to the boron concentration limits for the RWST and accumulators and considers these changes not to involve a significant hazards consideration. In support of this conclusion, the following analysis is provided:

( --

Attachment 2 Significant Hazards Evaluation Pursuant to 10CFR50.92 For the Proposed Increase in RWST and Accumulator Boron Concentration Limits Page 3 (1) The proposed changes will not significantly increase the probability or consequences of an accident previously evaluated aecause the evaluation provided in Attachment 3 has demonstrated that increasing the boron concentration of the ECCS injection water will provide additional, unmodeled conservatism in both the LOCA and non-LOCA accident analyses.

Additionally, the change to Bases 3/4.5.5 ir a clarification to make it consistent with the current accident analyses. Therefore, the probability or consequences of an accident previously evaluated will not be increased.

(2) The proposed changes will not create the possibility of a new or different kind of accident from any accident previously evaluated because the effects of the actuation of the RWST and accumulators have been considered in the design basis of the plant. Additionally, the proposed changes do not change the operation of the ECCS but rather provide additional shutdown capability for the plant. The effects of the increased ECCS boron E concentration have also been evaluated with respect to stress corrosion cracking in the system piping, RWST solubility limits, pH limits and equipment qualification. The results of the evaluation demonstrate that no new failure modes are introduced and that there is no adverse impact on the characteristics of the previously analyzed transients. Thus, the proposed changes will not create the possibility of a new or different kind of accident from any accident previously evaluated.

(3) The proposed changes will not involve a reduction in a margin of safety because, as demonstrated in Attachment 3, the increased boron concentration in the RWST and accumulators provides additional safety margin for both the large break and small break LOCA and non-LOCA accident analyses. The proposed changes will provide added assurance that the ECCS will perform its intended function of maintaining reactor core subcriticality during an accident. Therefore, the proposed changes will not involve a reduction in a margin of safety.

Conclusion:

Based upon the analysis provided herewith, Alabama Power Company has determined that the proposed changes to the technical specifications will not increase the probability or consequences of an accident previously evaluated, create the possibility of a new or different kind of accident from any accident previously evaluated, or involve a reduction in a margin of safety. Therefore, Alabama Power Company has determined that these proposed changes meet the requirements of 10CFR50.92(c) and do not involve a significant hazards consideration.

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r ATTACHMENT 3 Evaluation of RWST/ Accumulator Boron Concentration Change I. INTRODUCTION An evaluation has been performed to justify a technical specification change to increase the RNST boron concentration limits from 2000-2200 ppm to 2300-2500 ppm and to increase the accumulator boron concentration limits from 1900-2200 ppm to 2200-2500 ppm. This evaluation has considered all areas that could be potentially affected by an increase in the limits and includes the Large Break and Small Break LOCA analyses, the post-LOCA baron precipitation analysis, the post-accident sump pH and equipment qualification, the non-LOCA accident analyses, the RWST solubility limits, and plant chemistry. The assessment of each of these areas is provided in the following sections.

II. LOCA ANALYSES A. Large Break LOCA Assessment The large Break LOCA (LBLOCA) analysis can be generally characterized by two phases - ECCS operation and long-term cooling. The ECCS operation phase consists of the blowdown portion of the transient and the refill /reflood modeling of the reactor vessel, wherein peak clad temperature, maximum cladding oxidation and maximum hydrogen generation are calculated and a coolable core geometry is verified.

The long-term cooling phase is evaluated to ensure core temperatures are maintained at an acceptably low value and decay heat is removed for the extended period of time required by the long-lived radioactivity remaining in the core. The impact of the proposed changes for each of these phases is provided below.

1. ECCS Operation Raising the RWST and accumulator boron concentration will not impact the LBLOCA/ECCS analysis which is required bj 10CFR50.46.

Standard practice in the Westinghouse LBLOCA/ECCS analysis methodology does not explicitly model boration levels of ECCS injection in the SATAN, REFLOOD, LOCA, BART and BASH codes. This is regarded as a conservatism taken in the analysis methodology.

It has been demonstrated that void formation shuts down the reactor initially after a double-ended guillotine break and rod insertion following reactor trip and borated ECCS water would, in fact, complement void formation in causing rapid reduction of power to a residual level corresponding to fission product decay heat. However, only void formation is considered in computing core reactivity during blowdown.

The conclusions of this evaluation are valid for analyses using the February 1978 model, the 1981 model with BART or the 1981 model with the BASH code. It is indicated in the analyses that by the time boron becomes slynificant in maintaining core shutdown, the clad temperature would have already peaked and

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Attachment 3 Evaluation of RWST/ Accumulator Boron Concentration Change Page 2 receded. Consequently, increasing the boration level in the RWST and accumulators will not impact the analysis. Calculated peak clad temperature corresponding to the technical specification peaking factor limit would be the same. The proposed changes would only add additional, unmodeled margin for core shutdown and would result in a safer plant operating condition.

2. Long-Term Cooling Boron concentration becomes significant in maintaining core shutdown in the long-term cooling phase following a LOCA.

WCAP-8339 specifies, "After successful initial operation of the ECCS, the reactor core is recovered with borated ECCS water.

This ECCS water has enough boron concentration to maintain core shutdown." No credit is taken for rod insertion. Calculations are performed as part of the reload process to demonstrate that this criterion is met. For a given core design, the increase in boron concentration will provide assurance that the criterion of WCAP-8339 is met for the high boron concentration requirements of the reload core designs without the addition of a large number of burnable absorbers.

B. Small Break LOCA Impact The increased baron concentration in the RWST and accumulators would have no effect on the small break LOCA analysis. The small break model specifically takes credit for the insertion of all control rods less the most reactive assembly in the calculation of core shutdown.

Consequently, the boron concentration required to achieve the same level of negative reactivity is significantly lower than the concentration required to assure shutdown for the L8LOCA. Increasing the RWST and accumulator boron concentration limits will provide additional unmodeled conservatism for the small break LOCA analysis.

Therefore, it is concluded that the proposed technical specification changes will not alter the small break transient analysis.

C. LOCA Assessment Summary For a given core design similar to previous Farley reload designs, raising the limits for allowable boron concentration in the RWST and accumulators will provide additional margin for maintaining the core subcritical. Raising the limits will also provide added assurance that future reload designs with high energy requirements and high critical boron concentrations can be designed to ensure subcriticality for all phases of the postulated LOCA without the addition of an excessive number of burnable absorbers. As

Attachment 3 i Evaluation of RWST/ Accumulator Boron !

Concentration Change l Page 3 demonstrated above, these proposed changes will provide additional, unmodeled margin and conservatism for the Large Break and Small Break LOCA analyses. Therefore, these proposed changes are acceptable and will increase the safety of operating the plant.

III. POST-LOCA BORON PRECIPITATION ANALYSIS The present post-LOCA boron precipitation analysis was performed to determine the required time for hot leg switchover to prevent excessive concentration of boric acid and assure termination of boiling within the reactor vessel. This analysis calculated a hot leg switchover time of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The NRC staff required that the switchover time be reduced from 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to 20 hours2.314815e-4 days 0.00556 hours 3.306878e-5 weeks 7.61e-6 months to account for uncertainties in prediction of the boric acid concentration in the reactor vessel. As documented in the Farley Nuclear Plant SER, Supplement 2, Section 6.3.2.2, the shorter time interval will assure that the boric acid will not exceed 23.5 weight percent for a postulated cold leg break.

A new analysis was performed, with a maximum boric acid concentration of 2500 ppm in the RWST and accumulators, to support the proposed technical specification changes. The analysis considered the increase in boric acid concentration in the reactor vessel during the long-term cooling phase of a LOCA, assuming a conservatively small effective vessel volume. This volume includes only the free volumes of the reactor core and the upper plenum below the bottom of the hot leg nozzles. This assumption conservatively neglects the mixing of boric acid solution with directly connected volumes, such as the reactor vessel lower plenum. The calculation of boric acid concentration in the reactor vessel considers a cold leg break of the reactor coolant system in which steam is generated in the core from decay heat while the boron associated with the boric acid solution is completely separated from the steam and remains in the effective vessel volume.

The results of the analysis show that the maximum allowable boric acid concentration of 23.53 weight percent established by the NRC, which .is the boric acid solubility limit less 4 weight percent, will not be exceeded in the vessel if hot leg injection is initiated 11 hours1.273148e-4 days 0.00306 hours 1.818783e-5 weeks 4.1855e-6 months after the LOCA inception. Thereafter, the operator should alternate between hot leg and cold leg recirculation every 15 hours1.736111e-4 days 0.00417 hours 2.480159e-5 weeks 5.7075e-6 months . The calculated switchover time is referenced against the reactor-trip /SI actuation signal because the typical -time interval between the accident inception and the reactor-trip /SI actuation signal is negligible when compared to the switchover time.

Attachment 3 Evaluation of RWST/ Accumulator Boron Concentration Change Page 4 This analysis assumed a conservatively small vessel volume with no boron being carried out of the core with the steam. Due to the increase in the amount of boron in the RWST and accumulators, this analysis calculated a shorter hot-leg recirculation switchover time than was calculated in the original analysis. The shorter hot-leg recirculation switchover time calculated by this revised analysis will require a change to the Farley Nuclear Plant Emergency Event Procedures. Upon NRC approval of the proposed technical specification changes, the appropriate changes to the procedures will be implemented.

IV. POST-ACCIDENT SUMP pH and EQUIPMENT QUALIFICATION An evaluation was performed to determine the impact of increasing the RWST and accumulator boron concentrations on post-accident sump pH and environmental qualification of safety-related electrical equipment inside containment. The sump pH evaluation calculated the pH limits which would occur during the ECCS injection, recirculation and long-term cooling modes following a postulated LOCA. The results have demonstrated that the pH range will be maintained within the range of 8.5 to 11.0 as required by Technical Specification Bases 3/4.1.2 and Bases 3/4.5.5.

These calculations assumed the existing sodium hydroxide concentration and volume requirements of the containment spray additive tank were present in determining the pH values. Since the pH remains within the previously analyzed range, there will be no impact on the environmental qualification of safety-related electrical equipment inside containment.

An additional review of the equipment qualification test reports was performed to verify that a maximum boron concentration of 2500 ppm would not invalidate the environmental qualification of this equipment. This evaluation verified that the environmental qualification of safety-related electrical equipment inside containment does indeed remain valid for exposure to boron concentrations of 2500 ppm.

V. NON-LOCA ACCIDENT ANALYSES The p' oposed increase in the RWST and accumulator boron concentration limits was evaluated for impact on each of the non-LOCA accidents which model the RWST and/or the accumulators. The following description presents the results of these evaluations:

A. Uncontrolled Baron Dilution This accident is analyzed for power operation, startup and refueling to cover all phases of plant operation. This event involves the normal CVCS makeup system and the inadvertent injection of reactor makeup water from the reactor makeup water storage tank through the reactor makeup water pumps and the charging pumps into the reactor

Attachment 3 Evaluation of RWST/ Accumulator Boron Concentration Change Page 5 coolant system (RCS). . For all cases analyzed, the event assumes that the RCS boron concentration meets or exceeds the shutdown margin requirement and that the injection of reactor makeup water into the RCS dilutes the boron concentration. Operator action is required to isolate the dilution flow and terminate the transient.

Since the RWST and accumulators are not a part of the normal CVCS makeup system, increasing the boron concentration in the RWST and accumulators will have no adverse effect on this event. This is because the required RCS boron concentration to maintain shutdown margin will not be decreased by the proposed increase in RWST boron concentration. The proposed change may even increase the actual RCS-concentration during refueling and would provide additional benefit because a longer time would be required to dilute the RCS to the point of recriticality. Therefore, the proposed changes will have no adverse effect on the boron dilution event and the existing FSAR analysis is bounding for the proposed changes.

b. Rupture of a Main Steam Line This accident assumes the boric acid delivered by the safety injection system is used to ultimately shutdown the core on a return to power and to maintain the core in the shutdown condition. An increase in the boron concentration in the RWST and accumulators would be a benefit for this transient because it would shutdown the reactor sooner. The proposed boron concentration increases would

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result in a less limiting transient than the present FSAR Chapter 15 steam line break analysis and the FSAR Chapter 6 steam line break mass and energy release analysis. Therefore, the proposed changes are bounded by the e"isting FSAR analyses.

C. Inadvertent Operation of the ECC3 Luring Power Operation This transient involves the inadvertent actuation of a safety injection signal, causing the RWST contents to be injected into the RCS cold legs during power operation. The accumulator contents are not injected for this transient because the RCS pressure does not I fall to the accumulator injection pressure. This transient results in a negative reactivity excursion due to the injected boron, causing a decrease in reactor power. The power unbalance causes a drop in Tavg and a drop in pressurizer pressure. The transient is eventually terminated by the low pressurizer pressure reactor trip or a manual trip.

The existing FSAR analysis shows that DNBR increases from the start of the transient, increasing the RWST boron concentration will cause ,

a greater negative reactivity excursion and a larger decrease in l power. It will ~aiso cause pressure to decrease at a faster rate

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l Attachment 3 Evaluation of RWST/ Accumulator Boron Concentration Change Page 6 because of more pronounced reactor coolant shrinkage. A decrease in pressure tends to cause a decrease in DNBR. However, the negative reactivity excursion and the resultant increase in DNBR has a greater effect on DNBR than the decrease in pressure. Therefore, the trend of increasing DNBR will not change with the proposed increase in RWST boron concentration. Additionally, the increased boron concentration would cause a reactor trip to occur sooner and the existing FSAR analysis remains bounding.

D. Inadvertent Operation of the ECCS at Hot Zero Power This transient involves the inadvertent actuation of a safety injection signal, causing the RWST contents to be injected into the RCS cold legs with the plant in the hot zero power condition. With a critical boron concentration greater than 2000 ppm and the current minimum RWST boron concentration of 2000 ppm injected into the RCS, this event represents a dilution event. However, this proposed technical specification change, which will increase the minimum RWST boron concentration to 2300 ppm, will revert this potential dilution event back to a boration event. This event is then bounded by the inadvertent operation of the ECCS at r.ower operation event.

E. Accidental Depressurization of the Main Steam System This transient considers the effects of a steam release equivalent to the capacity of any single steam dump, relief or safety valve. This depressurization of the secondary system causes an initial increase in steam flow which increases energy removal from the RCS. This, in turn, causes a reduction in RCS temperature and pressure. Safety injection is initiated automatically by the low pressurizer pressure signal which injects boric acid solution from the RWST.

The present FSAR analysis demonstates that the 2000 ppm boron concentration from the RWST provides sufficient negative reactivity to the transient to prevent core damage. An increase in the RWST boron concentration will provide additional negative reactivity and will increase the margin of safety for this transient. Therefore, the proposed change to the RWST boron concentration is bounded by the existing FSAR analysis.

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Attachment 3 Evaluation of RWST/ Accumulator Boron Conce.'tration Change Page 7 F. Non-LOCA Accident Assessment Summary As demonstrated above, the proposed increase in the RWST and accumulator boron concentration limits will provide additional safety margin for each of the non-LOCA transients and accidents that assume ECCS injection from the RWST and/or accumulators. The current FSAR analyses provide more limiting results and bound the impact of the proposed changes on these transients and accidents.

VI. RWST SOLUBILITY LIMITS An evaluation was performed to determine the margin available to prevent local crystallization of the tank contents with the increased boron concentration limit of 2500 ppm. Margin in excess of 3'F exists with the current 35'F minimum RWST temperature technical specification limit.

This amount of margin is considered acceptable for operations.

Additionally, sufficient margin exists between the new maximun RWST boron concentration of 2500 ppm and the solubility limit of 4900 ppm at 35 F.

Therefore, crystallization of the RWST contents will not occur with the proposed increase in boron concentration limits.

VII. NORMAL OPERATION CHEMISTRY Normal operation chemistry specifications require a certain amount of Lithium be provid-d e a pH control agent for the boric acid to maintain pH between 4.2 and 10.5. Since the RCS may be filled from the RWST water volume during refueling, a greater boron concentration could exist in the RCS during initial plant ascension to power due to the proposed increase in RWST boron concentration. An evaluation was performed to determine the impact of increased boron concentration on normal operation RCS chemistry requirements. This evaluation determined that a revised Li/B curve for plant startup would be required to maintain coordinated L1/8 chemistry.

Upon NRC approval of the proposed technical specification changes, the appropriate Li/B curves will be developed for the fuel cycle that implements the increased boron concentrations on each unit.

The effect of increased boron concentration on stress corrosion cracking in pipes containing stagnant borated water has been evaluated. This evaluation specifically considered the piping of the RCS and ECCS, as well as the RWST and accumulators. Stress corrosion cracking can be caused by caustic stress corrosion or chloride stress corrosion. Caustic stress corrosion occurs when hyroxide ions concentrate in cracks or crevices on the surface of materials under tensile stresses. Aside from controlling the tensile stresses on the materials, control of pH also reduces the effects of caustic stress corrosion. The effect of increasing the RWST

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Attachment 3 Evaluation of RWST/ Accumulator Boron Concentration Change Page 8 boron concentration has been determined to reduce the pH less than 0.1 pH unit. This reduction in pH may potentially reduce the likelihood of occurrence of caustic stress corrosion cracking.

Chloride stress corrosion is an intergrannular corrosion which occurs in austenitic stainless steels in the presence of oxygen, chloride ions and tensile stress. The piping within the plant is designed to minimize the tensile stresses and the systems are designed to minimize the content of oxygen. Technical Specification 3.4.8 requires the chloride concentration to be <0.15 ppm and the dissolved oxygen to be <0.10 ppm. Increasing the boron concentration will have no effect on the chloride stress corrosion cracking. Additionally, maintaining the chloride concentration and dissolved oxygen within the above stated specifications provides adequate protection from chloride stress corrosion and ensures the structural integrity of the reactor coolant system.

VIII. CONCLUSION The potential impacts of increasing the boron concentration in the RWST and accumulators have been evaluated for the LOCA and non-LOCA accident analyses, the post-LOCA boron precipitation analysis, the post-accident sump pH and equipment qualification, the RWST solubility limits, and plant chemistry. As presented above, increasing the boron concentration is acceptable for each of these areas and provides additional safety margin with respect to the accident analyses while accommodating more economical fuel designs with high energy requirements. Therefore, the proposed technical specification changes to increase the RWST and accumulator baron concentration limits will provide both economic and safety benefits for Farley Nuclear Plant.

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ML20206T583

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