Text

Proposed Tech Specs Increasing Boron Concentration in Refueling Water Storage & Casing Cooling Tanks & Accumulators
	ML20212C691
Person / Time
Site:	North Anna
Issue date:	12/22/1986
From:	; VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	;
Shared Package
ML20212C598	List: ML20212C594; ML20212C691;
References
	NUDOCS 8612310144
	Download: ML20212C691 (23)
	v • d • e

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

O k ATTACHMENT 1 NORTH ANNA UNIT 1 - -

PROPOSED TECHNICAL SPECIFICATION CHANGES 8612310144 861222 PDR ADOCK 05000338 ,

P PDR l 40-DNB-2210B-1 hissii sm inisu imi ii i i e _ _ _ . _ _ _ . . . _ . . _ _ _

REACTIVITY CONTROL SYSTEMS BORATED WATER SOURCES - SHUTDOWN LIMITING CONDITION FOR OPERATION 3.1.2.7 As a minimum, one of the following borated water sources shall be OPERABLE:

a. A boric acid storage system and associated heat tracing with:

1. A minimum contained borated water volume of 1,378 gallons,

2. Between 12,950 and 15,750 ppm of boron, and

3. A minimum solution temperature of 115*F.

b. The refueling water storage tank with:

1. A minimum contained borated water volune of 51,000 gallons,

2. Between 2300 and 2400 ppm of boron, 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 until at least one borated water source is restored to OPERABLE status.

SURVEILLANCE REQUIREMENTS 4.1.2.7 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, 1

l 2. Verifying the contained borated water volume of the tank, 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 l is the source of borated water and the outside air temperature is l

< 35'F.

NORTH ANNA - UNIT 1 3/4 1-15 Amendment No.

l

l REACTIVITY CONTROL SYSTEMS BORATED WATER SOURCES - OPERATINC LIMITING CONDITION FOR OPERATION 3.1.2.8 Each of the following borated water sources shall be OPERABLE:

a. A boric acid storage system and associated heat tracing with:

1. A contained borated water volume of between 6,000 and 16,280 gallons,

2. Between 12,950 and 15,750 ppm of boron, and

3. A minimum solution temperature of 115*F.

b. The refueling water storage tank with:

1. A contained borated water volume of between 475,058 and 487,000 gallons,

2. Betveen 2300 and 2400 ppm of boron, and

3. A solution temperature between 40*F and 50*F.

APPLICABILITY: MODES 1, 2, 3 and 4.

ACTION:

a. With the boric acid storage system inoperable, 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 least 1.77% Ak/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 .

SURVEILLANCE REQUIRDENTS 4.1.2.8 Each borated water source shall be demonstrated OPERABLE:

NORTH ANNA - UNIT 1 3/4 1-16 Amendment No.

(

r s .

-3/4.5 EMERGENCY CORE COOLING SYSTEMS (ECCS)

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 7580 and 7756 gallons

c. Between 2200 and 2400 ppm of boron, and

d. A nitrogen cover-pressure of between 599 and 667 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 HOT SHUTDOWN within the next 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

b. With one accumulator inoperable due to the isolation valve being closed, either immediately open the isolation valve or be in HOT STANDBY within one hour and be in 110T SHUTDOWN within the next 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

SURVEILLANCE REQUIREMENTS 4.5.1 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 a

2. Verifying that each accumulator isolation valve is open.

Pressurizer Pressure above 1000 psig. Power lock out of valves is not permitted in MODE 3 when below 1000 psig.

NORTH ANNA - UNIT 1 3/4 5-1

[I~ -

A, 1 l

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

a. A contained borated water volume of between 475,058 and 487,000 gallons.-

b. Between 2300 and 2400 ppm of boron, and

c. A solution temperature between 40*F and .50*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:

1

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 verifying the RWST temperature.

NORTH ANNA - UNIT 1 3/4 5-9 Amendment No.

CONTAINMENT SYSTEMS-CONTAINMENT RECIRCULATION SPRAY SYSTEM LIMITING CONDITION FOR OPERATION 3.6.2.2 The containment recirculation spray system shall be OPERABLE with:

a. Four separate and independent containment recirculation spray subsystems, each composed of a spray pump, associated heat exchanger-and flow path,

b. Two separate and independent outside recirculation spray pump casing cooling subsystems, each composed of a casing cooling pump, and flow.

path capabic of transferring fluid from the casing cooling tank to the suction of the outside recirculation spray pumps,

c. One casing cooling tank shall be OPERABLE with:

1. Contained borated water volume of at least 116,500 gallons.

2. Between 2300 and 2400 ppm boron concentration.

3. A solution temperature 2 35*F and s 50*F.

APPLICABILITY: MODES 1, 2, 3 and 4.

ACTION:

a. With one containment recirculation spray subsystem or casing cooling system inoperable, restore the inoperable subsystem to OPERABLE status within 7 days 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 ; restore the inoperable subsystem to OPERABLE status within the next 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months 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 casing cooling tank inoperable, restore the tank 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 in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

h i

l l

1

NORTH ANNA - UNIT 1 3/4 6-12 Amendment No.

L

3/4.9 REFUELING OPERATIONS

. BORON CONCENTRATION LIMITING CONDITION FOR OPERATION 3.9.1 With the reactor vessel head unbolted or removed, the boron concentration of all filled portions of the Reactor Coolant System and the refueling canal shall be maintained uniform and sufficient to ensure that the more restrictive of the following reactivity conditions is met:

a. Either a K gf of 0.95 or less, or

b. -A boron concentration of 2 2300 ppm APPLICABILITY: MODE 6*.

ACTION:

With the requirements of the above specification not satisfied, immediately suspend all operations involving CORE ALTERATIONS or positive reactivity changes and initiate and continue boration at 2 10 gpm of 2 12,950 ppm boric acid solution or its equivalent until K is reduced to s 0.95 or the boron concentration is restored to 2 2300ppmfwhichever is the more restrictive. l The provisions of Specification 3.0.3 are not applicable.

SURVEILLANCE REQUIREMENTS , _

4.9.1.1 The more restrictive of the above two reactivity conditions shall be determined prior to:

a. Removing or unbolting the reactor vessel head, and

b. Withdrawal of any full length control rod located within the reactor pressure vessel, in excess of 3 feet from its fully inserted position.

4.9.1.2 The boron concentration of the reactor coolant system and the refueling canal shall be determined by chemical analysis at least once per 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

The reactor shall be maintained in MODE 6 when the reactor vessel head is unbolted or removed.

NORTH ANNA - UNIT 1 3/4 9-1 Amendment No.

REACTIVITY CONTROL SYSTEMS BASES 3/4.1.2 B0 RATION SYSTEMS (Continued)

With the RCS average temperature above 200*F, a minimum of two separate and redundant boron injection systems are provided to ensure single functional capability in 'the event an assumed failure renders one of the systems inoperable. Allowable out-of-service periods ensure. that minor component repair or corrective action may be completed without undu_e risk to overall facility safety from injection system failures during the repair period.

The boration capability of either system is sufficient to provide a SHUTDOWN MARGIN from expected operating conditions of 1.77% Ak/k after xenon decay and cooldown to 200*F. This expected boration capability requirement occurs at EOL from full power equilibrium xenon conditions and requires 6,000 t

gallons of 12,950 ppm borated water . from the boric acid storage tanks or 54,200 gallons of 2300 ppm borated water from the refueling water storage 4 tank.

The limitation for a maximum of one centrifugal charging pump to be 1

OPERABLE and the Surveillance Requirement to verify all charging pumps except I the required OPERABLE pump to be inoperable below 320*F provides assurance

', that a mass addition pressure transient can be relieved by the operation of a l,

single PORV.

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

The boron capability required below 200*F is sufficient to provide a SHUTDOWN MARGIN of 1.77% Ak/k af ter xenon decay and cooldown from 200*F to 140*F. This condition requires either 1378 gallons of 12,950 ppm borated water from the boric acid storage tanks or 3400 gallons of 2300 ppm borated l l water from the refueling water storage tank.

i The contained ~ water volume limits include allowance for water not available because of discharge line location and other physical characteristics. The OPERABILITY of one boron inj ection system during REFUELING insures that this system is available for reactivity control while in MODE 6.

1 i

NORTH ANNA - UNIT 1 B 3/4 1-3 Amendment No.

l

EMERGENCY CORE COOLING SYSTEMS 7

BASES 3/4.5.5 REFUELING WATER STORAGE TANK The OPERABILITY of the RWST as part of the ECCS 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. 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.

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 quench spray and between 7.7 and 9.0 for the solution recirculated within the containment after a LOCA. This pH minimizes the evolution of iodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components.

1 i

j NORTH ANNA - UNIT 1 B 3/4 5-3 Amendment No.

l

-3/4.9 REFUELING OPERATIONS BASES 3 /4.9.1 BORON CONCENTRATION-The -limitations on reactivity conditions during REFUELING ensure that:

1) the reactor will remain suberitical during CORE ALTERATIONS, and 2) a uniform boron concentration is maintained for reactivity control in the water volume 'having direct access to the reactor vessel. These limitations are consistent with the initial conditions assumed for the boron dilution incident in the accident analyses. The value of 0.95 or less for Keff includes a 1%

AK/K conservative allowance for uncertainties. Similarly, the boron concentration of 2300 ppm or greater includes a conservative uncertainty allowance of 50 ppm boron.

3/4.9.2 INSTRUMENTATION The OPERABILITY of the source range neutron flux monitors ensures that redundant monitoring capability is available to detect changes in the reactivity condition of the core.

3/4.9.3 DECAY TIME The minimum requirement for reactor subcriticality prior to movement of irradiated fuel assemblies in the reactor pressure vessel ensures that sufficient time has elapsed to allow the radioactive decay of the short lived fission products. This decay time is consistent with the assumptions used in the accident analyses.

3/4.9.4 CONTAINMENT BUILDING PENETRATIONS The requirements on containment building penetration closure and OPERABILITY ensure that a release of radioactive material within containment will be restricted from leakage to the environment. The OPERABILITY and closure restrictions are sufficient to restrict radioactive material release from a fuel element rupture based upon the lack of containment pressurization potential while in the REFUELING MODE.

< 3/4.9.5 COMMUNICATIONS The requirement for communication capability ensures that refueling station personnel can be promptly informed of significant changes in the facility status or core reactivity conditions during CORE ALTERATIONS.

i i

NORTH ANNA - UNIT 1 B 3/4 9-1

e ,

o ATTACHMENT 2 NORTH ANNA UNIT 2 ?

PROPOSED TECHNICAL SPECIFICATION CHANGES 40-DMB-22108-2

REACTIVITY CONTROL SYSTEMS BORATED WATER SOURCES - SHUTDOWN LIMITED CONDITION FOR OPERATION 3.1.2.7 As a minimum, one of the following borated water sources shall be OPERABLE:

a. A boric acid storage system and at least one associated heat tracing system with:

1. A minimum contained borated water volume of 1378 gallons,

2. Between 12,950 and 15,750 ppm of boron, and

3. A minimum solution temperature of 115'F.

b. The refueling water storage tank with:

1. A minimum contained borated water volume of 51,000 gallons,

2. Between 2300 and 2400 ppm of boron, 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 until at least one borated water source is restored to OPERABLE status.

SURVEILLANCE REQUIREMENTS 4.1.2.7 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 of the tank, 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.

NORTH ANNA - UNIT 2 3/4 1-13 Amendment No.

7

a

.. REACTIVITY CONTROL SYSTEMS r

g BORATED WATER SOURCES - OPERATING

! LIMITING CONDITION FOR OPERATION 3.1.2.8 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 and at.least one associated heat tracing system with:

) 1. A contained borated water volume of between 6000 and 16,280

i. gallons,

2. Between 12,950 and 15,750 ppm of boron, and-

3. A minimum' solution temperature of 115'F.

i - b. The refueling water storage tank with:

L 1. A contained borated water volume of between 475,058 and 487,000 i- gallons, i

2. Between 2300 and 2400 ppm of boron, and

3. A solution temperature between 40*F and 50*F.

APPLICABILITY: MODES 1, 2, 3 and 4.

f- ACTION:

i

a. - With the boric acid storage system inoperable and being used as one of l 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 i 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 1.77% Ak/k at 200*F; restore the boric acid storage system to OPERABLE I

status within the next 7 days or be in COLD SHUTDOWN within the next 30 I hours.

1

h. 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 I 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-r l

4 1

I

i. :

NORTH ANNA - UNIT 2 3/4 1-14 Amendment No. ,

~

3/4.5 EMERGENCY CORE COOLING SYSTEM (ECCS)

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 7580 and 7756 gallons

c. Between 2200 and 2400 ppm of boron, and

d. A nitrogen cover-pressure of between 599 and 667 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 GPERABLE status within one hour or be in HOT SHUTDOWN within the next 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

b. With one accumulator inoperable due to the isolation valve being closed, either immediately open the isolation valve or be in HOT STANDBY within one hour and be in HOT SHUTDOWN within the next 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 1000 psig. Power lock out of valves is not permitted in MODE 3 when below 1000 psig.

i l

( NORTH ANNA - UNIT 2 3/4 5-1 l

{

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

a. A contained borated water volume of between 475,058 and 487,000 gallons.

b. Between 2300 and 2400 ppm of boron, and

c. A solution temperature between 40*F and 50*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 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.

NORTH ANNA - UNIT 2 3/4 5-10

CONTAINMENT SYSTEMS CONTAINMENT RECIRCULATION SPRAY SYSTEM LIMITING CONDITION FOR OPERATION 3.6.2.2 The containment recirculation spray system shall be OPERABLE with:

a. Four separate and independent containment recirculation spray subsystems, each composed of a spray pump, associated heat exchanger and flow path,

b. Two separate and independent outside recirculation spray pump casing cooling subsystems, each composed of a casing cooling pump, and flow path capable of transferring fluid from the casing cooling tank to the suction of the outside recirculation spray pumps.

c. One casing cooling tank shall be OPERABLE with:

1. Contained borated water volume of at least 116,500 gallons.

2. Between 2300 and 2400 ppm boron concentration.

3. A solution temperature 235'F and s50*F.

APPLICABILITY: Modes 1, 2, 3 and 4.

ACTION:

a. With one containment recirculation spray subsystem or casing cooling subsystem inoperable, restore the inoperable subsystem to OPERABLE status within 7 days 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 ; restore the inoperable subsystem to OPERABLE status within the next 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months 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 casing cooling tank inoperable, restore the tank 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 in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

SURVEILLANCE REQUIREMENTS 4.6.2.2.1 Each containment recirculation spray subsystem and casing cooling subsystem shall be demonstrated OPERABLE:

a. At least once per 31 days by verifying that each valve (manual, power operated or automatic) in the flow path that is not locked, sealed or otherwise secured in position, is in its correct position.

NORTH ANNA - UNIT 2 3/4 6-11

3.4.'_ REFUELING OPERATIONS BORON CONCENTRATION LIMITING CONDITION FOR OPERATION 3.9.1 With the reactor vessel head unbolted or removed, the boron concentration of all filled portions of the Reactor Coolant System and the refueling canal shall be maintained uniform and sufficient to ensure that the more restrictive of the following reactivity conditions is met:

a. Either a K,ffof 0.95 or less, or

b. A boron concentration of greater than or equal to 2300 ppm.

APPLICABILITY: MODE 6*.

ACTION With the requirements of the above specification not satisfied, immediately suspend all operations involving CORE ALTERATIONS or positive reactivity changes and initiate and continue boration at greater than or equal to 10 gpm of a solution containing greater than or equal to 12,950 ppm boron or its equivalentuntilK[htive.is reduced l is the more restI The to less than of provisions or equal to 2300 ppm, Specification whichever 3.0.3 are not applicable.

i SURVEILLANCE REQUIREMENTS 4.9.1.1 The more restrictive of the above two reactivity conditions shall be determined prior to:

a. Removing or unbolting the reactor vessel head, and

u. Withdrawal of any full length control rod located within the reactor pressure vessel, in excess of 3 feet from its fully inserted position.

4.9.1.2 The boron concentration of the reactor coolant system and the refueling canal shall be determined by chemical analysis at least once per 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

The reactor shall be maintained in MODE 6 whenever the reactor vessel head is unbolted or removed and fuel is in the reactor vessel.

j NORTH ANNA - UNIT 2 3/4 9-1 Amendment No.

REACTIVITY CONTROL SYSTEMS BASES 3/4.1.2 B0 RATION SYSTEMS The boron injection system ensures that negative reactivity control is available during each mode of facility operation. The components required to perform this function include 1) borated water sources, 2) charging pumps, 3) separate flow paths, 4) boric acid transfer pumps, 5) associated heat tracing systems, and 6) an emergency power supply from OPERABLE diesel generators.

With the RCS average temperature above 200*F, a minimum of two boron injection flow paths are required to ensure single functional capability in the~ event an assumed failure renders one of the flow paths inoperable. The boration capability of either flow path is suf ficient to provide a SHUTDOWN MARGIN from expected operation conditions of 1.77% delta k/k after xenon decay l and cooldown to 200*F. The maximum expected boration capability requirement occurs at EOL from full power equilibrium xenon conditions and requires 6000 gallons of 12,950 ppm borated water from the boric acid storage tanks or 54,200 gallons of 2,300 ppm borated water from the refueling water storage l 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 change 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 340*F provides assurance that a mass addition pressure transient can be relieved by the operation of a single PORV.

The boron capability required below 200*F is sufficient to provide a SHUTDOWN MARGIN of 1.77% delta k/k af ter xenon decay and cooldown from 200*F to 140*F. This condition requires either 1378 gallons of 12,950 ppm borated water from the boric acid storage tanks or 3400 gallons of 2300 ppm borated l water from the refueling water storage tank.

NORTH ANNA - UNIT 2 B 3/4 1-3 Amendment No.

i EMERGENCY CORE COOLING SYSTEMS BASES 3/4.5.5 REFUELING WATER STORAGE TANK 4 The OPERABILITY of the RWST as part of the ECCS 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 1 cold condition following mixing of the RWST and the RCS water volumes with all

} control rods inserted except for the most reactive control assembly. 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.

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 quench spray and between 7.7 and 9.0 for the solution recirculated within the containment after a LOCA. This

.pH minimizes the evolution of iodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components.

j i

I NORTH ANNA - UNIT 2 B 3/4 5-3 m-. .- , . , ,,m,_.__,..-...,__-,___..,,.m.m____,__ .. .,.._ ,_ _ __ __ _ ___ __,.,v_._.-.___.,_._.,,,,,,,., -,m___,_,_,,,_,

3/4.9 REFUELING OPERATIONS BASES 3/4.9.1 BORON CONCENTRATION The limitations on reactivity conditions during REFUELING ensure that:

1) the reactor will remain suberitical during CORE ALTERATIONS, and 2) a uniform boron concentration is maintained for reactivity control in the water volume having direct access to the reactor vessel. These limitati~ons are consistent with the initial conditions assumed for the boron dilution incident in the accident analyses. The value of 0.95 or less for Keff includes a 1%

AK/K v conservati'e allowance for uncertainties. Similarly, the boron concentration of 2300 ppm or greater ~ includes a conservative uncertainty allowance of 50 ppm boron.

3/4.9.2 INSTRUMENTATION The OPERABILITY of the source range neutron flux monitors ensures that redundant monitoring capability is available to detect changes in the reactivity condition of the core.

3/4.9.3 DECAY TIME The minimum requirement for reactor suberiticality prior to movement of irradiated fuel assemblies in the reactor pressure vessel ensures that sufficient time has elapsed to allow the radioactive decay of the short lived fission products. This decay time is consistent with the assumptions used in the accident analyses.

3/4.9.4 CONTAINMENT BUILDING PENETRATIONS The requirements on containment building penetration closure and OPERABILITY ensure that a release of radioactive material within containment will be restricted from leakage to the environment. The OPERABILITY and closure restrictions are sufficient to restrict radioactive material release from a fuel element rupture based upon the lack of c~atainment pressurization potential while in the REFUELING MODE.

3/4.9.5 COMMUNICATIONS The requirement for communication capability ensures that refueling station personnel can be promptly informed of significant changes in the facility status or core reactivity conditions during CORE ALTERATIONS.

NORTH ANNA - UNIT 2 B 3/4 9-1

6 e ATTACHMENT 3 SAFETY EVALUATION l 40-DMB-22108-3

INTRODUCTION The fuel cycles currently being designed for North Anna Units 1 and 2 requ.re higher boron concentrations than previous cycles.to meet shutdown requirements because of the excess reactivity required to achieve an eighteen month fuel cycle at the recent uprated power level. A safety evaluation has been performed which justifies increasing the boron con-centration in ' the refueling water storage tank (RWST)'and the casing cooling tank (CCT) from the current Technical Specification limits of 2000-2100 ppm to 2300-2400 ppm. Additionally, the safety injection accu-mulator boron concentration is also being increased to 2200-2400 ppm.

PROPOSED TECHNICAL SPECIFICATION CHANGES Several Technical Specifications need to be changed to incorporate in-creased boron concentration limits. Proposed changes to the Unit 1 Tech-nical Specifications include:

1. T.S. 3.1.2.7 Borated Water Sources - Shutdown

2. T.S. 3.1.2.8 Borated Water Sources - Operating

3. T.S. 3.5.1 Accumulators

4. T.S. 3.5.5 Refueling Water Storage Tank

5. T.S. 3.6.2.2 Containment Recirculation Spray System

6. T.S. 3.9.1 Refueling Operations - Boron Concentration

7. T.S. B3/4.1.2 Boration Systems

8. T.S. B3/4.5.5 Refueling Water Storage Tank

9. T.S. B3/4.9.1 Refueling Operations - Boron Concentration i

i l

1

Proposed changes to the Unit 2 Technical Specifications include:

1. T.S. 3.1.2.7 Borated Water Sources - Shutdown

2. T.S. 3.1.2.8 Borated Water Sources - Operating

3. .T.S. 3.5.1 Accumulators ,

4. T.S. 3.5.5 Refueling Water Storage Tank

5. T.S. 3.6.2.2 Containment Recirculation Spray System

6. T.S. 3.9.1 Refueling Operations - Boron Concentration

7. T.S. B3/4.1.2 Boration Systems

8. T.S. B3/4.5.5 -Refueling Water Storage Tank

9. T.S. B3/4.9.1 Refueling Operations - Boron Concentration The boron concentration limits are changed from 2000-2100 ppm to 2300-2400 ppm'in T.S. 3.1.2.7, 3.1.2.8, 3.5.5, 3.6.2.2. These Specifica-tions present the limiting conditions for operation of the RWST and the CCT during different modes of operation. The boron concentration change is the only change being made to these Technical Specifications. Simi-larly, the boron concentration limits for the accumulators are being changed from 1900-2100 ppm to 2200-2400 ppm. The accumulator boron con-centration change is the only change to T.S. 3.5.1.

The references to uncertainties in T.S. 3.9.1 are being moved to the Bases to be more consistent with the format of the Westinghouse Standard Technical Specifications. Additionally, the lower limit boron concen-tration is changed from 2000 ppm to 2300 ppm in this specification.

]

i Technical Specification B3/4.1.2 has been modified to provide revised RWST volume requirements associated with shutdown from full power to 200'F and for shutdown from 200'F.to 140'F at the 2300 ppm boron concen-tration. The-basis for the calculation of the volume requirements is discussed later. An editorial change in the second paragraph of this section is also being made to reflect a shutdown margin requirement of 1.77%Ak/k as opposed to 1.60%Ak/k. This conservative correction is nec-essary to achieve consistency with the safety analysis and with other ap-p11 cable LCOs and surveillance requirements.

T.S. B3/4.5.5 is being revised to achieve consistency with the safety analysis regarding the pH of the quench and recirculation sprays and to achieve consistency between Units 1 and 2.

Technical Specification B3/4.9.1 has been expanded to include the dis-cussion of the uncertainties associated with reactivity and boron that are -

currently specified in T.S. 3.9.1.

DISCUSSION AND EVALUATION Introduction Each of the Chapter 15 transients from the UFSAR was evaluated. In addition, the time to switchover between cold and hot leg recirculation for long-term cooling following a loss of coolant accident (LOCA) was an-alyzed to determine the impact of the increased boron concentration. The l

post-LOCA containment sump pH was calculated with the increased boron concentration to _ ensure that the pH stays within acceptable limits.

Finally, the boron concentration used to qualify the equipment in con-tainment subject to quench spray was reviewed to make sure that a higher boron concentration does not violate the qualification envelope of any equipment.

Non-LOCA UFSAR Transients Of the Non-LOCA transients only the boron dilution was found to have potentially more severe results because of the increased boron concen-tration. The other Non-LOCA transients either were not impacted or actu-ally were made less severe as a result of the increased boron concentration due to safety injection initiation. Only the boron dilution transient was reanalyzed due to the postulated negative impact of the boron concentration increase.

T.S. 3.1.1.3.2 precludes the possibility of an unplanned boron dilution at North Anna by requiring that the primary grade water flow control valve be locked-closed during operation in Modes 3,4,5 and 6 except during planned boron dilution or makeup activities. The current Standard Review Plan (SRP) acceptance criteria for the boron dilution transient are met through this Technical Specification.1 For planned or makeup activities in Mode 6, the minimum dilution time to loss of shutdown margin is thirty-seven minutes, assuming the as-built maximum primary grade water flow rate. Consistent with the original UFSAR analysis, a conservatively

, n

. low RCS volume was assumed and a simple but conservative two volume mixing model was used.

LOCA Evaluation The effect cf an increased boron concentration on the LOCA transient was considered for both the large and small break scenario. The large break LOCA is characterized by'a rapid depressurination which causes the generation of significant voiding in the RCS. In accordance with Appendix K, the docketed North Anna LBLOCA analysis 8 '8 does not assume control rod insertion. As a result, heat generation in the core is reduced to decay heat levels by void reactivity. Therefore during the blowdown phase of the LBLOCA the core is shutdown and remains shutdown due to void reactiv-ity.

The Refill /Reflood portion of the injection phase begins with the highly volded core and continues from downcomer refill through core reflood.

During this time void reactivity is of primary importance at the start and gradually begins to be replaced by boron as the primary source of negative reactivity. The docketed North Anna LBLOCA analysis show, that the peak clad temperature is reached by the time boron becomes significant in maintaining the core shutdown. Therefore the increased boron concen-tration has no offect on the calculated results for the LBLOCA and would in fact provide a benefit if accounted for in the analysis. The proposed increase in boron concentration provides additional unmodeled conserva-tism.

The recirculation phase of the LBLOCA is characterized by the recircu-lation of water from Jte containment sump to the safety injection point of the cold leg and into the vessel where it removes heat being generated due to fission product decay. The water flows through the core and out the break as a steam-water mixture. The containment sump water comes from the various NSSS/B0P components which discharge during the injection phase of the LBLOCA. Thus, the containment sump boron concentration is an av-erage of the concentration in the accumulators, the RWST, the boron in-jection tank (BIT), the .hemical addition tank (CAT), the RCS and the CCT.

The boron concentration of this water is determined during the design process and verified during the reload safety evaluation process to be sufficient to maintain the core subcritical with all rods out at cold zero power. In this manner General Design Criterion (GDC) 26 is met and subcriticality is maintained. Thus, the increased boron concentration does not impact the design constraint to maintain suberiticality at cold zero power with all rods out so the recirculation phase of the transient is unaffected by the higher boron concentration.

The small break LOCA (SBLOCA) analysis falls into the category of those transients which cause safety injection actuation. The control rods are assumed to insert and cause a trip. Safety injection is actuated at the appropriate pressure and would provide increased shutdown capability with a higher boron concentration. As above, the core is designed to maintain subcriticality at cold zero power even without the control rods inserted and the presence of the increased boron in no way alters this design limit.

~s ,

' ?..

3 u A iN '

~

, ,e f V.

s ,

, i , i ..

Y

, t1 8

(

Recirculation Switchover Time ' '

.s

\ '

4 i

i e si s.

Following a LOCA borated water is injected'into the vessel from the PWST N. '

q -

and accumulators during the injection phas a of the transie'at. As the RWST empties, switchover to the recirculation phase occurs automatically based U

on a level setpoint. In the recirculation phase, borated; water is pumped ,-

y.

from the containment sump into the reactor vessel to remove decay heat.

5 Pool boiling heat transfer takes place in the vessel producing steam which

~

condenses in the containment. The boron concentration in the core gradu- .

e ally increases because the boron does not vaporize along with the water, g t'

The flow path of the recirculation water must be alternated between hot s

leg and cold leg injection periodically to sweep the core of the higher boron concentration water. Because of the proposed boron concentration increase the recirculation switchover must occur sooner to avoid boron i ',

e precipitation in the vessel. The currently accepted boron precipitation g:

., i' limit is 23.5 weight percent which includes a4four weight percent margin )

,i, , 4 for uncertainties." ~ +U Ni

,i At a concentration of 2400 ppm the switchover must cccur at ten hours ;

as opposed to the eighteen hour limit currently in the North Anna emergency .

procedures. Since the analysis assumed a simple, conservative two volume

('

6 \

, (i.e. containment and reactor vessel) model, the switchover intt.rval is

constant over time even though the decay heat diminishns as a function of time. The switchover affects only one emdrgency procedure. Furthermore, the switchover procedure contains onjy'four steps so more frequent switchovers do not substantially increase the burden on the operators.

, _ . _ ,~----_,-,.,..--,y_, _. .w, . , , , . , _ . . . . . . -. ,.,.,,,._.,-.-w,-.,._,,,,% , . . . . , . . , ..y, ymv, ..%..,,,y 7-

.,.---,,....-w , - , ,y

Quench and Recirculation Spray pH Limits are placed on the containment spray pH because of material con-siderations and.to reduce the evolution of iodine from the liquid. The pH for recirculation spray (i.e. containment sump water) is limited to a value of 7 units to avoid stress corrosion cracking.' Similarly, the pH of the quench spray system (i.e.RWST and CAT) is limited to a range of 8.55pH511.0 because iodine evolution is inversely proportional to solution pH.' Therefore conservative assumptions are made in order to calculate both a minimum and a maximum pH value for the quench spray and the recir-culation spray systems.

Since increasing the boron concentration makes the solution more acidic only the minimum spray pH was reanalyzed. The maximum pH remains within the limits set by T.S. B3/4.5.5. The minimum quench spray pH was found to increase slightly in spite of the increased boron concentration due primarily to a technical specificaticn change in the CAT Na0H ccncentration between the time of the original analysis and the analysis used to justify increasing the boron concentration (since the Na0H concentration was in-creased only the maximum quench spray pH was revised in the original analysis). Quench spray pH increased from 8.7 to 8.8 based on a conserv-ative analysis. The recirculation spray pH was analyzed and found to de-crease from 7.9 to 7.7 based on a conservative analysis. In both analyses

,? ,' j the pH values changed only slightly and remained between the limits spec-ified in the SRP.

Other Evaluations Other design constraints were also evaluated and shown to be met. Boron precipitation in'the RWST/CCT/ Accumulator was considered and found not to occur below concentrations of about 2.2 weight percent (~3850 ppm) at temperatures above 32'F.' The environmental qualification for the major-

ity of the electrical equipment in containment was performed at boron concentrations higher than 2400 ppm. In those instances where the con- I centration used for qualification was below 2400 ppm, it was determined that no degradation of the' equipment would occur at the slightly higher concentration because the long-term post accident sun: p pH is more neutral and therefore less corrosive.

j- Since the RWST boron concentration is being changed, the volume re-

j. quirements needed to achieve the shutdown conditions specified in T.S.

t B3/4.1.2 have been calculated. The required reactivity was determined in a conservative fashion by adding all of the following components: tem-perature defects, xenon reactivity, and shutdown margin. The conservatism applied in this process was the use of the reactivity associated with peak xenon instead of equilibrium xenon. A 500 pcm margin was added to the peak xenon reactivity to account for cycle-to-cycle variations. A simple mixing model was used to determine the volume of borated water from the RWST needed to achieve the required boron concentration in the vessel. After 4

+ - - ,m--,--..-.-.,y-.r

. , , + ,, .,r, --.-a , , - - - - - . , --i---- , ,,,-,.-,m,-s&. -%7. - . , - . , .,m, .o p. ,--g -,

l completing the above conservative calculations, the results were compared to a best estimate calculation of the needed borated water volume. The technical specification volumes were found to be conservative by a factor of 1.7.

BASIS FOR NO SIGNIFICANT HAZARDS DETERMINATION l

The proposed change does not involve a significant hazards consider-ation because operation of North Anna Units 1 & 2 in accordance with this change would not:

1. involve a significant increase in the probability or consequence of

an accident previously evaluated because appropriate design con- ,

straints were analyzed for changes to T.S. 3.1.2.7, 3.1.2.8, 3.5.1, 3.5.5, 3.6.2.2, 3.9.1 and none were found to be more limiting than currently documented in the UFSAR. Subcriticality is maintained fol-lowing a LOCA due to a combination of void formation, control rod in-sortion and soluble boron. The cold zero power boron concentration is determined -such that General Design Criterion (GDC) 26 is met.

f I

Boron dilution transients are effectively precluded by the technical specification requirement to lock the primary grade water flow control valve. Boron precipitation does not occur for low concentration sol-utions. The electrical equipment subject chemical spray qualification are not adversely affected by the higher boron concentration. Finally, the minimum sump pH remains above the SRP limit.

p

---,.----_w ,---...-v

. ,,,--.,m, , r, - - - - , . , , ,,,-%,-,,,,.- -

m-9 ..=w., v.n , ,9 4 . , . . - _ . , , . c-.q,-m ,- p,,..,

The changes to T.S. 3.9.1 and Bases sections B3/4.1.2, B3/4.5.5 and B3/4.9.1 are purely administrative in nature. They are necessary to achieve consistency with the safety analysis, with other technical specifications and with the format of the Westinghouse Standard Tech-nical Specifications.

2. create the possibility of a new or different kind of accident from any accident previously identified because the. proposed changes to T.S.

3.1.2.7, 3.1.2.8, 3.5.1, 3.5.5, 3.6.2.2, 3.9.1, B3/4.1.2, B3/4.5.5, and B3/4.9.1 do not involve any alterations to the physical plant which would introduce any new or unique operational modes or accident pre-I cursors. Procedural changes are limited to setpoint values or timing requirements.

3. involve a significant reduction in a margin or safety because an inadvertant baron dilution is precluded by lockout of the primary grade water flow control valve. The requirements of GDC 26 are met with the higher boron concentration. The reactivity and boron concentration uncertainties are unchanged. Finally, the refueling K,gf remains un-changed at 0.95. Therefore the margin of safety is unchanged by the proposed increase in the boron concentration.

Therefore, pursuant to 10 CFR 50.92, based on the above consideration, it has been determined that these changes do not involve a significant safety hazards consideration.

t

f ,

..'kp.

References:

1. Letter from B. R. Sylvia (VP) to J. P. O'Reilly(NRC), Serial No. 266, June 1, 1981.

2. Letter from W.L. Stewart (Virginia Electric and Power Company) to Harold R. Denton(NRC), Serial No.85-077, May 2, 1985, Forwarding Li-cense Amendment Request For Rated Thermal Power of 2893 MWt.

3. Letter from W.L. Stewart (Virginia Electric and Power Company) to Harold R. Denton(NRC), Serial No. 85-077A, August 2, 1985, Response To Request For Additional Information On Core Uprate.

4. Letter from R.P. Mcdonald (Alabama Power Company) to L.S. Rubenstein (NRC), Forewarding Proposed RWST/ Accumulators Boron Concentration In-crease, Farley Units 1 and 2 Technical Specification Change, July 3, 1986.

5. Branch Technical Position MTEB 6-1, "pH for Emergency Coolant Water For PWRs," (Rev. 2 - July, 1981), page 6.1.1-13.

6. " Containment Spray As A Fission Product Cleanup System," Standard Re-view Plan Section 6.5.2, Revision 1, July, 1981.

7. Ncrth Anna Power Station Updated Final Safety Analysis Report, Re-vision 4, June, 1986.

__

ML20212C691

Text

References:

Navigation menu

Search