Text

Amends 93 & 78 to Licenses NPF-4 & NPF-7,respectively, Revising Tech Specs to Increase Boron Concentration in Refueling Water Storage Tank,Casing Cooling Tank & Accumulators
	ML20209B686
Person / Time
Site:	North Anna
Issue date:	04/14/1987
From:	Rubenstein L; Office of Nuclear Reactor Regulation
To:	;
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ML20209B692	List: ML20209B686; ML20209B706;
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	NUDOCS 8704280496
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UNITED STATES E'

NUCLEAR REGULATORY COMMISSION c-WASHINGTON. D. C. 20555 s,

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VIRGINIA ELECTRIC AND POWER COMPAN_Y_

OLD DOMINTON ELECTRIC COOPERATIVE DOCKET Nn. 50-338 NORTH ANNA POWER STATION, UNIT NO. 1 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 93 License No. NPF-4 1.

The Nuclear Regulatory Comission (the Comission) has found that:

A.

The application for amendment by Virginia Electric and Power Company, et al., (the licensee) dated December 22, 1986, complies with the i....

standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Comission's rules and regulations set forth in 10 CFR Chapter I; P.

The facility will operate in confomity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.

There is reasonable assurance (1) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Comission's regulations; D.

The issuance of this amendment will not be inimical'to the comon defense and security or to the health and safety of the public; and E.

The issuance of this amendment is in accordance with 10 CFR Part 51 of the Comission's regulations and all applicable requirements have been satisfied.

2 8704280496 870414 PDR ADOCK 05000338 P

PDR

. 2.

Accordingly, the license is amended by changes to the Technical Speci-fications as indicated in the attachment to this license amendment and paraaraph 2.D.(2) of Facility Operating License No. NPF 8 is hereby amended to read as follows:

(2) Technical Specifications The Technical Specifications contained in Appendices A and R, as revised through Amendment No. 93, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications.

3.

This license amendment is effective prior to restart after the Cycle 6 refueling outace.

FOR THE NUCLEAR REGULATORY COWISSION

.s-Lester S. Rubenstein, Director Project Directorate II-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical Specifications Date of Issuance: April 14, 1987

I 1

ATTACPMENT TO LICENSE AMENDMENT NO. 93 TO FACILITY OPERATING LICENSE NO. NPF-4 DOCKET NO. 50-338 Replace the following pages of the Appendix "A"' Technical Specifications with the enclosed pages as indicated. The revised pages are identified by amendment number and contain vertical lines indicating the area of change.

The corresponding overleaf pages are also provided to maintain document completeness.

1-15 3/4 1-16 3/4 5-1 3/4 5-9 3/4 6-12 3/4 9-1 83/4 1-3 B3/4 5-3 B3/4 9-1 0

i l

t 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

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be OPERABLE:

A boric acid storage system and associated heat tracing with:

a.

l.

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 ll5'F.

j 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 l

l 3.

A minimum solution temperature of 35 F.

1 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 borate'd water source is restored to OPERABLE status.

SURVEILLANCE REQUIREMENTS 4.1.2.7 The above required borated water source shall be demonstrated GPERAELE:

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 < 35'F.

j i

NORTH ANNA-UNIT 1 3/4 1-15 Amendment !!o. 48' Sg'93

REACTIVITY CONTROL SYSTEMS BORATED WATER SOURCES:- OPERATING LIMITING CONDITICN FOR OPERATION 3.1.2.8 Each of theifollowing 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 6000 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:

t '"

1.

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

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 Sh0T00WN 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 SHUT-DOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months , SURVEILLANCE REOUIREMENTS i

4.1.2.8 Each borated water source shall be demonstrated OPERABLE:

NORTH ANNA-UNIT 1 3/4 1-16 Amendment No. E, 16 4S,93 i

I l

e EMERGENCY CORE COOLING SYSTEMS (ECCS) 3/4.5 ACCUMULATORS LIMITING CONDITION FOR OPERATION 3.5.1. Each reactor coolant system accumulator shall be OPERABLE with:

The isolation valve open, a.

A contained borated water volume of between 7580 and 7756 gallons b.

Between 2200 and 2400 ppm of boron, and c.

A nitrogen cover-pressure of between 599 and 667 psig.

d.

APPLICABILITY: MODES 1, 2 and 3*.

,,..a.

ACTION:

With one accumulator inoperable, except as a result of a closed isolation valve, restore the inoperable accumulator to a.

OPERABLE status within one hour or be in HOT SHUTDOWN wit the next 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months , With one accumulator inoperable due to the isolation valve b.

being clored, either inmediately 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 Each accumulator shall be demonstrated OPERABLE:

4.E.1 At least once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months by:

a.

Verifying the contained borated water volume and nitrogen 1.

cover-pressure in the tanks, and Verifying that each accumulator isolation valve is open.

2.

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

4 NORTH ANNA-UNIT 1 3/4 5-l Amendment No. 93

t 9

EMERGENCY CORE COOLING SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) b.

At least 'once per 31 days and within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months after each solution volume increase of > 5% of tank volume by verifying the boron concentration of the accumulator solution.

c.

At least once per 31 days when the RCS pressure is above 2000 psig by verifying that the breaker supplying power to the iso-lation valve operator is locked in the off position, d.

At least once per 18 months by verifying that each accumulator isolation valve opens automatically under each of the following conditions:

1.

When the RCS pressure exceeds 2010 psig, 2.

Upon receipt of a safety injection test signal.

NORTH ANNA-UNIT 1 3/4 5-2

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

3.5.5 A contained borated water volume of between 475,058 a.

ard 487,000 gallons.

l b.

Between 2300 and 2400 ppm of baron, and A solution temperature between 40 F and 50 F.

c.

APPLICABILITY: MODES 1, 2, 3 ar.d 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 .

1 l

l SURVEILLANCE REQUIREMENTS 4.5.5 The RWST shall be demonstrated OPERABLE:

a.

At least once per 7 days by:

l.

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.

i Amendment flo. E.)f,93 NORTH ANNA.-UNIT I 3/4 5-9

i CONTAINMENT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued)

At least _once per 5 years by performing an air or smoke flow i

d.

test through each spray header and verifying each spray nozzle is unobstructed.

4 s

9 l

NORTH ANNA-UNIT 1 3/4 6-11 i

i 1

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 i

l 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.

l 2.

Between 2300 and 2400 ppm boron concentration.

3.

A solution temperature > 35' and < 50*F.

APPLICABILITY: Modes 1, 2, 3 and 4.

ACTION:

a.

With one containment retirculation spray subsystem or casing cooling subsystem inoperable, restore the inoperable subsystem to OPERABLE status within 7 days or be in at least HOT STAND 8Y within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months ; restore the inoperable j

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 .

NORTH ANNA - UNIT 1 3/4 6-12 Amenchent No. F,93

3/4.9 REFUELING OPERATIONS BORON CONCENTRATION LIMITING CONDITION FOR OPERATION 3.9.1 With the reactor vessel head unbolted or removed, the boron concen-tration of all filled portions of the Reactor Coolant System and the refueling canal shall be maintained unifonn and sufficient to ensure that the more restrictive of the following reactivity conditions is met:

a.

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

A boron concentration of 1 2300 ppm APPLICABILITY: MODE 6*.

G.

ACTION:

With the requirements of the above specification not satisfied, inriedi-ately suspend all operations involving CORE ALTERATIONS or positive reactivity changes and initiate and continue boration at > 10 gpm of g 12,950 ppm boric acid solution or its equivalent until ~K is reduced to f

< 0.95 or the boron concentration is restored to > 2300 pp8 whichever is l

the more restrictive. 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 detennined prior to:

Removing or unbolting the reactor vessel head, and a.

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 .

l 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. 66,93 1

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7 REFUELING OPERATIONS INSTRUMENTATION s

i f

LIMITING CONDITION FOR OPERATION Asaminimuh,twosourcerangeneutronfluxmonitorsshallbe 3.9.2 operating, each with continuous visual indication in the control room l

j and one with audible indication in the containment.

4 APPLICABILITY: MODE 6.

ACTION:

With the requirements of the above specification not satisfied, im-mediately suspend all operations involving CORE ALTERATIONS or positive reactivity changes. The provisions of Specification 3.0.3 are not applicable.

s...

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i SURVEILLANCE REQUIREMENTS

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Each source range neutron flux monitor shall be demonstrated 4.9.2 OPERABLE by performance of:

A CHANNEL FUNCTIONAL TEST at least once per 7 days, and a.

i b.

A CHANNEL FUNCTIONAL TEST within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months prior to the initial start of CORE ALTERATIONS, and A CHANNEL CHECK at least once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months during CORE AL-i c.

TERATIONS.

f f

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

+

2 1

REACTIVITY CONTROL SYSTEMS BASES 3/4.1.2 BORATION 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-servi e periods ensure that minor component repair or corrective action mayle completed without undue risk to overall facility safety from injection system failures during the repair period.

The boration capabioity of either system is sufficient to provide a SHUTDOWN MARGIN from expected operating conditions of 1.77% ak/k after xenon This expected boration capability requirement decay and cooldown to 200*F.

occurs at EOL from full power equilibrium xenon conditions and requires li 6,000 gallons of 12,950 ppm borated water from the boric acid storage tanks

!} cr 54,200 gallons of 2300 ppm borated water from the refueling water storage l

il luk.

1i The limitation for a maximum of one centrifugal charging pump to be OPEEE LE and the Surveillance Requirement to verify all charging pumps except

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the required OPERABLE pump to be inoperable below 320*F provides assurance f,..

that a mass addition pressure transient can be relieved by the operation of i

a 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

,I condition of the reactor and the additional restriction; prohibiting CORE ALTERATIONS and positive reactivity change in the event the single injection system becomes inoperable.

The boron capability required below 200*F is sufficient to provide a SHUTDOWN MARGIN of 1.77% ak/k after 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.

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 injection system during REFUELING insures that l

this system is asailable for reactivity control while in MODE 6.

NORTH ANNA - UNIT 1 B 3/4 1-3 Amendment No. 5, 76, $$,93

REACTIVITY CONTROL SYSTEMS BASES 3/4.1. 2 BORATION SYSTEMS (Continued)

The licits on contained water volume and boron concentration of the RWST also ensure a pH value of betwer 8.5 and 11.0 for the solution recirculated withtn the containment after a LOCA. This pH minimizes the

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

At least one charging pump must remain operable at all times when the opposite unit is in MODE 1, 2, 3, or 4.

This is required to maintain the charging pump cross-connect system operational.

3/4.1. 3 MOVABLE CONTROL ASSEMBLIES The specifications of this section ensure that (1) acceptable power 4

distribution limits are maintained, (2) the minimum SHUTDOWN MARGIN is 8G 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.

The ACTION statements which permit limited variations from the basic requirements are accompanied by additional re'strictions which ensure that the original design criteria are met. Misalignment of a rod requires measurement of peaking factors or a restriction in THERMAL POWER; either of these restrictions provides assurance of fuel rod integrity during continued operation.

In addition those accident analyses affected by a misaligned rod are reevaluated to confirm that the results remain valid during future operation.

Control rod positions and OPERABILITY of the rod position indicators are required to be verified on a nominal basis of once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months with more frequent verifications required if an automatic monitoring channel is inoperable. These verification frequencies are adequate for assuring that the applicable LCO's are satisfied.

The maximum rod drop time restriction is consistent with the assumed roddgoptimeusedintheaccidentanalyses.> 500 F and with all reactor coolant pumps Measurement with T

_the measured drop times will be representative of insertion times experienced during a reactor trip at operating conditions.

NORTH ANNA UNIT 1 B 3/4 1-4 Amendment No. 76, 24

EMERGENCY CORE COOLING SYSTEMS BASES

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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 The limits on RWST minimum volume and boron concentration ensure of a LOCA.

that 1) sufficient water is available within containment to permit recircula-tion 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

= w.

caustic stress corrosion on mechanical systems and components.

l NORTH ANNA - UNIT 1 B 3/4 5-3 Amendment No. 76,93

3/4.9 REFUELING OPERATIONS BASES 3/4.9.l BORON CONCENTRATION The limitations or reactivity conditions during REFUELING ensure that:

1) the reactor will remain subcritical 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 includes a 1%

in the accident analyses. The value of 0.95 or less for K'be boron Similarly, ak/k conservative allowance for uncertainties.

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 a lack of containment pressurization potential while in the REFUELING MODE.

3 / 4. 9.,5 COMMUNICATIONS The requirement for communi ation 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 1 B 3/4 9-1 Amendment No. 93

REFUELING OPERATIONS BASES 3/4.9.6 MANIPULATOR CRANE OPERABILITY The OPERABILITY requirements for the manipulator cranes ensure that:

1) manipulator cranes will be used for movement of control rods and fuel assemblies, 2) each crane has sufficient load capacity to lift a control rod or fuel a~ssembly, and 3) the core internals and pressure vessel are protected from excessive lifting for.ce in the event they are inadvertently engaged during lift.ing operations.

3/4.9.7 CRANE TRAVEL - SPENT FUEL PIT The restriction on movement of loads in excess of the nominal weight of a fuel and control rod assenbly and associated handling tool over other fuel assemblies in the storage pool ensures that in the event this load is dropped,1) the activity release will be limited to that contained in a single fuel assembly, and 2) any possible distortion of fuel l

in the storage racks will not result in a critical array. This assumption is consistent with the activity release assumed in the accident analyses.

p.,

3/4.9.8 RESIDUAL HEAT REMOVAL AND COOLANT CIRCULATION The requirement that at least one residual heat removal (RHR) loop be in operation ensures that (1) sufficient cooling capacity is available to remove decay heat and maintain the water in the reactor pressure vessel below 140*F as required during the REFUELING MODE, and (2) sufficient coolant circulation is maintained through the reactor core to minimize the effect of a boron dilution incident and prevent boron stratification.

The requirement to have two RHR loops OPERABLE when there is less than 23 feet of water above the reactor pressure vessel flange ensures that a single failure of the operating RHR loop will not result in a complete loss cf residual heat removal capability. With the reactor vessel head removed and 23 feet of water above the reactor pressure vessel flange, a large heat sink is available for core cooling.

Thus, in the event of a failure of the operating RHR loop, adequate time is provided to initiate emergency procedures to cool the core.

3/9.9 CONTAINMENT PURGE AND EXHAUST ISOLATION SYSTEM The OPERABILITY of this system ensurcs that the containment vent and purge penetrations will be automatically isolated upon detection of high radiation levels within the containment. The OPERABILITY of this system is required to restrict the release of radioactive material from the containment atmosphere to the environment.

NORTH ANNA - UNIT 1 B 3/4 9-2 Amendment No. 32

._..,m_

psun jo, UNITED STATES s

NUCLEAR REGULATORY COMMISSION 9

g WASHINGTON. D. C. 20555 o

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%, *... +.4' VIRGINIA ELECTRIC AND POWER COMPANY OLD DOMINION ELECTRIC COOPERATIVE

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DOCKET NO. 50-339 NORTH ANNA POWER STATION, UNIT NO. 2 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 78 License No. NPF-7 1

1.

The Nuclear Regulatory Commission (the Commission) has found that:

A.

The application for amendment by Virginia Electric and Power Company, etal.,(thelicensee)datedDecember 22, 1986 complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B.

The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.

There is reasonable assurance (il that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that 'such activities will be conducted in compliance with the Commission's regulations; D.

The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.

The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.

l 1

. 2.

Accordingly, the license is amended by changes to the Technical Speci-fications as indicated in the attachment to this license amendment, and paragraph 2.C.(2) of Facility Operating License No. NPF-7 is hereby amended to read as follows:

(2) Technical Specifications The Technical Specifications contained in Appendices A and P, as revised through Amendment No. 78

. are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications.

3.

This license amendment is effective prior to restart after Cycle 5 refueling outage.

FOR THE NUCLEAR REGULATORY COFFISSION 1

Lester S.

ubenstein, Director Project Directorate II-2 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical Specifications Date of Issuance: April 14, 1987 l

l J

ATTACHMENT TO LICENSE AMEN 0 MENT NO. 78 TO FACTLITY OPERATING LICENSE No. NPF-7 DOCKET NO. 50-339 Replace the following pages of the Appendix "A" Technical Specifications with the enclosed pages as indicated. The revised pages are identified by amendment number and contain vertical lines indicating the area of change.

The corresponding overleaf pages are also provided to maintain document completeness.

Paae F 1-13 3/4 1-14 3/4 5-1 3/4 5-10 3/4 6-11 3/4 9-1 B3/4 1-3 B3/4 5-3 B3/4 9-1 o..

3/4.9 REFUELING OPERATIONS BORON CONCENTRATION LIMITING CONDITION FOR OPERATION 3.9.1 With the reactor vessel head unbolted or removed, the baron 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 reactiv.f ty conditions is met:

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

b.

A boron concentration of > 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 > 10 gpm of > 12,950 ppm boric is reduced to [0.95 or the boron acid solution or its equivalent until K f

concentrationisrestoredto>2300ppmiwhicheveristhemorerestrictive.

The provisions of Specification 3.0.3 are not applicable.

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

Removing or unbolting the reactor vessel head, and a.

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 AriNA - UNIT 2 3/4 9-1 Amendment Lo H, 78

REFUELING OPERATIONS INSTRUMENTATION

_ LIMITING CONDITION FOR OPERATION 3.9.2 As a minimum, two source range neutron flux monitors shall be operating, cach with continuous visual indication in the control room and one with audible indication in the containment.

APPLICABILITY: MODE 6.

ACTIO_N:

With one of the above required senitors inoperable, immediately a.

suspend all operatio.:s involving CORE ALTERATIONS or positive reactivity changes.

b.

With both of the above required monitors inoperable, determine the boron concentration of the reactor coolant system at least once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

The provisions of Specification 3.0.3 are not applicable.

c.

SURVEILLANCE REQUIREMENTS 4.9.2 Each source range neutron fiux monitor shall be demonstrated OPERABLE by performance of:

a.

A CRANNEL CHECK at least once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months , j

b.

A CHANNEL FUNCTIONAL TEST within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months prior to th'e initial start cf CORE ALTERATIONS, and l

A CHANNEL FUNCTIONAL TEST at least once per 7 days.

c.

t

't i

NORTH ANNA - UNIT 2 3/4 9-2

.=

.o o

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

4 a.

A boric acid storage system and at least one associated heat tracing j

system with:

i l

1.

A minimum contained borated water volume of 1378 gallons, i

2.

Between 12,950 and 15,750 ppm of boron, and 4

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.

l 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. 5A,78 q

REACTIVITY CONTROL SYSTEMS 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:

I 1.

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

gallons, l

2.

Between 12,950 and 15,750 ppm of boron, and 3.

A minimum solution temperature of 115*F.

j 1

"o ' ~-

b.

The refueling water storage tank with:

]

1.

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

gallons, 2.

Between 2300 and 2400 ppm of boron, and 3.

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

AP.PLICABILITY: MODES 1, 2, 3 and 4.

ACTION:

1 a.

With the boric acid storage system inoperable and being used as one j

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 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 l

30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

i l

l NORTH ANNA - UNIT 2 3/4 1-14 Amendment No. 54,78

.~

i 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:

i a.

The isolation valve open, l

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.

e-APPLICABILITY: MODES 1, 2 and 3*.

l ACTION:

i With one accumulator inoperable, except as a result of a closed a.

isolation valve, restore the inoperable accumulator to OPERABLE status within one hour or be in HOT SHUTDOWN within the next 12

hours, 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.

N3RTH ANNA - UNIT 2 3/4 5-1 Amendment No.78 I

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,,-,--,_--,__-_,.-y, m

,c..

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., - _r--

EMERGENCY CORE COOLING SYSTEMS SURVEILLANCE REQUIRERENTS (Continued) b.

At least once per 31rdays and within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months after each solution volume increase of greater than or equal to Et of tank volume by verifying the baron concentration of the accumulator solution.

c.

At least once per 31 days when 'the RCS pressure is above 2000 psig by verifying that the breaker supplying power to the isolation valve operator is locked ir. the off position.

d.

At least once per 18 months by verifying that each accumulator isolation valve opens automatically under each of the following conditions:

1.

When a simulated RCS pressure signal exceeds 2010 psig, A'

2.

Upon receipt of a safety injection test signal.

I 1

'e NORTH ANNA - UNIT 2 3/4 5-2 j

-4

- -. -. - ~ -.. - - - -

,--m-,.

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

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

gallons.

{

b.

Between 2300 and 2400 ppm of boron, and A solution temperature between 40'F and 50*F.

c.

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 .

i 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 Amendment No. 78

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

Four separate and independent containment recirculation spray sub-a.

systems, 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 >35'f and <50*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 , e

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 Amendment No.78

CONTAINMENT SYSTEMS CONTAINMENT RECIRCULATION SFRAY SYSTEM SURVEILLANCE REQUIREMENTS (Continued) b.

Verifying, that' on recirculation flow, each outside recirculation spray pump develops a discharge pressure of greater than or equal to 115 psig and each casing cooling pump develops a discharge pressure of greater than or equal to 46 psig when tested pursuant to Specification 4.0.5.

c.

At least once per 18 months by:

1.

Verifying that on a Containment Pressure--High-High signal, each casing cooling pump starts automatically without time delay, and each recirculation spray pump starts automatically with the following time delays:

inside 195 i 9.75 seconds, outside 210 1 21 secor.ds.

g,,.,.

2.

Verifying that each automatic valve in in the flow path actuates to its correct position on a Containment Pressure--high-high test signal.

d.

At least once per 5 years by performing an air or smoke flow test through each spray header and verifying each spray nozzle is unobstructed.

4.6.2.2.2 The casing cooling tank 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.

At least once per 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months by verifying the casing cooling tank b.

temperature.

1 NORTH ANNA - UNIT 2 3/4 6-12

s 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)separateflowpaths,4)boricacidtransferpumps,5)associatedheat 4

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 the event an assumed failure renders one of the flow paths inoperable.

boration capability of either flow path is sufficient to provide a SHUTDOWN l

MARGIN from expected operation conditions of 1.77% delta k/k after xenon decay and cooldown to 200*F. The maximum expected boration capability requirement occurs at EOL from full power equilibrium xenon conditions and requires v..

6000 gallons of 12,950 ppm borated water from the boric acid storage tanks l

or 54,200 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 I.

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 after 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 water from the refueling water storage tank.

NORTH ANNA - UNIT 2 B 3/4 1-3 Amendment No. S'4',78

REACTIVITY CONTROL SYSTEMS BASES 3/4.1.2 BORATION SYSTEMS (Continued)

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

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

The limits on contained water volume and boron concentration of the RWST also ensee a pH value of between 8.5 and 11.0 for the-solution re-circulated within the containment after a LOCA. This pH mininitzes the cvolution of iodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components.

At least one charging punp must remain operable at all times when the cpposite unit is in MODE 1, 2, 3 or 4.

This is required to maintain the charging pump cross-connect system operational.

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 cnsure compliance with the control rod alignment and insertion limits.

l The ACTION statements which permit limited variations from the basic requirements are accompanied by additional restrictions which ensure that the original design criteria are met. Misalignment of a rod requires j

measurement of peaking factors or a restriction in THERMAL POWER; either of these restrictions provides assurance of fuel rod integrity during l

continued operation.

In addition those accident analyses affected by a l

misaligned rod are reevaluated to confirm that the results remain valid i

during future operation.

Control rod positions and OPERABILITY of the rod position indicators i

are required to be verified on a nominal basis of once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months with l

ore frequent verifications required if an automatic monitoring channel is inoperable. These verification frequencies are adequate for assuring that i

the applicable LCO's are satisfied.

i The maximum rod drop time restriction is consistent with the assumed I

rod drop time used in the accident analyses. Measurement with T than or equal to 500*F and with all reactor coolant pumps operat $ greater i

ensures that the measured drop times will be representative of insertion times experienced during a reactor trip at operating conditions.

l l

NORTH ANNA - UNIT 2 B 3/41-4 Amendment No. 5 l

~

EMERGENCYCORECOOLINGSYSTFg 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 subtritical 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.

Ttlis pH mintmizes the evoluti6n of iodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components.

NORTH ANNA - UNIT 2 B 3/4 5-3 Amendment No.78

a 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 subcritical during CORE ALTERATI')NS, and 2) a uniform boron concentration is inaintained 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 includes a 1%

in the accident analyses. The value of 0.55 or less for K'be boron Similarly, ak/k conservative allowance for uncertainties.

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.

'* 'S 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 communications capability ensures that refueling station personnel can be promptly informed of significant changes inithe facility status or core reactivity condition,s during CORE ALTERATIONS.

NORTH ANNA - UNIT 2 B 3/4 9-1 Amendment No. 78

REFUELING OPERATIONS BASES 3/4.9.6 MANIPULATOR CRANE OPERABILITY 4

The OPERABILITY requimments for the manipulator cranes ensure that:

1) manipulator cranes will be used for movement of control rods and fuel i

assemblies, 2) each crane has sufficient load capacity to lift a control rod or fuel assembly, and 3) the core internals r.nd pressure vessel are protected from excessive lifting force in the event they are inadvertently engaged l

during lifting operations.

3/4.9.7 CRANE TRAVEL - SPENT FUEL PIT The restriction on movement of loads in excess of the nominal weight that of a fuel and control rod assemblies and associated handling tool over other

-fuel assemblies in the storage pool ensures that in the event this load is dropped, 1) the activity release will be limited to that contained in a single fuel assembly, and 2) any possible distortion of fuel in the storage racks will not result in a critical array. This assumption is consistent with the activity release assumed in the accident.

3/4.9.8 RESIDUAL HEAT REMOVAL AND COOLANT CIRCULATION The requirement that at least one residual heat removal (RHR) loop be in speration ensures that (1) sufficient cooling capacity is available to remove decay heat and maintain the water in the reactor pressure vessel below 140*F as required during the REFUELING MODE, and (2) sufficient coolar.t circulation is maintained through the reactor core to minimize the effect of a boron dilution incident and prevent boron stratification.

ll The requirement to have two RHR loops OPERABLE when there is less than 1

23 feet of water above the reactor pressure vessel flange ensures that a single failure of the operating RHR loop will not result in a complete loss of residu'al heat remeval capability. With the reactor vessel head removed and 23 feet of water above the reactor pressure vessel flange, a large heat sink j

is available for core cooling. Thus, in the event of a failure of the operating RHR loop, adequate time is provided to initiate emergency procedures to cool the core.

3/4.9.9 CONTAINMENT PURGE AND EXHAUST ISOLATION SYSTEM I

The OPERABILITY of this system ensures that the containment vent and i

purge penetrations will be automatically isolated upon detection of high radiation levels within the containment. The OPERABILITY of this system is required to restrict the release of radioactive material from the containment l

atmosphere to the environment.

I I

NORTH ANNA - UNIT 2 8 3/4 9-2

. ----

ML20209B686

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