ML20236U865

Proposed Tech Specs 3/4.1.2 & 3/4.5.5,re RWST & Boron Concentration Ph Range Bases Change to Address Discrepancies Between Previous NRC Issued Ser,Ts Bases & Applicable Sections of SRP

ML20236U865
Person / Time
Site:	North Anna
Issue date:	07/28/1998
From:	VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
Shared Package
ML20236U860	List: ML20236U857 ML20236U865
References
NUDOCS 9807310122
Download: ML20236U865 (5)

Text

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Attachment 2 Technical Specifications Bases Changes l

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I North Anna Power Station Units 1 and 2 Virginia Electric and Power Company 9807310122 980728' PDR ADOCK 05000338 P PDR

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REACTIVITY CONTROL SYSTEMS BASES

,3/4.1.2 BORATION SYSTEMS (Continued)

The limits on contained water volume and boron concentration of the RWST ensure a pH value of between 7.0 and 9.5 for the solution recirculated within the containment after a LOCA. l This pH minimizes the evolution ofiodine 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 j The specifications of this section (1) ensure that acceptable power distribution limits are maintained,(2) ensure that the minimum SHUTDOWN MARGIN is maintained, and (3) limit the potential effects of rod misalignment on associated accident analyses. OPERABILITY of the movable control assemblies is established by observing rod motion and determining that rods are ,

positioned within 12 steps (indicated position) of the respective demand step counter position. I The OPERABILITY of the individual rod position indication system is established by appropriate j periodic CHANNEL CHECKS, CHANNEL FUNCTIONAL TESTS, and CHANNEL CALIBRATIONS. OPERABILITY of the individual rod position indicators is required to .

determine control rod position and thereby ensure compliance with the control rod alignment and insertion limits. The OPERABLE condition for the individual rod position indicators is defined as being capable ofindicating rod position within il2 steps of the associated demand position indicator. For power levels below 50 percent of RATED THERMAL POWER, the specifications of this section permit a maximum one hour in every 24 stabilization period (thermal " soak time")

to allow stabilization of known thermal drift in the individual rod position indicator channels

during which time the indicated rod position may vary from demand position indication by no more l than i 24 steps. This "I in 24" feature is an upper limit on the frequency of thermal soak allowances and is available both for a continuous one hour period or one consisting of several discrete intervals. During this stabilization period, greater reliance is placed upon the demand position indicators to determine rod position. In addition, the i24 step / hour limit is not applicable l

when the control rod position is known to be greater than 12 steps from the rod group step counter l demand position indication. Above 50 percent of RATED THERMAL POWER, rod motion is not l cxpected to induce thermal transients of sufficient magnitude to exceed the individual rod position indicator instrument accuracy of 12 steps. Comparison of the demand position indicators to the bank insertion limits with verification of rod position by the individual rod position indicators (after thermal soak following rod motion below 50 percent of RATED THERMAL POWER) is sufficient verification that the control rods are above the insertion limits.

The control bank FULLY WITHDRAWN position, can be varied within the interval of 225 to 229 steps withdrawn, inclusive. This interval permits periodic repositioning of the parked RCCAs to minimize wear, while having minimal impact on the normal reload core physics and safety evaluations. Changes of the RCCA FULLY WITHDRAWN position within this band are administratively controlled, using the rod insertion limit operator curve.

NORTH ANNA - UNIT I B 3/4 1-4 Amendment No. 16,24,138, ME M9,

EMERGENCY CORE COOLING SYSTEMS BASES ECCS SUBSYSTEMS (Continued)

3) The requirements for reactor coolant pump sealinjection must be met during normal operation, and the effects of seal injection during accidents must be considered in meeting constraints 1) and 2) above.

3/4.5.4 BORON INJECTION SYSTEM The OPERABILITY of the boron injection system as part of the ECCS ensures that sufficient negative reactivity is injected into the core to counteract any positive increase in reactivity caused by RCS system cooldown. RCS cooldown can be caused by inadvertent depressurization, a loss-of-coolant accident or a steam line rupture.

The limits on injection tank minimum contained volume and boron concentration ensure that the assumptions used in the steam line break analysis are met.

The OPERABILITY of the redundant heat tracing channels associated with the boron injection system ensure that the solubility of the boron solution will be maintained above the solubility limit of 111*F at 15,750 ppm boron.

l 3/4.5.5 REFUELING WATER STORAGE TANK l

The OPERABILITY of the RWST as part of the ECCS ensures that a sufficient supply of l 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 l containment to permit recirculation cooling flow to the core, and 2) the reactor will remain l suberitical 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.

l The limits on contained water volume and boron concentration of the RWST also ensure a pH value of between 8.5 and 10.5 for quench spray and between 7.0 and 9.5 for the solution l recirculated within the containment after a LOCA. This pH minimizes the evolution ofiodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components.

An RWST wide range level instrument locp uncertainty was included in the sat:ty analysis and therefore need not be considered by the operator.

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NORTH ANNA - UNIT 1 B 3/4 5-3 Amendment No.16,93, i 10, I SS,

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REACTIVITY CONTROL SYSTEMS B ASES ,

3/4.1.2 D_QRATION SYSTEMS (Continued)

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 this system i.s available for reactivity control while in MODE 6.

The limits on contained water volume and boron concentration of the RWST also ensure a pH value of between 7.0 and 9.5 for the solution recirculated within the containment after a LOCA. l This pH minimizes the 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 speciGcations of this section (1) ensure that acceptable power distribution limits are maintained, (2) ensure that the minimum SHUTDOWN M ARGIN is maintained, and (3) limit the potential effects of rod mkalignment on associated accident analyses. OPERABILITY of the movable control assemble is established by observing rod motion and determining that rods are positioned within i 12 steps (indicated position) of the respective demand step counter position.

The OPERABILITY of the individual rod position indication system is established by appropriate periodic CHANNEL CHECKS, CHANNEL FUNCTIONAL TESTS, and CHANNEL CALIBRATIONS. OPERABILITY of the individual rod position indicators is required to determine control rod position and thereby ensure compliance with the control rod alignment and insertion limits. The OPERABLE condition for the individual rod position indicators is defined as being capable of indicating rod position within i 12 steps of the associated demand position indicator. For power levels below 50 percent of RATED THERM AL POWER, the specifications .

of this section permit a maximum one hour in every 24 stabilization period (thermal " soak time") I to allow stabilization of known thermal drift in the individual rod position indicator channels during which time the indicated rod position may vary from demand position indication by no more than 24 steps. This "I in 24" feature is an upper limit on the frequency of thermal soak allowances and is available both for a continuous one hour period or one consisting of several discrete intervals. During this stabilization period, greater reliance is placed upon the demand position indicators to determine rod position. In addition, the 124 step / hour limit is not applicable when the control rod position is known to be greater than 12 steps from the rod group step counter demand position indication. Above 50 percent of RATED THERM AL POWER, rod motion is not expected to induce thermal transients of sufficient magnitude to exceed the individual rod position indicator instrument accuracy of 12 steps. Comparison of the demand position indicators to the bank insertion limits with veriGcation of rod position by the individual rod position indicators l (after thermal soak following rod motion below 50 percent of RATED THERM AL POWER) is sufficient verification that the control rods are above the insertion limits.

The control bank FULLY WITHDRAWN position can be varied within the interval of 225 to 229 steps withdrawn, inclusive. This interval permits periodic repositioning of the parked RCCAs to minimize wear, while having minimal impact on the normal reload core physics and safety evaluations. Changes of the RCCA FULLY WITHDRAWN position within this band are administratively controlled, using the rod insertion limit operator curve.

NORTH ANNA - UNIT 2 B 3/41-4 Amendment No. 421,129,133, l l

EMERGENCY CORE COOLING SYSTEMS BASES ECCS SUBSYSTEMS (Continued)

3) The requirements for reactor coolant pump seal injection must be met during normal operation, and the effects of seal injection during accidents must be considered in meeting constraints 1) and 2) above.

3/4.5.4 BORON INJECTION SYSTEM The OPERABILITY of the boron injection system as part of the ECCS ensures that sufficient negative reactivity is injected into the core to counteract any positive increase in reactivity caused by RCS system cooldown. RCS cooldown can be caused by inadvertent depressurization, a loss-of-coolant accident or a steam line rupture.

The limits on injection tank minimum contained volume and boron concentration ensure that the assumptions used in the steam line break analysis are met. The contained water volume limit includes an allowance for water not usable because of tank discharge line location or other physical enaracteristics.

The OPERABILITY of the redundant heat tracing channels associated with the boron injection system ensure that the solubility of the boron solution will be maintained above the solubility limit of 111 F at 15,750 ppm boron.

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 suberitical 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 10.5 for quench spray and between 7.0 and 9.5 for the solution l recirculated within the containment after a LOCA. This pH minimizes the evolution ofiodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components.

An RWST wide range level instrument loop uncertainty was included in the safety analysis and therefore need not be considered by the operator.

NORTil ANNA - UNIT 2 B 3/4 5-3 Amendment No. 78,95,159,183, l

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