ML20046C357

Proposed Tech Specs Re RWST & SI Accumulators Allowable Boron Concentration Ranges

ML20046C357
Person / Time
Site:	South Texas
Issue date:	08/05/1993
From:	HOUSTON LIGHTING & POWER CO.
To:
Shared Package
ML20046C353	List: ML20046C352 ML20046C357
References
NUDOCS 9308100174
Download: ML20046C357 (9)

Text

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1 ATTACHMEliT 3 Marked-up South Texas Project Technical Specifications As Amended .

Reflecting the Proposed Revisions to the  ;

Refueling Water Storage Tank and SI Accumulators  !

Allowable Boron Concentration Ranges (Final Implementation) ,

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9308100174 930805  !?

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f REACTIVITY CONTROL SYSTEMS  !

s SORATED WATER SOURCES - SHUTDOWN  !

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LIMITING CONDITION FOR OPERATION  !

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

a. A Boric Acid Storage System with:

1) A minimum contained borated water volume of 2^00 gallen: for Unit I and 3200 gallons,'^- "ai+ '

2) A minimum boron concentration of 7000 ppm, and i l

3) A minimum solution temperature of 65'F.  !

b. The refueling water storage tank (PPST) with:

1) A minimum contained borated water volume of 122,000 gallons for MODE 5 and 33,000 gallons for MODE 6, and

2) A boron concentration between 2500 ppm and 2700 pp- for Ur" !

-end between 2800 ppa and 3000 ppm for Unit 2.

APPLICABILITY: MODES 5 and 6. l l

ACTION: I With no borated water source OPERABLE, suspend all operations -involving CORE' ALTERATIONS or positive reactivity changes. j SURVE!LLANCE REQUIREMENTS 4.1.2.5 The above required borated water source shall be demon ~strated OPERABLE at least once per 7 days by:

a. Verifying the baron concentration of the water,

b. Verifying the contained borated water volume, and

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

SOUTH TEXAS - UNITS 1 & 2 3/4 1-13 l'ait 1 - Amendment No. 51 Unit 2 - Amendment No. 40

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REACTIVITY CONTROL SYSTEMS-  !

DORATED WATER SOURCES - OPERATING {

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LIMITING CONDITION FOR OPERATION  ;

i 3.1.2.6 As a minimum, the following borated water source (s) shall be 01ERABLE as required by Specification 3.1.2.2 for MODES 1, 2, and 3 and one of the l following borated water sources shall be OPERABLE as required by Specification 3.1.2.1 for MODE 4:

a. A Boric Acid Storage System with:

1) A minimum contained borated water volume of 27,000 gallons,

2) A minimum boron concentration of 7000 ppm, and l

3) A minimum solution temperature of 65'F. i

b. The refueling water storage tank (RWST) with: ')

1) A minimum contained borated water volume of 458,000 gallons, and

2) A boron concentration between 2500 ppm and 2700 ppn for 'Jnit 1 )

and bctwccn 2800 ppm and 3000 ppm.for Unit 2. _

APPLICABILITY: MODES 1, 2, 3, and 4. '

ACTION:

a. With the Boric Acid Storage System inoperable and being used as one of the above required borated water sources, restore the system to

. OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and borated to a SHUTDOWN MARGIN equivalent to at least the limit as shown in Figure 3.1-2 at 200*F; restore the Boric Acid Storage System to OPERABLE status within the next 7 days or be in COLD SHUlDOWN within the next 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

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

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1 50VIH TEXAS - UNITS 1 & 2 3/4 1-14 Unit 1 - Amendment No. 51 Unit 2 - Amendment No. 40

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3/4.5 EMERGENCY CORE COOLING SYSTEMS 3/4.5.1 ACCUMULATORS tlMITING CONDITION FOR OPERATION 3.5.1 Each Safety injection System accumulator shall be OPERABLE with:

a. The isolation valve open and power removed,

b. A contained borated water volume of between 8800 and 9100 gallons,  !

c. A boron concentration of between 9400 and 2700 ppm for " nit 1 &nd  ;

'uineen 2700 ppm and 3000 ppm for Unit 2.

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d. A nitrogen cover-pressure of between 590 and 670 psig.

APPLICABILITY: MODES 1, 2, and 3*. )

ACTION:  ;

a. With one accumulator inoperable, except as a result of a closed isolation valve or the boron concentration outside the required limits, restore the inoperable accumulator to OPERABLE status within I hour or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and reduce pressurizer pressure to less than 1000 psig within the (

following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

b. With one accumulator inoperable due to the isolation valve being closed, either open the isolation valve within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> or be in at  :

least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and reduce pressurizer i pressure to less than 1000 psig within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

c. With the boron concentration of one accumulator outside the required ,

limit, restore the boron concentration to within the required limits i within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least HOT STANDBY within the next 6 i hours and reduce pressurizer pressore to less than 1000 psig within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.  ;

SU_RVEIJQ ANCE_ REQUIREMENTS

• 4.5.1.1 Each accumulator shall be demonstrated OPERABLE:

a. At least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> by:

1) Verifying, by the absence of alarms, the contained borated water volume and nitrogen cover-pressure in the tanks, and

2) Verifying that each accumulator isolation valve is open.

b. At least once per 31 days and within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> after each solution volume increase of greater than or equal to 1% of tank volume by verifying the boron concentration of the accumulator solution; and TPressurizer pressure aEove 1000 psig.

SOUTH TEXAS - UNITS 1 & 2 3/4 5-1 Unit 1 - Amendment No. 51 ,

l Unit 2 - Amendment No. 40

l EMERGENCY CORE COOLING SYSTEMS j 3/4.5.5 REFUELING WATER STORAGE TANK l

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

a. A minimum contained barated water volume of 458,000 gallons, and l

b. A boron concentration between 2500 ppm and 2700 pp.T. fer Unit I and- i

' cioeen 2800 ppm and 3000 ppm for-Unit 2.

u j APPLICABILITY: MODES 1, 2, 3, and 4. l ACTION: l With the RWST inoperable, restore the tank to OPERABLE status within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> or i be in at least HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the ,

following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

l SURVEILLANCE REQUIREMENTS l l

4.5.5 The RWST shall be demonstrated OPERABLE at least once per 7 days by:

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a. Verifying the contained borated water volume in the tank, and j

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b. Verifying the baron concentration of the water. ,

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SOUTH TEXAS - UNITS 1 & 2 3/4 5-10 Unit 1 - Amendment No. 51 Unit 2 - Amendment No. 40

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. i 3/4.9 REFUELING OPERATIONS ,

3/4.9.1 BORON CONCENTRATION LIMITING CONDITION FOR OPERATION  :

3.9.1 The boron concentration of all filled portions of the Reactor Coolant I System and the refueling canal shall be maintained uniform and sufficient to ensure that the more restrictive of the following reactivity conditions is +

met; either:

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a. A K,g of 0.95 or less, or l

b. A boron concentration of greater than or equal to 2500 ppa, for Unit

+-an+ 2800 ppm fu, Uiiit 2.

APPLICABILITY: MODE 6.* l l

ACTION.  !

With the requirements of the above specification not satisfied, immediately l suspend all operations involving CORE ALTERATIONS or positive reactivity l changes and initiate and continue boration at greater than or equal to 30 gpm I of a solution containing greater than or equal to 7000 ppm boron or its ,

equivalent until K,n is reduced to less than or equal to 0.95 or the boron concentration is restored to greater than or equal to 2500 ppr, for Unit I cad 3 2800 ppm for Unit 2, whichever is the more restrictivo.  ;

1 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 ::::: tor vessel head, and

b. Withdrawal of any full-length control rod _in excess of 3 feet from its fully inserted position within the reactor vessel.

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

- hours.

4.9.1.3' Valves FCV-Il0B, FCV-lllB, CV0201 A, and CV0221 shall be verified l closed and secured in position by mechanical stops or by removal of- air or electrical power at least once per 31 days.

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Mhe reactor shall be mafiit'ained in MODE 6 whenever fuel is in the reactor '

vessel with the vessel head closure bolts less than fully tensioned or with the head removed.

i SOUTH TEXAS - UNITS 1 & 2 3/4 9-1 Unit 1 - Amendment No. 51 Unit 2 - Amendment No. 40

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REACTIVITY CONTROL SYSTEMS

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l MODERATOR TEMPERATURE COEFFICIENT (Continued) l The most negative MTC value, equivalent to the most positive moderator l density coefficient (MDC), was obtained by incrementally correcting the MDC used in the FSAR analysis to nominal operating conditions. These corrections l involved: (1) a conversion of the MDC used in the FSAR analysis to its ,

equivalent MTC, based on the rate of change of moderator density with temperature at RATED THERMAL POWER conditions, and (2) subtracting from this value the largest differences in MTC observed at E0L, all rods withdrawn, RATED THERMAL POWER conditions, and those most adverse conditions of moderator temperature and pressure, rod insertion, axial power skewing, and xenon concentration that can occur in nominal operation and lead to a significantly more negative EOL MTC at RATED THERMAL POWER. These corrections transformed s l the MDC values used in the FSAR analysis into the limiting EOL MTC value specified in the CORE OPERATING LIMITS REPORT (COLR). The 300 ppm surveillance MTC value specified in the COLR represents a conservative value (with corrections for burnup and soluble boron) at a core condition of 300 ppm equilibrium boron concentration, and is obtained by making these corrections to the limiting MTC value.

l The Surveillance Requirements for measurement of the MTC at the beginning and near the end of the fuel cycle are adequate to confirm that the MTC remains within its limits since this coefficient changes slowly due

principally to the reduction in RCS boron concentration associated with fuel l burnup.

1 i 3/4.1.1.4 MINIMUM TEMPERATURE FOR CRITICALITY This specification ensures that the reactor will not be made critical with the Reactor Coolant System average temperature less than 561*F. This limitation is required to ensure: (1) the moderator temperature coefficient is within its analyzed temperature range, (2) the trip instrumentation is within its normal operating range, (3) the pressurizer is capable of being in an OPERABLE status with a steam bubble, and (4) the reactor vessel is above i its minimum RT , temperature.

3/4.1.2 BORAT10N SYSTEMS i The Boron Injection System ensures that negative' reactivity control is  !

available during each mode of facility operation. The components required to i' perform this function include: (1) borated water sources, (2) charging pumps, (3) separate flow paths, (4) boric acid transfer pumps, and (5) an emergency j power supply from OPERABLE diesel generators.

With the RCS average temperature above 350*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 sufficient to provide a SHUTDOWN MARGIN from expected operating conditions of 1.75% Ak/k after xenon decay and i cooldown to 200*F. The maximum expected boration capability requires 27,000 c 91ons of 7000 ppm borated water from the boric acid storage system or

,000 gallons of - ppm borated water for Ucit 1 (2000 ppo for Unit 2) from the refueling ater storage tank (RWST). The RWST volume is an ECCS requirement and is more than adequate for the required boration capability.

SOUTH TEXAS - NITS 1 & 2 B 3/4 1-2 Unit 1 - Amendment No. 27, 35, 51  !

Unit 2 - Amendment No. U , 26, 40 l e28M

REACTIVITY CONTROL SYSTEMS EAS.lS BORAT10N SYSTEMS (Continued)

With the RCS temperature below 350*F, one boron injection flow path / source is acceptable without single failure consideration on the basis of the stable reactivity condition of the reactor and the additional restrictions prohibiting CORE ALTERATIONS and positive reactivity changes in the event the i single boron injection flow path / source becomes inoperable.

The limitation for a maximum of one charging pump to be OPERABLE and the Surveillance Requirement to verify all charging pumps except the required OPERABLE pump to be inoperable below 350*F provides assurance that a mass addition pressure transient can be relieved by the operation of a single PORV.

The boration capability required below 200*F is sufficient to provide a variable SHUTDOWN MARGIN based on the results of a boron dilution accident analysis where the SHUTDOWN MARGIN is varied as.a function of RCS boron s concentration after xenon decay and cooldown from 200*F to 140*F. This condition requires either 2900 gallons for Unit 1 (3200 gallons for Unit 2) of '

gf 7000 ppm borated water from the boric acid storage system or 122,000 gallons QF o pm borated water for Unit 1 (2000 ppm for Unit 2) from the RWST for MODE 5 and 33,000 gallons of 250^.p m borated water Toc Unit 1 (2000 gea for Unit 2) from the RWST for MODE 6. gBoo ,

The contained water volume limits include allowance for water not available because of discharge line location and other physical characteristics. I The limits on contained water volume and baron concentration of the RWST also ensure a pH value of between 7.5 and 10.0 for the solution recirculated within containment after a LOCA. This pH band minimizes the evolution of iodine and minimizes the effect of chloride and caustic stress corrosion on mechanical systems and components.

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

3/4.1.3 MOVABLE CONTROL ASSEMBLIES The specifications of this section ensure that: (1) acceptable power distribution limits are maintained, (2) the minimum SHUTDOWN MARGIN is maintained, and (3) the potential effects of rod misalignment on associated accident analyses are limited. 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. Verification that the Digital Rod Position Indicator agrees with the demanded position within 12 steps at 24, 48, 120, and 259 steps withdrawn for the Control Banks and 18, 234, and 259 steps withdrawn for the Shutdown Banks provides assurances that the Digital Rod Position Indicator is operating correctly over the full range of indication. Since the Digital Rod Position Indication System does not indicate the actual shutdown rod position between 18 steps and 234 steps, only points in the indicated ranges are picked for verification of agreement with demanded position.

SOUTH TEXAS - UNITS 1 & 2 B 3/4 1-3 Unit 1 - Amendment No. 51 Unit 2 - Amendment No. 40

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 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 safety analyses. The value of 0.95 or less for K includes a 1% ok/k conservative allowance for. uncertainties.

SimilaYly,theboron concentration value of B500-ppm or greater-for-Urri+-1-(2800 ppm or greater -ftrr-tbit 2) includes a conservative uncertainty allowance of 50 ppm boron. The locking closed of the required valves during refueling operations precludes the possibility of uncontrolled boron dilution of the filled portion of the  :

RCS. This action prevents flow to the RCS of unborated water by closing flow paths from sources of unborated water.  !

r 3/4.9.2 INSTRUMENTATION The OPERABILITY of the Source Range Neutron Flux Monitors ensures that l 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 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  ;

safety analyses for the rapid refueling design.

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 in the facility status or core reactivity conditions during CORE ALTERATIONS.

SOUlH TEXAS --UNITS 1 & 2 B 3/4 9-1 Unit 1 - Amendment No. 51 Unit 2 - Amendment No. 40