ML20044H115

Amends 51 & 40 to Licenses NPF-76 & NPF-80,respectively, Changing App a TS by Revising Limiting Conditions for Operation of TS 3.2.1.5,3.2.1.6,3.5.5 & 3.9.1

ML20044H115
Person / Time
Site:	South Texas
Issue date:	05/25/1993
From:	Black S Office of Nuclear Reactor Regulation
To:
Shared Package
ML20044H116	List: ML20044H115 ML20044H117
References
NUDOCS 9306070420
Download: ML20044H115 (19)

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Io UNITED STATES g

NUCLEAR REGULATORY COMMISSION g

nE WASHINGTON, D. C, 20555 k..... /

HOUSTON LIGHTING & POWER COMPANY l

i CITY PUBLIC SERVICE BOARD OF SAN ANTONIO CENTRAL POWER AND LIGHT COMPANY-CITY OF AUSTIN. TEXAS DOCKET NO. 50-498 SOUTH TEXAS PROJECT. UNIT 1 AMENDMENT TO FACILITY OPERATING LICENSE i

Amendment No. 51 License No. NPF-76 i

1.

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

A.

The application for amendment by Houston Lighting & Power Company *

(HL&P) acting on behalf of itself and for the City Public Service Board of San Antonio ~(CPS), Central Power and Light Company (CPL), and City of Austin, Texas (C0A) (the licensees) dated January 14, 1993,.

i complies with the 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; B.

The facility will operate in conformity with the application, as amended, the provisions of the Act, and the rules and regulations of-the Comission; C.

There is reasonable assurance:

(i) that the' activities authorized by this amendment can be conducted without endangering the health.and safety of the public, and-(11) that such activities will be conducted in compliance with the Comission's regulations;-

D.

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

1 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.

1

• Houston Lighting & Power Co'npany is authorized to act for the City Public Service Board of San Antonio, Central Power and; Light Company and City of Austin, Texas and has exclusive responsibility and control over the physical construction, operation and maintenance of the facility.

9306070420 930525 PDR ADOCK-0500 8

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.- 2.

Accordingly, the license is amended by changes to the Technical Specifi-cations as indicated in the attachment to this license amendment and Paragraph 2.C.(2) of Facility Operating License No. NPF-76 is hereby amended to read as follows:

2.

Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No.

51, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.

3.

The license amendment is effective as of its date of issuance and to be implemented not later than the completion of the third refueling outage for Unit 2.

FOR THE NUCLEAR REGULATORY COMMISSION

._ k

[ Suzanne C. Black, Director 4

Project Directorate IV-2 Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical Specifications Date of Issuance:

May 25, 1993 4

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UNITED STATES NUCLEAR REGULATORY COMMISSION o

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E W ASHINGTON, D. C. 20555

\\...../

HOUSTON LIGHTING & POWER COMPANY CITY PUBLIC SERVICE BOARD OF SAN ANTONIO CENTRAL POWER AND LIGHT COMPANY CITY OF AUSTIN. TEXAS

. DOCKET NO. 50-499 SOUTH TEXAS PROJECT. UNIT _Z AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 40 License No. NPF-80 1.

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

A.

The application for amendment by Houston Lighting & Power Company *

(HL&P) acting on behalf of itself and for the City Public Service Board of San Antonio (CPS), Central Power and Light Company (CPL), and City of Austin, Texas (C0A) (the licensees) dated January 14, 1993, 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, as amended, the provisions of the Act, and the-rules and regulations of the Commission; C.

There is reasonable assurance:

(i) that the activities authorized by l

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 license 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.

i

• Houston Lighting & Power Company is authorized to act for the City Public Service Board of San Antonio, Central Power and Light Company and City of Austin, Texas and has exclusive responsibility and control over the physical

. construction, operation and maintenance of the facility.

j

.- 2.

Accordingly, the license is amended by changes to the Technical Specifi-cations as indicated in the attachment to this license amendment and Paragraph 2.C.(2) of Facility Operating License No. NPF-80 is hereby amended to read as follows:

2.

Technical Specifications The Technical Specifications contained in Appendix A, as revised through Amendment No.

40, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications and the Environnental Protection Plan.

3.

The license amendment is effective as of its date of issuance and to be implemented not later than the completion of the third refueling outage for Unit 2.

FOR THE NUCLEAR REGULATORY COMMISSION Suzanne C. Black, Director Project Directorate IV-2 Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical Specifications Date of Issuance:

May 25, 1993 G

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ATTACHMENT TO LICENSE AMENDMENT NOS. 51 AND 40 FACILITY OPERATING LICENSE NOS. NPF-76 AND NPF-80 DOCKET NOS. 50-498 AND 50-499 Replace the following pages of the Appendix A Technical Specifications with the attached pages. The revised pages are identified by Amendment number and contain vertical lines indicating the areas of change. The corresponding overleaf pages are also provided.to maintain document completeness.

REMOVE INSERT 3/4 1-13 3/4 1-13 3/4 1-14 3/4-1-14 3/4 5-1 3/4 5-1 3/4 5-10

-3/4 5-10 3/4 9-1 3/4 9-1 B 3/4 1-2 B 3/4 1-2' B 3/4 1-3 B 3/4 1-3 B 3/4 9-1 B 3/4 9-1 5

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I REACTIVITY CONTROL SYSTEMS BORATED WATER SOURCES - SHUTDOWN i

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

a.

A Boric Acid Storage System with:

1)

A minimum contained borated water volume of 2900 gallons for Unit I and 3200 gallons for Unit 2, 2)

A minimum boron concentration of 7000 ppm, and 1

3)

A minimum solution temperature of 65'F.

b.

The refueling water storage tank (RWST) 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 ppm for Unit I and between 2800 ppm and 3000 ppm for Unit 2.

APPLICABILITY: MODES 5 and 6.

ACTION:

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

SURVEILLANCE RE0VIREMENTS 4.1.2.5 The above required borated water source shall be demonstrated OPERABLE at least once per 7 days by:

a.

Verifying the boron concentration of the water, b.

Verifying the contained borated water volume, and Verifying the boric acid storage tank solution temperature when it c.

is the source of borated water.

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

4 REACTIVITY CONTROL SYSTEMS B0 RATED WATER SOURCES - OPERATING LIMITING CONDITION FOR OPERATION 3.1.2.6 As a minimum, the' following borated water-source (s) shall be OPERABLE as required by Specification 3.1.2.2 for MODES 1, 2, and 3 and one of the following borated water sources shall be OPERABLE as required by Specification 3.1.2.1 for MODE 4:

l 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 i

3)

A min'imum. solution temperature of 65'F.

b.

The refueling water storage tank (RWST) with:

1)

A minimum contained borated water volume of 458,000 gallons, t

and 2)

A boron concentration between 2500 ppm and.2700 ppm for Unit 1 and between 2800 ppm and 3000 ppm for Unit'2.

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

ACTION:

With the Boric Acid Storage System inoperable and being used as.one a.

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-i 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 i

in COLD SHUTDOWN 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

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 hours 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 SOUTH TEXAS - UNITS 1 & 2 3/4 1-14 Unit 1 - Amendment No. 51 Unit 2 - Amendment No. 40 i

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'I 3/4.5 EMERGENCY CORE COOLING SYSTEMS 3/4.5.1 ACCUMULATORS LIMITING 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 2400 and 2700 ppm for Unit I and between 2700 ppm and 3000 ppm for Unit 2.

d.

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

APPLICABIllTY: MODES 1, 2, and 3*.

ACTION:

I:

a.

With one' accumulator inoperable, except as a resultLoff a closed isolation va've or the boron concentration outside the required limits, restore the inoperable cccumulator 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 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 />.

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

limit, restore the boron concentration to within the required limits 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 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 />.

SURVEILLANCE RE0VIREMENTS

• 4.5.1.1 Each accumulator shall be demonstrated OPERABLE:

i 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 u

l verifying the boron concentration of the accumulator solution; and i

• Pressurizer pressure above 1000 psig.

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

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EMERGENCY CORE COOLING SYSTEMS

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SURVEILLANCE REOUIREMENTS-(Continued) j c.

At least once per-31 daysfwhen the RCS pressure is above 1000 psig-by verifying,that power to the isolation valve operator.is removed.

i d.

At least once per 18 months by verifying that each accumulator isola-

+

tion valve opens automatically under each of the following conditions:-

1)

When an actual or aLsimulated RCS pressure signal exceeds the P-11 (Pressurizer Pressure Block of Safety Injection) Setpoint, and l

2)

Upon receipt of a Safety Injection test signal.

4.5.1.2-Each accumulator water level and pressure channel shall be demon--

stratet OPERABLE:

~

At least once per 31 days by the performance'of an ANALOG CHANNEL a.

OPERATIONAL TEST, and b.

At least once per 18 months by. the performance of a CHANNEL CALIBRATION.

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- 3/4 5-2

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EMERGENCY CORE COOLING SYSTEMS l

3/4.5.4 (This specification number is not used.)

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SOUTH TEXAS - UNITS 1 & 2 3/4 5-9 l

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

a.

A minimum' contained borated water volume of 458,000. gallons, and b.

A boron concentration between 2500 ppm and 2700 ppm for Unit I and-f between 2800 ppm and 3000 ppm for Unit 2.

-l APPLICABILITY: MODES 1, 2, 3, and 4.

t ACTION:

i With the RWST inoperable, restore the tank to OPERABLE status within I hour or

(

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 i

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

i SURVEILLANCE RE0VIREMENTS I

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

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Verifying the contained borated water volume in' the tank, and

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a.

b.

Verifying the boron concentration of the water.

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. SOUTH TEXAS - UNITS 1 & 2

'3/4 5-10 Unit 1 - Amendment No. 51 i

Unit E - Amendment No. 40 l

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3/4.9 REFUELING OPERATIONS

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3/4.9.1 BORON CONCENTRATION i

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l LIMITING CONDITION FOR OPERATION I

3.9.1 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; either:

a.

A K,,, of 0.95 or less, or b.

A boron concentration of greater than or equal to 2500 ppm for Unit-I and'2800 ppm for Unit 2.

APPLICABILITY: MODE 6.*

ACTION:

I With'the requirements of the above specification-not satisfied, immediately suspend all operations involving CORE ALTERATIONS or positive reactivity l

changes and initiate and continue boration at greater than or equal to 30 gpm of a solution containing greater than or equal to_7000 ppm boron or its equivalent until K,,, is reduced to less than or equal to 0.95 or the boron

't concentration is restored to greater than or equal to 2500' ppm for Unit 1.and-2800 ppm for Unit 2, whichever is the more restrictive.

SURVEILLANCE RE0VIREMENTS l

l 1

l 4.9.1.1 The more restrictive of the above two reactivity conditions shall be i

determined prior to:

Removing or unbolting the reactor vessel' head, and a.

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 i

i refueling canal 'shall be determined by chemical analysis at least once per 72 l

hours.

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4.9.1.3 Valves FCV-110B, FCV-IllB, CV0201A, and'CV0221 shall be verified i

closed and secured in position by mechanical stops or by removal of air _or l

electrical power at least once per 31 days.

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• The reactor shall be maintained in MODE 6 whenever fuel is in the-reactor vessel with the vessel head closure bolts less than fully tensioned or with i

the head removed.

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SOUTH TEXAS - UNITS 1 & 2 3/4_9-1 Unit 1 - Amendment No. 51 Unit 2 - Amendment No. 40 j

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REFUELING OPERATIONS 3/4.9.2 INSTRUMENTATION j

LIMITING CONDil10N FOR OPERATION j

3.9.2 As 'a minimum, two Source Range Neutron Flux Monitort shall be OPERABLE, each with continuous visual indication in the control roor. and one with audible indication in the containment and control room.

t APPLICABILITY:

MODE 6.

i ACTION:

P a.

With one of the above required monitors inoperable or not operating, immediately suspend all operations involving CORE ALTERATIONS or positive reactivity changes.

b.

With both of the above required monitors inoperable or not operating, determine the boron concentration of the Reactor Coolant System at least once per.12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

SURVEILLANCE RE0VIREMENTS 4.9.2 Each Source Range Neutron Flux Monitor shall be' demonstrated OPERABLE Dy performance of:

a.

A CHANNEL CHECK at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, b.

An ANALOG CHANNEL OPERATIONAL TEST within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> prior to the initial start of CORE ALTERATIONS, and c.

An ANALOG CHANNEL OPERATIONAL TEST at least once per 7 days.

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SOUTH TEXAS - UNITS 1 & 2 3/4 9-2 l

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3/4.1 REACTIVITY CONTROL SYSTEMS t

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k BASES

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1 3/4.1.1 BORATION CONTROL j

3/4.1.1.1 and 3/4.1.1.2 SHUTDOWN MARGIN i

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A sufficient SHUTDOWN MARGIN ensures that:(1) the reactor can be made i

ciated with postulated accident conditions are controllabl j

limits, and (3) the reactor will be maintained sufficiently suberitical to i

preclude inadvertent criticality in the shutdown condition.

4 SHUTDOWN MARGIN requirements vary throughout core life as a function of l

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fuel depletion, RCS boron concentration, and RCS T,,.

In MODES I and 2, the i

most restrictive condition occurs at EOL, with T,yg,t no load operating a

temperature, and is associated with a postulated steam line break accident and-l resulting uncontrolled RCS cooldown.

In the analysis of this accident, a l

minimum SHUTDOWN MARGIN of 1.75% Ak/k is required to control the reactivit 1

transient.

The 1.75% Ak/k SHUTDOWN MARGIN is the design basis minimum for the 14-foot fuel using silver-indium-cadmium and/or Hafnium control rods (Ref. FSAR i

3 Table 4.3-3).

Accordingly, the SHUTDOWN MARGIN requirement for MODES I and 2l l

is based upon this limiting condition and is consistent with FSAR safety anal-ysis assumptions.

at BOL, when the beren concentration is the greatest.In MODES 3, 4, an i

In these modes the j

reovirement, which is a function of the RCS boron concentratio

~

SHUTDOWN MARGIN requirement of 1.75% Ak/k is based _on an uncontrolled RC The constant i

down from a steamline break accident.

is based on the results of a boron dilution accident analysis, where the S i

i DOWN MARGIN is varied as a function of RCS boron concentration, to guarante j

minimum of 15 minutes for operator action after a boron dilution alarm, prior j

to a loss of all SHUTDOWN MARGIN.

The boron dilution analysis assumed a common RCS volume, and maximum-1 dilution flow rate for MODES 3 and 4, and a different volume and flow rate for with the RHR system only. MODE 5. The MODE 5 conditions assumed limi 4

reactor coolant pump was operating.In MODES 3 and 4 it was assumed that at least o If at least one reactor coolant pump is i

not operating in MODE 3 or 4 then the SHUTDOWN MARGIN requirements for MODE i i

shall apply.

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4 3/4.1.1.3 MODERATOR TEMPERATURE COEFFICIENT i-to ensure that the value of this coefficient remains within a

condition assumed in the FSAR accident and transient analyses.

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The MTC values of this specification are applicable to a specific set of plant conditions; accordingly, verification of MTC values at conditions other I

than those explicitly stated will require extrapolation to those conditions in

]

1 order to permit an accurate comparison.

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F SOUTH TEXAS - UNITS 1 & 2 8 3/4 1-1 Unit 1 - Amendment No.10 1

Unit 2 - Amendment No. 2

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REACTIVITY CONTROL SYSTEMS I

BASES l

MODERATOR TEMPERATURE COEFFICIENT (Continued)

The most negative MTC value,- equivalent to the most positive moderator i

density coefficient. (MDC), was obtained by incrementally correcting the MDC used in the FSAR analysis to nominal operating conditions. These corrections 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 the MDC values used in the FSAR analysis into the limiting E0L 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.

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 burnup.

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 its minimum RT, terperature.

3/4.1.2 B0 RATION SYSTEMS The Boron Injection System ensures that negative reactivity control is availabic 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, and (5) an emergency power supply from OPERABLE diesel generators.

WiththeRCSaveragetemperatureabove350*F,aminimumofLtwo! boron injection flow paths are required to ensure'. single ~ functional capability in i

.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 l

cooldown to 200*F. The maximum expected boration capability requires 27,000 i

gallons of 7000 ppm borated water from the boric acid storage 1 system or 458,000 gallons of 2500 ppm borated water for Unit 1 (2800 ppm for Unit 2) from the refueling water storage tank'(RWST). The RWST volume is an ECCS requirement and is more than adequate for.the required boration capability.

SOUTH TEXAS.- UNITS 1 & 2-B 3/4 1-2 Unit 1 - Amendment No.. N M, ' 51 Unit 2 - Amendment No. W, M,- 40 1

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REACTIVITY CONTROL SYSTEMS BASES B0 RATION SYSTEMS (Continued)

With the RCS temperature below 350*F, one boron injection flow O

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.

i 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.

h e boration capability' required below 200*F is sufficient to provide a va-table SHUTDOWN MARGIN based on the' results of a baron dilution accident analysis where the SHUTDOWN MARGIN is varied as a function of RCS boron concentration after xenon decay and cooldown from 200*F to 140*F. This I

condition requires either 2900 gallons for Unit 1 (3200 gallons for Unit 2) of 7000 ppm borated water from the boric acid surage system or 122,000 gallons of 2500 ppm borated water for Unit 1 (2800 ppm for Unit ?) from the RWST for-MODE 5 and 33,000 gallons of 2500 ppm borated water for Unit 1 (2800 ppm for Unit 2) from the RWST for MODE 6.

The contained water volume' limits include allowance for water-not available because of discharge line locaticn and other physical ~

characteristics.

The limits on contained water volume and boron ~ 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 ASFotP M ]

The specifications of this section ensure that:

(1) acceptable power distribution limits are maintained,-(2) the minimum SHUTDOWN MARGIN is 3

maintained, and (3) the potential effects of rod misalignment 'en associated 2

accident analyses are limited. OPERABILITY of the control rod position indicators is required to deterinine 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 i 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 - t indicate the actual shutdown. rod' position between 18 steps and 234 steps, c V y points in the indicated ranges are picked for verification of agreement wi a demanded position.

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

e T

REACTIVITY CONTROL SYSTEMS BASES MOVABLE CONTROL ASSEMBLIES (Continued)

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.

Misaligr. ment of a rod requires measurement of peaking factors and a restriction in THERMAL POWER.

Th2se restrictions pro-vide assurance of fuel rod integrity during continued operation.

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

The maximum rod drop time. restriction is consistent with the assumed rod drop time used in the safety analyses.

Measurement with T,yg greater than or equal to 561*F and with all reactor coolant pumps operating ensures that the measured drop times will be representative of insertion times experienced -

during a Reactor trip at operating conditions.

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 <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> wit. sore fre-

- quent verifications required if an automatic monitoring channel'is inoperable.

These verification frequencies are adequate for assuring that the applicable LCOs are satisfied.

SOUTH TEXAS -' UNITS 1 &'2' B 3/4 1 1

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3/4.9 REFUELING OPERATIONS BASES l

3/4.9.1 BORON CONCENTRATION:

The limitations on reactivity conditions during REFUELING ensure that:

l (1) the reactor will remain 'subcritical during CORE ALTERATIONS, and (2) a uniform boron concentration lis 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% Ak/k conservative allowance for uncertainties. SimilN1y,theboron

~l l

concentration value of 2500 ppm or greater for Unit _1 (2800 ppm or greater.for l

Unit 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.

(

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.

L 3/4.9.3 DECAY TIME l

l l

l The minimum requirement for reactor subtriticality prior to movement of l

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 l

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 sufficien' to restrict radioactive material release L

from a fuel element rupture based upon the lack of containment pressurization L

potential while in the REFUELING MODE.

i 3/4.9.5 COMMUNICATIONS The requirement for communications capability ensures that refueling I

station personnel can be promptly informed of significant changes in the l

facility status or core reactivity conditions during CORE ALTERATIONS.

I SOUTH TEXAS - UNITS 1 & 2 B 3/4 9-1 Unit 1. - Amendment No. 51 l

Unit 2 - Amendment ?!o. 40

i REFUELING OPERATIONS l

BASES I

3_/4.9.6 REFUELING MACHINE The OPERABILITY requirements for the refuelin'g machine and auxiliary hoist ensure that: (1) the refueling machine and auxiliary hoist will be used for movement of drive rods and fuel assemblies',1 (2) the refueling machine has sufficient load capacity to lift a drive rod or fuel assembly, and (3);the core internals and reactor vessel are protected from' excessive lifting force in the.

event they are inadvertently engaged during lifting operations.

3/4.9.7 CRANE TRAVEL - FUEL HANDLING BUILDING The restriction on movement o^ loads in excess of the nominal weight of a fuel and control rod assembly and associated handling tool over other fuel l

assemblies in the storage pool, unless handled by the single-failure proof main hoist of the FHB 15-ton crane, ensures that in the event this load is dropped:

(1) the activity release will be limited to that contained in a single fuel-l 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 safety analyses.

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 vessel below 140 F as required during the REFUELING MODE, and (2) sufficient coolant circulation is maintained through the 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 vessel flange ensures that a single failure of the operating RHR loop will not result in a complete loss of residual heat removal capability. With the reactor vessel head removed. and at 1(ast 23 feet i

of water above the reactor pressure vessel flange, a large heat sink is avail-able for core cooli.ng. Thus, in the event of a failure of_ the operating RHR loop, adequate time is provided to initiate emerger;y procedures to cool the core.

l 3/4.9.9 CONTAINMENT VENTILATION ISOLATION SYSTEM The OPERABILITY of this system ensures that.the containment purge and l

exhaust penetrations will be automatically isolated upon detection of high f

radiation levels in the purge exhaust.

The OPERABILITY of this system is required to restrict the release of radioactive material from the containment atmosphere to the environment.

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SOUTH TEXAS - UNITS 1 & 2 B 3/4 9-2 i

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