ML20029B247

Proposed Tech Spec 3.1.1.3 Re Boron Dilution Sys

ML20029B247
Person / Time
Site:	Arkansas Nuclear
Issue date:	02/25/1991
From:	ENTERGY OPERATIONS, INC.
To:
Shared Package
ML20029B246	List: ML20029B245 ML20029B247
References
NUDOCS 9103060295
Download: ML20029B247 (3)

Text

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z PROPOSED TECHNICAL SPECIFICATION CHANGES t

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9193060295 910225 PDR ADOCK 05000360 P PDR

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PEACTIV1TY CONTROL SYSTEMS BORON OILUTION 3.1.1.3 The flow rate of reactor coolant through the reactor coolant system shall be 22000 gpm whenever a reduction in Reactor Coolant System l boren concentration is being made.

AEPLICABillll: ALL MODES.

ACTION:

With the flow rate of reactor coolant through the reactor c :lant system

<2000 gpm, immediately suspend all operations involving a reuuction in 1 boron concentration of the Reactor Coolant System.

t 4.1.1.3 Yhe flow rate of reactor coolant through the -eactor coolant system shall be determined to be 22000 gpm within one hour prior to the j start of and at least once per hour during a reduction in the Reactor Coolant System boron concentration by either:

a. Verifying at least one reactor coolant pump is in operation, or

b. Verifying that at least one low pressure safety injection pump or containment spray pump is in operation as a shutdown cooling pump and supplying 22000 gpm through the reactor coolant system.

S ARKANSAS - UNIT 2 3/4 1-4 Amendment No.

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).L4.J REACTIVITY CONTROL SYSTEMS

-3/4.1.1 BORATION CONTROL

')/4.1.L 1 and 3/4.1.1.2 SHUTDOWN MARGIN ,

A sufficient SHUTDOWN MARGIN ensures that 1) the reactor can be made subcritical from all operating conditions, 2) the reactivity transients associated with postulated accident conditions ar.s controllable within  ;

acceptable limits, and 3) the reactor will be miintained suf ficiently suberitical to preclude inadvertent criticality in the shutdown condition.

ShuiDOWN MARGIN requirements vary throughout core life as a function.

of fuel depletion, RCS boron concentration, and RCS Tayg. The most restrictive condition of: curs _at EOL, with Tavg.at no load operating

' temperature, and is associated with a postulated steam'line break

' accident,-and resulting uncontrolled RCS cooldown. In the analysis of this accident, a minimum SHUTDOWN MARGIN of 5.5% Ak/k is required to control the reactivity transient. Accordingly, the SHUTDOWN MARGIN. requirement is-based upon this limiting condition and is consistent.with FSAR' safety analysis assumptions. With Tavg 5200*F, the reactivity tr'ansients resulting from any postulated accident are minimal 1 a 5% ak/k shutdown

- margin provides adequate protection.

3/4.1.1.3 -BDRON DILUTIQS i A-minimum flow rcte;of at least 2000 GPM provides adequate mixing, 'l

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1 prevents stratification.and ensures that reactivity changes will be

', . ' gradual during boron concentration reductions in'the Reactor Coolant.

System.-. A; flow-rate of at least 2000 GPM will circulate an equivalent e ' Reactor. Coolant. System volume of 6,650 cubic feet:in approximately 25 l minutes. LThe reactivity change rate associated with boron concentration

-reductions will the efore be within the capability of- o'peratorLrecognition and control.

3/4.1.1.4 MODERATOR TEMPERATURE COEFFICIENT JMTC)

JThe: limitations _on MTC-are provided to ensure.that.the assumptionsu used in the accident:and transient analysis:remainjvalid through each fuel cycle. .The surveillance requirements _ for measurement of the' MTC during P_ . _

each fuel: cycle =are adequate to confirm the MTC value since this coefficient: changes slowly due principally to the reduction in RCS boron.

O tconcentrations associated with fuel burnup. The confirmation that the meas'ured MTC ~value is within- its limit provided assurances that the coef ficient will be maintained rii% acmptable : values throughnut-each

/ fuel cycle.

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ARKANSAS - UNIT 2 .8 3/4 1-1 Amendment No. 2,4. BJ

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