ML20040A520

Proposed Revision to Tech Spec Section 3/4.1.1,changing Limiting Condition for Operation,Surveillance Requirements & Bases for Shutdown Margin Required in Modes 1-4

ML20040A520
Person / Time
Site:	Millstone
Issue date:	01/30/1982
From:	NORTHEAST NUCLEAR ENERGY CO.
To:
Shared Package
ML20040A516	List: ML20040A515 ML20040A520
References
TAC-47355, TAC-47389, TAC-47473, NUDOCS 8201210205
Download: ML20040A520 (3)

Text

Docket No. 50-336 Attachment l Millstone Nuclear Power Station, Unit No. 2 4

Proposed Revisions to Technical Specifications January, 1982

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3/4.1 REACTIVITY CONTROL SYSTEMS 3/4.1.1 BORAT10N CONTROL SHUTDOWN MARGIN - T,yg > 200*F LIMITING CONDITION FOR OPERATION 3 .1.1.1 The SHUTDOWN MARGIN shall be 1 2.90% ok/k.

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

ACTION:

With the SHUTDOWN MARGIN < 2.10% ak/k, immediately initiate and continue boration at 1 40 gpm until the required SHUTDOWN MARGIN is restored.

SURVEILLANCE REQUIREMENTS

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4 .1.1.1.1 The SHUTDOWN MARGIN shall be determined to be 3 2.9 0% ok/k :

Immediately upon detection of an inoperaole CEA. If the e.

inoperable CEA is imnovable or untrippable, the SHUTDOWN MARGIN, required by Specification 3.1.1.1, shall be increased by an amount at least equal to the withdrawn worth of the immovable or untriprable CEA. .

b. Vhen in MODES I or 2, at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by verifying that CEA group withdrawal is within the Transient Insertion Limits of Specification 3.1.3.5. .

c. Prior to initial operation above 5% RATED THERMAL POWER after each refueling, with the CEA groups at the Transient Insertion Limits of Specification 3.1.3.6.

See Special Test Exception 3.10.1.

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MILLSTONE - UNIT 2 3/4 1-1

e 3/4.1 REACTIVITY CONTROL SYSTEMS BASES 3/4.1.1 BORATION CONTROL 3/4.1.1.1 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 are controllable within acceptable limits, and 3) the reactor will be maintained sufficiently subcritical to preclude inadvertent criticality in the shutdown condition.

SHUTDOWN MARGIN requirements vary throughout core life as a function of fuel depletion, RCS boron concentration, and RCS T,yg. The most restrictive condition occurs at EOL, with T, 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 2.9% ak/k is initially required to control '

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the reactivity transient. Accordingly, the SHUTDOWN MARGIN required by Specification 3.1.1.1 is based upon this limiting condition For earlierand is con-periods sistent with FSAR accident analysis assumptions.

during the fuel cycle, this value is conservative. With T 1 200*f, the reactivity transients resulting from any postulated accident arc minimal and a 21 ak/k shutdown margin provides adequate protection.

3/4.1.1.3 BORON DILUTION AND ADDITION A minimum flow rate of at least 3000 GPM provides adequate mixing, prevents stratification and ensures that reactivity changes will be gradual during boron concentration changes in the Reactor Coolant System.

A flow rate of at least 3000 GPM will circulate an equivalent Reactor Coolant System volume of 10,060 + 700/-0 cubic feet in approximately 30 minutes. The reactivity change rate associated with boron concentration changes will be within the capability for operator recognition and control.

3/4.1.1.4 MODERATOR TEMPERATURE COEFFICIENT (MTC)

The limitations on MTC are provided to ensure that the assumptions used in the accident and transient analyses remain valid through each fuel cycle. The surveillance requirements for measurement of the MTC during each fuel cycle are adequate to confirm the MTC value since this coefficient changes slowly due principally to the reduction in RCS boron concentration associated with fuel burnup. The confirmation that the I neasured MTC value is within its limit provides assurance that the co-efficient will be maintained within acceptable values throughout each fuel cycle.

l MILLSTONE - UNIT 2 B 3/4 1-1 B