ML17212A852

Proposed Revisions to Tech Spec Pages B3/4 1-1 & 3/4 1-3 Adding Limitations to Address Mode 5 Operation W/Rcs Partially Drained

ML17212A852
Person / Time
Site:	Saint Lucie
Issue date:	09/28/1981
From:	FLORIDA POWER & LIGHT CO.
To:
Shared Package
ML17212A851	List: ML17212A850 ML17212A852
References
NUDOCS 8110050210
Download: ML17212A852 (3)

Text

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 a The most restrictive condition occurs at EOL, with T aat no load oiIerating temperature, and is associated with a postulated steam line break accident and resulting uncontrolled RCS cooldown. In the analysis of this accident, a minimum

'HUTDOWN MARGIN of 3.3// A, k/k is required to control the reactivity transient. Accordingly, the SHUTDOWN MARGIN required by Specification 3. 1. 1. 1 is based upon this limiting condition and is consistent with FSAR accident analysis assumptions. For earlier periods during the fuel cycle, this value is conservative. With T v < 200 F the reactivity transient resulting from a boron dilution event witk 3 partially drained Reactor Coolant System requires a 2$ h k/k SHUTDOWN MARGIN and restrictions on charging pump ooeration to provide adequate protection. A 2$ a k/k SHUTDOWN MARGIN is 1.0g a k/k conservative for Mode 5 operation with total RCS volume present, however LCO

3. 1. 1.2 is written conservatively for simplicity.

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 11,400 cubic feet in approximately 26 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 limiting values assumed for the MTC used in the accident and transient analyses were + 0.5 x 10 a k/k/'F for THERMAL POWER levels <7(5 of RATED TWERliAL POWER, + 0.2 x 20 c k/k/'F for TERNAL POWER levels > 7OX of RATED THERMAL and -2."2 x 10 ~ k/k/'F at RATED THERMAL POWER. Therefore, these limiting values are included in this specification. Determination of MTC at the specified conditions ensures that the maximum positive and/or negative valUes of the ETC will not exceed the limiting values.

810928&

8l 10050210 05000335 PDR ADOCK P PDRy 83/4 1-1 9-28-81 ST. LUC I E - UNIT 1

REACTIVITY CONTROL SYSTEMS SHUTDOWN MARGIN T ('00 F LIMITING CONDITION FOR OPERATION 3.1.1.2 The SHUTDOWN MARGIN shall be:

> 2.0%a k/k, and in addition with the Reactor Coolant System drained below the hot leg centerline, one charging pump shall be rendered inoperable.*

APPLICABILITY: Mode 5 ACTION:

If the SHUTDOWN MARGIN requirements cannot be met, immediately initiate and continue boration at > 40 gpm of 1720 ppm boron or equivalent until the required SHUTDOWN MARGIN is restored.

SURVEILLANCE RE UIREMENTS 4.1.1.2 The SHUTDOWN MARGIN requirements of Specification 3.1.1.2 shall be

'etermined:

a. Within one hour after detection of an inoperable CEA(s) and at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> thereafter while the CEA(s) is inoperable. If the inoperable CEA is immovable or untrippable, the above required SHUTDOWN MARGIN shall be increased by an amount at least equal to the withdrawn worth of the immovable or untrippable CEA(s).

b. At least once per 24 hours by consideration of the following factors:

. 1. Reactor coolant system boron concentration,

2. CEA position,

3. Reactor coolant system average temperature,

4. Fuel burnup based on gross thermal energy generation,

5. Xenon concentration, and

6. Samarium concentration.

c. At least once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, when the Reactor Coolant Sytem is, drained below the hot leg centerline, by consideration of the factors in 4.1.1.2.b and by verifying at least one charging pump is rendered inoperable.*

• Breaker racked-out.

ST. LUCIE UNIT 1 3/4 1-3 9-28-81

TO: DISTRIBUTION FROP'I: ROBERT E. UFIRIG NRC CORRESPONDENCE ST. LUCI E UN 1'I'S 1 R 2 GO: H. L. Allen PSL 1: A. rU. 13ailey

$ U. B. Derrickson R. R. Jennings H. W. Dotson J. ICrumins P. G. Plugger N. Roos J. FI. Francis N. T. Neems F. P. Green C. M. Nethy IC. N. FIarris Q. C. Supervisor C. S. Kent Steven A. Elrod (NRC)

N. B. Lee J. E. Moaba PSL 2: B. J. Hscue H. N. Paduano Geo. Cromwell A. D. Schmidt N. T. Weems A. H. Siebe D. R. Stone PTP 3/4: H. H. Yaeger J. R. Tomonto J. Vl. Nilliams PT. PIERCE OFC: H. Schindehette C. O. Woody Documentary Piles STUART OFC: Gene Van Curen VJ. PALM BCH. OFC: T. R. Moffet OTHHR: Norman Coll (Steel Hector 8c Davis)

R. R. Mills (Combustion PSLI)

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Harold Reis, Esq. (Lowenstein)

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