ML17325A345

Proposed Tech Specs,Deleting Requirement to Measure Moderator Temp Coefficient (Mtc) Near End of Cycle,Provided Certain Restrictions on Mtc Met

ML17325A345
Person / Time
Site:	Cook
Issue date:	10/20/1987
From:	AMERICAN ELECTRIC POWER SERVICE CORP.
To:
Shared Package
ML17325A344	List: ML17325A342 ML17325A345
References
NUDOCS 8710260166
Download: ML17325A345 (6)

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I REACTIVITY CONTROL SYSTEMS MODERATOR TEMPERATURE COEFFICIENT LIMITING CONDITION FOR OPERATION 3.1.1.4 The moderator temperature coefficient (MTC) shall be:

a.

Within the region of acceptable operation in Figure 3.1-2, and b.

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Less negative than -3.5 x 10 d,k/k/ F at RATED THERMAL POWER.

APPLICABILITY:

MODES 1 and 2~¹ ACTION:

With the moderator temperature coefficient outside any one of the above limits, be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

SURVEILLANCE RE UIREMENTS 4.1.1.4

~ 1 The MTC shall be determined to be within its limits by confirmatory measurements.

MTC measured values shall be extrapolated and/or compensated to permit direct comparison with the above limits.

4.1.1.4.2 The MTC shall be determined at the following frequencies and THERMAL POWER conditions during each fuel cycle:

a

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b.

Prior to initial operation above 5% of RATED THERMAL POWER, after each fuel loading.

At any THERMAL POWER, within 7 EFPD after reaching a

RATED THERMAL POWER equilibrium boron concentration of 300 ppm, if either of the following conditions are met:

1.

The value for the MTC obtained from the test specjfied in Specification 4.1.1.4.2.a is not within 0.3 x 10 dk/k/ F of its design value.

2.

The end-of-life design MTC is more negative than -3.0 x 10 Ak/k/ F.

With K greater than or equal to 1.0 eff See Special Test Exception 3.10.4 D.

C.

COOK - UNIT 1 3/4 1-5 Amendment No.

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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 Zhe most restrictive condition occurs at EOL, with T at no Po5d operating temperature, and is associated with a postuPafed steam line break accident and resulting uncontrolled RCS cooldown.

In the analysis of this accident, a minimum SHUTDOWN MARGIN of 1.60%

4k/k is initially required to control the reactivity transient.

Accordingly, the SHUTDOWN MARGIN requirement's based upon this limiting condition and is consistent with FSAR accident analysis assumptions.

With T

<350 F, the reactivity transients resulting from a postulated s8e5m line break cooldown are minimal and a 1$

hk/k shutdown margin provides adequate protection.

3 4.1.1.3 BORON DILUTION 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 reductions in the Reactor Coolant System.

A flow rate of at least 3000 GPM will circulate an equivalent Reactor Coolant System volume of 12,612

+ 100 cubic feet in approximately 30 minutes.

The reactivity change rate associated with boron reductions will therefore 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 requirement for measurement of the MTC at the beginning of each fuel cycle is in most cases adequate to confirm the MTC value since this coefficient changes slowly due principally to the reduction in RCS boron concentration associated with fuel burnup.

For cases when the measured beginning of life MTC is substantially different from the calculated value or the calculated end of cycle MTC is close to the limiting value, an additional MTC measurement is required near the end of the cycle.

The confirmation that the measured and appropriately compensated MTC value is within the allowable tolerance of the predicted value provides additional assurances that the coefficient will be maintained within its limits during cycle operation.

D.

C.

COOK - UNIT 1 B 3/4 1-1 Amendment No.

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REACTIVITY CONTROL SYSTEMS SURVEILLANCE RE UIREMENTS 4.1.1.4 The MTC shall be determined to be within its limits during each fuel cycle as follows.

The MTC shall be measured and compared to the BOL limit of Specification 3.1.1.4.a, above, prior to initial operation above 5% of RATED THERMAL POWER, after each fuel loading.

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If the BOL MTC measurement is not within 0.3 x 10 hk/k/ F of the calculated BOL MTC value or the EOL design MTC is more negative than -3.4 x 10 6 k/k/ F (all rods withdrawn, RATED THERMAL POWER condition) then the MTC shgll be measured at any THERMAL POWER and compared to -3.0'x 10 Ak/k/ F (all rods withdrawn, RATED THERMAL POWER condition) within 7 EFPD after reaching an equilibrium boron concentration of 300 ppm.

In the event this4comparison indicates the MTC is more negative than

-3.0 x 10 hk/k/ F, the MTC shall be remeasured and compared to the EOL MTC limit of Specification 3.1.1.4.b, at least once per 14 EFPD during the remainder of the fuel cycle.

D.

C.

COOK - UNIT 2 3/4 1-6 Amendment No.

ly 3 4.1 REACTIVITY CONTROL SYSTEHS BASES 3 4.1.1.4 MODERATOR TEMPERATURE COEFFICIENT MTC The limitations on HTC are provided to ensure that the value of this coefficient remains within the limiting conditions assumed for this parameter in the FSAR accident and transient analyses.

The MTC values of this specification are applicable to a specific set of plant conditions; accordingly, verification of HTC values at conditions other than those explicitly stated will require extrapolation to those conditions in order to permit an accurate comparison.

It is confirmed by cycle specific neutronic analyses that the value of the HTC at

EOC, HZP (All rods in) is greater than the value at

EOC, HFP (All rods out),

thus assuring that the surveillance at the latter condition, if required, is adequate to maintain MTC within safety analysis assumptions.

The surveillance requirement for measurement of the MTC at the beginning of each fuel cycle is in most cases 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.

For cases when the measured beginning of life MTC is substantially different from the calculated value or the calculated end of cycle HTC is close to the limiting value, an additional MTC measurement is required.

This additional measurement near the end of the cycle provides extra assurance that the HTC value is maintained within the allowable limits.

3 4.1.1.5 HINIMUM TEMPERATURE FOR CRITICALITY This specification ensures that the reactor will not be made critical with the Reactor Coolant System average temperature less than 541 F.

This 0

limitation is required to ensure

1) the moderator temperature coefficient is within its analyzed temperature

range,

2) the protection instrumentation is within its normal operating range,

3) the pressurizer is capable of being in a OPERABLE status with a steam bubble, and 4) the reactor pressure vessel is above its minimum RT T temperature.

Administrative procedures will be established to ensure (Pie P-12 blocked functions are unblocked before taking the reactor critical..

3 4.1.2 BORATION SYSTEMS The boron injection system ensures that negative reactivity control is available 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,

5) associated heat tracing systems, and 6) an emergency power supply from OPERABLE diesel generators.

D.

C.

COOK - UNIT 2 B 3/4 1-2 Amendment No.

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