ML20204F719

Proposed Changes to Tech Specs 3.3.3.2,4.2.1.2,4.2.2.1, 4.2.2.2 & 4.2.3.2 Re Operation of in-core Instrumentation Sys

ML20204F719
Person / Time
Site:	Yankee Rowe
Issue date:	07/31/1986
From:	YANKEE ATOMIC ELECTRIC CO.
To:
Shared Package
ML20204F703	List: ML20204F699 ML20204F719
References
NUDOCS 8608040287
Download: ML20204F719 (5)

Text

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POWER DISTRIBUTION LIMITS SURVEILLANCE REQUIREMENTS (Continued) 4.2.1.2 The below factors shall be included in the calculation of peak full power LHCR:

Heat flux power peaking factor, F, measured using incore insgrumentation a.

at a power >10%.

b.

The multiplier for xenon redistribution is a function'of core' lifetime as given in Figure 3.2-3.

In addition, if Control Rod Group C 19 inserted below 80 inches, allowable power may not be regained until pcwer has been at a reduced level defined below for at least twenty-four hours with Control Kod Group C between 80 and 90 inches.

Reduced Power = Allowable fraction of full power times multiplier given in Figure 3.2-4.

Exceptions:

1.

If the rods are inserted below 80 inches and power deus not go below the reduced power calculated above, hold at the lowest attained power level for at least twenty-four hours with Control Rod Group C between 80 and 90 inches before returning to allowable power.

2.

If the rods are inserted below 80 inches and zero power le held for more than forty-eight hours, no reduced power level need be held on the way to the allowable fraction of full power.

c.

Shortened stack height factor, 1.009.

d.

Measurement uncertainty:*

1, 1.05, when at least 17 incore detection system neutron detector thimbles are OPERABLE, or 2,

1.068, when less than 17, and greater than or equal to 12, incore l

detection system neutron detector thimbles are OPERABLE, or 3.

1.080, when less than 12, and greater than or equal to 9, incore detection system neutron detector thimbles are OPERABLE.

YANKEE-ROWE 3/4 2-2 Amendment No. 43, 53, 72, 77, 88 8600040287 860731 PDR ADOCK 05000029 P

PDR

POWER DISTRIBUTION LIMITS SURVEILLANCE REQUIREMENTS 4.2.2.1 F shall be determined to be within its limit by:

q a.

Using the movable incore detectors to obtain a power distribution map:

1.

Prior to initial operation above 75% of RATED THERMAL POWER after each fuel loading, and 2.

At least once per 1000 Effective Full Power Hours, b.

Increasing the measured F component of the power distribution map q

by:

1.

4% to account for engineering tolerances, 2.

5% when at least 17 incore detection system neutron detector thimbles are OPERABLE, to account for measurement uncertainty, t

3.

6.8% when less than 17, and greater than or equal to 12, incore detection system neutron detector thlmbles are OPERABLE, to account for measurement uncertainty, 4.

8.0% when less than 12, and greater than or equal to 9, incore detection system neutron detector thimbles are OPERABLE, to account for measurement uncertainty, and 5.

3% to account for fuel densification.

4.2.2.2 When F la measured pursuant to Specification 4.10.2.2, an overall q

measured F shall be obtained from a power distribution map and increased by:

q 1.

4% to account for engineering tolerances, 2.

5% when at least 17 incore detection system neutron detector thlmbles are OPERABLE, to account for measurement uncertainty, 3.

6.8% when less than 11, and greater than or equal to 12, incore l

detection system neutron detector thimbles are OPERABLE, to account for measurement uncertainty, 4.

8.0% when less than 12, and greater than or equal to 9. Incore detection system neutron detector thlmbles are OPERABLE, to account for measurement uncertainty, and 5.

3% to account for fuel densification.

4.2.2.3 The provisions of Specification 4.0.4 are not applicable.

YANKEE-ROWE 3/4 2-9 Amendment No. 53, 72, 77

f.

POWER DISTRIBUTION LIMITS SURVEILLANCE REQUIREMENTS 4.2.3.1 FEAH shall be determined to be within its limit by using the movable incore detectors to obtain a power distribution map:

a.

Prior to operation above 75% RATED THERMAL POWER after each fuel loading, and

.b.

At least once per 1000 Effective Full Power Hours, c.

The provisions of Specification 4.0.4 are not applicable.

4.2.3.2 The measured FNAH of 4.2.3.1 above shall be increased, for I

measurement uncertainty, by:

a.

5%, when at least 17 incore detection system neutron detector thimbles are OPERABLE; or b.

6.8%, when less than 17, and greater than or equal to 12, incore l

detection system neutron detector thimbles are OPERABLE, or c.

8.0%, when less than 12, and greater than or equal to 9, incore detection system neutron detector thimbles are OPERABLE.

?

d 4

YANKKE-ROWE 3/4 2-11 Amondmont flo. 43, 53, 72, 77

f INSTRUNENTATION INCORE DETECTION SYSTEM LIMITING CONDITIONS FOR OPERATION 3.3.3.2 The incore detection system shall be OPERABLE with:

a.

At least twelve (12) neutron detector thimbles OPERABLE.

b.

A minimum of two (2) OPERABLE neutron detector thimbles per core quadrant, and c.

Sufficient OPERABLE movable neutron detectors, drive and readout equipment to map these thimbles.

Exception:

For Cycle 18, Items a and b above are not required if operation is at or beyond 4,000 MWD /MTU. However, there shall be at least nine (9) detector thimbles OPERABLE and a minimum of one (1) OPERABLE neutron detector thimbles per quadrant.

+>I, APPLICABILITY: When the incore detection system is used for core power distribution measurements.

ACTION With the incore detection system inoperable, do not use the system for the above applicable monitoring or calibration functions. The provisions of Specifications 3.0.3 and 3.0.4 are not applicable.

SURVEILtAMCE REOUIREMENTS 4.3.3.2 The incore neutron detectors shall be demonstrated OPERABLE by normalizing each detector output to be used within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> prior to its use for core power distribution measurements.

YANKEE-ROWE 3/4 3-23 Amendment No. 49, 53, 72, 77, 95

3/4.2 POWER DISTRIBUTION LIMITS i

BASES (Continued)

The limits on power level and control rod position following control rod insertion were selected to prevent exceeding the maximum allowable linear heat generation rate limits in Figure 3.2-1 within the first few hours following return to power after the insertion. With Yankee's highly damped core, the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> hold allows sufficient time for the initial xenon maldistribution to accommodate itself to the new power distribution. The restriction on control rod location during these 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> assures that the return to alicwable fraction of full power will not cause additional redistribution due to rod motion.

Af ter 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> at zero power, the average xenon concentration has decayed to about 20% of the full power concentration. Since the xenon concentrations are so low, an increase in power directly to maximum allowable power creates transient peaking well below the value imposed by the xenon redistribution multiplier. Thus, any increase in power peaking due to this operation is below the value accounted for in the calculation of the LHGR.

These conclusions are based on plant tests and cn calculations performed with the SINULATE three dimensional nodal code used in the analysis of Core XI (reference cycle) described in Proposed Change No. 115, dated March 29, 1974.

The Factors d, e, and f in Specification 4.2.1.2 will be combined statistically as the " root-sum-square" of the individual parameters. This method for combining parameter uncertainties is valid due to the independence of the parameters involved.

Factor d accounts for uncertainty in the power distribution measurement with the movable incore instrumentation system.

Factor e accounts for uncertainty in the calorimetric measurement for determining core power level. Factor f accounts for uncertainty in engineering and fabrication tolerances of the fuel. Together these factors, when combined statistically, yield an uncertainty of 9.4% for less th'an 12 operating thimbles, 8.5% for less than 17, and greater than or equal to 12 cperating incore thimbles and 7.1% for greater than 17 operating thimbles.

This factor and Factors a, b, c, and g will be combined multiplicatively to obtain peak LHGR values.

3/4.2.2 and 3/4.2.3 HEAT FLUX HOT CHANNEL FACTOR AND NUCLEAR ENTHALPY RISE HOT CHANNEL FACTOR The limits on heat flux and enthalpy hot channel factors ensure that

1) the design limits on peak local power density and minimum DNBR are not exceeded, and 2) in the event of a LOCA the peak fuel clad temperature will 0

not exceed the 2200 F ECCS acceptance criteria limit.

Each of these hot channel factors are measurable but will normally only be determined periodically as specified in Specification 4.2.2.1 and 4.2.3.1.

This periodic surveillance is sufficient to insure that the hot channel factor limits are maintained provided:

YANKEE-ROWE B3/4 2-2 Amendment No. 43, 88