ML20247M632

Proposed Tech Specs Re Power Distribution Limits

ML20247M632
Person / Time
Site:	Yankee Rowe
Issue date:	07/24/1989
From:	YANKEE ATOMIC ELECTRIC CO.
To:
Shared Package
ML20247M533	List: ML20247M529 ML20247M632
References
NUDOCS 8908020169
Download: ML20247M632 (4)

Text

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.ro i-JPower Distribution Limits 0

DNB Parameters-Limitina Condition for Operation

'3.2.4 The following.DNBlrelated parameters shall be maintained within the

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> Dlimits shown on Table 3.2-1:

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Highest Operating Loop' Average Temperature b.

Main lCoolaat System Pressure

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c.

. Main Coolant' System Total Flow Rate In Applicability: Mode 1.

Action

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'With any of the above parameters exceeding its limit, restore the parameter to

'within.its-limit within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or reduce THERMAL POWER to less than 5% of

!1

. RATED THERMAL' POWER within the next 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.~

Surveillance Requirements;

'4.2.4.11 Each of the parameters of Table 3.2-1 shall be verified to be within their limits at;least once'per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

4.2.4.2 The. Main Coolant System total flow rate shall be determined to be within its limit.by measurement at least once per 18 months.

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' YANKEE-ROWE 3/4 2-12 Amendment No. 88 fDR0802OJ69 890724

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-TABLE ~3.2-1 j,'

A gg DNB Parameters

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Limits v;

~ Parameter :

4 Loops in Operation i

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< 542oF for P > 0.5 Operating Loop Average Temperature K

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< 5360F+[(12)(P)].-

for:P < 0.5" i

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'- " Main Coolant System Pressure 1-1950 psig*

6 Main Cool'nt System Total' Flow Rate.

138.3X10 1b/hr l

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2 THERMAL' POWER RATED THERMAL POWER s

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'* Limit'not' applicable during either a THERMAL POWER ramp increase in excess of E?

5% RATED THERMAL POWER per minute or a THERMAL POWER step increase f.n excess l

of.101: RATED THERMAL POWER.

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YANKEE-ROWE 3/4 2-13 Amendment No. 43, 88 Y-_-____---________________-___

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3/4.2 POWER DISTRIBUTION LIMITS BASES (Continued) a.

Control rods in a single group move together with no individual rod insertion differing by more than i 8 inches from any other rod in the

group, b.

Control rod groups are sequenced with overlapping groups as described in Specification 3.1.3.5.

c.

The control rod insertion limits of Specification 3.1.3.5 is maintained.

l TherelaxationifFgasafunctionofTHERMALPOWERallows 3

changes in the radial power shape for all permissible rod insertion limits.

FgwillbemaintainedwithitslimitsprovidedConditionsathrough a

c above are maintained.

When an F measurement is taken, experimental error, engineering q

tolerance and fuel'densification must be allowed for.

5% is the appropriate allowance for a full core map taken with the incore Detector Flux Mapping System, 4% is the appropriate allowance for engineering tolerance and 3% is the appropriate allowance fuel densification.

WhenFgismeasured,experimentalerrormustbeallowedforand5%

g is the appropriate allowance for a full core map taken with the Incore detection system.

3/4.2.4 DNB PARAMETERS The limits on the DNB related parameters assure that each of the parameters are maintained within the normal steady state envelope of operation assumed in the transient and accident analyses. The limits are consistent with the accident analysis assumptions and have been analytically demonstrated adequately to maintain a minimum DNBR of 1.30 throughout each analyzed transient. The cold leg temperature assumed in the analysis is based on the loop average tergerature limit and design MCS operating conditions. This results in a cold leg temperature of 5200F at full power, increasing linearly to 5310F at 50% power. Below 50% power, the cold leg tempera *_co increases linearly to 536'F at zero pcwer. The cold leg temperature ' istmied in the analysis is conservatively 40F in excess of the value deter...oed from the average temperature limit to allow for uncertainty in plant measurement.

The drop in the average temperature limit below 50% power ensures acceptable results for low power main steam line breaks. The Main Coolant System pressure assured in the analysis is 1,925 psig, conservatively 25 psig lest than the limit to allow for uncertainty in plant measurement. The assumed operating deadband of 1 50 psig is applied to the nominal 2,000 psig limit, yielding a minimum operation limit of 1,950 psig.

YANKEE-ROWE B 3/4 2-3 Amendment No. #3, 88

r 3/4.2.4 DNB PARAMETERS BASES (Continued)

The 12-hour periodic surveillance of these parameters through instrument readout is sufficient to ensure that the paransters are restored within their limits following load changes and other expected transient operation. The 18 month periodic measurement of the Main Coolant System total flow rate is adequate to detect flow degradation and ensure correlation of the flow indication channels with measured flow such that the indicated percent flow will provide sufficient verification of flow rate on a 12-hour basis.

A 34% DNBR credit is needed to offset the full-closure rod bow penalty for the fuel in Yankee Rowe. The full-closure penalty was previously approved (D. Ross and D. Eisenhut memorandum of December 12, 1976) for Yankee Rowe since a gap closure model was not available. Generic credits (D. Edwards letter to NRC dated February 9,1977) equivalent to 13.2% DNBR margin were apprcved for Yankee Rowe. The lin.iting transient for Yankee Rowe with respect to DNB is the 2 of 4 pump loss of flow. Based on design conditions, this event results on a minimum DNBR in excess of 1.82.

Thus, 27.8% margin to a DNBR of 1.3 exists for this limiting event, which is applied to the remaining 20.8% mergin required by the rod-bow penalty.

YANKEE-ROWE B 3/4 2-4 Amendment No. 59, 88

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