ML18085A138

Proposed Changes to Tech Specs 3/4.2 Re Power Distribution Limits

ML18085A138
Person / Time
Site:	Salem
Issue date:	10/20/1980
From:	Public Service Enterprise Group
To:
Shared Package
ML18085A137	List: ML18085A136 ML18085A138
References
NUDOCS 8010290323
Download: ML18085A138 (7)

Text

PROPOSED CHANGE AXIAL FLUX DIFFERENCE TECHNICAL SPECIFICATION SALEM UNIT NO. 1 Description of Change Change the axial flux difference target band to +6,- 9% about the target flux difference.

Reason for Change Increased flexibility for operating the unit under Constant Axial Offset Control {CAOC), especially during power change maneuvers.

Safety Evaluation An analysis of total peaking factor versus core height for normal plant operation has been performed for Salem Unit 1 starting with a cycle 2 core burnup of 3000 MWD/MTU. The bases for the analyses included CAOC with +6, -9% Li. I control band and that the limit on F at fractional thermal power was modified to include a multiplie£Ychange from 0.2 to 0.3. The power peaking calculations were performed using the 18 case analysis discussed in the "Westinghouse Reload Safety Evaluation Methodology", WCAP-9273, and documented in a Westinghouse letter from c. Eicheldinger to D. B. Vassallo of the NRC {NS-CE-687 dated July 16, 1975).

NRC approval to use the 18 case analysis for.:1I bandwidening was given in a letter from D. B. Vassallo to c. Eicheldinger, dated April 15, 1976. The results of these calculations are shown in figure 1. It can be seen that F 0 x Power satisfied the generic FAC boundry with the +6, -9%A.I Earget band and the revised multiplier on the Fxv limit at fractional thermal power. There-fore, the peaking factor and DNBR criteria are met with margin for the +6, -9%.A I band and revised Fxy limit at fractional thermal power.

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• .o a.o HE ICHT (FT. )

KEY FAC Boundary Limit I Calculated values at +6,-9~~1

3/4.2 POWER DISTRJBUTION LIMITS AXIAL FLUX DIFFERENCE (AFO)

LIMITING CONDITION FOR OPERATION

+6,-Cf % . .

3.2.l Thetfndicated AXIAL Fl.UX DIFFERENCE (AFO) shall be maintained within a~ target band (flux difference units) about the target flux difference. IA a~aitieA, d~riAg the firsi 72 EFPD (2700 MWBf+rrti} operation

-iA-..Cysle 2,tl:le indicated AFB shall be-maiAte;ned less than +_7.5~ -at RATED THERMAt:-POW~R-wit11 ~e a+lewed-AFO i11creas1ng by l .M-for-eaeh-

-'.J .Q% reduetien in THER.""AL PO'tlER.

APPLICABILITY: MODE l ABOVE SM RATED THERMAL POWER*

ACTION:

a. With the indicated AXIAL FLUX DIFFERENCE outside of the above limits and with THERMAL POWER:

l. Above 90% of RATE~ THERMAL POWER, within 15 minutes:

a) Either restore the indicated AFD to within the target band limits, or b) Reduce THERMAL POWER to less than 90~ of RATED THERMAL POWER.

2. Between 50~ and 90% of RATED THERMAL POWER:

a) POWER OPERATION may continue provided:

l) The indicated AFD has not been outside of the above limits for more than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> penalty deviation cumulative during the previous 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, and

2) The indicated AFD is within the limits shown on Figure 3.2-1. Otherwise, reduce THERMAL POWER to less than 50% of RATED THERMAL POWER within 30 minutes and reduce the Power Range Neutron Flux-High Trip Setpoints to !. 55% of 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 />.

b) Surveillance testing of the Power Range Neutron Flux Channels may be perfonned pursuant to Specification 4.3.1.1.1 provided the indicated AFD is maintained within the limits of Figure 3.2-1. A total of 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> operation may be accumulated with the AFD outside of the target band during this testing without penalty deviation.

• See Special Test Exception 3.10.2 SALEM - UNIT 1 3/4 2-1 Amendment No. J, 20

e

• POWER DISTRIBUTION LIMITS BASES

. c+(p1-'1%

Although it is intended that~~~ plant will be operated with the AXIAL FLUX DIFFERENCE within the ~target band about the target flux difference, during rapid plant THERMAL POWER reductions, control rod motion will cause the AFD to deviate outside of the target band at re-duced THERMAL POWER levels. This deviation will not affect the xenon redistribution sufficiently to change the envelope of peak.,ing factors which may be reached on a subsequent return to RATED THERMAL POWER (with

• the AFO within the target band) provided the time duration of the devi-ation is limited. Accordingly, a 1 hour* penalty deviation limit cumu-lative during the previous 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is provided for operation outside of the target band but within the limits of Figure 3.2-1 while at THERMAL POWER levels between 50% and 90% of RATED THERMAL POWER. For THERMAL POWER levels between 15% and 50~ of rated THERMAL POWER, deviations of the AFC.outside of the target band are less significant. The penalty of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> actual time reflects this reduced signif~cance.

Provisions for monitoring the AFD are derived from the plant nuclear instrumentation system through the AFO Monitor Alarm. A control room recorder continuously displ~ys the auctioneered high flux difference and the target band limits as a function of power level. A first alarm is received any time the auctioneered high flux difference exceeds the target band limits. A second alarm is received if the AFC exceeds its allowable limits for a cumulative time of one hour during any 24 hour*

time period starting with the occurrence of the first alarm. Time out-side the target band is graphically presented on the strip chart.

Figure B 3/4 2-1 shows a typical monthly target band.

SALEM - UNIT 1 B 3/4 2-2

,~

• 10% 0 +10%

INDICATED AXIAL FLUX DIFFERENCE Figure B 3/4 2*1 TYPICAL INDICATED AXIAL FLUX DIFFERENCE VERSUS

' THERMAL POWER SALEM

• UNIT 1 B 3/4 2-3

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e

• PROPOSED CHANGE HEAT FLUX HOT CHANNEL FACTOR - FQ(Z)

TECHNICAL SPECIFICATION SALEM UNIT NO. 1 Description of Change Modify the limit on F at fractional thermal power by changing the multiplier from o:~ to 0.3 as follows:

F xy L = F xy RTP[l + 0.3(1-P)]

Reason for Change Allow optimization of core loading patterns at hot full power conditions without incurring a restrictive F limit at low power. This could lead to increased fuel utllization, since fresh *or depleted burnable poison rod assemblies are often used to flatten power at reduced power level at the expense of cycle lifetime.

Safety Evaluation Included in safety evaluation on proposed change to Axial Flux Difference Technical Specification.

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POWER DISTRIBUTION LIMITS SURVEILLANCE REQUIREMENTS 4.2.2.l The provisions of Spetification 4.0.4 are not applicable.

4.2.2.2 F shall be evaluated to determine if Fg(Z) is within its limit by: xy

a. Using the movable incore detectors to obtain a power distribu-tion map at any THERMAL POWER greater than 5% of RATED THERMAL POWER.

b. Increasing the measured Fxv component of the power distribution map by 3% to account for manufacturing tolerances and further increasing the value by 5% to account for measurement uncertainties.

c. Comparing the Fxy computed (Fx;) obtained in b, above to:

1. The Fxy limits for RATED THERMAL POWER (F~~p) for the appropriate measured core planes given in e and f below, and

2. The relationship:

0.3

• FL = FRTP [1+~(1-P)]

xy where FL is the limit for fractional THERMAL POWER operati~~ expressed as a function of F~~P and P is the fraction of RATED THERMAL POWER at which Fxy was xy measured.

d. Remeasuring Fxy according to the following schedule:

1. When Fx; is greater than the F~~p limit for the appropriate measured core plane but less than the Fx~ relationship, additional power distribution maps shall be taken and C RTP L Fxy compared to Fxy and Fxy : I a) Either within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after exceeding by 20% of I RATED THERMAL POWER or greater, the THERMAL POWER at which FxyC was last determined, or SALEM - UNIT 1 3/4 2-6 J