ML20198N830

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Proposed Tech Specs Pages Allowing Use of Moveable Incore Detector Thimble Reduction for Unit 1,cycle 19
ML20198N830
Person / Time
Site: Prairie Island  Xcel Energy icon.png
Issue date: 01/15/1998
From:
NORTHERN STATES POWER CO.
To:
Shared Package
ML20070L182 List:
References
NUDOCS 9801210228
Download: ML20198N830 (13)
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Text

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Exhibit B l Prairie Island Nuclear Generating Plant l License Amendment Request Dated January 15, 1998 f t

Proposed Changes Marked Up i On Existing Technfcal Specification Pages  !

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I Exhibit B consists of existing Technical Specification pages with the proposed changes highlighted on those pages. The pages affected by this License Amendment.; Request are listed below:

TS.3.10 1-TS.3.10 2 TS.3.10-3 TS.3.11-1 B.3.11-1 t

y-. -

I

. TS.3.10 1

F'.' ! ? ': 10/10/95 3.10 CONTROL ROD AND POWER DISTRIBUTION LIMITS 6policability Applies to the limits on core fission power distribution and to the limits on control rod operations.

Obiective l l

To assure 1) core suberiticality after reactor trip, 2) acceptable core power l distributions during POWER OPERATION, and 3) limited potential reactivity insertions

~

caused by hypothetical control rod ejection. j Specification l A. Shutdown Marcin

1. Reactor Coolant System Averare Temnorature > 200'F The SIIUTDOWN MARGIN shall be greater than or equal to the applicable value shown in Figure TS.3.101 when in 110T SHUTDOWN and INTERMEDIATE S!!UTDOWN.

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2. Reactor Coolant Svstem Averare Temperature s 200'F '

The SHUTDOWN MARCIN shall be greater than or equal to Itok/k when in COLD SHUTDOWN. 1

3. With che SHUTDOWN MARGIN less, than the applicable limit specified in 3.10.A.1 or 3.10.A.2 above, rithin 15 minutes initiate boration to restore SHUTDOWN MARGIN to within the applicable limit.

B. Power Distribution Limits 1.Atalltimes,exceytduringlowpowerPilYSICSTESTING,measuredhotchannel factors F"o and F a, as defined below and in the bases, shall meet the following limits:

P.TP 8

Fn x 1.03 x 1.05* s (Fg / P) x K(Z)

RTP j F"a x 1.04** 5 Fu x [1+ PFDH(1 P)) I where the following definitions apply:

RTP l

- Fq is the Fn limit at RATED THERMAL POWER specified in the CORE OPERATING l LIMITS REPORT.

J RTP

- Fu is the Fa limit at RATED THERMAL POWEk specified in the CORE OPERATING l LIMITS REPORT.

- PFDH is the Power Factor Multiplier for F"a specified in the CORE OPERATING LIMITS REPORT. I l

- K(Z) is a normalized function that limits Fn(z) axially as specified in the CORE OPERATING LIMITS REPORT.

  • For Unit 1, Cycle 149, when the number of available moveable detector thimbles is greater than or equal to 50% and less than 75% of the total, the 56 measurement I uncertainty shall be increased to [51 + (3-T/9)(3%)] where T is the number of available thimbles.
    • For Unit 1,. Cycle 139, when tha number of available moveable detector thimbles is I greater than or equal to 50% and less than 75% of the total, the 44 measurement uncertainty shall be increased to [4% + (3-T/9)(2%)] where T is the number of available thimbles. 1 i

im .3--+ .- _ w .~ -- ._a. "4. .

. TS.3.10 b ett 197 3

in /in inf 3.10.B.1. Z is the core height location. l P is the fraction of RATED TilERMAL POWER at which the core is operating. In the F"o limit determination when P 50,50, set P - 0.50 F*n or Fug is defined as the measured Fn or Fan respectively, with the snailest margin or greatest excess of limit.

- 1.03 is the engineering hot channel factor, Frn , applied to the measutti F*n to account for manufacturing tolerance.

- 1.05* is applied to the measured F*n to account for measurement uncertainty.

- 1.04** is applied to the measured F5m to account for measurement uncertainty.

2. Hot channel factors F*n and F5m , shall be measured and the target

> flux difference determined, at equilibrium conditions according to the following conditions, whichever occurs first:

(a) At least once per 31 effective full power days in conjunction with the target flux difference determination, or (b) Upon reaching equilibrium conditions after exceeding the reactor power at which target flux difference was last determined, by 10% or more of RATED TilERMAL POWER.

F*n (equil) shall meet the following limit for the middle axial 80%

of the core:

RTP F"o (equil) x V(Z) x 1.03 x 1.05* s (Fo / P) x K(7) where V(Z) is specified in the CORE OPERATING LIMITS REPORT and other terms are defined in 3.10.B.1 above.

3. (a) If either measured hot channel factor exceeds its limit specified in 3.10 B.1, reduce reactor power and the high neutron flux trip set point by 1% for each percent that the measured F"n or by the factor specified in the CORE OPERATING LIMITS REPORT for each percent that the measured F5m exceeds the 3.10.B.1 limit. Then follow 3.10.B.3(c).

(b) If the measured F*n (equil) exceeds the 3.10.B.2 limits but not the 3.10.B.1 limit, take one of the following actions:

1. Within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> place the reactor in an equilibrium configuration for which Specification 3.10.B.2 is satisfied, or
2. Reduce reactor power and the high neutron flux trip setpoint by 14 for each percent that the measured F*n (equil) x 1.03 x 3.05* x V(Z) exceeds the limit.
  • For Unit 1, Cycle 189, when the number of available moveable detector thimbles is greater than or equal to 50% and less than 75% of the total, the St neasurement uncertainty shall be increased to

[5% + (3 T/9)(3%)] where T is the number of available thimbles.

    • For Unit 1, Cycle 189, when the number of available moveable detector thimbles is greater than or equal to 50% and less than 75% of the total, the 4% measurement uncertainty shall be increased to

[4% +-(3-T/9)(2%)} where T is the number of available thimbles.

O TS.3.10 3 i i V !?': 10/10/a' l l

3.10.8.3. (c) If subsequent in core mapping cannot, within a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period, l demonstrate that the hot channel factors are met the reactor i shall be brought to a HOT SHUTDOWN condition with return to l power authorized up to 50% of RATED THERMAL POWER for the purpose of PHYSICS TESTING. Identify and correct the cause j of the out of limit condition prior to increasing THERMAL POWER $

above 50% of RATED THERMAL POWER. THERMAL POWER may then be  :

increased provided f$ or }*a is demonstrated through in. core l mapping to be within its limits.

(d) If two successive measurements indicate an increase in the  ;

peak rod power f*a with exposure, either of the followingJ ,

actions shall be taken: [

1. f*o (equil) shall be multiplied by 1.02 x V(Z) x 1.03 x ,

1.0$** for comparison to the limit specU ted in 3.10,B.2, or ]

2 f*n (equil) shall be measured at least once per seven effective full power days until two successive maps -

5 indicate that the peak pin power, F u, is not increasing.  ;

4. Except during PHYSICS TESTS, and except as provided by specifica-tions 5 through a below, the indicated axial flux difference for at least three operable excore channels shall be maintained within the target band about the target flux difNrence. The target band e is specified in the CORE OPERA *1NG LIMITS REPORT.

I 5 Above 90 nereent of RATED THERMAL PCWER!

If the indicated axial flux difference of two OPERABLE excore i channels deviates- from the target band, within 15 minutes either  ;

eliminate such deviation, or reduce THERMAL POWER to less than 90 percent of RATED THERMAL POWER.

6. Between 50 and 90 oercent of RATED THERMAL POWER: .
a. The indicated axial flux difference may deviate from the target band for a maximum of one* hour (cumulative) in any 24 [

hour period provided that the difference between the indicated t axial flux difference about the target flux difference does not exceed the envelope specified in the CORE OPERATING LIMITS  ;

REPORT.

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b. IE 6.a is violated for two OPERABLE excore channels then the THERMAL POWER shall be reduced to less than 50% of RATED ,.

. THERMAL POWER and the high neutron flux setpoint reduced to

less than 55% of-RATED THERMAL POWER. i
  • May be extended to 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> during incore/excore calibration. ,
    • For Unit 1, Cycle 14!, when the number of available moveable detector f thimbles is greater than or equal to 50% and less than 75% of the -

total, the 54 measurement uncertainty shall be increased to

~(54 +-(3 T/9)(34)) where T is the. number of available thimbles.

. . ~ __

-_. .- ~_ . . . .

l TS.3.11 1 RE'1 12': 10/10/94 3.11 CORE SURVEILLANCE INSTRUMENTATION Anolicability Applios to the OPERABILITY of *.he moveable detector instrumentation  :

system and the core thermocouple instrumentation system.

Obiectlyg To specify OPERABILITY requirements for the moveable detector and ,

core thermocouple systems.

Specification A. Tho moveable detector system shall be OPERABLE following each refueling so that the power distribution can be confirmed. If the moveable detector system is degraded to the extent that less than 75% of the detector thimbios are available, the measurement error allowance due to incomplete mapplug sha?1 be substantiated by the licensee.

B. A minimum of 2 moveable detector thimbles per quadrant *, and sufficient detectors, drives, and readout equipment to map these thimbles, shall be operable during recalibration of the excore axial offset detection system per specification 4.1. If this OPERABILITY for recalibration of excoro nuclear instruments when required by Specification 4.1 cannot be achieved, power shall be limited to 90%

of' RATED THERMAL POWER until recalibration is completed in accor-dance with this specification.

O. A minimum cl 4 thermocouples or 2 moveable detectors per quadrant shall b operable for readout if the reactor is operated above 85% of RATED THERHAL POWER with one excore nuclear power channel inoperable (see Specification 3.10.C.4),

D. The provisions of specification 3.0,C are not applicable.

  • For Unit 1, Cycle ISS, when the number of available moveable detector thimbles is greater than or equal to 50% and less than 75% of the total, there should be a minimum of two thimoles available per quadrant, where quadrant includes both horizontal vertical quadrants and diagonally-bounded quadrants (eight individual quadrants in total).
v .

_- . . _ - - . _ _ _-. = _ _ _ . - _ . . - -- .

, B.3.11 1 P.r' 126 10/10/94 3.11 CORE SURVEIILANCE INSTRUMENTATION

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Bases The moveable detector systeta is used to measure the core fission power density distribution. A power map made with this system following each fuel loading will confirm the proper fuel arrangement within the cote. The moveable detector system is designed with substantial redundancy so that part of the system could be out of service without reducing the value of a power map. If the system is severely degraded, largo peasurement uncertainty factors must be applied. The uncertainty factors would necessarily depend on the operable configuration.

Two detector thimbles per quadrant are sufficient to provide data for the normalization of the excore detector system's axial power offset feature.

For Unit 1, Cycle 149, when the number of available moveable detector thimblem is greater than or equal to 50% and ices than 75% of the total, the requirements are modified to require a minimum of two thimbles available per quadrant, where quadrant includes both horizontal vertical quadrants and diagonally bounded quadrants (eight individual quadrants in total). This requirement arises from the use of random thimble deletion events as the basis for the Westinghouse analysis. As a result of randoi va ilures, distribution of remain.ing thimbles would be relatively uniform, while systematic failure could result in large areas of the core being uninstrumented. In order to apply the error correction developed in the Westinghouse analysis and to establish the bounds of applicability of the peaking factor uncertainties, coverage is required in each of the eight quadrants defined above.

The core thermocouples provide an independent means of measuring the balance of power among the core quadrants. If one excore power channel is out of service, it is prudent to have available an independent means of determining the quadrant power balance.

The moveable dett- or system and the thermocouple system are not integral parts of tne reactor protection system. These systems are, rather, surveillance systems which may be required in the event of an abnormal occurrence such as a power tilt or a control rod misalignment. Since such occurrences cannot be predicted a priori, it is prudent to have the surveillance systems in an OPERABLE state.

I Exhibit C ,

Prairie Island Nuclear Generating Plant  ;

r License Amendment Request Dated January 15, 1998 [

Revised Technical Specification Pages ,

e Exhibit C consists of revised pages for the Prairie Island Nuclear Generating Plant Technical Specifications with the proposed changes incorporated. Tha l revised pages ara listed below:

i TS.3.10 1 TS.3.10 2 TS.3.10 3 TS.3.11 1 B,3.11 1 i

t I

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w- w ~ . , -.i.,y,- .w-., y p -- v m

o TS.3.10 1 3.10 CONTROL ROD AND POWER DISTRIBUTION LIMITS Applicability Applies to the limits on core fission power distribution and to the limits on control rod operations.

Obiective To assure 1) core suberiticality after reactor trip, 2) acceptable core power distributions during POWER OPERATION, and 3) limited potential reactivity inser. ons caused by hypothetical control rod ejection.

Specification A. Shutdewn Marcin

1. Reactor Coolant System Averace Temperature > 200'F The SilUTDOWN MARGIN shall be greater than or equal to the applicable value shown in Figure TS.3.101 when in 110T SHUTDOWN and INTERMEDIATE CHUTDOWN.
2. Reactor Coolant System Averace Temperature s 200'F

".he S!!UTDOWN MARGIN shall be greater than or equal to Itak/k when in COLD SHUTDOWN.

3. With the SIIUTDOWN MARGIN less than the applicable limit specified in 3.10.A.1 or 3.10.A.2 above, within 15 minutes initiate boration to rostore SHUTDOWN MARGIN to within the applicable limit.

B. Pcwer Distribution Limits

1. At all times, except during low pcwer PHYSICS TESTING, measured hot channel factors , F" and F6s, as defined below and in the bases, shal' meet the f ollowing 1 mits:

RTP F"g x 1.03 x 1.0$* s (Fo / P) x K(Z)

RTF F"a x 1.04** s Fa x [1+ PFDH(1 P))

where the following definitions apply:

-F q is the Fo limit at RATED T11ERMAL POWER specified in the CORE OPERATING LIMITS REPORT.

RTP Fin is the Fin limit at RATED TilERMAL POWER specified in the CORE OPERATING LIMITS REPORT.

- "FDH is the Power Factor Multiplier for F"a specified in the CORE OPERATING LIMITS REPORT.

K(Z) is a normalized function that limits Fn(z) axially as specified in the CORE OPERATING LIMITS REPORT.

  • For Unit 1, Cycle 19, when the number of available moveable detector thimbles is l greater than or equal to-50% and less than 75% of the total, the 5% measurement
  • ncertainty shall be increased to [St + (3 T/9)(3%)] where T is the number of svailable thimbles.
    • For Unit 1, Cycle.19, when the number of available moveable detector thia.bles is l greater than or equal to 50% and less than 75t of the total, the 44 measurement uncertainty shall be increased to [4% + (3 T/9)(24)] where T is the number of available thimbles.

e TS.3.10 2 3.10.B.1 - Z is the core height location.

- P is the fraction of RATED THERMAL POWER at which the core is -

operating. In the F"n limit determination when P 50.50, set P - 0.50

- F"o or Fu or F6 respectively, with the umal$a is defined as the measured Foestmarginorgreatestexcessoflim5t.

- 1.03 is the engineering hot channel factor, Frn , applied to the measured F"o to account for manufacturing tolerance.

- 1.0$* is applied to the measured Fs to account for measurement uncertainty.

1.04** is appli the measured FN g to account for measurement uncertainty.

2. Ilot channel factors F"o and F"a , shall be measured and the target flux difference det... mined, at eq'ailibrium conditions according to the following conditions, whichever occ'.rs first:

(a) At least once per 31 effective full power days in conjunction with the target flux difference determination, or (b) Upon reaching equilibrium conditions after exceeding the reactor power at which target flux difference was last determined, by 10% or more of RATED THERMAL POWER.

F"o (equil) shall meet the following limit for the middle axial 80%

of the core:

RTP F"o (equil) x V(Z) x 1.03 x 1.05* 5 (Fg / P) x K(Z) where V(Z) is specified in the CORE OPERATING LIMITS REPORT and other terms are defined in 3.10,B.1 above.

3. (a) If either measured hot channel factor exceeds its limit specified in 3.10.B.1, reduce reactor power and the high neutron flux trip set point by in for each percent that the measured F"o or by the factor specified in the CORE OPERATING LIMITS REPORT for each percent that the measured FN g exceeds the 3.10.B.1 limit. Then follow 3.10.B.3(c).

(b) If the measured F"o (equil) exceeds the 3.10.B.2 limits but not the 3.10 B.1 limit, take one of the following actions:

1. Within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> place the reactor in an equilibrium configuration for which Specification 3.10.B.2 is satisfied, or
2. Reduce reactor power and the high neutron flux trip setpoint by it for each percent that the measured F"o (equil) x 1.03 x 1.01 x V(Z) exceeds the limit.
  • For' Unit 1. Cycle 19, when the number of available moveable detector l thimbles is greater than or equal to 50% and less than 75% of the total, the 54 measurement uncertainty shall be increased to

[5% + (3-T/9)(3%)] where T is the number of available thimbles.

    • For Unit 1 Cycle 19, when the number of available moveable detector l thimbles is greater than or equal to 50% and less than 75% of the ,

total, the 44 measurement uncertainty shall be increased to

[4% + (3-T/9)(24)) where T is the number of available thimbles.

TS.3.10-3 3.10.B.3. (c) If subsequent in core mapping cannot, within a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period, demonstrate that the hot channel factors are met, the reactor shall be brought to a 110T SHUTDOWN condition with return to power authorized up to 50% of RATED THERMAL POWER for the purpose of PHYSICS TESTING. Identify and correct the cause  !

of the out of limit condition prior to increasing THERMAL POWER above 50% of RATED THERMAL POWER. THERMA 1, POWER may then be increased provided F*n or F*a is demonstrated through in core mapping to be within its limits.

(d) If two 6secessive measurements indicate an increase in the peakrodpowerF%a with exposure, either of the following actior, still be taken:

1. do (egall) shall be multiplied by 1.02 x V(2) x 1.03 x 1.05** for comparison to the limit specified in 3.10.B.2, or
2. F*n (equil) shall be measured at least once per seven effective full power days until two successive maps indicate that the peak pin power, F%a, is not increasing.

l

4. Except during PHYSICS TESTS, and except as provided by specifica-tions 5 through 8 below, the indicated axial flux difference for at least three operable excore channels shall be maintained within the target band about the target flux difference. The target band is specified in the CORE OPERATING LIMITS REPORT.
5. Above 90 percent of RATED THERMAL POWER:

If the indicated axial flux difference of two OPERABLE excore channels deviates from the target band, within 15 minutes either eliminate such deviation, or reduce THERMAL POWER to less than 90 percent of RATED THERMAL POWER.

6. Between 50 and 90 percent of RATED THERMAL POWER:
a. The indicated axial flux difference may deviate from the target band for a maximum of one* hour (cumulative) in any 24-hour period provided that the difference between the indicated axial flux difference about the target flux difference does not exceed the envelope specified in the CORE OPERATING LIMITS REPORT.
b. If 6.a is violated for two OPERABLE excore channels then the THERMAL POWER shall be reduced to less than 50% of RATED THERMAL POWER and the high neutron flux setpoint reduced to less than 55% of RATED THERMAL POWER.
  • May be extended to 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> during incore/excore calibration.
    • For Unit 1 Cycle 1?, when the number of available moveable detector l thimbles is greater than or equal to 50% and less than 75% of the total, the 54 measuremene uncertainty shall be increased to (5% + (3 T/9)(3%)] where T is the number of available thimbles.

e - - - ,. ,

TS.3.11 1 3.11 CORE SURVEILLANCE INSTRUMENTATION Apolicability Applies to the OPERABILITY of the moveable detector instrumentation system and the core thermocouple instrumentation system.

Obiective To specify OPERABILITY requirements for the moveable detector and core thermocouple systems.

Snecification A. The moveable detector system shall be OPERABLE following each refueling so that the power distribution can be confirmed. If the moveable detector system is degraded to the extent that lean than 75% of the detector thimbles are available, the measurement error allowance due to incomplete mapping shall be substantiated by the licensee.

B. A minimum of 2 moveable detector thimbles per quadrant *, and sufficient detectors, drives, and readout equipment to map these thimbles, shall be operable during recalibration of the excore axial offset detection system per Specification '4.1. If this OPERABILITY for recalibration of excore nuclear instruments when required by Specification 4.1 cannot be achieved, power shall be limited to 90%

of RATED THERMAL POWER until recalibration is completed in accor-dance with this specification.

C. A minimum of 4 thermocouples or 2 moveable detectors per quadrant shall be operable for readout if the reactor is operated above 85% of RATED THERMAL p0WER with one excore nuclear power channel inoperable (see Specification 3.10.C 4).

D. The provisions of specification 3.0.C are not applicable.

  • For Unit 1, Cycle 19, when the number of available moveable detector l thimbles is greater than or equal to 50% and less than 75% of the total, there should be a minimum of two thimbles available per quadrant, where quadrant includes both horizontal vertical quadrants and diagonally-bounded quadrants (eight individual quadrants in total).

l .

l , B.3.11 1 r

3.11 QORE SURVEILLANCE Q$QttMENTATION Enses The moveable detector system is used to measure the core fission power density distribution. A power map made with this system following each fuel loadin5 will confirm the proper fuel arrangement within the core. The moveable detector system is designed with substantial redundancy so that part of the system ceuld be out of service without reducing the value of a power map. If the system is severely degraded, large measurement uncertainty factors must be applied. The uncertainty factors would necessarily depend on the operable configuration.

Two detector thimbles per quadrant are sufficient to provide data for the normalization of the excore detector system's axial power offset feature.

For Unit 1, Cycle 19, when the number of available moveable detector thimbles is 6teater than or equal to 50% and less than 75% of the total, the requirements are modified to require a minimum of two .

thimbles available per quadrant, where quadrant includes both horizontal vertical quadrants and diagonally bounded quadrants (eight individual quadrants in total). This requirement arises from the use of random thimble deletion events as the basis for the Westinghouse analysis. As a result of random failures, distribution of remaining thimbles would be relatively uniform, wlile systematic failure could result in large areas of the core being uninstrumented. In order to apply the error correction developed in the Westinghouse analysis, and to establish the bounds of applicability of the peaking factor uncertainties, coverage is required in each of the eight quadrants defined above.

The core thermocouples provide an independent means of measuring the balance of power among the core quadrants. If one excore power channel is out of service, it is prudent to hcve available an independent means of determining the quadrant power balance.

The moveable detector system and the thermocouple system are not integral parts of the reactor protection system. These systems are, rather, surveillance systems which may be required in the event of an abnormal occurrence such as a power tilt or a control rod misalignment. Since such occurrences cannot be predicted a priori, it is prudent to have the surveillance systems in an OPERABLE state.

i Exhibit E .

I Prairie Island Nuclear Generating Plant i License Amendment Request Dated January 15,1998 Prairie Island Unit 1 Cycle 19 Thimble Deletion Study NON PROPRIETARY i

s

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