ML20054C319
| ML20054C319 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 04/13/1982 |
| From: | Clark R Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20054C320 | List: |
| References | |
| NUDOCS 8204200370 | |
| Download: ML20054C319 (22) | |
Text
{{#Wiki_filter:, e f * , UNITED STATES eN r NUCLEAR REGULATORY COMMISSION ) j WASHINGTON, D. C. 20555 N....=/ VIRGINIA ELECTRIC AND POWER COMPANY j DOCKET NO. 50-338 NORTH ANNA POWER STATION, UNIT NO. 1 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 39 License No. NPF-4 1. The Nuclear Regulatory Commission (the Commission) has found that: A. The application for amendment by Virginia Electric and Power Company (the licensee) dated November 12, 1981 as supplemented February 12, 1982 complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act) and the Connission's rules and regulations set forth in 10 CFR Chapter I; B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (1) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (.11) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied. j 8204200370 820413 PDR ADOCK 05000338 P PDR l [
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Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.D.(2) of Facility Operating License No. NPF-4 is hereby amended to read as follows: (2) Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 39, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications. 3. This license amendment is effective as of the date of its issuance. FOR THE NUCLEAR REGULATORY COMMISSION S f;6'Mu u m Robert A. Clark, Chief Operating Reactors Branch #3 Division of Licensing
Attachment:
Changes to the Technical Specifications Date of Issuance: April 13, 1982
ATTACHMENT TO LICENSE AMENDMENT AMENDMENT NO. 39 TO FACILITY OPERATING LICENSE NO. NPF-4 DOCKET NO. 50-338 Replace the following pages of the Appendix "A" Technical Specifications with the enclosed pages as indicated. The revised pages are identified by Amendment number and contain vertical lines indicating the area of change. The corresponding overleaf pages are also provided to maintain document completeness. Pages 3/4 2-5 3/4 2-8 3/4 2-16 B 3/4-2-1
4 POWER DISTRIBUTION LIMITS HEAT FLUX HOT CHANNEL FACTOR-F (Z) LIMITING CONDITION FOR OPERATION 1 3.2.2 F (Z) shall be limited by the following relationships: q F (Z) < {2.141 [K(Z)]for P > 0.5 q P F (Z) < [4.28] [K(Z)]for P 10.5 3 q where P = THERMAL POWER RATED THERMAL POWER and K(Z) is the function obtained from Figure 3.2-2 for a given core height location. APPLICABILITY: MODE 1. ACTION: With F (Z) exceeding its limit: q a. Comply with either of the following ACTIONS: 1. Reduce THERMAL POWER at least 1% for each 1% F (Z) exceeds the q limit within 15 minutes and similarly reduce'the Power Range Neutron Flux-High Trip Setpoints within the next 4 hours; POWER OPERATION may proceed for up to a total of 72 hours; subsequent POWER OPERATION may proceed provided the Overpower AT Trip Setpoints have been reduced at least 1% for each 1% F (Z) q exceeds the limit. The Overpower AT Trip Setpoint reduction shall be performed with the reactor in at least HOT STANDBY. 2. Reduce THERMAL POWER as necessary to meet the limits of l Specification _ 3.2.6 using the APDMS with the latest incore map and updated R. b. Identify and correct the cause of the out of limit condition prior to increasing THERMAL POWER above the reduced limit required by a, above; THERMAL POWER may then be increased provided F (Z) is q demonstrated through incore mapping to be within its limit. NORTH ANNA - UNIT 1 3/4 2-5 Amendment No. 3, 5, 16. 3 9
POWER DISTRIBUTION LIMITS SURVEILLANCE REQUIREMENTS J 4.2.2.1 The provisions of Specification 4.0.4 are not applicable. 4.2.2.2 F*Y shall be evaluated to determine if F (Z) is within its q limit by: a. Using the movable incore detectors to obtain a power distribution map at any THERMAL POWER greater than 5% of RATED THERMAL POWER. b. Increasing the measured F component of the power distribution map by 3% to account for Mnufacturing tolerances and further increasing the value by 5% to account for measurement uncertainties, c. Comparing the F computed (F ) obtained in b, above to: xy 1. The F limits for RATED THERMAL POWER (FRTP) for the xy xy appropriate measured core planes given in e and f, below, and 2. The relationship: F =F P [1 + 0.2(1-P)] l where F is the limit for fractional THERMAL POWER operation P expressed as a function of F and P is the fraction of RATED THERMAL POWER at which F was measured. xy d. Remeasuring F according to the following schedule: P 1. When F is greater than the F limit for the appropMate measured core plane but less than the F relationship, xy additional power distribution maps shall be taken and F RTP compared to F and Fx x a) Either within 24 hours after exceeding by 20% of RATED THERMAL POWER or greater, the THERMAL POWER at which F was last determined, or x NORTH ANNA-UNIT 1 3/4 2-6
POWER DISTRIBUTION LIMITS SURVEILLANCE REQUIREMENTS (Continued) (b) At least once per 31 EFPD, whichever occurs first. 2. When the F is less than or equal to the F limit for the appropriate measured core plane, additional power distribution maps shall be taken and F compared to F and Fy at least once per 31 EFPD. e. The F limits for Rated Thermal Power (F RTP) shall be provided xy xy for all core planes containing Bank "D" control rods and all unrodded core planes, in a Core Surveillance Report per Technical Specification 6.9.1.10. f. The F limits of e, above, are not applicable in the following xy 1 core plane regions as measured in percent of core height from the bottom of the fuel: 1. Lower core region from 0 to 15%, inclusive. 2. Upper core region from 85 to 100%, inclusive. 3. Grid plane regions at 17.8 12%, 32.1 2%, 46.412%, 60.6 2% and 74.9!2%, inclusive (17 x 17 fuel elements). 4. Core plane regions within !2% of core height ( 2.88 inches) about the bank demand position of the bank "D" control rods. l g. With F exceeding FK the effects of F on F (Z) shall be y Xy q evaluated to determine if F (Z) is within its limit. q 4.2.2.3 When F (Z) is measured for other than F determination, an overall q I measured F (Z) shall be obtained from a power distribution map and increased q by 3% to account for manufacturing tolerances and further increased by 5% to account for measurement uncertainty. l NORTH ANNA-UNIT 1 3/4 2-7 Amendment No. 76, 22, i
) i ) 1 l i E-t I i l t i - (6; 0 /1;-0) i -t i--- 1.0 i ...______j__.____
- .-(IU 9,0'.93) ~
i i i I j i i 5 I O. 8 4 l l I l 7 n .i ,i i-i i ea v i w i cr 0.6 w i f, O ____...______._._.._____I I i. t i t ea t i i I i j j~(12 K OJ+67-i i 0.4 S i ___q _ ~ i i n i N i I 0.2 i i i i e I i ~ i 0 2 4 6 8 10 12 CORE HEIGHT (FT) Figure 3.2-2 K(Z) - Normalized F (Z) as a Function of Core Height NORTH ANNA - UNIT 1 3/4 2-8 Amendment No. 3, 5, 76, 3 9
.s s s ~^^ TABLE 3.2-1 sE$ DNB PARAMETERS x E ji LIMITS h 2 Loops In Operation ** 2 Loops In Operation ** 5 3 Loops In & Loop Stop & Isolated Loop PARAMETER Operation Valves Open Stop Valves Closed Reactor Coolant System T < 585 F avg Pressurizer Pressure > 2205 psig* Reactor Coolant System > 278,400 gpm Total Flow Rate M = '?3 i
- Limit not applicable during either a THERMAL POWER ramp increase in excess of 5% RATED THERMAL POWER per minute or a TilERIML POWER step increase in excess of 10% RATED THERMAL POWER.
- Values dependent on NRC approval of ECCS evaluation for these conditions
-..m i POWER DISTRIBUTION LIMITS I j AXIAL POWER DISTRIBUTION LIMITING CONDITION FOR OPERATION 3.2.6 The axial power distribution shall be limited by the following relationship: ) i I*' E(} f [F(Z)]3 = 3 (R))(P )(1.03)(1 + a))(1.07) [ Where: a. F (Z) is the normalized axial power distribution from thimble j at core elevation Z. b. P is the fraction of RATED THERMAL POWER. c. K(Z) is the function obtained from Figure 3.2-2 for a given core height location. d. R, for thimble j, is determined from at least n=6 incore flux maps covering the full configuration of permissible rod patterns above P,% of RATED THERMAL POWER in accordance with: n j ij i=1 Where: s R = fj [Ffj(Z)] Max and[F (Z)] Max is the maximum value of the normalized axial distribution at elevation Z from thimble j in map i which had a measured peaking factor without uncertainties .eas or densification allowance of F 4 2-16 Amendment No. 3, 5 M 22, 37,,13 NORTH ANNA - UNIT 1 - - - - - -,, - ~ -, y -,i.,---.- ,,.r --y ,e --,,.--------w--ym-
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___ - _. = - - .~. _ a tr 1 i i 3/4.2 POWER DISTRIBUTION LIMITS l BASES i The specifications of this section provide assurance of fuel integrity during Condition I (Normal Operation) and II (Incidents of Moderate Frequency) i events by: (a) maintaining the minimum DNBR in the core 11.30 during normal 'j operation and in short term transients, and (b) limiting the fission gas release, fuel pellet temperature & cladding mechanical properties to within assumed design criteria. In addition, limiting the peak linear power density l during Condition I events provides assurance that the initial conditions assumed for the LOCA analyses are met and the ECCS acceptance criteria limit of 2200 F is not exceeded. 4 4 The definitions of certain hot channel and peaking factors as used in ) these specifications are as follows: F (Z) Heat Flux Hot Channel Factor, is defined as the maximum local q heat flux on the surface of a fuel rod at core elevation Z divided by the average fuel rod heat flux, allowing for man-ufacturing tolerances on fuel pellets and rods. N F g Nuclear Enthalpy Rise Hot Channel Fr.ctor, is defined as the ratio of the integral of linear power along the rod with the highest integrated power to the average rod power.
- Y(Z)
Radial Peaking Factor, is defined as the ratio of peak power F density to average power density in the horizontal plane at l core elevation Z. 1 { 3/4.2.1 AXIAL FLUX DIFFERENCE (AFD) The limits on AXIAL FLUX DIFFERENCE assure that the F (Z) upper bound q envelope of 2.14 times the normalized axial peaking factor is not exceeded l during either normal operation or in the event of xenon redistribution l following power changes. i Target flux difference is determined at equilibrium xenon conditions. The full length rods may be positioned within the core in accordance with I their respective insertion limits and should be inserted near their normal position for steady state operation at high power levels. The value of the target flux difference obtained under these conditionr. divided by the fraction l of RATED THERMAL POWER is the target flux difference at RATED THERMAL POWER for the associated core burnup conditions. Target flux differences for other THERMAL POWER levels are obtained by multiplying the RATED THERMAL POWER value by the appropriate fractional THERMAL POWER level. The periodic updating of the target flux difference value is necessary to reflect core burnup considerations. l NORTH ANNA - UNIT 1 B 3/4 2-1 Amendment No. 3, E, 76,., i l I ~ _ _ _,
J l 2 POWER DISTRIBUTION LIMITS a BASES l Although it is intended that the plant will be operated with the AXIAL FLUX DIFFERENCE within the + 5% 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 reduced THERi1AL POWER levels. This deviation will not affect the xenon redistribution sufficiently to change the envelope of peaking factors which may be reached on a subsequent return to RATED THERMAL POWER (with the AFD within the target band) provided the time duration of the deviation is limited. Accordingly, a i hour penalty deviation limit cumulative during the previous 24 hours is provided for operation outside of the target band but within the limits of Figure 3.2-1 while at THERMAL POWER levels j between 50% and P % of RATED THERMAL POWER. For THERMAL POWER levels between l f 15% and 50% of RATED THERMAL POWER, deviations of the AFD outside of the j target band are less significant. The penalty of 2 hours actual time reflects this reduced significance. } Provisions for mon'itoring the AFD on an automatic basis are derived from the plant process computer through the AFD Monitor Alarm. The i computer determines the one minute average of each of the OPERABLE excore detector outputs and provides an alarm message immediately if the AFD for at least 2 of 4 or 2 of 3 OPERABLE excore channels are outside the target band and the THERMAL POWER is greater than P % of RATED THERMAL POWER. f During operation at THERMAL POWER levels between 50% and P % and 15% and f 50% RATED THERMAL POWER. the computer outputs an alarm message when the penalty deviation accumulates beyond the limits of 1 hour and 2 hours, respectively. Figure B 3/4 2-1 shows a typical monthly target band. l 1 I I i i i I I i NORTH ANNA - UNIT 1 B 3/4 2-2 Amendment No. 3, 5, 22, 37 I t_.
o [@ MCyo, UNITED STATES f 'g NUCLEAR REGULATORY COMMISSION
- /* ',
d E WASHINGTON, D. C. 20555 tfs%,f[at[ VIRGINIA ELECTRIC AND POWER COMPANY DOCKET NO.__50-339 NORTH ANNA POWER STATION, UNIT NO. 2 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 20 License No. NPF-7 1. The Nuclear Regulatory Commission (the Commission) has found that: A. The application for amendment by Virginia Electric and Power Company (the licensee) dated November 12, 1981 as supplemented February 12, 1982 complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act) and the Commission's rules and regulations set forth in 10 CFR Chapter I; B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied. t l i i l L
- 2.
Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C.(2) of Facility Operating License No. NPF-7 is hereby amended to read as follows: (2) Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 20, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications. 3. This license amendment is effective as of the date of its issuance. FOR THE NUCLEAR REGULATORY COMMISSION -+ f Lh d+ Robe #rt X.' Clark, Chief Operating Reactors Branch #3 Division of Licensing
Attachment:
Changes to the Technical Specifications Date of Issuance: April 13, 1982 i i 0
o ATTACHMENT TO LICENSE AMENDMENT AMENDMENT NO. 20 TO FACILITY OPERATING LICENSE NO. NPF-7 DOCKET NO. 50-339 Replace the following pages of the Appendix "A" Technical Specifications with the enclosed pages as indicated. The revised pages are indentified by Amendment number and contain vertical lines indicating the area of change. The corresponding overleaf pages are also provided to maintain document completeness. Pages 3/4 2-5 3/4 2-8 3/4 2-17 3/4 2-18 8 3/4 2-1
i 4 I POWER DISTRIBUTION LIMITS i HEAT FLUX HOT CHANNEL FACTOR-F (Z) LIMITING CONDITION FOR OPERATION 3.2.2 F (Z) shall be limited by the following relationships: q j F (Z) 1 [2.141 [K(Z)] for P > 0.5 9 P l F (Z) 1 [4.28] [K(Z)]for I' 10.5 q RA HE POWER T and K(Z) is the function obtained from Figure 3.2-2 for a given core height location. 4 APPLICABILITY: MODE 1. ACTION: With F (Z) exceeding its limit: q i a. Comply with either of the following ACTIONS: 1. Reduce THERMAL POWER at least 1% for each 1% F (Z) exceeds the q limit within 15 minutes and similarly reduce the Power Range l Neutron Flux-High Trip Setpoints within the next 4 hours; POWER OPERATION may proceed for up to a total of 72 hours; subsequent i POWER OPERATION may proceed provided the Overpower AT Trip l Setpoints have been reduced at least 1% for each 1% F (Z) 9 i exceeds the limit. The Overpower AT Trip Setpoint reduction shall be performed with the reactor in at least HOT STANDBY. 2. Reduce THERMAL POWER as necessary to meet the limits of l Specification _ 3.2.6 using the APDMS with the latest incore map and updated R. i l b. Identify and correct the cause of the out of limit condition prior to increasing THERMAL POWER above the reduced limit required by a, above; THERE\\L POWER may then be increased provided F (Z) is j demonstrated through incore tr.apping to be within its limit. l 4 l l NORTH ANNA - UNIT 2 3/4 2-5 Amendment No.l 5 i l
POWER DISTRIBUTION LIMITS SURVEILLANCE REQUIREMENTS 4.2.2.1 The provisions of Specification 4.0.4 are not applicable. 4.2.2.2 F shall be evaluated to determine if F (Z) is within its
- Y 0
limit by: a. Using the movable incore detectors to obtain a power distribution map at any THERMAL POWER greater than 5% of RATED THERMAL POWER. b. Increasing the measured F component of the power distribution map by 3% to account for E nufacturing tolerances and further increasing the value by 5% to account for measurement uncertainties. c. Comparing the F computed (F ) obtained in b, above to: xy 1. The F limits for RATED THERMAL POWER (FRTP) for the x appropriate measured core planes given in e and f, below, and 2. The relationship: F =F Li + 0.2(1-P)] x l where F*Y is the limit for fractional THERMAL POWER operation expressed as a function of F )TP R and P is the fraction of x. RATED THERMAL POWER at which F was measured. xy d. Remeasuring F according to the following schedule: xy P 1. When F is greater than the F limit for the appropriate measured core plane but less than the F relationship, xy C additional power distribution maps shall be taken and F P compared to F and F, : a) Either within 24 hours after exceeding by 20% of RATED THERMAL POWER or greater, the THERMAL POWER at which F was last determined, or NORTH ANNA - UNIT 2 3/4 2-6 n-
4 o 4 i POWER DISTRIBUTION LIMITS SURVEILLANCE REQUIREMENTS (Continued) I (b) At least once per 31 EFPD, whichever occurs first. 2. When the F is less than or equal to the F limit for the xy xy appropriate measured core plane, additional power distribution maps shall be taken and F compared to F and F at least xy xy xy ,i once per 31 EFPD. i e. The F limits for Rated Thermal Power (Fxy ) shall be provided xy for all core planes containing Bank "D" control rods and all unrodded core planes, in a Core Surveillance Report per Technical Specification 6.9.1.10. f. The F limits of e, above, are not applicable in the following xy core plane regions as measured in percent of core height from the bottom of the fuel: 1. Lower core region from 0 to 15%, inclusive. 2. Upper core region from 85 to 100%, inclusive. 3. Grid plane regions at 17.8 12%, 32.1 !2%, 46.412%, l 60.612% and 74.912%, inclusive (17 x 17 fuel elements). 4. Core plane regions within !2% of core height ( 2.88 inches) about the bank demand position of the bank "D" control rods, g. With F exceeding F xy xy 1. The effects of F on F (Z) shall be evaluated to determine if F(Z)iswithinIEslimkt,and g 4 2. Tne F (Z) limit shall be reduced at least 1% for each 1% 9 F exceeds F 4.2.2.3 When F (Z) is measured for other than F determination, an overall 9 j measured F (Z) shall be obtained f rom a power distribution map and increased q by 3% to account for manufacturing tolerances and further increased by 5% to account for measurement uncertainty. I NORTH ANNA-UNIT 2 3/4 2-7 Amendment No. .n,-,., ,.a ._,,..,. ~,,., - ..s.
..__7 1 .._} 7.. _ l i l l l l 1.0 ~ i ~ -~(6.0/1-0)1 - 7 i i i 1 j l 1 a i j l -] _.'-{l0 W 0~.} 3)__ i i i.. ,_4 4 j I I i i i i 0.8 I i l i ~ i i 1 i i } i i i i 3 d I i i I i i _.._..__}_ O 0.6 i A l { i j i \\- l e t 3 j l g-l g j ~ i 0; 6) f .. - f _._ __ _. f._. _ _ I__. I I t 2 i x 0.4 t 9 i. I i 1 i g 1 t e i j y 0.2 I i i l j l l i e i I i i t i 0 2 4 6 8 10 12 1 1 CORE HEIGHT (FT) Figure 3.2-2 K(Z) - Nomalized F (Z) as a Function of Core Height 1 NORTH ANNA - UNIT 2 3/4 2-8 Amendment No. o.0 1 1
e 0 i POWER DISTRIBUTION LIMITS AXIAL POWER DISTRIBUTION 4 LIMITING CONDITION FOR OPERATION .i 3.2.6 The axial power distribution shall be limited by the following relationship: [F (Z)]g = (I))(P )(1.03)(1 + a))(1.07) Where: F)(Z) is the nomalized axial power distribution from thimble a. j at core elevation Z. b. P is the fraction of RATED THERMAL POWER. c. K(Z) is the function obtained from Figure 3.2-2 for i a given core height location. i R), for thimble j, is determined from at least n=6 incore i d. flux maps covering the full configuration of permissible rod patterns above p % of RATED THERMAL POWER in accordance m with: n j ij i=1 l Where: eas Qi ij [F (Z)]g and [F (Z)]g is the maximum value of the normalized axial distribution at elevation Z from thimble j in map i ( l l l l l 1 NORTH ANNA - UNIT 2 3/4 2-17 Amendment No. 77, J 0 l t --,., =, -.~ . - - -. - - - - - - -, - -.. - - - - - - _, - - ~,, - ---
-- -. _ _ - ~ r i POWER DISTRIBUTION LIMITS LIMITING CONDITION FOR OPERATION (Continued) l 4 4 which had a measured peaking factor without uncertainties eas or densification allowance of F ) aj is the standard deviation associated with thimble j, expressed e. as a fraction or percentage of R}, and is derived from n flux maps i from the relationship below, or 0.02, (2%) whichever is greater. 1 b nI 1 i=1(I - Rij)2]1/2 o - j j j f. The factor 1.07 is comprised of 1.02 and 1.05 to account for the j axial power distribution instrumentation accuracy and the measure-ment uncertainty associated with F using the movable detector system, respectively. g. The factor 1.03 is the engineering uncertainty fact'or. i i APPLICABILITY: MODE 1 AB0VE P,% of RATED THERMAL POWER #, where the value for Py is established in the Core Surveillance Report per Technical Specification 6.9.1.10. i ACTION: With a F.(Z) factor exceeding [F (Z)hc]ent for every percent by which by less than or equal to 4 a. percent,JreduceTHERMALPOWERondpe i
- The APDMS may be out of service when surveillance for determining power distribution maps is being performed.
NORTH ANNA - UNIT 2 3/4 2-18 Amendment No.17. 2 0 i i
3/4.2 POWER DISTRIBUTION LIMITS BASES The specifications of this section provide assurance of fuel integrity during Condition I (Normal Operation) and II (Incidents of Moderate Frequency) events by: (a) maintaining the minimum DNBR in the core greater than or equal to 1.30 during normal operation and in short term transient s, and (b) limiting the fission gas release, fuel pellet temperature & cladding mechanical properties to within assumed design criteria. In addition, limiting the peak linear power density during Condition I events provides assurance that the initial conditions assumed for the LOCA analyses are met and the ECCS acceptance criteria limit of 2200 F is not exceeded. The definitions of certain hot channel and peaking factors as used in these specifications are as follows: F (Z) Heat Flux Hot Channel Factor, is defined as the maximum local q heat flux on the surface of a fuel rod at core elevation Z divided by the average fuel rod heat flux, allowing for man-ufacturing tolerances on fuel pellets and rods. F Nuclear Enthalpy Rise Hot Channel Factor, is defined as the ~ ratio of the integral of linear power along the rod with the highest integrated power to the average rod power.
- Y(Z)
Radial Peaking Factor, is defined as the ratio of peak power F density to average power density in the horizontal plane at core elevation Z. 3/4.2.1 AXIAL FLUX DIFFERENCE (AFD) The limits on AXIAL FLUX DIFFERENCE assure that the F (Z) upper bound 9 envelope of 2.14 times the normalized axial peaking factor is not exceeded during either no rmal operation or in the event of xenon redistribution following power changes. Target flux difference is determined at equilibrium xenon conditions. The full length rods may be positioned within the core in accordance with their respective insertion limits and should be inserted near their normal position for steady state operation at high power levels. The value of the target flux difference obtained under these conditions divided bv the fraction of RATED THERMAL POWER is the target flux difference at RATEI< THERMAL POWER for the associated core burnup conditions. Target flux differences for other NORTH ANNA - UNIT 2 B 3/4 2-1 Amendment No..: 0
POWER DISTRIBUTION LIMITS BASES THERMAL POWER levels are obtained by multiplying the RATED THERMAL POWER value by the appropriate fractional THERMAL POWER level. The periodic updating of l the target flux difference value is necessary to reflect core burnup considerations. Although it is intended that the plant will be operated with the AXIAL FLUX DIFFERENCE within the + 5% 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 reduced THERMAL POWER levels. i This deviation will not affect the xenon redistribution sufficiently to change the envelope of peaking factors which may be reached on a subsequent return to RATED THERiiAL POWER (with the AFD within the target band) provided the time duration of the deviation is limited. Accordingly, a 1 hour penalty deviation limit cumulative during the previous 24 hours 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 P % of RATED THERMAL POWER. For THERMAL POWER j f 1evels between 15% and 50% of rated THERMAL POWER, deviations of the AFD outside of the target band are less significant. The penalty of 2 hours actual time reflects this reduced significance. Provisions for monitoring the AFD on an automatic basis are derived from the plant process computer through the AFD Monitor Alarm. The computer determines i the one minute average of each of the OPERABLE excore detector outputs and provides an alarm message immediately if the AFD for at least 2 of 4 or 2 of 3 OPERABLE excore channels are outside the target band and the THERMAL POWER is greater than P % of RATED THER!iAL POWER. During operation at THERMAL POWER f levels between 50% and P % and 15% and 50% RATED THERMAL POWER, the computer f outputs an alarm message when the penalty deviation accumulates beyond the limits of I hour and 2 hours, respectively. Figure B 3/4 2-1 shows a typical monthly target band. 1 NORTH ANNA - UNIT 2 B 3/4 2-2 Amendment No.17, _ - _ _}}