ML031260548

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Core Operating Limits Report
ML031260548
Person / Time
Site: North Anna Dominion icon.png
Issue date: 04/24/2003
From: Funderburk C
Virginia Electric & Power Co (VEPCO)
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
03-068A, NL&OS/MM
Download: ML031260548 (23)
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Text

VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 April 24, 2003 United States Nuclear Regulatory Commission Serial No.:

03-068A Attention: Document Control Desk NL&OS/MM Washington, D.C. 20555-0001 Docket No.:

50-339 License No.:

NPF-7 VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)

NORTH ANNA POWER STATION UNIT 2 CORE OPERATING LIMITS REPORT By letter dated January 23, 2003 (Serial No.03-068), Dominion submitted the Core Operating Limits Report for North Anna Unit 2 Cycle 16 Pattern TP, Rev. 1. In that report, the value of the rod overlap was incorrectly documented as 98 steps in lieu of 100 steps withdrawn. The correct value was implemented at the plant. Revision 2 to this report is being issued to correct the error in reported value of control rod overlap.

No new commitments are intended by this letter. If you have any questions or require additional information, please contact us.

Very truly yours, C.L. Funderburk Director - Nuclear Licensing & Operations Support Attachment cc:

U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth St. SW, Suite 23 T85 Atlanta, Georgia 30303-8931 Mr. M. J. Morgan NRC Senior Resident Inspector North Anna Power Station

CORE OPERATING LIMITS REPORT Rev 2 North Anna 2 Cycle 16 Pattern TP April 2003 N2C16 COLR Rev 2 Page 1 o f 2 2

N2C16 CORE OPERATING LIMITS REPORT INTRODUCTION The Core Operating Limits Report (COLR) for North Anna Unit 2 Cycle 16 has been prepared in accordance with North Anna Technical Specification 5.6.5. The technical specifications affected by this report are listed below:

TS 2.1.1 Reactor Core Safety Limits TS 3.1.1 Shutdown Margin (SDM)

TS 3.1.3 Moderator Temperature Coefficient (MTC)

TS 3.1.5 Shutdown Bank Insertion Limit TS 3.1.6 Control Bank Insertion Limits TS 3.2.1 Heat Flux Hot Channel Factor TS 3.2.2 Nuclear Enthalpy Rise Hot Channel Factor (FNAH)

TS 3.2.3 Axial Flux Difference (AFD)

TS 3.3.1 Reactor Trip System (RTS) Instrumentation TS 3.4.1 RCS Pressure, Temperature, and Flow DNB Limits TS 3.9.1 Boron Concentration In addition, a technical requirement (TR) in the NAPS Technical Requirements Manual (TRM) refers to the COLR:

TR 3.1.1 Boration Flow Paths - Operating The analytical methods used for determining the core operating limits are those previously approved by the NRC and are discussed in the documents listed in the References Section. Cycle-specific values are presented in bold, while text in italics is provided for information only.

N2C16 COLR Rev 2 Page 2 of 22

REFERENCES

1. VEP-FRD-42 Rev 1-A, Reload Nuclear Design Methodology, September 1986; Supplement 1, November 1993; Supplement 2, September 1996.

(Methodology for TS 3.1.1 - Shutdown Margin, TS 3.1.3 - Moderator Temperature Coefficient, TS 3.1.5 - Shutdown Bank Insertion Limit, TS 3.1.6 - Control Bank Insertion Limits, TS 3.2.1 -

Heat Flux Hot Channel Factor, TS 3.2.2 - Nuclear Enthalpy Rise Hot Channel Factor and TS 3.9.1 - Boron Concentration)

2. WCAP-9220-P-A Revl, Westinghouse ECCS Evaluation Model-1981 Version, February 1982.

(Methodology for TS 3.2.1 - Heat Flux Hot Channel Factor)

3. WCAP-9561-P-A Rev 1 Add. 3, BART A-1: A Computer Code for the Best Estimate Analysis of Reflood Transients - Special Report: Thimble Modehng in W ECCS Evaluation Model, July 1986.

(Methodology for TS 3.2.1 - Heat Flux Hot Channel Factor)

4. WCAP-10266-P-A Rev 2, The 1981 Version of the Westinghouse ECCS Evaluation Model Using the BASH Code, March 1987.

(Methodology for TS 3.2.1 - Heat Flux Hot Channel Factor)

5. WCAP-10054-P-A, Westinghouse Small Break ECCS Evaluation Model Using the NOTRUMP Code, August 1985.

(Methodology for TS 3.2.1 - Heat Flux Hot Channel Factor)

6. WCAP-10079-P-A, NOTRUMP, A Nodal Transient Small Break and General Network Code, August 1985.

(Methodology for TS 3.2.1 - Heat Flux Hot Channel Factor)

7. WCAP-12610-P-A, VANTAGE+ Fuel Assembly - Reference Core Report, April 1995.

(Methodology for TS 3.2.1 - Heat Flux Hot Channel Factor)

8. VEP-NE-2-A, Statistical DNBR Evaluation Methodology, June 1987.

(Methodology for TS 3.2.2 - Nuclear Enthalpy Rise Hot Channel Factor and TS 3.4.1 - RCS Pressure, Temperature and Flow DNB Limits)

9. VEP-NE-3-A, Qualification of the WRB-1 CHF Correlation in the Virginia Power COBRA Code, July 1990.

N2C16 COLR Rev 2 Page 3 of 22

(Methodology for TS 3.2.2 - Nuclear Enthalpy Rise Hot Channel Factor and TS 3.4.1 - RCS Pressure, Temperature and Flow DNB Limits)

10. VEP-NE-1-A, Virginia Power Relaxed Power Distribution Control Methodology and Associated FQ Surveillance Technical Specifications, March 1986; Supplement 1, September 1996.

(Methodology for TS 3.2.1 - Heat Flux Hot Channel Factor and TS 3.2.3 - Axial Flux Difference)

11. WCAP-8745-P-A, Design Bases for the Thermal Overpower AT and Thermal Overtemperature AT Trip Functions, September 1986.

(Methodology for TS 2.1.1 - Reactor Core Safety Limits and TS 3.3.1 - Reactor Trip System Instrumentation)

12. WCAP-14483-A, Generic Methodology for Expanded Core Operating Limits Report, January 1999.

(Methodology for TS 2.1.1 - Reactor Core Safety Limits, TS 3.1.1 - Shutdown Margin, TS 3.3.1

- Reactor Trip System Instrumentation, TS 3.4.1 - RCS Pressure, Temperature, and Flow DNB Limits and TS 3.9.1 - Boron Concentration)

N2C16 COLR Rev 2 Page 4 of 22

2.0 SAFETY LISITS (SLs) 2.1 SLs 2.1.1 Reactor Core SLs In MODES 1 and 2, the combination of THERMAL POWER, Reactor Coolant System (RCS) highest loop average temperature, and pressurizer pressure shall not exceed the limits specified in COLR Figure 2.1-1; and the following SLs shall not be exceeded.

2.1.1.1 The departure from nucleate boiling ratio (DNBR) shall be maintained greater than or equal to the 95/95 DNBR criterion for the DNB correlations and methodologies specified in the References Section.

2.1.1.2 The peak fuel centerline temperature shall be maintained < 4700 OF.

N2C16 COLR Rev 2 Page 5 of 22

COLR Figure 2.1-1 NORTH ANNA REACTOR CORE SAFETY LIMITS 660 655 650 645 640 635 630 625 XL 620 at X 615 t

610 605 600 595 590 585 580 575 570 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 POWER (fraction of nominal)

N2C16 COLR Rev 2 Page 6 o f 2 2

3.1 REACTIVITY CONTROL SYSTEMS 3.1.1 SHUTDOWN MARGIN (SDM)

LCO 3.1.1 SDM shall be 2 1.77 % Ak/k.

3.1.3 Moderator Temperature Coefficient (MTC)

LCO 3.1.3 The MTC shall be maintained within the limits specified below. The upper limit of MTC is +0.6 x 104 Ak/k/0F, when < 70 % RTP, and 0.0 Ak/k/0F when Ž 70 %

RTP.

The BOC/ARO-MTC shall be < +0.6 x 104 Akf/ 0F (upper limit), when <

70% RTP, and < 0.0 AkkftF when Ž 70% RTP.

The EOC/ARO/RTP-MTC shall be less negative than -5.0 x 104 Ak/kftF (lower limit).

The MTC surveillance limits are:

The 300 ppm/ARO/RTP-MTC should be less negative than or equal to

-4.0 x 104 Ak/k/OF [Note 2].

The 60 ppm/ARO/RTP-MTC should be less negative than or equal to

-4.7 x 104 AkVkfF [Note 3].

SR 3.1.3.2 Verify MTC is within -5.0 x 104 Ak/WF (lower limit).

Note 2: If the MTC is more negative than -4.0 x 104 AkIkF, SR 3.1.3.2 shall be repeated once per 14 EFPD during the remainder of the fuel cycle.

Note 3: SR 3.1.3.2 need not be repeated if the MTC measured at the equivalent of equilibrium RTP-ARO boron concentration of < 60 ppm is less negative than -4.7 x 104 Ak/kI0F.

3.1.4 Rod Group Alignment Limits Required Action A. 1.1 Verify SDM to be 2 1.77 % Ak/k.

Required Action B. 1.1 Verify SDM to be 2 1.77 % Ak/k.

Required Action D. 1.1 Verify SDM to be 2 1.77 % Ak/k.

N2C16 COLR Rev 2 Page 7 of 22

3.1.5 Shutdown Bank Insertion Limits LCO 3.1.5 Each shutdown bank shall be withdrawn to at least 228 steps.

Required Action A. 1.1 Verify SDM to be 2 1.77 % Ak/k.

Required Action B. 1 Verify SDM to be 2 1.77 % Ak/k.

SR 3.1.5.1 Verify each shutdown bank is withdrawn to at least 228 steps.

3.1.6 Control Bank Insertion Limits LCO 3.1.6 Control banks shall be limited in physical insertion as shown in COLR Figure 3.1-1. Sequence of withdrawal shall be A, B, C and D, in that order; and the overlap limit during withdrawal shall be 100 steps.

Required Action A. 1.1 Verify SDM to be 2 1.77 % Ak/k.

Required Action B. 1.1 Verify SDM to be 2 1.77 % Ak/k.

Required Action C. 1 Verify SDM to be 2 1.77 % Ak/k.

SR 3.1.6.1 Verify estimated critical control bank position is within the insertion limits specified in COLR Figure 3.1-1.

SR 3.1.6.2 Verify each control bank is within the insertion limits specified in COLR Figure 3.1-1.

SR 3.1.6.3 Verify each control bank not fully withdrawn from the core is within the sequence and overlap limits specified in LCO 3.1.6 above.

3.1.9 PHYSICS TESTS Exceptions - MODE 2 LCO 3.1.9.b SDM is 21.77 % Ak/k.

SR 3.1.9.4 Verify SDM to be 21.77 % Ak/k.

N2C16 COLR Rev 2 Page 8 of 22

COLR Figure 3.1-1 230 220 210 200 190 180 170 160 150 In 140 C)

I 130 o 120 o 110 a-CL M 100 CD go 0

s 80 70 60 50 40 30 20 10 0

North Anna 2 Cycle 16 Control Rod Bank Insertion Limits

_(0.

539, 2 8)

.0,194 Fully wdpo ition = 28 steps (0,11

<. 7t0-BA IK MM l)

.048,- X 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Fraction of Rated Thermal Power 0.8 0.9 1.0 N2C16 COLR Rev 2 Page 9 of 22

3.2 POWER DISTRIBUTION LIMITS 3.2.1 Heat Flux Hot Channel Factor (FQ(Z))

LCO 3.2.1 FQ(Z), as approximated by FQM(Z), shall be within the limits specified below.

The change in the FQ(Z) limit for coastdown operation is accommodated by defining a variable quantity, CFQ as indicated below. Then, the following expressions apply to both normal operation and Tavg coastdown regimes.

CFQ = 2.19, for normal operation at full power; CFQ = 2.15, for flux map immediately preceding EOC temperature coastdown and during subsequent power coastdown operation.

The Measured Heat Flux Hot Channel Factor, FQ^ 1(Z), shall be limited by the following relationships:

F I'f (Z) <

for P>0.5 Q

P N(Z)

CFQ K(Z)

M (Z) 5 K-Z-for P<0.5 0.5 N(Z)

THERMAL POWER w e RATED THERMAL POWERa K(Z) is provided in COLR Figure 3.2-1; and N(Z) is a cycle-specific non-equilibrium multiplier on FQW'(Z) to account for power distribution transients during normal operation, provided in COLR Table 3.2-1.

The discussion in the Bases Section B 3.2.1 for this LCO requires the application of a cycle dependent non-equilibrium multiplier, N(Z), to the measured peaking factor, FQM(Z), before comparing it to the limit. N(Z) accounts for power distribution transients encountered during normal operation. As function N(Z) is dependent on the predicted equilibrium FQ(Z) and is sensitive to the axial power distribution, it must be generatedfrom the actual EOC burnup distribution that can only be obtained after the shutdown of the previous cycle. The cycle-specific N(Z) function is presented in COLR Table 3.2-1.

N2C16 COLR Rev 2 Page 10 of 22

COLR Table 3.2-1 N2C16 Normal Operation N(z)

NODE HEIGHT (FEET) 10 10.2 11 10 0 12 9.8 13 9.6 14 9.4 15 9.2 16 9.0 17 88 18 8.6 19 8.4 20 8.2 21 8.0 22 7.8 23 76 24 7.4 25 72 26 70 27 6.8 28 66 29 6.4 30 6.2 31 6.0 32 5.8 33 5.6 34 5.4 35 5.2 36 50 37 4.8 38 4.6 39 4.4 40 4.2 41 4.0 42 3.8 43 3.6 44 3.4 45 3.2 46 3.0 47 2.8 48 2.6 49 2.4 50 2.2 51 2.0 52 1.8 0 to 1000 MWD/MTU 1.112 1.111 1.110 1.109 1.108 1.110 1.111 1.115 1.119 1.126 1.133 1.139 1.142 1.142 1 139 1.137 1.134 1.131 1.126 1.121 1.114 1.106 1.098 1.091 1.088 1.087 1.091 1.096 1.106 1.119 1.132 1.144 1.156 1.167 1.178 1.187 1.196 1.204 1.212 1.218 1.225 1.231 1.237 1000 to 3000 MWD/MTU 1.112 1.111 1.110 1.109 1.108 1.110 1.111 1.115 1.119 1.126 1.133 1.139 1.142 1.142 1.139 1.137 1.134 1.131 1.126 1.121 1.114 1.106 1.098 1.091 1.088 1.087 1.091 1.096 1.106 1.119 1.132 1.144 1.156 1.167 1.178 1.187 1.196 1.204 1.212 1.218 1.225 1.231 1.237 3000 to 5000 MWD/MTU 1.148 1.148 1.146 1 146 1.147 1.151 1.153 1.156 1.160 1.163 1.167 1.170 1.172 1.172 1.170 1 167 1.162 1.157 1.152 1.146 1.141 1.137 1.132 1.125 1.117 1.107 1.103 1.104 1.110 1.120 1.131 1.144 1.156 1.167 1.177 1.187 1.196 1.204 1.212 1.218 1.225 1.231 1.237 5000 to 7000 MWD/MTU 1.148 1.148 1.146 1.146 1.147 1.151 1.153 1.156 1.160 1.163 1.167 1.170 1.172 1 172 1.170 1.167 1.162 1.157 1.152 1.146 1.141 1.137 1.132 1.125 1.117 1.108 1.103 1.105 1.109 1.111 1.115 1.120 1.124 1.128 1.130 1.134 1.141 1.151 1.159 1.167 1.174 1.182 1.191 7000 to 9000 MWD/MTU 1.148 1.148 1.146 1.146 1.147 1.151 1.153 1.156 1.160 1.163 1.167 1.170 1.172 1.172 1.170 1.167 1.162 1.157 1.152 1.146 1.141 1.137 1.132 1.125 1.117 1.108 1.103 1.105 1.109 1.111 1.115 1.120 1.124 1.128 1.130 1.134 1.141 1.151 1.159 1.167 1.174 1.182 1.191 9000 to 20400 MWD/MTU 1.148 1.148 1.146 1.145 1.146 1.150 1.156 1.162 1.167 1.170 1.172 1.174 1.177 1.181 1.187 1.191 1.191 1.189 1.184 1.177 1.168 1.162 1.156 1.152 1.145 1.134 1.124 1.120 1.120 1.124 1.126 1.127 1.127 1.128 1.129 1.133 1.140 1.150 1.158 1.166 1.173 1.182 1.193 These decks were generated for normal operation flux maps which are typically taken at full power. Additional N(z) decks may be generated if necessary, consistent with the methodology described in the RPDC topical.

N2C16 COLR Rev 2 Page 11 of 22

COLR Figure 3.2-1 K(Z) - Normalized FQ as a Function of Core Height N

0 a

-J0zL 1.2 1.1 -

1.0 0.9 08 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0

1 2

3 4

5 6

7 8

CORE HEIGHT (FT) 9 10 11 12 13 N2C16 COLR Rev 2 Page 12 of 22

3.2.2 Nuclear Enthalpy Rise Hot Channel Factor (FNH)

LCO 3.2.2 FNAH shall be within the limits specified below.

FeH < 1.49{1 + 0.3(1 - P)}

THERMAL POWER where:

p =

RATED THERMAL POWER SR 3.2.2.1 Verify FNA is within limits specified above.

3.2.3 AXIAL FLUX DIFFERENCE (AFD)

LCO 3.2.3 The AFD in % flux difference units shall be maintained within the limits specified in COLR Figures 3.2-2, 3.2-3 and 3.2-4.

N2C16 COLR Rev 2 Page 13 of 22

COLR Figure 3.2-2 N2C16 Axial Flux Difference Limits 0 to 5000 MWD/MTU c) 0 E

C) co a:

  • 0 0

ID EL 120 110 100 90 80 70 60 50 40 30 20 10 0

-30

-20

-10 0

10 Percent Flux Difference (Delta-l) 20 30 N2C16 COLR Rev 2 Page 14 of 22

COLR Figure 3.2-3 N2C16 Axial Flux Difference Limits 5000 MWD/MTU to EOR 120 110 100 90 80 I.

0 IL a) la (U

I.-

a)..

a-70 60 50 40 30 20 10 0

-30

-20

-10 0

10 Percent Flux Difference (Delta-l) 20 30 N2C16 COLR Rev 2 Page 15 of 22

COLR Figure 3.2-4 N2C16 Axial Flux Difference Limits EOR to EOC (Coastdown) 120 110 100 90 80 LC 0.

I-EL a)

Se-0 C,

0)

U IL 70 60 50 40 30 20 10 0 4-

-30

-20

-10 0

10 20 Percent Flux Difference (Delta-I) 30 N2C16 COLR Rev 2 Page 16 of 22

3.3 INSTRUMENTATION 3.3.1 Reactor Trip System (RTS) Instrumentation TS Table 3.3.1-1 Note 1: Overtemperature AT The Overtemperature AT Function Allowable Value shall not exceed the following nominal trip setpoint by more than 2% of AT span, with the numerical values of the parameters as specified below.

AT < ATO {K-K2(I + r s[T-T']+K3 (P-P )-fi W) where: AT is measured RCS AT, OF.

ATo is the indicated AT at RTP, OF.

s is the Laplace transform operator, sec-'.

T is the measured RCS average temperature, OF.

T' is the nominal Tavg at RTP, < 586.8 OF.

P is the measured pressurizer pressure, psig.

P' is the nominal RCS operating pressure, > 2235 psig.

K1 < 1.2715 K2 2 0.02172 /°F K3 > 0.001144 /psig T), r2 = time constants utilized in the lead-lag controllerfor Tavg tl 2 23.75 sec T2 5 4.4 sec (1+-rls)/(1 + s2s)

= function generated by the lead-lag controllerfor Tavg dynamic compensation f1(AI) 2 0.0165{ (q, - qb)}

when (q, - qb) < -44% RTP 0

when -44% RTP < (q, - qb) < +3% RTP 0.0198{(q, - qb) - 31 when (q, - qb) > +3% RTP

[See footnote]

Where qt and qb are percent RTP in the upper and lower halves of the core, respectively, and q, + qb is the total THERMAL POWER in percent RTP.

Footnote: The units for f1(AI) = 0 in the North Anna TS and NUREG-143 1 are incorrectly specified as "% of RTP." f,(AI) being dimensionless should have no units. This discrepancy is being addressed by the North Anna Corrective Action System.

N2C16 COLR Rev 2 Page 17 of 22

TS Table 3.3.1-1 Note 2: Overpower AT The Overpower AT Function Allowable Value shall not exceed the following nominal trip setpoint by more than 2% of AT span, with the numerical values of the parameters as specified below.

AT*ATo{K 4 -K 5 [1 3]T-K6 [T-T']-f 2(I)}

where: AT is measured RCS AT, OF.

ATO is the indicated AT at RTP, OF.

s is the Laplace transform operator, sec-.

T is the measured RCS average temperature, OF.

T' is the nominal Tavg at RTP, < 586.8 'F.

K4 < 1.0865 K5 2 0.0197 /OF for increasing Tavg K6 2 0.00162 PF when T > T' 0 /OF for decreasing Tavg 0 PF when T < T' T3 = time constant utilized in the rate lag controllerfor Tavg

¶3 2 9.5 sec r3s/(1+ rys) = function generated by the rate lag controllerfor Tavg dynamic compensation f2(QI) = 0, for all Al.

N2C16 COLR Rev 2 Page 18 of 22

3.4 3.4.1 LCO REACTOR COOLANT SYSTEM (RCS)

RCS Pressure, Temperature, and Flow Departure from Nucleate Boiling (DNB) Limits 3.4.1 RCS DNB parameters for pressurizer pressure, RCS average temperature, and RCS total flow rate shall be within the limits specified below:

a. Pressurizer pressure is greater than ortequal to 2205 psig;
b. RCS average temperature is less than or equal to 591 OF; and
c. RCS total flow rate is greater than or equal to 295,000 gpm.

SR 3.4.1.1 SR 3.4.1.2 SR 3.4.1.3 SR 3.4.1.4 Verify pressurizer pressure is greater than or equal to 2205 psig.

Verify RCS average temperature is less than or equal to 591 0F.

Verify RCS total flow rate is greater than or equal to 295,000 gpm.

NOTE--

Not required to be performed until 30 days after > 90% RTP.

Verify by precision heat balance that RCS total flow rate is 2 295,000 gpm.

N2C16 COLR Rev 2 Page 19 of 22

3.5 EMERGENCY CORE COOLING SYSTEMS (ECCS) 3.5.6 Boron Injection Tank (BIT)

Required Action B.2 Borate to an SDM 2 1.77 % Ak/k at 200 'F.

N2C16 COLR Rev 2 Page 20 of 22

3.9 REFUELING OPERATIONS 3.9.1 Boron Concentration LCO 3.9.1 Boron concentrations of the Reactor Coolant System (RCS), the refueling canal, and the refueling cavity shall be maintained 2 2600 ppm.

Note: The refueling boron concentration satisfies the more restrictive of the following conditions: (a) keff <0.95, or (b) boron concentration 22600 ppm.

SR 3.9.1.1 Verify boron concentration is within the limit specified above.

N2C16 COLR Rev 2 Page 21 of 22

NAPS TECHNICAL REQUIREMENTS MANUAL TRM 3.1 REACTIVITY CONTROL SYSTEMS TR 3.1.1 Boration Flow Paths - Operating Required Action E.2 Borate to a SHUTDOWN MARGIN 2 1.77 % Ak/k at 200 oF, after xenon decay.

N2C16 COLR Rev 2 Page 22 of 22

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