2CAN040202, Cycle 16 Core Operating Limits Report

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Cycle 16 Core Operating Limits Report
ML021280561
Person / Time
Site: Arkansas Nuclear Entergy icon.png
Issue date: 04/25/2002
From: Cotton S
Entergy Operations
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
2CAN040202
Download: ML021280561 (15)


Text

at Entergy Operations, Inc.

1448 S. R. 333 Russellville, AR 72802 Tel 501 858 5000 2CAN040202 April 25, 2002 U. S. Nuclear Regulatory Commission Document Control Desk Mail Station OPl-17 Washington, DC 20555

Subject:

Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6 ANO-2 Cycle 16 Core Operating Limits Report

Dear Sir or Madam:

Arkansas Nuclear One, Unit 2 (ANO-2) Technical Specification 6.9.5 requires submittal of the Core Operating Limits Report (COLR) for each reload cycle. Attached is Revision 0 of the COLR for ANO-2 Cycle 16. This completes the reporting requirement for the referenced specification. This submittal contains no commitments. Should you have any questions, please contact me.

Sincerely,

/

Sherrie R. Cotton Director, Nuclear Safety Assurance SRC/nbm Attachment Aoo0

2CAN040202 Page 2 cc: Mr. Ellis W. Merschoff Regional Administrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 NRC Senior Resident Inspector Arkansas Nuclear One P.O. Box 310 London, AR 72847 Mr. Thomas W. Alexion NRR Project Manager Region IV/ANO-2 U. S. Nuclear Regulatory Commission NRR Mail Stop 07-D-01 One White Flint North 11555 Rockville Pike Rockville, MD 20852

ENTERGY OPERATIONS ARKANSAS NUCLEAR ONE - UNIT 2 CORE OPERATING LIMITS REPORT FOR CYCLE 16 1

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CORE OPERATING LIMITS REPORT FOR CYCLE 16 INDEX PAGE I. INTRODUCTION 3 II.

SUMMARY

OF CHANGES 3 III. AFFECTED TECHNICAL SPECIFICATIONS 5 IV. CORE OPERATING LIMITS 6 V. LIST OF FIGURES 8 2

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ARKANSAS NUCLEAR ONE - UNIT 2 CORE OPERATING LIMITS REPORT FOR CYCLE 16 I. INTRODUCTION This CORE OPERATING LIMITS REPORT (COLR) has been prepared in accordance with the requirements of Arkansas Nuclear One - Unit 2 (ANO-2) Technical Specification 6.9.5 for ANO-2's Cycle 16. This is Revision 0 of the Cycle 16 COLR.

II.

SUMMARY

OF CHANGES Listed below are the changes to the COLR from the latest revision of the Cycle 15 COLR.

"* The lower limit for MTC (Figure 1) has been revised form -3.4 E-04 Ak/k/°F to -3.8 E-04 Ak/k/ 0 F.

" Modified the EFPD breakpoints in the Core Operating Limit for Moderator Temperature Coefficient (MTC) that specifies where a less positive (burnup dependent) MTC was credited in the safety analyses. The first breakpoint is at 124.9 EFPD. The second breakpoint is 353.2 EFPD.

" The required downpower and time frame for a dropped CEA (Figure 2) has changed. Also the title to this figure was changed to "Required Power Reduction After Inward CEA Deviation".

" Linear Heat Rate has been changed from _<13.5 kW/ft to _<13.7 kW/ft up to a burnup of 187 EFPD and _*12.6 kW/ft for burnups exceeding 187 EFPD.

" With COLSS in service and neither CEAC operable, COLSS calculated core power must be maintained less than or equal to COLSS calculated core power operating limit based on DNBR decreased by 10%. The 10% was 13%.

" DNBR Margin with COLSS out of service and at least one CEAC operable (Figures 4).

Added a note to this figure to clarify that DNBR greater than that indicated at the top of the figure is acceptable, provided the indicated ASI limits remain between the bounds that are shown for lower DNBR.

" DNBR Margin with COLSS out of service and both CEACs inoperable (Figure 5). Added a note to this figure to clarify that DNBR greater than that indicated at the top of the figure is 3

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acceptable, provided the indicated ASI limits remain between the bounds that are shown for lower DNBR.

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I1. AFFECTED TECHNICAL SPECIFICATIONS

1) 3/4. 1.1. 1 Shutdown Margin - Tavg > 200'F
2) 3/4. 1.1.2 Shutdown Margin - Tavg *ý 200OF
3) 3.1.1.4 Moderator Temperature Coefficient
4) 3.1.3.1 CEA Position
5) 3.1.3.6 Regulating CEA Insertion Limits
6) 3/4.2.1 Linear Heat Rate
7) 3.2.3 Azimuthal Power Tilt - Tq
8) 3/4.2.4 DNBR Margin
9) 3.2.7 Axial Shape Index 5

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IV. CORE OPERATING LIMITS The cycle-specific operating limits for the specifications listed are presented below.

1) 3/4.1.1.1 - SHUTDOWN MARGIN- Tavg_> 200'F The SHUTDOWN MARGIN shall be greater than or equal to 5.0 % Ak/k in Modes 1, 2, 3, and 4.
2) 3/4.1.1.2 - SHUTDOWN MARGIN - Tavg_< 200OF The SHUTDOWN MARGIN shall be greater than or equal to 5.0% Ak/k in Mode 5.
3) 3.1.1.4 - MODERATOR TEMPERATURE COEFFICIENT The Moderator Temperature Coefficient (MTC) shall be in accordance with Figure 1. The Beginning of Cycle (BOC) positive COLR MTC limit line of Figure 1 is from BOC to 124.9 EFPD. From 353.2 EFPD to End of Cycle (EOC) the positive COLR MTC limit line is linear from an MTC of 0.0 E-4 Ak/k/0 F at 0% power to an MTC of -1.0 E-4 Ak/k/0 F at 100% power which is bounded by the BOC positive MTC limit. Between 124.9 EFPD and 353.2 EFPD the positive MTC limit may be interpolated linearly with burnup.
4) 3.1.3.1 - CEA POSITION With one or more CEAs trippable but misaligned from any other CEAs in its group by more than the Technical Specification 3.1.3.1 allowed value, the minimum required core power reduction for Modes 1 and 2 is specified in Figure 2.
5) 3.1.3.6 - REGULATING CEA INSERTION LIMITS The regulating CEA groups (Groups 6 & P) shall be limited to the withdrawal and insertion limits shown on Figure 3. Figure 3 assumes that Groups 1 through 5 are at or above the Programmed Insertion Limit.

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6) 3/4.2.1 - LINEAR HEAT RATE With COLSS out of service, the linear heat rate shall be maintained < 13.7 kW/ft for cycle burnup up to 187 EFPD; and _ 12.6 kW/ft for burnup exceeding 187 EFPD.
7) 3.2.3 - AZIMUTHAL POWER TILT- Tq The measured AZIMUTHAL POWER TILT shall be maintained _ 0.03.
8) 3/4.2.4 - DNBR MARGIN The DNBR limit shall be maintained by one of the following methods:

a) With COLSS in service and neither CEAC operable - Maintain COLSS calculated core power less than or equal to COLSS calculated core power operating limit based on DNBR decreased by 10%.

b) With COLSS out of service and at least one CEAC operable - Operate within the Region of Acceptable Operation shown on Figure 4, using any operable CPC channel.

c) With COLSS out of service and neither CEAC operable - Operate within the Region of Acceptable Operation shown on Figure 5, using any operable CPC channel.

9)

  • j 3 2 7 - AXIAL SHAPE TNDF.X The core average AXIAL SHAPE NINDEX (ASI) shall be maintained within the following limits:

a) COLSS IN SERVICE

- 0.27*_< ASI*_< + 0.27 b) COLSS OUT OF SERVICE (CPC)

- 0.20

  • ASI _ + 0.20 7

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V. LIST OF FIGURES Figure 1. Moderator Temperature Coefficient Figure 2. Required Power Reduction After Inward CEA Deviation Figure 3. CEA Insertion Limits Versus Thermal Power Figure 4. DNBR Margin Operating Limit Based on Core Protection Calculators (COLSS Out of Service, CEAC Operable)

Figure 5. DNBR Margin Operating Limit Based on Core Protection Calculators (COLSS Out of Service, Both CEACs Inoperable) 8 01-R-2008-04 Revision 0

FIGURE 1 Moderator Temperature Coefficient 5.OOE-05 (0,0.50)Unacceptable Operating Region 0.00E+00 (50, 0.05) (60, .00)

-5.00E-05

-1.OOE-04 LL d)

  • -1.50E-04 a

Ac4ptable Operatinc Regil:)n I I-

-2.50E-04

-3.OOE-04

-3 SOE-n4________________

-3.80 E-04

-4.00E-04 Ul.accep..able peratij g Regi on I 0 10 20 30 40 50 60 70 80 90 100 Core Power (% of Rated Thermal Power)

Note:

Per Technical Specification 3.1.1.4.a. and b., the Moderator Temperature Coefficient (MTC) maximum upper design limit shall be less positive than +0.5 x 10-4 Ak/k/ 0F whenever THERMAL POWER is _< 70% of RATED THERMAL POWER and less positive than 0.0 x 10-4 Ak/k/°F whenever THERMAL POWER is > 70% of RATED THERMAL POWER. Therefore, the actual MTC must be less than the COLR upper limit at zero power. At all other powers, the actual MTC may be equal to the COLR upper limit.

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FIGURE 2 REQUIRED POWER REDUCTION AFTER INWARD CEA DEVIATION*

30 25 0

20 0.

0 IL_

1 0

0 5

0 0 15 30 45 60 75 90 105 120 Time After Deviation (minutes)

  • When core power is reduced to 60% of rated power per this limit curve, further reduction is not required 10 01-R-2008-04 Revision 0

FIGURE 3 CEA INSERTION LIMITS VERSUS THERMAL POWER Groups 6 and P PDIL 110 100 90 80 70 a

60 0 50 fa 40 30 20 10 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 -10 CEA Position, Inches Withdrawn Note: Regulating Groups 1 through 5 at or above the Programmed Insertion Limit.

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FIGURE 4 DNBR MARGIN OPERATING LIMIT BASED ON CORE PROTECTION CALCULATORS ANO-2 Cycle Independent COLSS OOS Limit One CEAC Operable ACCEPTABLE OPERATION 2.9f Any Power Level (0.04, 2.83) (0.20, 2.83) 2.8f 2.7f 2.6t (-0.20, 2.58) ACCEPTABLE OPERATION Power at or above 80%

2.5f

(-0.09, 2.41) (0.20, 2.41) 2.4f D

N 2.3f (-0.20, 2.31)

B R

2.21 ACCEPTABLE OPERATION Power at or above 90%

2.1t

(-0.(10, 1.99) 20Ot (0.20, 1.99)

(-0.20, 1.94) 1.9 1.8 UNACCEPTABLE OPERATION 1.7 Any Power Level I

-0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 CPC Indicated ASI NOTE: DNBR greater than that indicated at the top of the figure is acceptable, provided the indicated ASI limits remain between the bounds that are shown for lower DNBR.

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FIGURE 5 DNBR MARGIN OPERATING LIMIT BASED ON CORE PROTECTION CALCULATORS ANO-2 Cycle Independent COLSS OOS Limit Both CEACs Inoperable D

N B

R

-0.30 -0.20 -0.10 0.00 0.10 0.20 0.30 CPC Indicated ASI NOTE: DNBR greater than that indicated at the top of the figure is acceptable, provided the indicated ASI limits remain between the bounds that are shown for lower DNBR.

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