CP-200900010, Core Flux Maps Data, Cycle 11

Core Flux Maps Data, Cycle 11

ML090230626
Person / Time
Site:	Comanche Peak
Issue date:	01/07/2009
From:	Blevins M Luminant Generation Co, Luminant Power
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CP-200900010, TXX-09007 ERX-08-004, Rev 0
Download: ML090230626 (19)

Text

Mike Blevins Luminant Power Executive Vice President P 0 Box 1002 Lum inant & Chief Nuclear Officer Mike.Blevins@Luminant.com 6322 Norlh FM 56 Glen Rose, TX 76043 T 254 897 5209 C 8175599085 F 254 897 6652 CP-200900010 Log # TXX-09007 January 7, 2009 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION DOCKET NO. 50-446 UNIT 2 CORE FLUX MAPS

Dear Sir or Madam:

Per discussions with the NRC, Luminant Generation Company LLC (Luminant Power) agreed to provide the NRC with the first 6 months of flux map data for Comanche Peak Unit 2, Cycle 11. The enclosure to this letter provides the subject Unit 2 Cycle 11 the flux map data.

This communication contains no new licensing basis commitments regarding Comanche Peak Units 1 and 2.

Should you have any questions, please contact Mr. J. D. Seawright at (254) 897-0140.

Sincerely, Luminant Generation Company LLC Mike Blevins By: ,*

Fred W. Madden Director, Oversight & Regulatory Affairs Enclosure Engineering Report ERX-08-004, CPNPP Fq(Z) Margin Impact of Measured Axial Offset Following RAOC Methodology Transition c- E. E. Collins, Region IV B. K. Singal, NRR Resident Inspectors, Comanche Peak A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Ac i)/

Callaway

• Comanche Peak

• Diablo Canyon

• Palo Verde

• San Onofre

• South Texas Project

• Wolf Creek

Luminant Generation Company LLC COMANCHE PEAK NUCLEAR POWER PLANT

/

ENGINEERING REPORT CPNPP Fq(Z) Margin Impact of Measured Axial Offset Following RAOC Methodology Transition ERX-08-004 Revision 0 12/3/08 Prepared By: -__ Date:_-

od' ~emons Core Performance Engineering Reviewed By: .an Date:--

Mar'k Bryant Core Perlbnnance Approved By: !___- Date:'4O Bill Reppa System Engineering Manager

DISCLAIMER This information contained in this report was prepared for the specific requirements of Luminant Generation Company LLC (Luminant Power) and may not be appropriate for use in situations other than those for which it was specifically prepared. Luminant Power PROVIDES NO WARRANTY HEREUNDER, EXPRESS OR IMPLIED, OR STATUTORY, OF ANY KIND OR NATURE WHATSOEVER, REGARDING THIS REPORT OR ITS USE, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES ON MERCHANTABILITY FOR FITNESS FOR A PARTICULAR PURPOSE.

By making this report available, Luminant Power does not authorize its use by others, and any such use is forbidden except with the prior written approval of Luminant Power. Any such written approval should itself be deemed to incorporate the disclaimers of liability and disclaimers of warranties provided herein. In no event should Luminant Power have any liability for any incidental or consequential damages of any type in connection with the use, authorized or unauthorized, of this report or the information in it.

ERX-08-004 Rev 0 Page 2

TABLE OF CONTENTS SECTION TITLE PAGE T itle Pag e .................................................................................. 1 Disclaim er ................................................................................ 2 T able of C ontents .............................. ........................................ 3 List of Tables and Figures .......................................................... 4 1.0 Purpose ............................................................................... . . 5 2.0 U2C 1I Power Distribution Data ...................................... 6 2.1 Axial Offset Trend .......................................................... 6 2.2 Fq(z) Measurement Results ................................................... 7 2.3 W(z) Update Function Results ............................................ 11 3.0 References........................................................................... 18 ERX-08-004 Rev 0 Page 3

LIST OF TABLES and FIGURES TITLE PAGE Figure 1 CPNPP Unit 2, Cycle 11 Axial Offset Trend .................................... 6 Figure 2 CPNPP Unit 2, Cycle 11 Fq(Z) Trends .......................................... 7 Table 1 U2C 11 Power Distribution Measurement Summary .......................... 8 Table 2 U2C1 1 Fq(Z) Margin Impact Summary ......................................... 8 Figure 3 Map 01 W(z) Update Function Results ............ ............ 11....

1 Figure 4 Map 02 W(z) Update Function Results ............................................ 12 Figure 5 Map 04 W(z) Update Function Results ....................................... 12 Figure 6 Map 05 W(z) Update Function Results ............................................ 13 Figure.7 Map 06 W(z) Update Function Results ............................................ 13 Figure 8 Map 07 W(z) Update Function Results ............................................ 14 Figure 9 Map 08 W(z) Update Function Results ............................................ 14 Figure 10 Map 09 W(z) Update Function Results ............................................ 15 Figure 10 Map 10 W(z) Update Function Results ......................... 15 Figure 12 Map 10 W(z) Update Function Results ............................................ 16 Figure 13 Map 12 W(z) Update Function Results ............................................ 16 Figure 14 Map 13 W(z) Update Function Results ......................... 1 Figure 15 Map 14 W(z) Update Function Results ............................................ 17 ERX-08-004 Rev 0 Page 4

1.0 Purpose During the licensing process for implementation of Westinghouse Relaxed Axial Offset Control (RAOC) Methodology at Comanche Peak Nuclear Power Plant (CPNPP),

discussions were held with the NRC regarding the Westinghouse Axial Offset Validity Criteria Guidance.. As a result of these discussions (Reference 1 and Reference 2), it was agreed that CPNPP would not utilize the standard Westinghouse AO Validity Criteria, but rather would perform the following:

• For each Power Distribution Measurement, CPNPP would evaluate differences in the Measured and Predicted Axial Power Shape, and the impact of these differences on the available Fq Margin.

• CPNPP would revise the W(z) curves based on measured Axial Offset when appropriate. From Reference 2, (also CPNPP Commitment 3475619):

Luminant Generation Company LLC will revise, as appropriate,the W(z) curves to ensure they are representativeof the current core conditions should the value of W(z) *[PredictedP(z) / Measured P(z)] become less than 1.04.

The revised W(z) curves will be calculatedpriorto performance of the next requiredsurveillance. Since the W(z) function is set to 1.0 near the top and bottom of the core, this commitment does not apply to the FQ(z) measured in the exclusion zones.

• CPNPP would report to the NRC following implementation of the actions described above. Per Reference 1:

Luminant Power will provide data regardingthe completion of Technical Specification SurveillanceRequirement (SR) 3.2.1.1 after thefirst six months of Unit 2 Cycle 11 operation.

This Engineering Report provides relevant Power Distribution Measurement and Fq(z) margin data related to Unit 2 Cycle 11 from April through November 2008.

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2.0 U2C01 Fq MEAUREMENT DATA 2.1 Axial Offset Trend CPNPP utilizes two measurement methods to complete a Power Distribution Measurement and Fq(z) surveillance. A 'MIDS Map' utilizes data from the Movable Incore Detector System to infer a measured power distribution. The results of the MIDS Map are used to perform the required Power Distribution surveillances as well as calibrate the BEACON Power Distribution Monitoring System (PDMS). A 'PDMS Map' may then be performed for following measurements using BEACON to generate a report based on the monitored power distribution.

Figure 1 shows the Axial Offset trend for full power measurements taken during U2C 11, compared to Design Predictions for Hot Full Power, All Rods Out (HFP, ARO) conditions.

The maximum difference for a full power map was 3.11% for Map 08 taken at a bumup of 2125 MWD/MTU.

Figure 1, CPNPP Unit 2, Cycle 11 Axial Offset Trend 12

• MeasuredAO 10 - - Predicted ARO AO 6- U 4-

'9 t 2 0 - -; -

-2 L

-4

-6 EMIDS MW

-8 0 200 400 600 M11 loa 120010 14000 16000] I3m 20000) 2200 240D Eunmq @IWDIM7U)

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2.2 Fq(z) Measurement Results Figure 2 shows the Fq(Z) and FqC(Z)*W(Z)/K(Z) trends for Unit 2 Cycle 11 for Full Power Flux Maps. Prior to Map #08 taken at 2125 MWD/MTU, the Core Operating Limits Report was revised to increase the width of the RAOC AFD limits to provide additional operational margin. The widening of the RAOC AFD limits was facilitated by revision to the W(Z) curves, thus the step change in the Predicted Transient Fq curve in Figure 2.

Figure 2, CPNPP Unit 2, Cycle 11 Fq(Z) Trends 2.8 I

& Max Meosured Fq(Z)

---

Predicted Fq(Z) 2.6

• Measured FqC(Z) *W(Z) / K(Z)

- - Predicted Fq(Z) *W(Z)

• 1.03

• 1.05 / K(Z)

-F-ull Power Tech S iec Limit - 2.5 2.4 SImplementaton of-COLR Rev 2,2 2.0 1.8 A A A I . 4 1.6 --------------------------

0 200 4000 6000 8MW 1W 12000 14W1 16000 I=~ 200D 22MO 24DOO DurV (MWDMAJ)

ERX-08-004 Rev 0 Page 7

Tables 1 and 2 summarize the Fq Data for the first 6 months of operation of Unit 2 Cycle 11, including partial. power measurements taken during power ascension. A description of each column of data is included in the following discussion. In the table, bolded data corresponds to MIDS Map measurements.

Table 1 - U2C 1I Power Distribution Measurement Summary Power Map Burnup CBD AO Lowest Margin Margin Map # Date (%RTP) Type (MWD/MTU) (steps) (%) FqC(Z)*W(Z)/K(Z) (%)

M01 4/20/08 27.4 MIDS 7.0 180 9.0 2.83 43.4 M02 4/21/08 78.7 MIDS 27.0 193 1.2 2.46 22.5 M04 4/23/08 99.6 MIDS 123.0 212 0.3 2.41 3.8, M05 4/24/08 100.0 PDMS 165.5 215 2.1 2.39 4.6 M06 5/12/08 99.7 PDMS 935.1 215 2.4 2.19 12.8 M07 6/5/08 99.9 PDMS 1952.0 215 3.1 2.21 11.8 M08 6/10/08 99.8 MIDS 2125.0 215 3.5 2.31 7.9 M09 7/7/08 99.9 PDMS 3330.1 215 3.2 2.15 14.2 M10 8/4/08 100.1 PDMS 4528.5 215 2.0 2.14 14.4 Mll 9/2/08 100.0 MIDS 5764.0 215 0.6 2.13 14.9 M12 9/29/08 100.0 PDMS 6935.1 215 -0.7 2.10 15.9 M13 10/27/08 99.9 PDMS 8129.9 215 -1.9 2.13 15.0 M14 11/24/08 100.0 MIDS 9321.0 215 -3.2 2.11 15.6 Table 2 - U2C 11 F (Z) Margin Im act Summary Power Min Fq Margin Axial Power Dist Adjusted Transient Minimum value from Map # (%RTP) HFP ARC (%) Impact (%) Fq Margin (%) 'Updated W(Z)' output M01 27.4 5.23 -1.22 6.46 1.038 M02 78.7 2.82 0.77 2.05 1.103 M04 99.6 3.23 0.22 3.01 1.098 M05 100.0 3.16 0.71 2.45 1.079 M06 99.7 10.86 -2.28 13.14 1.103 M07 99.9 11.80 -3.25 15.03 1.147 M08 99.8 see note -3.49 11.37 1.145 M09 99.9 15.47 -1.44 15.60 1.138 M10 100.1 15.84 -1.10 15.52 1.127 Mll 100.0 17.04 0.28 14.57 1.126 M12 100.0 15.59 -0.09 15.68 1.125 M13 99.9 16.46 0.34 14.64 1.108 M14 100.0 16.00 -0.60 16.22 1.094 Note Regarding Map 08 - For Map 08, the HFP ARO report was incorrectly generated, and the value of Min Fq Margin HFPARO (%) from this report is not available. The issue was captured in the CPNPP Corrective Action Program for resolution. Since the map was taken near HFP ARO conditions, this value would have been within a few percent of the "Margin (%)" value from Table 1 (7.9% for Map 08).

ERX-08-004 Rev 0

. Page 8

Ma, # - A sequential number assigned to each flux map. Note that Map 03 was voided due to data collection issues, and Map #04 was the first Full Power Map for the cycle.

Map Type - PDMS if a BEACON Monitor Report was used in the Fq surveillance, MIDS if the Movable Incore Detector System was used.

Burnup - Total core burnup at the time of the measurement in MWD/MTU.

CBD - Control Bank D position at the time of the measurement. CBD is normally kept at 215 steps during normal operation, and a position of 223 steps is considered Full Out (above the active fuel region).

AO - The measured Axial Offset at the time of the measurement. A positive value represents power distributed towards the top of the core.

Lowest Margin FqC(Z)*W(Z)/K(Z) - The value of measured Fq at the limiting core location, including uncertainty, W(Z) and K(Z) factors.

Margin (%) - The Margin to the Technical Specification Fq Limit at the lowest margin location, defined as:

Margin = 100% x (Limit - Measured) / Limit Min Fq Margin HFP ARO (%) - This value is determined by BEACON PDMS, and represents the available Fq Margin which would be available under HFP ARO steady state conditions. For a MIDS Map, this is determined after utilizing the measured incore data to calibrate BEACON Monitor. This is consistent with the description found in Reference 1 for an alternative acceptable method to determine the impact of the measured axial power distribution on the available Fq Margin. Per Reference 1:

"Alternatively, the BEACON Power DistributionMonitoring System may be used to perform the power distributionsurveillancefunction. When the surveillance is performed, the BEACON 'measured'powerdistributionis updated tofull power, steady state conditionsand used to determine the 'measured' maximum transient FQ(z) x Power. To do this, thefull power 'measured' steady state FQ(z) from the BEACON core model is multiplied by the W(z) curve and the result, FQW(z), is compared to the FQ(z) limit. Thus, the full power W(z) curves are appropriatesince the transientFQ(z) measurement is always based on full power conditions."

ERX-08-004 Rev 0 Page 9

Axial Power Distribution Impact (%) - This value represents the impact of the Measured Axial Power Distribution on the Fq Margin, and is equivalent to Equation 2 from Reference 1 (shown below). This value is obtained by generating a W(Z) Update Report from the calibrated BEACON model and subtracting the 'original' and 'updated' FqW(z) margin values.

Equation 2 from TXX-08032:

Effect of axial power distributiondifferences

= FoW(z) * (SS-P(z))/(M-P(z)) - FoW(z)

See Section 2.3 for graphical representations of the SS-P(z), M-P(z), and W(z) curves for each power distribution measurement.

Adjusted Transient Fq Margin (%) - This value is obtained by subtracting the Axial Power Distribution Impact from the lesser of (a) or (b):

(a) Margin from the flux map (Margin (%) from Table 1), or (b) the Margin from the HFP ARO Report (Min Fq Margin HFP ARO (%) from Table 2).

If this value were negative, it would be concluded that the Power Distribution Impact is greater than the available margins, and Surveillance Requirement for Technical Specification 3.2.1.2 would not be satisfied. The appropriate Actions of Technical Specification would be taken, although this has not been necessary for any measurements taken during U2C 11.

Minimum value from 'Updated W(Z)' output - This value represents the minimum Updated W(Z) value determined by the BEACON W(Z) Update Report described above. Note that the 'Updated W(z)' values include M-P(z) affects, and are used to assess margin impacts.

Per Reference 2, CPNPP committed to revising the W(z) curves, as appropriate, should this value be less than 1.04. A description of CPNPP commitment #3475619 may be found in section 1.0.

Note that for Map 01, which was performed at 27.4% RTP, the Minimum value from

'Updated W(Z)' output was slightly less than 1.04 for two axial locations. This was evaluated in the CPNPP corrective action program, and it was determined that it was not appropriate to revise the W(z) curves based on the low power flux map. To summarize this evaluation:

• The axial power distribution impact assessment performed at the 28% RTP plateau resulted in positive adjusted Fq margin and therefore requires no action or LCO entry.

Two core elevations had a resulting adjusted W(Z) slightly less than 1.04. These T

elevations are not the location of the limiting Fq, nor would they be if the W(Z) was limited to 1.04. Thus, the adjusted W(Z) values have no impact on the conclusion of the margin assessment.

• Revision of the W(Z) factors based on the 28% RTP measurement would not provide representative W(Z) factors for the core conditions expected at the next required surveillance and therefore would not be "appropriate" as described in the commitment.

• Therefore, revised W(Z) factors are not required as a result of this surveillance.

ERX-08-004 Rev 0 Page 10

2.3 W(z) Update Function Results Figures 3 through 15 below graphically show the results of the W(z) Update Function described in section 2.2. For each map, a plot of SS-P(z) versus M-P(z) and a plot of Original W(z) and Updated W(z) are provided. The "Minimum value from 'Updated W(Z)'

output" shown in Table 2 is the minimum value from this "Updated W(z)" plot.

Figure 3, Map 01 W(z) Update Function Results 160

-- Orig W(z) - -. Updated W(z) 140 120 100 2 80 - -- C-- -

'I

<60 40 20 - - '~~4 0

0 0.5 1 1.5 CI

• a o N a)

ERX-08-004 Rev 0 Page I11

Figure 4, Map 02 W(z) Update Function Results 160

- Orig W(z) - - -- Updated W(z)I 140 120 S I 100 C 80 --- V I'

60

• I 40 4

20 n.

0 0.5 1 1.5 o o " - ,

-ý COo N. 0)

Figure 5, Map 04 W(z) Update Function Results 160 SS-P(z) -.. M-P(z) - Orig W(z) .... Updated W(

140 ----

120 " 1 2 100180 1001 C, 4',

x 60 -

40) 20 I -.

0 0 0.5 1 1.5 40o '

Coý 00 ) 4h ERX-08-004 Rev 0 Page 12

Figure 6, Map 05 W(z) Update Function Results 160 SS-P(z) .... M-P(z) - Orig W(z) -. Updated V 140-120 1 - "I i j 100 - A-r

- i80 S60 i 40 1 5.

20 1 "-  !

0 0.5 1 1.5 6 6 - - k i)

Fig 0r r7, CMa 0d Figure 7, Map 06 W(z) Update Function Results 160 - Orig W(z) - - -. Updated W(z) 140 120 I

'5, _____ ____

100 S.

S80 x 60 - -1 Ii 40

-' I 20

- I 0

0 0.5 1 1.5 4- 00 cc M ~ _4 C ERX-08-004 Rev 0 Page 13

Figure 8, Map 07 W(z) Update Function Results 160 140 120 0 100 U

0 80 I

x 60 4o 20 0

0 0.5 1 1.5 K N I W *W 4 Figure 9, Map 08 W(z) Update Function Results 160 140 120 iU C

100 80 0

I (U

x 60 40 20

.0 0 0.5 1 1.5 6 K Qr w w -P.

ERX-08-004 Rev 0 Page 14

Figure 10, Map 09 W(z) Update Function Results 160 140 120 100 80 x 60 40 20 0

0 0.5 1 1.5 Figure 11, Map 10 W(z) Update Function Results 160 140 120 100 2 80 x 60 40 20 0

00.5 1 1.5 6 6 - o 1- -P ERX-08-004 Rev 0 Page 15

Figare 12, Map 11 W(z) Update Function Results 160 140 120 100 80 3:

.T x 60 40 20 0

2 0.5 1 1.5 *A. bO " .-- a . ) . .P.-

J .10 0, .r)_t.

.0) .. .i*

Figure 13, Map 12 W(z) Update Function Results 160 SS-P(z) . . . - M-P(z) -- Orig W(z) ....- Updated W(z)

I 140 120 100 80 60 40 20 0

0 0.5 1 1..5 Jýb 00 N) a) 41. 00 a) Jý,

ERX-08-004 Rev 0 Page 16

Figure 14, Map 13 W(z) Update Function Results 160 140 120

' 100 80 x 60 40 20 0

0 0.5 1 1.5 Figure 15, Map 14 W(z) Update Function Results 160 - SS-P(z) .... M-P(z) F 140 120 100 I S80 x 60 40 20 0

0 0.5 1 1.5 o o *:

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3.0 REFERENCES

1. TXX-08032, "Supplement to License Amendment Request (LAR)07-003 Response to Request for Additional Information Related to License Amendment Request Associated with Methodology used to Establish Core Operating Limits" (CPNPP Memo CP-200800264)

2. TXX-08054, "Supplement to License Amendment Request (LAR)07-003 Additional Information Related to License Amendment Request Associated with Methodology used to Establish Core Operating Limits" (CPNPP Memo CP-200800455)

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