RA-22-0134, Unit 1 Cycle 23 Mellla+ Eigenvalue Tracking Data

Unit 1 Cycle 23 Mellla+ Eigenvalue Tracking Data

ML22146A006
Person / Time
Site:	Brunswick
Issue date:	05/25/2022
From:	Dewire M Duke Energy Progress
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RA-22-0134
Download: ML22146A006 (14)

Text

((_~DUKE Brunswick Nuclear Plant 8470 River Rd SE

~'ENERGY. Southport, NC 23461 May 25, 2022 Sedal: RA-22..0134 U.S. Nuclear Regulatory Commission ATTN: Document Con.trot Desk washington, DC 20555-0001

Subject:

Brunswick Steam Electric Plant, Unit No. 1 Renewed Facility Operating License No. DPR-71 Docket No. 50-325 Unit 1 C.ycle 23 MELLLA+ Eigenvalue Tracking Data

References:

1. Duke Energy Letter to NRC dated November 9, 2016, "Brunswick, Units 1 and 2

- Response to Request for Supplemental Information for License Amendment Request Regarding Core Flow Operating Range Expansion" (ADAMS Accession No. ML16330A504)

2. NRC Letter to Duke Energy, dated September 18, 2018, "Brunswick Steam Electric Plant, Units 1 and 2 - Issuance of Amendment Regatding Core Flow Operating Range Expansion (MELLLA+)" (ADAMS Accession Number ML18172A258)

Ladies and Gentlemen:

In Reference 1, Duke Energy Progress,. LLC (Duke Energy), informed the NRC that it would evaluate and submit cycle-specific eigenvalue tracking data after the first full Maximum Extended Load Line Limtt Analysis Plus (MELLLA-i-) operating cycle for each unit using AREVA methods. The enclosure provides this information for Brunswick Steam Electric Plant (BSEP),

Unit 1, Cycte 23, which was completed in March 2022.

This document contains no regulatory commitments.

Please refer any questions regarding this submittal to Mr. Stephen Yodersmlth, Brunswi.ck Regulatory Affairs, at (91 O) 832-2568.

Mark R. eWire Manager - Nuclear Support Services Brunswick Steam Electric Plant SBY/sby

U.S. Nuclear Regulatory Commission Page 2 of 2

Enclosure:

Brunswick Unit 1 MELLLA+ Eigenvalue Tracking Data cc (with Enclosure):

Ms. Laura Dudes, NRC Regional Administrator, Region II Mr. Luke Haeg, NRC Project Manager Mr. Gale Smith, NRC Senior Resident Inspector Chair - North Carolina Utilities Commission

RA-22-0134 Enclosure Brunswick Steam Electric Plant, Unit No. 1 Renewed Facility Operating License No. DPR-71 Docket No. 50-325 Brunswick Unit 1 MELLLA+ Eigenvalue Tracking Data

Facility Code : NGO Applicable Facilities : NGO Document Number : DPND-1553.63-1286 Document Revision Number : 000 Document EC Number :

Change Reason : Original Issue Document Title : Brunswick Unit 1 MELLLA+ Eigenvalue Tracking Arasim, Lois Preparer 4/27/2022 Wells, Ryan E. Reviewer 4/27/2022 Lambert, Brad Approver 4/27/2022 Notes :

Brunswick Unit 1 MELLLA+ Eigenvalue Tracking April 2022 Prepared by: Signed Electronically Lois Arasim (Brunswick Nuclear Design)

Reviewed by: Signed Electronically Ryan Wells (Brunswick Nuclear Design)

Approved by: Signed Electronically Brad Lambert (Manager - Brunswick/Oconee Nuclear Design)

Duke Energy, Nuclear Fuels Engineering Page 2 of 10 Brunswick Unit 1 MELLLA+ Eigenvalue Tracking

1. Purpose and Scope The purpose of this letter report is to document the fulfillment of Limitation and Condition (L/C) 23 of NEDC-33173P (Reference 1). This L/C states:

In the first plant-specific implementation of MELLLA+, the cycle-specific eigenvalue tracking data will be evaluated and submitted to NRC to establish the performance of nuclear methods under the operation in the new operating domain. The following data will be analyzed:

• Hot critical eigenvalue,

• Cold critical eigenvalue,

• Nodal power distribution (measured and calculated TIP comparison),

• Bundle power distribution (measured and calculated TIP comparison),

• Thermal margin,

• Core flow and pressure drop uncertainties, and

• The MIP Criterion (e.g., determine if core and fuel design selected is expected to produce a plant response outside the prior experience base).

Provision of evaluation of the core-tracking data will provide the NRC staff with bases to establish if operation at the expanded operating domain indicates: (1) changes in the performance of nuclear methods outside the EPU experience base; (2) changes in the available thermal margins; (3) need for changes in the uncertainties and NRC-approved criterion used in the SLMCPR methodology; or (4) any anomaly that may require corrective actions.

Based on Reference 2, the MIP Parameter will not be provided. Reference 2 states:

The NRC staff previously determined that submittal of the MIP was not necessary in letter to GEH dated November 20, 2015 (ADAMS Accession No. ML15292A421). That NRC staffs determination was generic and is applicable to AREVA methods as well.

2. Comparison Approach Brunswick Nuclear Plant Unit 1 completed its first full cycle with MELLLA+, B1C23, in March 2022. For each metric being compared, data from the previous 3 cycles (including the B1C22 partial MELLLA+ cycle) will be provided for a basis of comparison.

The eigenvalues, at cold and hot reactor conditions, are presented in the attached plots as a function of exposure. The thermal margins (MAPRAT, MFDLRX, and MFLCPR) are presented also as a function of exposure. The definitions of the thermal margin parameters are as follows:

• MAPRAT: Maximum ratio of bundle measured Maximum Average Planar Linear Heat Generation Rate (MAPLHGR) to the appropriate limit.

• MFDLRX: Maximum fraction of limiting Linear Heat Generation Rate (LHGR) to the Fuel Design Limit (FDL)

Duke Energy, Nuclear Fuels Engineering Page 3 of 10 Brunswick Unit 1 MELLLA+ Eigenvalue Tracking

• MFLCPR: Maximum fraction of limiting Critical Power Ratio The ratio of on-line core monitoring system (PPX) to offline-evaluation (MCB) or bias is presented. The power distributions assessment uses nodal and radial Traversing In-Core Probe (TIP) statistics, consistent with Reference 3, from plant measured/calculated data as a function of exposure, core average void fractions, and power-to-flow ratio (P/F in units of MWt/Mlbm/hr). The plot of core flow and pressure drop uncertainties is presented also as a function of P/F ratio.

For convenience and better visualization, the MELLLA+ values plotted (relevant B1C22 and B1C23 data) are presented in red.

3. Conclusions The results provided demonstrate the Methods performance in the MELLLA+ domain continues to meet expectations set by prior submittals and historical data at non-MELLLA+

conditions. Therefore, the intent of Limitation & Condition 23 has been satisfied. Similar data was provided for Unit 2 in Reference 4 and no further reporting is required.

4. References

1. NEDC-33171P-A, Revision 4, Applicability of GE Methods to Expanded Operating Domains, November 2012 (ADAMS Accession No. ML12313A107/ML12313A106 (Publicly Available/Non-publicly Available)).

2. Letter from the NRC, September 18, 2018, Brunswick Steam Electric Plant, Units 1 and 2 - Issuance of Amendment Regarding Core Flow Operating Range Expansion (MELLLA+) (EPID L-2016-LA-0009) (ADAMS Accession No. ML18172A258).

3. EMF-2158(P)(A), Revision 0, Siemens Power Corporation Methodology for Boiling Water Reactors: Evaluation and Validation of CASMO-4/MICROBURN-B2, October 1999.

4. Letter to the NRC, June 7, 2021, Brunswick Steam Electric Plant, Unit No. 2 Renewed Facility Operating License No. DPR-62 Docket No. 50-324 Unit 2 Cycle 24 MELLLA+

Eigenvalue Tracking Data, (ADAMS Accession No. ML21158A056).

Duke Energy, Nuclear Fuels Engineering Page 4 of 10 Brunswick Unit 1 MELLLA+ Eigenvalue Tracking Hot and Cold Critical Eigenvalues Hot Eigenvalue 1.01 1.00 1.00 Hot Eigenvalue B1C20 1.00 B1C21 B1C22 1.00 B1C22 (M+)

B1C23 (M+)

1.00 0.99 0 2 4 6 8 10 12 14 16 18 20 Exposure (GWd/MTU)

Cold Eigenvalue 0.99700 0.99500 0.99300 Cold Eigenvalue B1C20 0.99100 B1C21 B1C22 0.98900 B1C22 (M+)

B1C23 (M+)

0.98700 0.98500 0 2 4 6 8 10 12 14 16 18 20 Exposure (GWd/MTU)

Duke Energy, Nuclear Fuels Engineering Page 5 of 10 Brunswick Unit 1 MELLLA+ Eigenvalue Tracking Thermal Margin Thermal Margin - MAPRAT 1.1 1.05 Bias (PPX/MCB)

B1C20 B1C21 1

B1C22 B1C22 (M+)

B1C23 (M+)

0.95 Bias 0.9 0 5 10 15 20 Cycle Exposure (GWd/MTU)

Thermal Margin - FDLRX 1.1 1.05 Bias (PPX/MCB)

B1C20 B1C21 1

B1C22 B1C22 (M+)

B1C23 (M+)

0.95 Bias 0.9 0 5 10 15 20 Cycle Exposure (GWd/MTU)

Duke Energy, Nuclear Fuels Engineering Page 6 of 10 Brunswick Unit 1 MELLLA+ Eigenvalue Tracking Thermal Margin - MFLCPR 1.1 1.05 Bias (PPX/MCB)

B1C20 B1C21 1

B1C22 B1C22 (M+)

B1C23 (M+)

0.95 Bias 0.9 0 5 10 15 20 Cycle Exposure (GWd/MTU)

Duke Energy, Nuclear Fuels Engineering Page 7 of 10 Brunswick Unit 1 MELLLA+ Eigenvalue Tracking Nodal and Radial TIP Uncertainties Nodal TIP Uncertainty vs Power/Flow Ratio 0.06 0.05 Nodal (3D) TIP Uncertainty 0.04 B1C20 0.03 B1C21 B1C22 0.02 B1C22 (M+)

B1C23 (M+)

0.01 0

33.00 35.00 37.00 39.00 41.00 43.00 45.00 P/F Ratio (MWth/Mlbm/hr)

Radial TIP Uncertainty vs. Power/Flow Ratio 0.06 0.05 Radial (2D) TIP Uncertainty 0.04 B1C20 0.03 B1C21 B1C22 0.02 B1C22 (M+)

B1C23 (M+)

0.01 0

33.00 35.00 37.00 39.00 41.00 43.00 45.00 P/F Ratio (MWth/Mlbm/hr)

Duke Energy, Nuclear Fuels Engineering Page 8 of 10 Brunswick Unit 1 MELLLA+ Eigenvalue Tracking Nodal TIP Uncertainty vs Core Average Void Fraction 0.06 0.05 Nodal (3D) TIP Uncertainty 0.04 B1C20 0.03 B1C21 B1C22 0.02 B1C22 (M+)

B1C23 (M+)

0.01 0

0.300 0.350 0.400 0.450 0.500 0.550 CAVF Radial TIP Uncertainty vs Core Average Void Fraction 0.06 0.05 Radial (2D) TIP Uncertainty 0.04 B1C20 0.03 B1C21 B1C22 0.02 B1C22 (M+)

B1C23 (M+)

0.01 0

0.300 0.350 0.400 0.450 0.500 0.550 CAVF

Duke Energy, Nuclear Fuels Engineering Page 9 of 10 Brunswick Unit 1 MELLLA+ Eigenvalue Tracking Nodal TIP Uncertainty vs Exposure 0.06 0.05 Nodal (3D) TIP Uncertainty 0.04 B1C20 0.03 B1C21 B1C22 0.02 B1C22 (M+)

B1C23 (M+)

0.01 0

0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000 Cycle Exposure (MWd/MTU)

Radial TIP Uncertainty vs Exposure 0.06 0.05 Radial (2D) TIP Uncertainty 0.04 B1C20 0.03 B1C21 B1C22 0.02 B1C22 (M+)

B1C23 (M+)

0.01 0

0 2000 4000 6000 8000 10000 12000 14000 16000 18000 20000 Cycle Exposure (MWd/MTU)

Duke Energy, Nuclear Fuels Engineering Page 10 of 10 Brunswick Unit 1 MELLLA+ Eigenvalue Tracking Core Flow and Pressure Drop Uncertainties Core Plate Pressure Drop vs Power/Flow Ratio 1.03 1.01 0.99 Bias (PPX/MCB)

B1C20 0.97 B1C21 B1C22 0.95 B1C22 (M+)

B1C23 (M+)

0.93 0.91 27 29 31 33 35 37 39 41 43 45 P/F Ratio (MWth/Mlbm/hr)