RA-21-0176, Cycle 24 Mellla+ Eigenvalue Tracking Data
| ML21158A056 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 06/07/2021 |
| From: | Salazar S Duke Energy Progress |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RA-21-0176 | |
| Download: ML21158A056 (14) | |
Text
(-, DUKE ENERGY Serial: RA-21-0176 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001
Subject:
References:
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 Brunswick Nuclear Plant 8470 River Rd SE Southport, NC 28461
- 1. Duke Energy Letter to NRG 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. NRG Letter to Duke Energy, dated September 18, 2018, "Brunswick Steam Electric Plant, Units 1 and 2 - Issuance of Amendment Regarding Core Flow Operating Range Expansion (MELLLA+)" (ADAMS Accession Number ML18172A258)
Ladies and Gentlemen:
In Reference 1, Duke Energy Progress, LLC (Duke Energy), informed the NRG that it would evaluate and submit cycle-specific eigenvalue tracking data after the first full operating Maximum Extended Load Line Limit Analysis Plus (MELLLA+) cycle for each unit using AREVA methods. The enclosure provides this information for Brunswick Steam Electric Plant (BSEP),
Unit 2, Cycle 24, which was completed in March 2021.
This document contains no regulatory commitments.
Please refer any questions regarding this submittal to Ms. Sabrina Salazar, Manager - Nuclear Support Services, at (910) 832-3207.
Sincerely, Sabrina Salazar Manager - Nuclear Support Services Brunswick Steam Electric Plant MAT/mat June 7, 2021
U.S. Nuclear Regulatory Commission Page 2 of 2
Enclosure:
Brunswick Unit 2 MELLLA+ Eigenvalue Tracking Data cc (with Enclosure):
Ms. Laura Dudes, NRC Regional Administrator, Region II Mr. Andrew Hon, NRC Project Manager Mr. Gale Smith, NRC Senior Resident Inspector Chair - North Carolina Utilities Commission
RA-21-0176 Enclosure Brunswick Steam Electric Plant, Unit No. 2 Renewed Facility Operating License No. DPR-62 Docket No. 50-324 Brunswick Unit 2 MELLLA+ Eigenvalue Tracking Data
Facility Code :
Applicable Facilities :
Document Number :
Document Revision Number :
Document EC Number :
Change Reason :
Document Title :
Notes :
5/27/2021 Approver Lambert, Brad 5/27/2021 Reviewer Evans, Steve 5/27/2021 Preparer Arasim, Lois Brunswick Unit 2 MELLLA+ Eigenvalue Tracking Original Issue 000 DPND-1553.63-1230 NGO NGO
Brunswick Unit 2 MELLLA+ Eigenvalue Tracking May 2021 Prepared by:
Lois Arasim (Brunswick Nuclear Design)
Reviewed by:
Steve Evans (Brunswick Nuclear Design)
Approved by:
Brad Lambert (Manager - Brunswick/Oconee Nuclear Design)
Signed Electronically Signed Electronically Signed Electronically
- 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 2 completed its first full cycle with MELLLA+, B2C24, in March 2021. For each metric being compared, data from the previous 3 cycles 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 Brunswick Unit 2 MELLLA+ Eigenvalue Tracking Page 2 of 10
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 (B2C24 data) are presented in red squares.
- 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 and no further reporting is required for Unit 2. Similar data will be provided for Unit 1 following the shutdown of the current cycle in March 2022.
- 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.
Duke Energy, Nuclear Fuels Engineering Brunswick Unit 2 MELLLA+ Eigenvalue Tracking Page 3 of 10
Hot and Cold Critical Eigenvalues 0.99 0.995 1
1.005 1.01 0
5 10 15 20 K-Effective Cycle Exposure (GWd/MTU)
Hot Eigenvalue B2C21 B2C22 B2C23 B2C24 (M+)
0.98500 0.98700 0.98900 0.99100 0.99300 0.99500 0.99700 0.99900 1.00100 1.00300 1.00500 0
5 10 15 20 K-Critical Cycle Exposure (GWd/MTU)
Cold Eigenvalue B2C21 B2C22 B2C23 B2C24 (M+)
Duke Energy, Nuclear Fuels Engineering Brunswick Unit 2 MELLLA+ Eigenvalue Tracking Page 4 of 10
Thermal Margin 0.9 0.95 1
1.05 1.1 0
5 10 15 20 Bias (PPX/MCB)
Cycle Exposure (GWd/MTU)
Thermal Margin - MAPRAT B2C21 B2C22 B2C23 B2C24 (M+)
Bias 0.9 0.95 1
1.05 1.1 0
5 10 15 20 Bias (PPX/MCB)
Cycle Exposure (GWd/MTU)
Thermal Margin - FDLRX B2C21 B2C22 B2C23 B2C24 (M+)
Bias Duke Energy, Nuclear Fuels Engineering Brunswick Unit 2 MELLLA+ Eigenvalue Tracking Page 5 of 10
0.9 0.95 1
1.05 1.1 0
5 10 15 20 Bias (PPX/MCB)
Cycle Exposure (GWd/MTU)
Thermal Margin - MFLCPR B2C21 B2C22 B2C23 B2C24 (M+)
Bias Duke Energy, Nuclear Fuels Engineering Brunswick Unit 2 MELLLA+ Eigenvalue Tracking Page 6 of 10
Nodal and Radial TIP Uncertainties 0
0.01 0.02 0.03 0.04 0.05 33.00 35.00 37.00 39.00 41.00 43.00 45.00 Nodal (3D) TIP Uncertainty P/F Ratio (MWth/Mlbm/hr)
Nodal TIP Uncertainty vs Power/Flow Ratio B2C21 B2C22 B2C23 B2C24 (M+)
0 0.01 0.02 0.03 0.04 0.05 33.00 35.00 37.00 39.00 41.00 43.00 45.00 Radial (2D) TIP Uncertainty P/F Ratio (MWth/Mlbm/hr)
Radial TIP Uncertainty vs. Power/Flow Ratio B2C21 B2C22 B2C23 B2C24 (M+)
Duke Energy, Nuclear Fuels Engineering Brunswick Unit 2 MELLLA+ Eigenvalue Tracking Page 7 of 10
0 0.01 0.02 0.03 0.04 0.05 0.3 0.35 0.4 0.45 0.5 0.55 Nodal (3D) TIP Uncertainty CAVF Nodal TIP Uncertainty vs Core Average Void Fraction B2C21 B2C22 B2C23 B2C24 (M+)
0 0.01 0.02 0.03 0.04 0.05 0.3 0.35 0.4 0.45 0.5 0.55 Radial (2D) TIP Uncertainty CAVF Radial TIP Uncertainty vs Core Average Void Fraction B2C21 B2C22 B2C23 B2C24 (M+)
Duke Energy, Nuclear Fuels Engineering Brunswick Unit 2 MELLLA+ Eigenvalue Tracking Page 8 of 10
0 0.01 0.02 0.03 0.04 0.05 0
2000 4000 6000 8000 10000 12000 14000 16000 18000 20000 Nodal (3D) TIP Uncertainty Cycle Exposure (MWd/MTU)
Nodal TIP Uncertainty vs Exposure B2C21 B2C22 B2C23 B2C24 (M+)
0 0.01 0.02 0.03 0.04 0.05 0
2000 4000 6000 8000 10000 12000 14000 16000 18000 20000 Radial (2D) TIP Uncertainty Cycle Exposure (MWd/MTU)
Radial TIP Uncertainty vs Exposure B2C21 B2C22 B2C23 B2C24 (M+)
Duke Energy, Nuclear Fuels Engineering Brunswick Unit 2 MELLLA+ Eigenvalue Tracking Page 9 of 10
Core Flow and Pressure Drop Uncertainties 0.95 0.96 0.97 0.98 0.99 1
1.01 1.02 1.03 1.04 1.05 27 29 31 33 35 37 39 41 43 45 Bias (PPX/MCB)
P/F Ratio (MWth/Mlbm/hr)
Core Plate Pressure Drop vs Power/Flow Ratio B2C21 B2C22 B2C23 B2C24 (M+)
Duke Energy, Nuclear Fuels Engineering Brunswick Unit 2 MELLLA+ Eigenvalue Tracking Page 10 of 10