ML15335A322
| ML15335A322 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 12/10/2015 |
| From: | NextEra Energy Duane Arnold |
| To: | Office of Nuclear Reactor Regulation |
| Chawla M, NRR/DORL/LPLIII-1, 415-8371 | |
| References | |
| Download: ML15335A322 (19) | |
Text
Pre-Submittal Meeting for Duane Arnold Energy Center Spent Fuel Pool Criticality Analyses December 10, 2015
2
- Describe the NextEra Energy (NEE) criticality analyses methodology for the proposed Duane Arnold Energy Center (DAEC) License Amendment Request (LAR)
- Seek feedback on the approach from NRC staff Purpose
3
Background
Criticality Analysis Methodology Technical Specification Changes Closing Summary Agenda
4
- The Duane Arnold Energy Center (DAEC) spent fuel pool is composed of ~50/50 split of original PaR racks and Holtec racks
- Both rack types use Boral as neutron absorber Background - Spent Fuel Pool Rack Absorber Type Areal Density (gm-B10/cm2)
Spacing (in)
PaR Boral 0.0250 +/- 0.0018 6.625 Holtec Boral 0.0162 +/- 0.0012 6.060
5 Background - Current Technical Specification
6
- Results did not support PaR rack areal density used in spent fuel pool criticality analysis
- DAEC currently operating with non-conservative TS for PaR racks
- Instead of k limit of 1.39, using same limit of 1.29 as for Holtec racks
- DAEC has a commitment to submit a license amendment request with a new spent fuel pool criticality analysis by 3/15/2016 Background - Current State
7
Background
Criticality Analysis Methodology Technical Specification Changes Closing Summary Agenda
8
- DAEC performing new spent fuel criticality analysis for entire pool
- Performing in-house
- Will follow NRC Guidance DSS-ISG-2010-01, Staff Guidance Regarding the Nuclear Criticality Safety Analysis for Spent Fuel Pools
- Main codes will be CASMO4 and MCNP6.1 with ENDF/B-VII.1 Criticality Analysis Methodology
9
- Will model most reactive lattice over entire axial length
- No blankets
- Will establish maximum in-core k-infinity so that k95/95 < 0.95 for normal and accident conditions Criticality Analysis Methodology
10
- No significant changes or factors to address
- No change in fuel design
- No change in operating conditions
- No rack design changes
- No burnup credit
- No Boraflex
- No loading patterns
- No inserts
- No new SFP loading restrictions
- No New Fuel Vault analysis Criticality Analysis Methodology
11
- Fuel Assembly Selection (IV.1)
- Analysis will address all fuel designs used at DAEC 7 X 7 Various 8 X 8 designs Various 10 X 10 designs
- Depletion Uncertainty (IV.2.a)
- Will use 5 percent to cover uncertainty in isotopic number densities, per ISG and Kopp memo Criticality Analysis Methodology
12
- Reactor Parameters (IV.2.b)
- Bounding values for moderator temperature, fuel temperature, and power density
- Evaluated at multiple void conditions
- Rodded Operation (IV.2.d)
- Included with Reactor Parameters Criticality Analysis Methodology
13
- Rack Model (IV.3.b)
- Reduced B-10 areal density for PaR racks (lower than minimum)
- Minimum B-10 areal density for Holtec racks
- Conservative modeling of small amount of blisters
- Will demonstrate Holtec rack is limiting, and
- Normal Conditions (IV.3.d)
- Will address normal fuel handling configurations
- Will address eccentricity, orientation, de-channeled assemblies Criticality Analysis Methodology
14
- Area of Applicability (IV.4.a)
- HTC experiments will be included
- Will include >200 experiments from International Handbook of Evaluated Criticality Safety Benchmark Experiments, September 2014
- Trend Analysis (IV.4.b)
- Will perform for all experiments combined, and also for subsets based on various parameters (e.g., HTC cases, non-HTC cases, square lattices)
Biases and uncertainties will be based on most limiting result Criticality Analysis Methodology
15
Background
Criticality Analysis Methodology Technical Specification Changes Closing Summary Agenda
16 Technical Specification Changes
- It if can be supported by analysis results, will simplify TS 4.3.1.1.a to read as follows:
Fuel assemblies having a maximum k-infinity of TBD in the normal reactor core configuration at cold conditions.
- Otherwise, TS 4.3.1.1.a will remain split by rack design and fuel design, with update limits
- Additionally, will modify TS 4.3.1.2 to prohibit loading the New Fuel Vault
17
Background
Criticality Analysis Methodology Technical Specification Changes Closing Summary Agenda
18 Closing Summary
- Review action items
- Summary of path forward
- Schedule for LAR submittal
- Commitment to submit LAR by 3/15/2016
19 Questions
Pre-Submittal Meeting for Duane Arnold Energy Center Spent Fuel Pool Criticality Analyses December 10, 2015
2
- Describe the NextEra Energy (NEE) criticality analyses methodology for the proposed Duane Arnold Energy Center (DAEC) License Amendment Request (LAR)
- Seek feedback on the approach from NRC staff Purpose
3
Background
Criticality Analysis Methodology Technical Specification Changes Closing Summary Agenda
4
- The Duane Arnold Energy Center (DAEC) spent fuel pool is composed of ~50/50 split of original PaR racks and Holtec racks
- Both rack types use Boral as neutron absorber Background - Spent Fuel Pool Rack Absorber Type Areal Density (gm-B10/cm2)
Spacing (in)
PaR Boral 0.0250 +/- 0.0018 6.625 Holtec Boral 0.0162 +/- 0.0012 6.060
5 Background - Current Technical Specification
6
- Results did not support PaR rack areal density used in spent fuel pool criticality analysis
- DAEC currently operating with non-conservative TS for PaR racks
- Instead of k limit of 1.39, using same limit of 1.29 as for Holtec racks
- DAEC has a commitment to submit a license amendment request with a new spent fuel pool criticality analysis by 3/15/2016 Background - Current State
7
Background
Criticality Analysis Methodology Technical Specification Changes Closing Summary Agenda
8
- DAEC performing new spent fuel criticality analysis for entire pool
- Performing in-house
- Will follow NRC Guidance DSS-ISG-2010-01, Staff Guidance Regarding the Nuclear Criticality Safety Analysis for Spent Fuel Pools
- Main codes will be CASMO4 and MCNP6.1 with ENDF/B-VII.1 Criticality Analysis Methodology
9
- Will model most reactive lattice over entire axial length
- No blankets
- Will establish maximum in-core k-infinity so that k95/95 < 0.95 for normal and accident conditions Criticality Analysis Methodology
10
- No significant changes or factors to address
- No change in fuel design
- No change in operating conditions
- No rack design changes
- No burnup credit
- No Boraflex
- No loading patterns
- No inserts
- No new SFP loading restrictions
- No New Fuel Vault analysis Criticality Analysis Methodology
11
- Fuel Assembly Selection (IV.1)
- Analysis will address all fuel designs used at DAEC 7 X 7 Various 8 X 8 designs Various 10 X 10 designs
- Depletion Uncertainty (IV.2.a)
- Will use 5 percent to cover uncertainty in isotopic number densities, per ISG and Kopp memo Criticality Analysis Methodology
12
- Reactor Parameters (IV.2.b)
- Bounding values for moderator temperature, fuel temperature, and power density
- Evaluated at multiple void conditions
- Rodded Operation (IV.2.d)
- Included with Reactor Parameters Criticality Analysis Methodology
13
- Rack Model (IV.3.b)
- Reduced B-10 areal density for PaR racks (lower than minimum)
- Minimum B-10 areal density for Holtec racks
- Conservative modeling of small amount of blisters
- Will demonstrate Holtec rack is limiting, and
- Normal Conditions (IV.3.d)
- Will address normal fuel handling configurations
- Will address eccentricity, orientation, de-channeled assemblies Criticality Analysis Methodology
14
- Area of Applicability (IV.4.a)
- HTC experiments will be included
- Will include >200 experiments from International Handbook of Evaluated Criticality Safety Benchmark Experiments, September 2014
- Trend Analysis (IV.4.b)
- Will perform for all experiments combined, and also for subsets based on various parameters (e.g., HTC cases, non-HTC cases, square lattices)
Biases and uncertainties will be based on most limiting result Criticality Analysis Methodology
15
Background
Criticality Analysis Methodology Technical Specification Changes Closing Summary Agenda
16 Technical Specification Changes
- It if can be supported by analysis results, will simplify TS 4.3.1.1.a to read as follows:
Fuel assemblies having a maximum k-infinity of TBD in the normal reactor core configuration at cold conditions.
- Otherwise, TS 4.3.1.1.a will remain split by rack design and fuel design, with update limits
- Additionally, will modify TS 4.3.1.2 to prohibit loading the New Fuel Vault
17
Background
Criticality Analysis Methodology Technical Specification Changes Closing Summary Agenda
18 Closing Summary
- Review action items
- Summary of path forward
- Schedule for LAR submittal
- Commitment to submit LAR by 3/15/2016
19 Questions