ML21130A053
| ML21130A053 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 09/30/2019 |
| From: | Nuclear Energy Institute |
| To: | Vaughn Thomas Plant Licensing Branch II |
| Thomas V | |
| References | |
| Download: ML21130A053 (8) | |
Text
NEI 12-16, Revision 4 September 2019 APPENDIX C: CRITICALITY ANALYSIS CHECKLIST The criticality analysis checklist is completed by the applicant prior to submittal to the NRC. It provides a useful guide to the applicant to ensure that all the applicable subject areas are addressed in the application, or to provide justification/identification of alternative approaches.
The checklist also assists the NRC reviewer in identifying areas of the analysis that conform or do not conform to the guidance in NEI 12-16. Subsequently, the NRC review can then be more efficiently focused on those areas that deviate from NEI 12-16 and the justification for those deviations.
Subject Included Notes / Explanation 1.0 Introduction and Overview Purpose of submittal YES Increase enrichment, update methods &
codes, include gadolinium.
Changes requested YES Change Tech. Spec burnup curve, change maximum enrichment, add empty cell requirement to NFSA Summary of physical changes YES No physical changes Summary of Tech Spec changes YES Change burnup curve, change maximum enrichment, add burnable absorber requirement Summary of analytical scope YES SFP and new fuel storage criticality safety analysis including normal storage and fuel handling, abnormal conditions, boron dilution analysis, and accompanying code benchmarking analysis 2.0 Acceptance Criteria and Regulatory Guidance Summary of requirements and guidance YES Requirements documents referenced YES Multiple Guidance documents referenced YES Mainly RG 1.240 Acceptance criteria described YES 3.0 Reactor and Fuel Design Description Describe reactor operating parameters YES Bounds historical and anticipated Describe all fuel in pool YES Geometric dimensions (Nominal and YES Tolerances)
Schematic of guide tube patterns YES 15x15 PWR fuel and four 17x17 assemblies (>30 years old)
Material compositions YES Describe future fuel to be covered NO None proposed. Using composite bounding fuel design Geometric dimensions (Nominal and NO None proposed.
Tolerances)
Schematic of guide tube patterns NO None proposed.
1
NEI 12-16, Revision 4 September 2019 Subject Included Notes / Explanation Material compositions NO None proposed.
Describe all fuel inserts YES Borosilicate glass, Alumina B4C, Secondary Sources, Control Rods Geometric Dimensions (Nominal and YES Tolerances)
Schematic (axial/cross-section) YES Material compositions YES Describe non-standard fuel YES Fuel Rod Canister for failed fuel rods and reconstituted fuel.
Geometric dimensions YES Describe non-fuel items in fuel cells NO Non-fuel items can be stored in cells that can store fuel. Therefore, non-fuel items displace fuel Nominal and tolerance dimensions NO 4.0 Spent Fuel Pool/Storage Rack Description New fuel vault & Storage rack description YES Two storage options:
-4 out of 4 for enrichments 4.35%
-3 out of 4 for enrichments >4.35%
Nominal and tolerance dimensions YES Schematic (axial/cross-section) YES Rack diagrams Material compositions YES Spent fuel pool, Storage rack description YES One rack type, two storage regions Region 1: Takes burnup credit Region 2: No burnup credit Nominal and tolerance dimensions YES Schematic (axial/cross-section) YES Rack diagrams Material compositions YES Other Reactivity Control Devices (Inserts) NO No installed rack inserts.
Nominal and tolerance dimensions NO Schematic (axial/cross-section) NO Material compositions NO 5.0 Overview of the Method of Analysis New fuel rack analysis description YES Storage geometries YES Two storage options:
-4 out of 4 for enrichments 4.35%
-3 out of 4 for enrichments >4.35%
Bounding assembly design(s) YES Integral absorber credit NO No absorber material credited Accident analysis YES - Flooded with water
- Flooded with optimum density water
- Dropped/misplaced assembly
- Seismic event Spent fuel storage rack analysis description YES Storage geometries NO All regions are 4 out of 4. No empty cells are required.
Bounding assembly design(s) YES 2
NEI 12-16, Revision 4 September 2019 Subject Included Notes / Explanation Soluble boron credit YES Boron dilution analysis YES Burnup credit YES Region 1 credits burnup Region 2 does not credit burnup Decay/Cooling time credit NO The criticality analysis does not credit cooling time (Decays to 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> for all cases). The dose assessment analysis requires 150 days of cooling for Region
- 1. This analysis is not changing this requirement.
Integral absorber credit NO Other credit NO Fixed neutron absorbers NO No neutron absorber material installed in the racks Aging management program NO Accident analysis YES Temperature increase YES Assembly drop YES Into racks and outside of racks Single assembly misload NO No empty cells required.
Fresh, 5.0wt% assemblies in all cells meet regulatory limits with normally spaced cells.
Multiple misload NO No empty cells required.
Fresh, 5.0wt% assemblies in all cells meet regulatory limits with normally spaced cells.
Boron dilution YES Other YES Cask drop analysis. Modeled by moving all of the Region 1 assemblies and pins towards each other until optimum moderation.
Fuel out of rack analysis YES Handling YES Movement YES Inspection YES 6.0 Computer Codes, Cross Sections and Validation Overview Code/Modules Used for Calculation of keff YES SCALE 6.2.3 / CSAS5 - KENO V.a Cross section library YES 238 group ENDF/B-VII Description of nuclides used YES 233 isotopes used Convergence checks YES Convergence tests run on all cases Code/Module Used for Depletion Calculation YES SCALE 6.2.3 / Triton t5-depl (depletion) and ORIGAMI (decay)
Cross section library YES 238 group ENDF/B-VII Description of nuclides used YES 233 isotopes used Convergence checks YES Test cases displayed convergence 3
NEI 12-16, Revision 4 September 2019 Subject Included Notes / Explanation Validation of Code and Library YES Appendix A is the validation of CSAS5 Appendix B is the validation of TRITON/ORIGAMI Major Actinides and Structural Materials YES Minor Actinides and Fission Products YES 1.5% bias (NUREG/CR-7109)
Absorbers Credited YES Soluble boron 7.0 Criticality Safety Analysis of the New Fuel Rack Rack model YES Full storage area with structure and concrete.
Boundary conditions YES Void Source distribution YES Uniform in fissile material Geometry restrictions YES Two storage options:
-4 out of 4 for enrichments 4.35%
-3 out of 4 for enrichments >4.35%
Limiting fuel design YES Fuel density YES Bounding high Burnable Poisons NO No credit taken Fuel dimensions YES Composite bounding design Axial blankets NO No credit taken Limiting rack model YES Storage vault dimensions and materials YES Temperature YES Multiple regions/configurations NO Only one region / type of rack Flooded YES Low density moderator YES Eccentric fuel placement YES Tolerances YES Fuel geometry YES Fuel pin pitch YES Fuel pellet OD YES Fuel clad OD YES Fuel content Enrichment YES Density YES Integral absorber NO No credit Rack geometry Rack pitch YES Cell wall thickness YES Storage vault dimensions/materials YES Code uncertainty YES Biases YES Temperature YES Code bias YES 4
NEI 12-16, Revision 4 September 2019 Subject Included Notes / Explanation Moderator Conditions YES Fully flooded and optimum density YES moderator 8.0 Depletion Analysis for Spent Fuel Depletion Model Considerations YES Time step verification YES Verified (similar to prior LARs).
Convergence verification YES Verified (similar to prior LARs).
Simplifications YES Bounding high grid volume homogenized in fuel lattice water, constant depletion conditions (except reduced power for final 40 days).
Non-uniform enrichments NO Post Depletion Nuclide Adjustment YES Reduced volatile fission product content (same as prior LARs).
Cooling Time YES Only peak reactivity decay used (100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br />)
Depletion Parameters YES Burnable Absorbers YES Bounding Alumina B4C discrete burnable absorber used.
Integral Absorbers NO IFBA and Gad tested and shown to be bounded by Alumina B4C discrete burnable poison. Rules set up for use mixture of discrete BP with integral BP (similar to prior LARs).
Soluble Boron YES Bounding high boron concentration used. 1 unbounded assembly justified.
Fuel and Moderator Temperature YES Calculated using bounding high fuel assembly power history and bounding high core moderator exit temperature Power YES Bounding high power reduced near end of depletion to maximize depleted fuel reactivity.
Control rod insertion NO Shown to be bounded by the bounding burnable poison Atypical Cycle Operating History YES Bounded or justified.
9.0 Criticality Safety Analysis of Spent Fuel Pool Storage Racks Rack model YES Two rack models. Region 1 models the entire region while Region 2 is an infinite array.
Boundary conditions YES Region 1: Reflective with large amount of water and concrete between fuel and boundary.
Region 2: Reflective Source distribution YES Uniform in fissile material Geometry restrictions NO No required empty cells or low reactivity cells Design Basis Fuel Description YES Composite bounding design.
5
NEI 12-16, Revision 4 September 2019 Subject Included Notes / Explanation Fuel density YES Bounds all fuel assemblies.
Burnable Poisons NO Burnable poison credit not utilized Fuel assembly inserts NO Control rod credit not utilized Fuel dimensions YES Present, past, and anticipated future designs bounded Axial blankets NO Axial blanket credit not utilized.
Configurations considered YES Evaluated with and without boron.
Borated YES Unborated YES Multiple rack designs NO Only one rack type present in SFP Alternate storage geometry NO No required empty cells or low reactivity cells Reactivity Control Devices NO Fuel Assembly Inserts NO Control rod credit not utilized Storage Cell Inserts NO Storage Cell Blocking Devices NO No empty cells required Axial burnup shapes YES Uniform/Distributed YES NUREG/CR-6801 shapes and uniform.
Justified with Surry shapes.
Nodalization YES NUREG/CR-6801 - 18 nodes.
Blankets modeled NO No credit.
Tolerances/Uncertainties YES Fuel geometry YES Fuel rod pin pitch YES Fuel pellet OD YES Cladding OD YES Axial fuel position YES Fuel content YES Enrichment YES Density YES Assembly insert dimensions and NO No inserts used materials Rack geometry YES Flux-trap size (width) NO No flux trap racks Rack cell pitch YES Rack wall thickness YES Neutron Absorber Dimensions NO No neutron absorber material Rack insert dimensions and materials NO No rack inserts used Code validation uncertainty YES Criticality case uncertainty YES Depletion Uncertainty YES EPRI 3002016888 method used (calculated depletion uncertainty)
Burnup Uncertainty YES 5% of measured burnup. From NEI 12-16 and justified using Surry measurement uncertainties.
6
NEI 12-16, Revision 4 September 2019 Subject Included Notes / Explanation Biases YES Design Basis Fuel design YES Code bias YES Temperature YES Eccentric fuel placement YES Incore thimble depletion effect YES Incore thimble included in fuel depletion model.
NRC administrative margin YES Modeling simplifications YES Identified and described YES 10.0 Interface Analysis Interface configurations analyzed YES Between dissimilar racks NO Only one type of rack in SFP Between storage configurations within a YES Region 1 (burned fuel) - Region 2 (fresh rack fuel) interface analyzed Interface restrictions NO Benign interface 11.0 Normal Conditions Fuel handling equipment YES Administrative controls YES Fuel inspection equipment or processes YES Fuel reconstitution YES Evaluated and limitations applied 12.0 Accident Analysis Boron dilution YES 0 ppm keff < 1.0 including bias and uncertainties Normal conditions YES keff < 0.95 with minimum boron dilution analysis boron concentration Accident conditions YES keff < 0.95 with TS boron concentration Single assembly misload YES Bounded by cask drop accident Fuel assembly misplacement YES Bounded by cask drop accident Neutron Absorber Insert Misload NO No neutron absorbing material Multiple fuel misload YES Bounded by cask drop accident Dropped assembly YES Bounded by cask drop accident Temperature YES Between racks. Bounded by cask drop accident Seismic event/other natural phenomena YES No interface effect from shifting racks due to racks being fastened to the SFP floor.
13.0 Analysis Results and Conclusions Summary of results YES Burnup curve(s) YES Bounding polynomial coefficients Intermediate Decay time treatment NO No decay credit utilized.
New administrative controls NO Technical Specification markups YES 7
NEI 12-16, Revision 4 September 2019 Subject Included Notes / Explanation 14.0 References YES Appendix A: Criticality Computer Code Validation:
Code validation methodology and bases YES NUREG 6698 Method New Fuel YES Depleted Fuel YES MOX YES HTC YES Convergence YES Trends YES Bias and uncertainty YES Range of applicability YES Analysis of Area of Applicability YES coverage Appendix B: Depletion Computer Code Validation:
Code validation methodology and bases YES EPRI 3002010613 (Benchmark Report)
EPRI 3002016888 (Utilization Report)
Convergence YES Trends YES Bias and uncertainty YES Range of applicability YES 8