ML21159A070
| ML21159A070 | |
| Person / Time | |
|---|---|
| Issue date: | 06/08/2021 |
| From: | Michael Orenak Licensing Processes Branch |
| To: | |
| Orenak M | |
| References | |
| Download: ML21159A070 (72) | |
Text
Higher Burnup Workshop II Will Begin Shortly Public Meeting Slides:
- NRC Presentation
- Industry Presentation
- ML21159A140 Please log into Microsoft Teams: Meeting Link.
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HIGHER BURNUP WORKSHOP II July 10, 2021 9:00 am - 3:00 pm
Workshop Agenda (morning)
Topic Presenter Time
Introductions
NRC 9:00 AM ATF Project Plan NRC 9:10 AM Regulatory Framework Applicability Analysis NRC 9:20 AM Discussion NRC/Industry 9:30 AM Licensing Pathway NRC 9:40 AM Research Information Letter NRC 9:50 AM Discussion NRC/Industry 10:00 AM Break 10:10 AM Spent Fuel Storage and Transportation NRC 10:20 AM Environmental Review of ATF LARs NRC 10:30 AM Discussion NRC/Industry 10:40 AM Need For Integrated Fleet-Wide Schedule NRC 10:50 AM Industry Adoption Plans Industry 10:55 AM Discussion NRC/Indusry 11:00 AM Public Comments Everyone 11:05 AM Break 11:20 AM 3
Workshop Agenda (afternoon)
Topic Presenter Time CRAFT/ESCP Industry 12:30 PM Risk-Informed Method for FFRD Industry 12:40 PM Discussion NRC/Industry 12:50 PM AST vs. Normal Source Term Industry 1:00 PM Discussion NRC/Industry 1:10 PM Severe Accident PIRT Impacts Industry 1:20 PM Discussion NRC/Industry 1:30 PM Break 1:40 PM Discussion for Any Topic NRC/Industry 1:50 PM Public Comments Everyone 2:30 PM Adjourn 3:00 PM 4
Welcome Joe Donoghue - Director, Division of Safety Systems
Introductions
Joan Olmstead, NRC Facilitator Corps -
Meeting Facilitator Mike Orenak, NRR - ATF Lead Project Manager Joey Messina, NRR - Technical Reviewer, Nuclear Codes Branch Kim Green, NRR - Senior Licensing Project Manager James Corson, RES - Reactor System Engineer Drew Barto, NMSS - Senior Nuclear Engineer Don Palmrose, NMSS - Senior Reactor Engineer Paul Clifford, NRR - Senior Advisor for Fuels Welcome
Introductions
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Meeting Logistics Meeting is held through Microsoft Teams.
Participants will be on mute until the question-and-answer periods where the NRC will call on those with their hands up to ask their question one at a time.
Todays meeting is an Observation meeting. Public participation and comments are sought during specific points during the meeting.
No regulatory decisions will be made at todays meeting.
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Purpose of Todays Meeting 1.
Provide all stakeholders with updated information about current NRC and industry activities for higher burnup and increased enrichment 2.
Exchange of information between NRC and industry on higher burnup and increased enrichment activities.
3.
Provide an open question and answer period on higher burnup and increased enrichment for the public.
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ATF PROJECT PLAN HOW WERE FOLLOWING THE PLAN AND WHAT CHANGES ARE COMING Mike Orenak Lead ATF Project Manager Office Of Nuclear Reactor Regulation 8
ATF Project Plan
- Designed to:
- Increase regulatory stability and certainty
- Enhance and optimize NRC review
- How to accomplish the above goals?
- Increased stakeholder engagement
- Proactive licensing activities
- Independent confirmatory calculations 9
Increased Engagement
- Public meetings with vendors
- Conferences
- NRC-led meetings (e.g., this workshop)
- Meetings with DOE 10
Proactive Activities Literature Reviews Coated cladding Higher burnup fuel performance Coated cladding transportation FeCrAl cladding FeCrAl cladding transportation Coated and FeCrAl cladding spent fuel transportation and storage Severe accidents PIRTs Coated cladding Severe accidents Interim Staff Guidance
- Coated cladding 11
Proactive Activities (contd)
Example: Possible Increased Enrichment Rulemaking
- With industry interested in increased enrichment, NRC staff is exploring rulemaking to update existing regulations.
- Commission approval is needed to pursue rulemaking.
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Proactive Activities (contd)
Example: Source Term Analysis
- NRC source term memo
- rolled into the Regulatory Guide 1.183, Rev. 1, update
- MELCOR analysis of 75 GWd/MTU rod average (or equivalent) burnup 13
Independent Confirmatory Calculations
- Materials property libraries in FAST and TRACE have been separated from the main codes for efficiency in modifying for ATF properties Zircaloy properties UO2 properties Fuel Performance Zircaloy properties UO2 properties Thermal Hydraulic BEFORE AFTER Fuel Performance (FAST)
Thermal Hydraulic (TRACE)
Zircaloy Properties Zircaloy Properties ATF Properties ATF Properties 14
Project Plan Revision 1.2 Revision forthcoming due to:
- Change in industry plans
- NRC accomplishments and activities
- Streamlining to improve useability 15
Revision 1.2 Changes
- Incorporation of Appendix A of higher burnup and increased enrichment into main body 16
Revision 1.2 Changes (contd)
- Delete Appendix B due to outdated information
- Removal of exact dates and specific products 17
Revision 1.2 Changes (contd)
- Addition of Regulatory Framework Applicability Analysis 18
Regulatory Framework Applicability Analysis Joseph Messina Nuclear Methods and Fuels Branch Office of Nuclear Reactor Regulation 19
Purpose
- Improve upon the initial scoping study presented in Tables A.1 and A.2 in the ATF Project Plan
- Evaluate the applicability of existing regulations and guidance, as well as identify any updates needed 20
Initial Scoping Study
- An initial, rough scoping study was presented in Appendix A of the Project Plan 21
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Regulatory Framework Applicability Analysis
- NRC staff has been working to more thoroughly assess its regulatory framework and expand Tables A.1 and A.2 in the Project Plan 23
Example 1: NRC responsibility Note: Green text indicates the NRC is responsible for closure.
Blue text indicates that the industry is responsible for closure.
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Example 2: Industry responsibility Note: Blue text indicates that industry is responsible for closure.
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Next Steps
- Update the Regulatory Framework Applicability table and develop and pursue expanding range of applicability, if necessary
- The Regulatory Framework Applicability table will replace Tables A.1 and A.2 in the updated ATF Project Plan Revision 1.2 26
NRC/Industry Discussion 27
LICENSING PATHWAY Kim Green Senior Project Manager Office Of Nuclear Reactor Regulation 28
Licensing Pathway
- What the Licensing Pathway is NOT:
- All-inclusive
- A Timeline
- A Checklist
- What the Licensing Pathway is:
- Ideal depiction of remaining tasks
- Draft 29
Higher Burnup Topical Report Reviews Submit TR Approve TR NRC ACTIONS VENDOR ACTIONS SRP 4.2 RIA testing RG 1.203 Validate evaluate models for higher burnup ACRS Meeting RG 1.236 Empirical database limitations FFRD and possible loss of coolable geometry during RIA HBU effects on RIA Define cladding failure thresholds Update SRP 4.2 FFRD not addressed RG 1.236 not appliable to 75 GWd/MTU NUREG-2121 Recent FFRD research findings not included NUREG-2121 Data needed to address FFRD if burst is predicted to occur 75 GWd/MTU 68 GWd/MTU Licensing Pathway (contd.)
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Higher Burnup Plant-Specific LAR Reviews Submit LAR Approve Amendment Perform EA NRC ACTIONS VENDOR OR LICENSEE ACTIONS Update SRP 4.2 ACRS Review Reference NRC analysis or assess environmental effects of transportation of fuel and waste (10 CFR 51.52(b))
Evaluate if spent ATF is covered by NUREG-2157 Preliminary environmental study based on CoC applications so storage casks are pre-approved for storage of spent ATF Use RG 1.183, Revision 1 for release fractions (for plants not approved for AST for non-LOCA accidents)
Issue RG 1.183, Rev.1 (NUREG-1465)
Assumes fuel cycle facilities have been approved by NRC Perform analysis of transportation impacts based on NUREG/CR-6703 for up to 80 GWd/MTU Evaluate SFP criticality analysis 10 CFR 50.46 Address burnup effects RG 1.183, Rev. 1 RIA transient FGR quantified for up to 75 GWd/MTU Licensing Pathway (contd.)
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Research Information Letter on Fuel Fragmentation, Relocation, and Dispersal James Corson, Ph.D.
Reactor Systems Engineer Office of Nuclear Regulatory Research 32
Experiments Have Shown That Fuel Can Fragment during a Loss of Coolant Accident 33
NRC Has Studied FFRD and Published Findings
- NUREG-2121 (March 2012) discussed history of fuel fragmentation
- NUREG-2160 (Aug. 2013) provided results of NRC-sponsored tests
- SECY-15-0148 (Nov. 2015) concluded that rulemaking was not needed to address FFRD at that time
- Conclusion based on existing burnup limits, existing fuel management practices 34
NRC Continues to Participate in FFRD Research
- Significant advancements in understanding of FFRD since 2015
- Third phase of the Studsvik Cladding Integrity Project completed in 2019
- Fourth phase of SCIP (2019-2024) is ongoing
- Oak Ridge National Laboratory recently performed hot cell LOCA tests 35
RES Staff Intend to Communicate Recent FFRD Findings in a RIL
- Research Information Letters summarize research findings and discuss how information may be used in regulatory decisions
- RILs are meant for internal use, but they can be made publicly available
- Intent is to make FFRD RIL public
- Some information in the FFRD RIL will need approval from SCIP and Halden management boards to publish
- Goal of RIL is to synthesize recent FFRD research 36
The RIL Will Address Five Elements of NRCs Interpretation of FFRD Research
- Fine fragmentation burnup threshold
- Dispersible mass fraction
- Strain threshold for fragmentation
- Transient fission gas release
- Fuel packing fraction 37
At What Burnup Is Fuel Susceptible to Fine Fragmentation?
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How Much Mass Can Be Dispersed?
Particle size distribution from NRC-sponsored LOCA tests conducted at Studsvik (Fig. 4-40 in NUREG-2121) 39
How Much Cladding Strain Is Needed for Fragmentation and Relocation?
Results from Argonne National Laboratory hot cell LOCA tests performed on BWR rods (56 GWd/MTU) (Fig.
4-25 in NUREG-2121) 40
How Does Fragmentation Influence Transient Fission Gas Release?
GASPARD data from Pontillon et al., Proceedings of the 2004 International Meeting on LWR Fuel Performance, Paper 1025 (Article)
Halden data from Bianco et al., Journal of Nuclear Materials 465 (2015) 260-267 (Article) 41
What Is the Packing Fraction of Fuel in the Balloon Region?
Post-test gamma scan of Halden IFA-650.4 fuel rod (92 GWd/MTU) (Fig. 4-28 in NUREG-2121) 42
The Goal Is to Publish the RIL by the End of 2021
- Current status: draft RIL under internal review
- Future steps
- June-July 2021: internal review
- End of July 2021: seek approval from SCIP management board to publish data
- August 2021: peer review
- Fall 2021: ACRS review 43
NRC/Industry Discussion 44
10 minute Break 45
High Burnup and Increased Enrichment Spent Fuel in Transportation and Dry Storage Andrew Barto Division of Fuel Management Office of Nuclear Material Safety and Safeguards 46
Overview
- Background on HBU Spent Fuel Storage and Transportation
- Research on Neutronics Codes Capabilities for Higher Burnup and Increased Enrichment
- Validation of Neutronics Codes at Higher Burnup and Increased Enrichment 47
=
Background===
- All commercial SNF storage and transportation limited to 5% initial enrichment
- Large SNF storage or rail transportation casks limited to 60 GWd/MTU burnup for most fuel, but can go as high as 70 GWd/MTU
- Smaller transportation packages can ship higher burnups for single assemblies or groups of removed rods
- Burnup credit criticality limited to 60 GWd/MTU for code validation considerations 48
Higher Burnup/ Increased Enrichment Neutronics Code Research Isotopic and Fuel Lattice Parameter Trends in Extended Enrichment and Higher Burnup LWR Fuel (ORNL)
- Volume I: PWR Fuel (ML21088A336)
- Volume II: BWR Fuel (ML21088A354)
- Research goals:
o Identify important effects on reactivity, lattice physics, and isotopic effects o
Provide code-to-code comparisons with higher order cross section libraries and/or codes o
Identify anomalous trends in the results for further investigation 49
Higher Burnup/ Increased Enrichment Neutronics Code Research (contd)
- Calculations performed using SCALE/Polaris, TSUNAMI, and ORIGEN
- Evaluated changes from base case to higher burnup /
increased enrichment case:
5% / 60 GWd/MTU 8% / 80 GWd/MTU Key conclusions for storage and transportation:
- No unexpected trends found with use of the Polaris code for depletion, lattice physics, and isotopic content calculations
- TSUNAMI calculations show that 5% / 60 GWd/MTU case is similar to 8% / 80 GWd/MTU case in rack cell (ck > 0.98) 50
Neutronics Code Validation
- Burnup credit in storage and transportation recommended to be limited to 5% / 60 GWd/MTU based on:
Available radiochemical assay data for validation of depletion codes Available critical experiments similar to SNF in storage and transportation configuration
- SRPs for storage and transportation endorse approaches for validating actinide and fission product burnup credit criticality safety analyses for:
Isotopic composition predictions in NUREG/CR-7108 Criticality predictions in NUREG/CR-7109 51
Neutronics Code Validation (contd)
Applicants need to provide additional technical basis to extend SNF burnup credit criticality isotopic depletion analyses to 8% /
80 GWd/MTU:
Ongoing research for high fidelity radiochemical assay measurements of DOE HBU storage demo sister rods for depletion code validation Several samples over 65 GWd/MTU 16 samples total with very low measurement uncertainties No samples over 5% initial enrichment
- Update to NUREG/CR-7108 for depletion code validation 52
Neutronics Code Validation (contd)
Applicants need to provide additional technical basis to extend SNF burnup credit criticality analyses to 8% / 80 GWd/MTU:
Are mixed oxide experiments applicable at increased enrichment and burnup?
Can methodology for estimating keff bias based on cross section uncertainty be applied at increased enrichment and burnup?
Update to NUREG/CR-7109 on criticality code validation 53
Summary
- Lattice physics codes can model higher burnup and increased enrichment in transportation and storage systems, and there are no surprises regarding predicted SNF characteristics
- Applicants need to ensure that depletion and criticality codes can be properly validated at higher burnup and increased enrichment.
- NRC is sponsoring research which will assist staff in reviewing applications for higher burnup and increased enrichment 54
Environmental Review of ATF License Amendment Requests Donald Palmrose, Ph.D.
Senior Reactor Engineer Office of Nuclear Material Safety and Safeguards 55
Problem Statement
- New site-specific impacts
- Modified fuel cycle facilities
- Table S-4 criteria will be exceeded:
- 5 wt % U-235
- Burnup up to 62 GWD/MTU
Affected Environmental Resources
- Some environmental impacts are principally driven by radionuclide inventory (i.e., source term)
- Environmental resource areas of specific interest:
- Radiological health (site-specific)
- Postulated accidents (site-specific)
- Fuel cycle (offsite)
- Transportation of unirradiated and spent ATF fuel assemblies (offsite) 57
- Updated FSAR for site-specific impacts
- Evaluation of off-site impacts:
- Prior fuel cycle facility NEPA assessment(s)
- Characteristics of transportation packages
- Bounding assumptions
- Information and analytical methodologies from prior studies and NEPA assessments Factors to be Considered in the Environmental Evaluation 58
Planned Path Forward
- NRC is assessing the following:
- Environmental Assessment (EA) vs Categorical Exclusion (CATX)
- Impacts from higher enrichment and burnup could require an EA for the first LAR of an ATF design with the potential of a CATX for subsequent LARs.
- Performance of an environmental transportation analysis
- Expected license changes for fuel cycle facilities
- Information and data needs 59
Summary
- Goal of early resolution of environmental issues to the extent practicable
- Leverage prior NEPA assessments and technical studies
- Must identify and resolve information and data needs 60
NRC/Industry Discussion 61
Integrated Fleet-Wide Schedule Paul Clifford Senior Level Advisor for Fuels Office of Nuclear Reactor Regulation 62
HBU/IE Licensing Actions
- Integrated, fleet-wide schedule for HBU/IE licensing actions would be beneficial to prioritize and balance work-load
- Both industry and staff resources are limited
- Multiple strategies for implementing HBU/IE complicate work-load management
- Coincident deployment of multiple ATF design concepts further complicate work-load management
- Fuel vendors have provided detailed schedules for HBU/IE and ATF topical reports Unknown scope and schedule of future licensing actions (e.g., LARs, exemptions)
= RISK 63
50.46c Implementation Plan Exceptional level of communication and coordination to develop implementation plan
- 4 separate, focused public workshops held in 2015 Industry developed a comprehensive, integrated GANTT chart illustrating the parallel and in-series work activities which needed to be completed in order to implement the new requirements of 50.46c.
- Up to 24 vendor topical reports
- Up to 65 LARs 29 Level 1 LARs; maintain EMs, no new LOCA simulations 5 Level 2 LARs; maintain EMs, partial re-analysis 31 Level 3 LARs; new EMs, complete break spectrum 50.46c implementation plan should reduce scheduling risk and burden, while improving flexibility and efficiency 64
Industry Goals
- Timely HBU/IE implementation
- Prioritize and balance work-load among fuel vendor and licensee staff to complete plant-specific licensing actions
- Flexibility to accommodate outage schedules, plant modifications, vendor contracts, ATF deployment, etc
- Assurance that NRC reviews do not delay implementation 65
NRC Goals
- Effective and efficient HBU/IE reviews
- Prioritize and balance work-load
- Manage staff resources and contractors (as needed) 66
Industry Adoption Plans Presentation 67
NRC/Industry Discussion 68
Public Comments 69
Lunchtime!
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Final Closing Remarks Joe Donoghue Director Division of Safety Systems, NRR 71
Thank you for Participating in Todays Workshop!
For further information, please email accident_tolerant_fuel@nrc.gov or visit https://www.nrc.gov/reactors/atf.html 72