ML21123A265
| ML21123A265 | |
| Person / Time | |
|---|---|
| Issue date: | 05/03/2021 |
| From: | Diaz-Maldonado M, John Wise NRC/NMSS/DFM/IOB, NRC/NMSS/DFM/MSB |
| To: | |
| Tomeka Terry NMSSDFMIOB 3014151488 | |
| References | |
| Download: ML21123A265 (27) | |
Text
1 NRCs Accident Tolerant Fuel Project Plan and Regulatory Perspectives on Storage and Transportation US Nuclear Waste Technical Review Board Public Meeting May 12-13, 2021 US Nuclear Regulatory Commission Division of Fuel Management Office of Nuclear Material Safety and Safeguards
2 NRCs Accident Tolerant Fuel Project Plan Marilyn Diaz Project Manager
Topics
- Accident Tolerant Fuel (ATF) concepts
- ATF Project Plan
- Project Plan Revision
- Fuel Cycle, Transportation, and Storage Regulatory Framework
- Research Activities and Findings
- Closing Remarks 3
ATF Project Plan 4
- Project plan facilitates the efficient and effective licensing of ATF
- Project plan outlines the activities to prepare NRC for licensing ATF
- Project plan covers complete (front-end to back-end) fuel cycle
- Active stakeholder engagement to keep up with the latest information ADAMS Accession No. ML19301B166
Near-Term ATF Technologies
- Chromium-coated Cladding
- Multiple vendors
- Reduce corrosion and metal-water reaction
- Completed phenomena Identification and Ranking Table (PIRT) report and Interim Staff Guidance
- Doped Pellets
- Multiple vendors
- Reduce pellet clad interaction
- Approved for boiling water reactors applications
- Steel Cladding
- Iron-Chromium-Aluminum based alloy fuel cladding (FeCrAl) 5
Long-Term ATF Technologies
- Silicon carbide cladding
- Multiple Vendors
- Uranium nitride pellets
- Higher fuel density
- Metallic fuel
- Fuel thermal conductivity compared to ceramics.
6 Lightbridge
The ATF Project Plan New Paradigm Development of Technical Bases Licensee Actions NRC Actions Project Timeline Development of guidance, codes and expertise Regulatory Activities 7
Communications early and often
ATF Project Plan Activities 8
ATF Project Plan Revision 9
- Changes to project plan will be updating and streamlining the information provided
- Plan provides a regulatory gap analysis.
New revision will expand on gap analysis
- Adding a discussion on the efficiency of the new paradigm
- NRC will issue a draft version and will hold a public meeting in summer 2021
- The new version will be published by Fall 2021
10 ATF Preparatory Activities John Wise Senior Materials Engineer
In-Reactor Cr-Coated Cladding (and doped fuel)
- Regulatory preparatory activities largely complete; Issued Interim Staff Guidance: ATF-ISG-2020-01
- Remain engaged with fuel vendors prior to their submittal of a topical report for NRC review and approval
- Fuel performance codes continue to be assessed/updated FeCrAl Cladding
- Anticipate holding an expert elicitation (Phenomena Identification and Ranking Table (PIRT) exercise) when technology readiness has increased and a topical report is being developed
- Decision to issue supplemental staff guidance will follow 11
Fuel Cycle, Transportation, and Storage 12
- UF6 transportation
- Fuel facilities - enrichment, fabrication
- Unirradiated (Fresh) fuel transportation Front End
- Irradiated (Spent) fuel storage
- Spent fuel transportation
- Disposal Back End
Regulatory Preparedness Activities
- Identification of critical paths for required regulatory actions
- Research: Technical assessments, confirmatory code development, and expert elicitations (i.e., PIRTs)
- Fuel performance data expected to be obtained by applicants or DOE
- Scope and timelines of activities consistent with industrys targets for batch loading 13
Front End UF6 Transportation
- Existing transportation packages are approved for up to 5%
enrichment
- Consideration of 10 CFR 71.55 limit to 5% enrichment - need cylinder water intrusion analysis for higher enrichments or an exemption Fuel Facilities (Enrichment / Fuel Fabrication)
- All commercial fuel cycle facilities are licensed to produce up to 5%
enriched material
- No anticipated challenges for ATF expected enrichments (up to 10%)
Fresh Fuel Transportation
Front End - Critical Path Public letter sent to the Nuclear Energy Institute on critical path timeline to assist mutual understanding with applicants
- Enrichment facility license amendment
- Revised UF6 transportation package design
- Fuel fabrication facility license amendment
- Revised fresh fuel transportation package design
- Kathryn M. Brock (NRC) to Janet R. Schlueter (NEI), Preparing for Efficient and Effective Licensing of Accident Tolerant Fuel with Higher Enrichment, August 26, 2019 (ADAMS Accession No. ML19235A261) 15
Research - Front and Back Ends 16
- UF6 transportation
- Fuel facilities -
enrichment, fabrication
- Fresh fuel transportation Front End
- Spent fuel storage
- Spent fuel transportation Back End Cr-Coated Zr cladding FeCrAl cladding Enrichments up to 10 %
Fuel Burnup up to 80 GWd/MTU Cladding Performance Neutronics (e.g., reactivity, radioactive source terms)
Cladding Performance Activity Status Transportation of Unirradiated (Fresh)
Fuel Technical report on fresh fuel transportation of Cr-coated zirconium-based cladding ATF Complete PNNL-29773*
Technical report on fresh fuel transportation of FeCrAl cladding ATF Complete PNNL-30086 Storage and Transportation of Irradiated (Spent)
Fuel Technical report on spent fuel storage and transportation of Cr-coated and FeCrAl cladding ATF Complete PNNL-30451 Phenomena Identification Ranking Table (PIRT) exercise on storage and transportation of spent ATF concepts (materials, structural, thermal)
FY23 17
- All reports available at the public NRC ATF website
Cladding Performance Increased Enrichment and Higher Burnups Activity Status Standard Fuels (non-ATF)
In-reactor, storage, and transportation Fuel Performance Considerations and Data Needs for Burnup above 62 GWd/MTU Complete PNNL-29368 Accident Tolerant Fuels Technical report on data availability and needs for assessing IE/HBU ATF spent fuel performance in dry storage and transportation September 2021 Fuel performance code updates 18
Findings - Fresh Fuel Cladding Review of open literature:
- Cr-coated Zr alloys Negligible/minimal impacts to cladding mechanical and thermal properties Fatigue endurance may be impacted
- FeCrAl Cladding mechanical and thermal properties expected to be different than zirconium-based alloys Fatigue endurance expected to be different than zirconium-based alloys Applicants are expected to supply technical basis in support of their design-basis assumptions NRC staff is ready to review applicant-supplied technical basis and will use open literature findings as confirmatory basis 19
Findings - Spent Fuel Cladding Cr-coated Zr alloys
- No available information on cladding mechanical and thermal properties
- No available information on fatigue endurance impacts FeCrAl
- No available information on cladding mechanical and thermal properties
- No available information on fatigue endurance impacts 20
Technical Information Needs Spent ATF (Cr-coated, FeCrAl)
Supporting Information Recommended Source Mechanical properties Separate effects tests to identify phenomena that can lead to gross cladding rupture Mechanical property tests performed on cladding segments irradiated to target burnup Failure limits at high burnup should be confirmed for creep strain capacity and delayed hydride cracking Fatigue life Fatigue tests performed on cladding segments that contain fuel or have been de-fueled irradiated to target burnup Justification for peak cladding temperature limits Hydride reorientation; ductility and strength tests on cladding segments irradiated to target burnup 21
Technical Information Needs (cont.)
Spent ATF (Cr-coated, FeCrAl)
Supporting Information Recommended Source Limiting rod internal pressure, oxide thickness, and hydrogen content Thermal-mechanical code approved to target burnup for rod with limiting power history Thermal properties (thermal conductivity, specific heat, thermal expansion)
Thermal property tests performed on cladding segments irradiated to target burnup Cladding cross section and activation Code prediction from code such as ORIGEN 22
Neutronics (Criticality, Shielding)
Activity Status All portions of fuel cycle SCALE Code development Evaluations of the impact of increased enrichment and higher burnup on reactivity, decay heat, and radioactive source terms (Oak Ridge National Laboratory)
Several reports complete, others forthcoming through FY23*
Spent fuel storage and transportation (initial plan) PIRT exercise on storage and transportation of spent ATF concepts with increased enrichment and higher burnup No longer being pursued
- All reports available at the public NRC ATF website 23
Findings - Criticality and Shielding
- The research has not identified any new neutronics phenomena associated with ATF with increased enrichment and higher burnup that cannot be adequately analyzed with current methodologies
- Gaps remain in the data to validate the neutronics codes at higher enrichments - can be addressed by incorporating new validation data as it becomes available or using conservatisms in the analyses
- Applicants expected to supply criticality and shielding analyses in support of their design basis 24
Disposal
- Preparatory work on ATF disposal is not being pursued at this time
- The need for preparatory activities (e.g., confirmatory research) is continually assessed as ATF technologies develop
- The NRC is not aware of any issues with near-term ATF that would preclude safe disposal
- Near-term technologies are reasonably similar to current zirconium-based and stainless steel fuels
- Continuing to monitor national and international activities 25
Concluding Remarks
- The current regulatory framework is adequate for the licensing of ATF cladding, increased enrichment, and higher burnup fuels
- The NRC is following the ATF project plan to facilitate efficient and effective licensing
- The NRC is continuing to assess ATF technologies, higher burnup, and increased enrichment to identify data needs to support licensing
- Opportunities to strengthen regulatory guidance continue to be explored
- To improve the efficiency of regulatory efforts, the NRC encourages applicants to engage early and often 26
Visit the NRCs ATF Website https://www.nrc.gov/reactors/atf.html 27