ML21123A265

Nrc'S Accident Tolerant Fuel Project Plan and Regulatory Perspectives on Storage and Transportation Slides

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

NRCs AccidentTolerant Fuel Project Plan and Regulatory Perspectives on Storage andTransportation 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 1

NRCs Accident Tolerant Fuel Project Plan Marilyn Diaz Project Manager 2

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

• 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 4

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.

Lightbridge 6

The ATF Project Plan New Paradigm Licensee Development of Technical Bases Actions Development of guidance, codes and expertise NRC Actions Regulatory Activities Communications early and often Project Timeline 7

ATF Project Plan Activities 8

ATF Project Plan Revision

• 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 9

ATF Preparatory Activities John Wise Senior Materials Engineer 10

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 Front End

• UF6 transportation

• Fuel facilities - enrichment, fabrication

• Unirradiated (Fresh) fuel transportation Back End

• Irradiated (Spent) fuel storage

• Spent fuel transportation

• Disposal 12

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

• The NRC has approved the transportation of limited quantities of ATF for lead test assemblies 14

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 Cr-Coated Zr Front End cladding

• UF6 transportation FeCrAl Cladding

• Fuel facilities -

cladding Performance enrichment, fabrication

• Fresh fuel transportation Neutronics Enrichments (e.g., reactivity, up to 10 % radioactive source Back End terms)

• Spent fuel storage Fuel Burnup

• Spent fuel transportation up to 80 GWd/MTU 16

Cladding Performance Activity Status Technical report on fresh fuel Complete transportation of Cr-coated zirconium-Transportation of PNNL-29773*

based cladding ATF Unirradiated (Fresh)

Fuel Technical report on fresh fuel Complete transportation of FeCrAl cladding ATF PNNL-30086 Technical report on spent fuel storage Complete Storage and and transportation of Cr-coated and PNNL-30451 Transportation of FeCrAl cladding ATF Irradiated (Spent) Phenomena Identification Ranking Fuel Table (PIRT) exercise on storage and FY23 transportation of spent ATF concepts (materials, structural, thermal)

• All reports available at the public NRC ATF website 17

Cladding Performance Increased Enrichment and Higher Burnups Activity Status Standard Fuels (non-ATF) Fuel Performance Considerations and Complete Data Needs for Burnup above 62 PNNL-29368 In-reactor, storage, GWd/MTU and transportation Technical report on data availability and needs for assessing IE/HBU ATF spent fuel performance in dry storage Accident Tolerant and transportation Fuels 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 Mechanical property tests performed on cladding segments irradiated to target burnup

• Separate effects tests to identify phenomena that Failure limits at high burnup should be confirmed for creep strain can lead to gross cladding capacity and delayed hydride cracking rupture

• Fatigue life Fatigue tests performed on cladding segments that contain fuel or have been de-fueled irradiated to target burnup

• Justification for peak Hydride reorientation; ductility and strength tests on cladding cladding temperature segments irradiated to target burnup limits 21

Technical Information Needs (cont.)

Spent ATF (Cr-coated, FeCrAl)

Supporting Information Recommended Source

• Limiting rod internal Thermal-mechanical code approved to target burnup for rod pressure, oxide with limiting power history thickness, and hydrogen content

• Thermal properties Thermal property tests performed on cladding segments (thermal conductivity, irradiated to target burnup specific heat, thermal expansion)

• Cladding cross section Code prediction from code such as ORIGEN and activation 22

Neutronics (Criticality, Shielding)

Activity Status SCALE Code development Several reports Evaluations of the impact of All portions of complete, others increased enrichment and higher fuel cycle forthcoming through burnup on reactivity, decay heat, FY23*

and radioactive source terms (Oak Ridge National Laboratory)

(initial plan) PIRT exercise on storage Spent fuel and transportation of spent ATF No longer being storage and concepts with increased enrichment pursued transportation and higher burnup

• 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