ML23083B366

M230330: Slides/Supporting Presentation Material - D. Pickett - Briefing on Nuclear Regulatory Research Program

ML23083B366
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Issue date:	03/30/2023
From:	NRC/OCM
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M230330
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Research Supporting Long-Term Storage of Nuclear Materials David Pickett Senior Program Manager, Center for Nuclear Waste Regulatory Analyses Nuclear Regulatory Commission Briefing on Nuclear Regulatory Research Program March 30, 2023 1

Long-Term Storage of Spent Nuclear Fuel Two central challenges

- Dry storage for much longer than originally envisioned

- Less is known about advanced reactor fuels and wastes in long-term storage Long-term storage must be safe for humans and the environment, and compatible with subsequent transportation, storage, and disposal, e.g.,

- Fuel cladding integrity

- Containment integrity A longer storage thermal management period could be needed, possibly at higher temperatures There has been much research, including sponsored by NRC, but important research needs remain Images from www.nrc.gov 2

CNWRA Support for NRC in Spent Nuclear Fuel Long-Term Storage Research Regulatory and technical gaps associated with regulating extended storage Thermal and gas flow modeling of dry cask systems using computational fluid dynamics (CFD)

Evaluated cask-drying requirements; developed vacuum drying test plan CFD model of airflow in a horizontal Experimental measurements of chloride-induced stress storage cask system corrosion cracking of stainless-steel canister materials Assessment of instrumentation for functional monitoring Technical development of aging management guidance for Stainless steel specimens in dry cask storage chloride-induced stress corrosion cracking tests 3

CNWRA Support for NRC in Spent Nuclear Fuel Long-Term Storage Licensing MAPS Report Process for Renewal Reviews Scoping Evaluation Several licensing reviews of Independent Spent Fuel Aging Management Review Storage Installations and Certificates of Compliance Development of the Managing Aging Processes in Time-Limited Aging Aging Management Analyses or Other Programs Storage (MAPS) license renewal guidance document Supporting Analyses Continued Storage rulemaking Related: Safety or environmental reviews for three centralized interim storage facilities Schematic of Related: Evaluation of information needs and irradiated metal regulatory gaps for storage of advanced reactor fuel pin wastes (TRISO, metal, molten salt) 4

Notable Ongoing U.S. Research Extended Storage Collaboration Program (ESCP)

- International cooperation in research and model benchmarking

- Aging management research, such as inspection technologies High Burnup Dry Storage Cask Research Project

- Monitoring & modeling temperatures

- Gas pressure and composition

- Sister rod studies Chloride-induced stress corrosion cracking

- Stress mitigation and crack repair

- Continued stress corrosion cracking testing and modeling, including improvements in duplicating relevant conditions

- Consequences of cracking Fuel condition, such as cladding integrity and hydride reorientation 5

High-Priority Research Needs High-burnup fuel extended storage (e.g., cladding and fuel integrity, thermal conditions)

Stress corrosion cracking (e.g., mitigation and repair, inspection, consequence models)

Thermal and decay heat model benchmarking Structural integrity under external loads (e.g., seismic)

Extended storage of advanced reactor spent fuels and associated wastes (e.g., fuel condition, identification and characterization of non-fuel wastes, criticality modeling, thermal characteristics)

Continued evaluation of greater-than-Class C waste if extended storage is needed (e.g., radiolytic gas production, thermal evolution) 6

Disclaimer This presentation describes work performed by the Center for Nuclear Waste Regulatory Analyses (CNWRA) and its contractors for the U.S. Nuclear Regulatory Commission (NRC) under Contract No. 31310018D0001.

This presentation is an independent product of CNWRA and does not necessarily reflect the views or regulatory positions of the NRC.

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