ML23018A054

M230124: Slides/Supporting Presentation Material - E. Lyman - Overview of Accident Tolerant Fuel Activities

ML23018A054
Person / Time
Issue date:	01/24/2023
From:	NRC/OCM
To:
Shared Package
ML22293A420	List: ML23018A049 ML23018A050 ML23018A051 ML23018A052 ML23018A053 ML23018A054 ML23018A055 ML23026A288
References
M230124
Download: ML23018A054 (7)

Text

UCS Perspectives on Accident-Tolerant Fuel Dr. Edwin Lyman Director of Nuclear Power Safety Climate and Energy Program Union of Concerned Scientists January 24, 2023

Is Accident-Tolerant Fuel False Advertising?

• UCS strongly supports efforts to develop fuels that would genuinely increase safety

• But that no longer appears to be the main goal of the current accident-tolerant fuel (ATF) program

• Because of the economic link between ATF technologies, higher burnup, and increased enrichment

... NRC staff considers the pursuit of higher burnup and increased enrichment a component of the ATF program

- NRC ATF Licensing Project Plan, version 2.1 (2021)

• Raises the possibility that higher-burnup risks will outweigh the safety margins (if any) that accident-tolerant features might provide 2

ATF uncertainties

• Uncertainties and tradeoffs of ATF concepts relative to conventional fuels (even the near-term approaches) make it difficult to assess the overall safety benefits

- FeCrAl cladding in particular

• NUREG/CR-7282/ERI-NRC/21-203, 2021:

- It is seen that there is conflicting information about the impact of doping on fission gas release behavior

- The available literature is much more complete with respect to ATF design characteristics than with the behavior of ATF under severe accident conditions.

- Within considerable variation, [ATF-related severe accident simulations] tend to confirm a widely held impression that ATF designs typically afford a modest increase in coping time and a reduction of hydrogen generation, at least until very late times. 3

High-burnup/increased enrichment risks UCS is concerned about the EPRI alternate licensing strategy to allow fuel fragmentation, relocation, and dispersal (FFRD) to be excluded from large-break loss-of-coolant accident analysis

- The potentially serious safety implications of FFRD must be fully assessed for any HBU fuel proposal Safety impacts of increased enrichment also must be thoroughly evaluated Power peaking, lower control rod worth, recriticality 2021 NRC-led Phenomena Identification and Ranking Tables severe accident study examined ATF concepts and high-burnup/increased enrichment (HBU/IE) with conventional fuel/cladding, but did not consider ATF and HBU/IE together, even though that is the most likely batch loading that licensees will pursue 4

And dont forget the spent fuel

• Potentially deleterious impacts of alternative cladding materials and HBU/IE on spent fuel management and disposal should be fully assessed before batch loading is approved 5

The need for 50.46(c)

• The proprietary nature of much fuel design and performance data limits opportunities for public understanding of the basis for regulatory decisions and diminishes public confidence

• This is exacerbated by the absence of clear and consistent regulatory requirements for approving the safety of new fuel types

• Swift approval of the 50.46(c) rule by NRC would go a long way toward closing this gap 6

7 Acronyms

• ATF: Accident-Tolerant Fuel

• ERI: Energy Research, Inc.

• FeCrAl: Advanced Stainless Steel

• FFRD: Fuel Fragmentation, Relocation, and Dispersal

• HBU: High Burnup

• IE: Increased Enrichment

• UCS: Union of Concerned Scientists