Text

NRC Slides for the Higher Burnup Workshop III on August 24, 2022
	ML22230D012
Person / Time
Issue date:	08/24/2022
From:	; Licensing Processes Branch
To:	;
	Devlin-Gill S, NRR/DORL/LPL2-1
References
	Download: ML22230D012 (65)
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Higher Burnup Workshop III August 24, 2022 9:00 am - 11:30 am

Workshop Agenda Time Topic Speaker 9:00-9:05 Welcome and Meeting Logistics NRC 9:05-9:15 Overview and Status Update (IE Rulemaking & RFAA Table)

NRC 9:15-9:35 Research Information Letter (RIL) on Fuel Fragmentation, Relocation, and Dispersal (FFRD) on Higher Burnup Fuel NRC 9:35-9:55 Update on FFRD and Licensing Implications Industry 9:55-10:10 Discussion NRC and Industry 10:10-10:20 Break All 10:20-10:35 Storage and Transportation NRC 10:35-10:45 Performing an Environmental Evaluation of the Transportation of Accident Tolerant Fuel (ATF)

NRC 10:45-11:05 Update on the Collaborative Research on Advanced Fuel Technologies for Light-Water Reactors (CRAFT)

Industry 11:05-11:20 Discussion NRC and Industry 11:20-11:30 Public Comments Public

Opening Remarks Bo Pham Director Division of Operating Reactor Licensing (DORL)

Joe Donoghue Director Division of Safety Systems (DSS)

Introductions

Richard Chang, NRR/DORL - LLPB Branch Chief

Stephanie Devlin-Gill, NRR/DORL - ATF Lead Project Manager

Daniel King, NRR/DORL - ATF & Increased Enrichment (IE) Rulemaking DORL Project Manager

Joey Messina, NRR/DSS - Technical Reviewer, Nuclear Methods & Fuels Analysis Branch

Carla Roque-Cruz, NRR/DORL - IE Rulemaking DORL Lead Project Manager

Stacy Joseph, NMSS - IE Rulemaking Project Manager

James Corson, RES - Reactor System Engineer

Drew Barto, NMSS - Senior Nuclear Engineer

Jason Piotter, NMSS - Senior Mechanical Engineer

John Wise, NRR/DNRL - Senior Technical Advisor

Don Palmrose, NMSS - Senior Reactor Engineer Welcome and Introductions

Meeting visuals and audio are through MS Teams.

Participants are in listen-only mode until the discussion and public feedback period. During which, the NRC will allow attendees to un-mute.

This is an Observation meeting. Public participation and comments are sought during specific points during the meeting.

NRC will consider the input received but will not prepare written responses.

No regulatory decisions will be made during this meeting.

This meeting is being recorded.

Meeting Logistics

Meeting Purpose

Provide all stakeholders with updated information about current NRC and industry activities for higher burnup and increased enrichment.

Exchange of information between NRC and industry on higher burnup and increased enrichment activities.

Provide an opportunity for members of the public to ask questions of the NRC staff.

Increased Enrichment Rulemaking Update Carla Roque-Cruz, NRR/DORL Stacy Joseph, NMSS/REFS

Status of Rulemaking Activity

Comment-Gathering Public Meeting held on 6/22/2022

Meeting Summary: ML22208A001

NRC staff is developing the regulatory basis

Discusses regulatory issues and alternatives to resolve them

Considers legal, policy, and technical issues

Considers costs and benefits of each alternative

Identifies the NRC staff's recommended alternative

Considers feedback obtained from the 6/22/2022 public meeting

Possible alternatives:

Maintain status quo

Revise regulations

Revise guidance

Next Steps 2022 2023 2024 2025 2026 SRM 3/16/22 Regulatory Basis 3/16/22-9/15/23 Public Comment Period 9/16/23-12/1/23 Proposed Rule Package 12/2/23-12/16/24 Commission Review 12/16/24-3/16/25 Revise Proposed Rule 3/17/25-4/16/25 Public Comment Period 4/17/25-6/30/25 Final Rule to Commission 6/30/26 Note: Dates listed are estimates only, and thus are subject to change.

Stay Updated on IE Rulemaking

Go to https://www.regulations.gov/ and search for docket ID NRC-2020-0034.

Regulatory Framework Applicability Assessment Joseph Messina Nuclear Methods and Fuel Analysis Branch Office of Nuclear Reactor Regulation 12

Introduction

The Regulatory Framework Applicability Assessment was issued in May 2022 and can be accessed at ADAMS Accession No. ML22014A112 13

Purpose

Improve upon the initial scoping study presented in Tables A.1, A.2, and A.4 in the previous revision of the ATF Project Plan (version 1.1)

Evaluate the applicability of existing regulations and guidance, as well as identify any updates needed 14

Initial Scoping Study

An initial, rough scoping study was presented in Appendix A of version 1.1 the ATF Project Plan 15

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Regulatory Framework Applicability Assessment

NRC staff has more thoroughly assessed its regulatory framework and expand Tables A.1, A.2, and A.4 in version 1.1 of the ATF Project Plan

This applicability analysis assesses the NRCs regulatory framework to specifically:

identify regulations and guidance that are impacted,

whether pertinent regulations and guidance do not speak to phenomena unique to high burnup, increased enrichment, or near-term ATF concepts

how those could be addressed 17

Example 1 18

Applicability: identified as fully applicable or not fully applicable Reason(s) stated for why the regulation or guidance is not fully applicable If closure is necessary and has been identified, it is listed here 19

Example 2 20

Green text indicates that the NRC may have an action to facilitate closure

Next Steps

Update the Regulatory Framework Applicability Assessment table as necessary

Pursue closures identified in the table 21

Research Information Letter on Fuel Fragmentation, Relocation, and Dispersal James Corson, Ph.D.

Reactor Systems Engineer Office of Nuclear Regulatory Research 22

Experiments have shown that fuel can fragment during Loss of Coolant Accident Current rod average burnup limit = 62 GWd/MTU 23

NRC Has Studied FFRD and Published Findings

RIL 2008-01, Technical Basis for Revision of Embrittlement Criteria in 10 CFR 50.46

NUREG-2121, Fuel Fragmentation, Relocation, and Dispersal During the Loss-of-Coolant Accident

SECY-15-0148, Evaluation of Fuel Fragmentation, Relocation and Dispersal under Loss-of-Coolant Accident (LOCA) Conditions Relative to the Draft Final Rule on Emergency Core Cooling System Performance during a LOCA (50.46c)

RIL 2021-13, Interpretation of Research on Fuel Fragmentation, Relocation, and Dispersal at High Burnup 24

RES Staff Has Communicated Recent FFRD Findings in RIL 2021-13

Research Information Letters summarize research findings and discuss how information may be used in regulatory decisions

- RIL 2021-13 is addressed to technical staff in NRR

- RILs are not guidance

Goal of RIL is to synthesize recent FFRD research 25

Data Sources for RIL 2021-13 2000 2020 2010 SCIP-III, Hot-cell NRC

@Studsvik, Hot-cell

ORNL, Hot-cell S

E C

Y

Halden, In-Pile 26

Most tests reported in RIL 2021-13 were performed in hot cells 30-50 cm refabricated fueled segment from commercially irradiated rod Pressure line establishes segment pressure 4 heating elements in furnace 27

RIL 2021-13 Addresses Five Elements of NRCs Interpretation of FFRD Research

1. Fine fragmentation burnup threshold

2. Strain threshold for fragmentation

3. Dispersible mass fraction

4. Transient fission gas release

5. Fuel packing fraction 28

Element 1: Empirical threshold at which fuel pellets become susceptible to fine fragmentation Research supports a pellet-average burnup conservative limit of 55 GWd/MTU as the onset of fine fuel fragmentation Segment from NRCs ANL LOCA program at 55 GWd/MTU before and after testing FFRD 29

Element 2: A local cladding strain threshold below which relocation is limited Research suggests fuel relocation is limited in regions of the fuel rod experiencing less than 3% cladding strain.

NRC test #

Strain threshold, top (%)

Strain threshold, bottom (%)

189 6.0 3.0 191 6.0 4.0 192 5.0 4.0 193 1.0 4.0 196 3.0 5.0 198 4.5 9.0 FFRD 30

What do dispersal measurements look like?

Element 3: A conservative value for the mass of dispersible fuel as a function of burnup Dispersal during the test 31

What do dispersal measurements look like?

Element 3: A conservative value for the mass of dispersible fuel as a function of burnup Dispersal during shaking 32 Video

Element 3: A conservative value for the mass of dispersible fuel as a function of burnup FFRD 33

Recommend a conservative model to predict the mass of fuel dispersal to be all fuel above the burnup threshold of 55 GWd/MTU in the length of the rod with greater than 3%

cladding strain to disperse.

Difference between dispersal predicted by the model and all mobile fuel observed in the experiment SCIP test Mass (g)

Prediction/Measured OL1L04-LOCA-2 125 250%

N05-LOCA

-19 76%

VUR1-LOCA-1 15 109%

WZR0067-LOCA

-16 83%

VUL2-LOCA1

-7 94%

VUL2-LOCA3 8

105%

VUL2-LOCA4 5

102%

ALL collected fuel Element 3: A conservative value for the mass of dispersible fuel as a function of burnup FFRD 34

Element 4: Provide evidence of significant tFGR that may impact ballooning and burst behavior of high burnup fuel rods Data shows increasing transient fission gas release with burnup. However, many other factors besides burnup impact tFGR (e.g., fuel temperature, stresses in fuel).

Licensees will need to address tFGR in their LOCA evaluation models. Some models exist for tFGR, but more validation of those models is needed.

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Element 5: Establish a value for the packing fraction of relocated but non-dispersed fuel in the balloon region It is reasonable to use packing fraction values between 70 to 85 percent for fuel susceptible to fine fragmentation. (Fuel at lower burnup would likely have a lower packing fraction).

To determine the impact on ballooning and burst, it is important to examine a range of packing fractions to account for these effects.

FFRD 36

The RIL helps identify which rods are susceptible to FFRD Fine fragmentation requires ~55 GWd/MTU Relocation requires balloning Dispersal requires fine fragmentation, relocation and burst Overlap influenced by:

ECCS response

Plant design

Loading pattern

Fuel and cladding design

Transient FGR This information is prototypical of PWR. BWRs will have few if any rods susceptible to dispersal due to different operating practices, system pressure, etc.

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There are limitations to the conclusions of the RIL

Limits are not applicable to doped fuel or coated cladding.

Limits are simplistic, derived as a function of burnup only

Limits anticipate accurate prediction of cladding strain along the axial length of a fuel rod

Burst opening size is presumed to be stochastic and therefore limits assume large opening size 38

NRC continues to participate in programs related to FFRD

SCIP-IV (2019-2024) includes tests near burnup threshold identified in the RIL and tests on doped fuel

- NRC is currently reviewing Studsviks proposals for next phase of SCIP

Idaho National Laboratory is working on a LOCA test plan for the TREAT reactor

- NRC has provided feedback through EPRIs Collaborative Research on Advanced Fuel Technologies program 39

RIL 2021-13 Provides a Snapshot in Time of Our Understanding of FFRD and tFGR

NRC continues to participate in experimental programs that may provide new information

NRC encourages industry to engage with us to understand the impact of FFRD on licensing

NRC welcomes questions and challenges from industry regarding our current understanding of FFRD outlined in the RIL 40

Questions?

41

Industry Presentation:

Update on FFRD and Licensing Implications

Discussion Period

Break

High Burnup and Increased Enrichment Spent Fuel Transportation and Dry Storage Research and Licensing Andrew Barto Division of Fuel Management Office of Nuclear Material Safety and Safeguards 45

Overview

Phase 1, 2, and 3 ATF/HALEU Research

Other DFM-Sponsored Research related to ATF/HALEU

ATF/HALEU Licensing Activity 46

ATF/HALEU Phase 1

ORNL/TM-2020/1725: Assessment of Existing Transportation Packages for Use With HALEU (ML21040A518)

ORNL/TM-2020/1833: Isotopic and Fuel Lattice Parameter Trends in Extended Enrichment and Higher Burnup LWR Fuel, Vol. I: PWR Fuel (ML21088A336)

ORNL/TM-2020/1835: Isotopic and Fuel Lattice Parameter Trends in Extended Enrichment and Higher Burnup LWR Fuel, Vol. II: BWR Fuel (ML21088A354)

ORNL/TM-2021/1961: Extended Enrichment Accident-Tolerant LWR Fuel Isotopic and Lattice Parameter Trends (ML21088A254)

ATF/HALEU Phase 2 ORNL/TM-2021/2330: Impacts of LEU+ and ATF on Fresh Fuel Storage Criticality Safety (ML22098A137)

Impacts of LEU+ and HBU Fuel on Decay Heat and Radiation Source Term Light Water Reactor LEU+ Lattice Optimization Assessment of Core Physics Characteristics of Extended Enrichment and Higher Burnup LWR Fuels using the Polaris/PARCS Two-Step Approach Vol. 1: PWR Fuel Assessment of Core Physics Characteristics of Extended Enrichment and Higher Burnup LWR Fuels using the Polaris/PARCS Two-Step Approach Vol. 2: BWR Fuel Transition Core Modeling for Extended Enrichment, Accident Tolerant Fuels in LWR using Polaris/PARCS SCALE 6.2.4 Validation:

Criticality Safety Radiation Source Term Spent Fuel Applications

ATF/HALEU Phase 3

Nuclear Data Updates for SCALE 7

Polaris+PARCS Micro Depletion Assessment

Detailed investigation of Decay Heat Validation at higher burnup for LEU+

LEU+ Impact for Burnup Credit

SCALE 6.3 Validation:

- Criticality Safety

- Radiation Shielding

- Spent Fuel Applications

- Reactor Physics

Additional DFM HALEU Research

Update NUREG/CR-7108 on burnup credit depletion code validation:

- Include bias estimates for new cross section data (ENDF/B-VII.1)

- include new radiochemical assay measurements (e.g., DOE sibling rod HBU RCA samples w/BU up to 66 GWd/MTU)

Update NUREG/CR-7109 on burnup credit

- Include fission product bias estimates for new cross section data (ENDF/B-VII.1)

- Evaluate applicability of French HTC critical experiments at higher burnups

Develop NUREG/CR with recommendations for sensitivity uncertainty (S/U) methods to select critical experiments for criticality code validation

ATF/HALEU Transportation Licensing

BU-D: Fresh UO2 powder package

- DOT Revalidation request to increase enrichment from 5% to 10%

Traveller: Fresh PWR fuel assembly package

- Loose rods enriched up to 7%

- Fuel assemblies enriched up to 6%

Versa-Pac: Various uranium contents

- Increased mass for uranium enriched up to 20%

ATF/HALEU Transportation Licensing, continued

DN-30X: UF6 package

- Modification of existing DN-30 package to transport 30B-X UF6 cylinders

- 30B-10 for up to 10% enriched UF6

- 30B-20 for up to 20% enriched UF6

- Internal criticality control system

- Still under review - Certificate of Compliance anticipated by end of calendar year 2022.

Key Messages

We are proactively working on our regulatory readiness for the front and back end of the nuclear fuel cycle to enable the safe use of new fuels to support industrys timelines for deployment of ATF/HALEU LWR fuel

We are actively certifying transportation packages for new fuels.

Performing a Transportation Evaluation of ATF with Increased Enrichment and Higher Burnup Donald Palmrose, PhD Senior Reactor Engineer Office of Nuclear Material Safety and Safeguards August 24, 2022

Outline 10 CFR 51.52 and Table S-4 Past NRC Transportation Analyses and Assessments Need for a New Evaluation Leveraging Prior Transportation Reports and New ATF Studies Methodology Summary of Efforts to Date

10 CFR 51.52 and Table S-4

10 CFR 51.52, Environmental effects of transportation of fuel and waste -

Table S-4 Environmental Reports for CPs, ESPs, or COLs of a light-water-cooled nuclear power reactor shall contain a statement concerning transportation of fuel and waste

The transportation of fuel and waste can be considered a connected action under NEPA

Two options under § 51.52 Meet the conditions of § 51.52(a) for use of Table S-4 (§ 51.52(c)), or Provide a full description and detailed analysis of the environmental effects

NUREG-1437 Revision 1 (2013) extended the § 51.52(a)(2) and (3) conditions to:

Not to exceed 5 percent by weight for uranium enrichment Not to exceed 62 GWd/MTU for the average level of burnup

WASH-1238 (1972) and Supplement 1 to WASH-1238 (NUREG-75/038 in 1975) for the basis of Table S-4

NUREG-0170 (1977) Final Environmental Statement on the Transportation of Radioactive Material by Air and Other Modes

NUREG/CR-4829 (1987) Shipping Container Response to Severe Highway and Railway Accident Conditions also known as the Modal Study

NUREG-1437 (1996) Generic Environmental Impact Statement for License Renewal of Nuclear Plants with Section 6.3

NUREG-1437 Addendum 1 (1999) in part for Section 6.3 -

Transportation

NUREG/CR-6672 (2000) Reexamination of Spent Fuel Shipment Risk Estimates

NUREG/CR-6703 (2001) on Environmental Effects of Extending Fuel Burnup

NUREG-1437, Revision 1 (2013) with Section 4.12.1.1

NUREG-2125 (2014) Spent Fuel Transportation Risk Assessment

Need for a New Evaluation

As shown by past transportation analyses, the NRC has made generic assessments to extend conditions in § 51.52(a) and allow use of Table S-4

Industry plans to deploy ATF concepts with increases in enrichment above 5 weight-percent U-235 and burnup higher than 62 GWd/MTU (i.e., outside of current conditions)

There are two options on the NEPA evaluation of ATF deployment

Assess transportation effects at the time of an ATF LAR submittal with the potential of a site-specific transportation evaluation for every NPP site

Perform a transportation study of ATF deployment now to assess the potential application of Table S-4 insupport of the environmental review of an ATF LAR submittal