ML23244A198

NRC-Slides Aco Pub Mtg Sept 7 2023

ML23244A198
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Issue date:	09/07/2023
From:	Yawar Faraz NRC/NMSS/DFM/FFLB
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U.S. Nuclear Regulatory Commissions Public Meeting on its Licensing and Oversight Status of the American Centrifuge Operating, LLC (ACO) High Assay Low-Enriched Uranium (HALEU)

Program at the American Centrifuge Plant in Piketon, Ohio ACO is a subsidiary of the Centrus Energy Corp, Bethesda, MD September 7, 2023 Yawar Faraz, Sr. Project Manager, NRC Headquarters

Purpose of the meeting

• Overview of NRC's regulation, licensing and inspection of fuel cycle facilities

• NRC and the Department of Energy (DOE) roles and responsibilities at the Piketon site

• Licensing and oversight activities for the American Centrifuge Plant (ACP) and the high assay low enriched uranium (HALEU) demonstration program

• Potential hazards related to HALEU production

• NRC's environmental review 2

Overview of NRC's regulation, licensing and inspection of fuel cycle facilities 3

What does the NRC do?

• The NRC licenses and regulates the Nation's civilian use of radioactive materials to provide reasonable assurance of adequate protection of public health and safety, and to promote the common defense and security, and to protect the environment

• The NRC sets rules, licenses, inspects, enforces rules, and performs incident response for commercial uses of radioactive materials 4

Uranium Enrichment in the Fuel Cycle Enrichment generally takes in high purity natural uranium as UF6 (U-235 concentration of 0.71%) and produces enriched UF6 (U-235 concentration 3-8 %) and a tails stream (U-235 concentration ~ 0.25%)

There can be specialized enrichment processes that use different feed material (i.e., not UF6) and produce different concentration product or tails 5

NRC Fuel Cycle Facility Regulation NRC-Licensed Fuel Cycle Facilities 6

NRC Fuel Cycle Licensing

• To obtain an NRC license (or to amend, renew, or transfer an existing license), an entity or individual submits an application to the NRC

• NRC staff reviews the application to ensure that the applicants descriptions and commitments comply with NRC requirements and that the proposed activities will not adversely impact safety, security or the environment 7

NRC Fuel Cycle Licensing (cont'd)

NRC reviewers use a combination of documents to conduct their technical review, including the Code of Federal Regulations (CFR),

guidance documents, and industry standards NRC staff documents its safety and security reviews, including the bases for the findings, in a Safety Evaluation Report, and if needed, its environmental review in an Environmental Assessment or Environmental Impact Statement 8

NRC Fuel Cycle Inspection

• NRC inspectors from Region 2 in Atlanta, Georgia conduct facility inspections to confirm that the facility has been constructed and will be operated safely and securely per NRC requirements and as described in the license application

• Inspections can occur during construction, following construction but prior to starting operations, and during operations

• After a license for a new facility, or an amendment involving a major facility modification, is issued, and before special nuclear material or SNM is brought onsite, the NRC may conduct, per the license, inspections, also known as operational readiness reviews or ORRs

• If the ORRs confirm that the applicant or licensee is in conformance with the NRC's safety and security requirements, Region 2 will issue a letter allowing SNM to be brought onsite and operations to begin as described in the application 9

NRC Fuel Cycle Inspection (cont'd)

• The NRC also performs routine inspections in the following areas:

- Radiation protection

- Environmental protection

- Emergency preparedness

- Plant operations

- Criticality safety

- Fire protection

- Plant modifications

- Material control and accounting

- Physical security

- Information security 10

NRC-DOE Oversight of Activities at the Piketon Site 11

American Centrifuge Operating, LLC licenses

• ACO possesses two NRC licenses for the Piketon site

- Lead Cascade Facility or LCF (demonstration/research & development)

- American Centrifuge Plant or ACP (commercial) 12

Lead Cascade Facility (LCF)

American Centrifuge Plant (ACP)

• LCF

- 240 operating centrifuges

- licensed in 2004

- operated in recycle mode 2006 to 2016

- decommissioned in 2018

• ACP

- 11,500 operating centrifuges (at full capacity)

- licensed in 2007

- Never built 13

High-assay low-enriched uranium (HALEU) cascade

• HALEU Cascade

- 16 operating centrifuges (+2 spares)

- Authorized by the NRC in June 2021 as an amendment to the ACP license

- Partial authorization was confirmed in June 2023 after the NRC conducted its ORR inspections of the HALEU cascade

- The HALEU contract between DOE and ACO signed on November 30, 2022, calls for production of a minimum of 20 kg HALEU for phase 1 and 900 kg of HALUE per year for phases 2 and 3 14

Previously licensed commercial ACP vs HALEU cascade process summary

• The purpose of the commercial ACP was to enrich UF6 to reactor grade material up to 10% enrichment

• The purpose of the 16-centrifuge HALEU cascade is to enrich UF6 up to 20%

enrichment

• The ACP at full capacity would have over 700 times more centrifuges than the HALEU cascade while the LCF had 15 times more centrifuges than the HALEU cascade 15

Process Material Characteristics

• The HALEU cascade will process uranium as uranium hexafluoride (UF6)

• Throughout all processes the uranium will remain as UF6 whose physical form may be solid or gas (no liquid)

• UF6 is a solid at room temperature 16

Piketon site activities

• DOE owns all major facilities on the Piketon site

• ACO, a subsidiary of Centrus Energy Corp., leases the ACP from DOE

- NRC has the primary responsibility for regulating and overseeing activities at the ACP

- DOE-Nuclear Energy (NE) oversees certain specific activities as described in a memorandum of understanding (MOU) for the ACP that is currently being updated

• DOE-Environmental Management (EM) regulates and provides oversight for

- Gaseous Diffusion Plant (currently being decommissioned)

- Depleted uranium hexafluoride deconversion facility

• DOE-EM has an emergency response plan for the entire Piketon site, that also applies to the ACP; however, due to very low offsite impacts, the NRC does not require a separate emergency plan for the HALEU program at this time 17

DOE Reservation (fenced area)

Piketon, OH American Centrifuge Plant (formally DOE's GCEP) 18

GCEP Centrifuges ACOs American Centrifuge is based on the DOEs original centrifuges (pictured here),

19 which operated in the 1980s at the Piketon facility

ACOs HALEU cascade at the ACP 20

Mid-America DUF6 Deconversion Facility (DOE-EM) 21

Gas Centrifuge Enrichment Technology and HALEU Production Overview 22

Gas Centrifuge 23

Enrichment Cascade Setup

• One or more centrifuges (in parallel) form a stage

• Several stages (in series) form a cascade

• Each cascade can provide the needed enrichment level (product)

• Several cascades (in parallel) provide the needed product flow rate 24

Uranium Enrichment Cascade (UF6) 25

Seven Step HALEU Process

1) Receipt and Storage of UF6 Feed

2) Feed Operation

3) Enrichment Cascade

4) Tails Withdrawal

5) Tails Storage

6) Product Withdrawal

7) Product Storage 26

1. Receipt and Storage of UF6 Feed

• Feed cylinders (30B ~2.3 tons UF6) shipped to site via truck

• Feed cylinders weighed 27

2. Feed Operation

• Vacuum drawn on UF6 feed cylinder to sublime the UF6 (solid to gas)

• Gaseous UF6 piped to the HALEU cascade for enrichment 28

3. Enrichment Cascade

• All process pressures are sub-atmospheric

• Service module routes utilities and process gas (UF6) to centrifuges 29

Purge and Evacuation Vacuum Systems

• Purge and evacuation of centrifuges achieved via purge vacuum (PV) and evacuation vacuum (EV) systems

• Chemical (alumina) traps used prior to gaseous discharge to atmosphere

• Two continuously monitored gaseous discharge points per process building 30

Purge and Evacuation Systems (contd) 31

4. Depleted UF6 Withdrawal

• Empty cylinder placed in cold box

• Cylinder connected to process and chilled

• Gaseous UF6 desublimed (solidified) in tails cylinder 32

5. Depleted UF6 Storage

• Depleted UF6 cylinders at about 1% enrichment to be stored securely onsite for DOE 33

6. Product Withdrawal

• Gaseous UF6 desublimed (solidified) in product cylinder in cold box

• Off gases pass through cold traps to evacuation cold traps and chemical traps 34

7. Product Storage

• Product cylinders are weighed and will be stored securely onsite for DOE 35

Transportation

• Enriched UF6 is transported in protective overpacks on trucks in accordance with DOT requirements and the shippers approved security plan

• Initially, ACO has no plans to transport any HALEU from the Piketon site 36

Enriched UF6 Cylinder Overpack 37

Hazards 38

Integrated Safety Analysis In 10 CFR 70.60, ACO is required to conduct an ISA to:

(1) Identify all credible accident sequences with significant consequences to workers and the public based on a hazards analysis (2) Identify Items Relied On For Safety (IROFS) to prevent/mitigate accidents (3) Establish management measures to ensure IROFS are available and reliable 39

Potential for Criticality

• Credible criticality accidents can only occur in process areas that handle large amounts of enriched uranium in solid form

• A criticality accident cannot occur at the ACP without inadvertent introduction of moderator

• All credible criticality accident sequences are required to be identified and made highly unlikely by applying controls

• Double contingency applied to all criticality sequences 40

Potential for UF6 Releases

• UF6 release hazard is controlled by IROFS in process areas that handle UF6

• IROFS in place to ensure UF6 sources are isolated upon system breach

• IROFS in place to prevent fires and to ensure UF6 containment is maintained if a fire occurs in process, and during transport and storage of UF6 cylinders 41

Emergency Planning DOE has an Emergency Response Plan for the entire Piketon site, that also applies to the ACP ACO has shown that for the possession limits associated with producing 600 kg HALEU in the form of UF6, the maximum dose to a member of the public offsite from the worst-case accident would not exceed 1 rem effective dose equivalent (Environmental Protection Agencys protective action guide) or an intake of 2 milligrams of soluble uranium, which are the thresholds for requiring an Emergency Plan per 10 CFR 70.22(i)(1)(i) 42

NRC's Environmental Reviews 43

Environmental Review Process 44

References

• 10 CFR Part 70 Domestic Licensing of Special Nuclear Material (specifically 70.22(i)(1) for Emergency Plan, Subpart H for safety analysis

• NUREG-1520, Rev. 2 Standard Review Plan for Fuel Cycle Facilities License Applications for a Fuel Cycle Facility June 2015

• NRCs public website: https://www.nrc.gov/materials/fuel-cycle-fac/gas-centrifuge.html 45