ML21180A135

U.S. Perspective on Developing Safety Cases for Various Radioactive Waste Disposal Facilities

ML21180A135
Person / Time
Issue date:	06/24/2021
From:	Chris Mckenney NRC/NMSS/DDUWP/PAB
To:
Chris McKenney, 301-415-6663
References
Download: ML21180A135 (15)

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U.S. Perspective on Developing Safety Cases for Various Radioactive Waste Disposal Facilities NEA Expert Roundtable June 24, 2021 Chris McKenney Risk and Technical Analysis Branch Division of Decommissioning, Uranium Recovery, and Waste Programs Office of Nuclear Material Safety and Safeguards

Major Considerations of a Near-Surface Safety Case Waste Hazard Considerations Role of Engineering for Short-lived (half-life <~30 years)

Radionuclides Utilization of Features, Events and Processes (FEPs)

Lessons Learned from Early U.S. Experience Human Inadvertent Intrusion Community Outreach Regulatory Oversight Considerations 2

Current U.S. Commercial Low-Level Waste (LLW) Sites US Ecology

Hanford, Washington (1965)

EnergySolutions Clive, Utah (1990)

EnergySolutions Barnwell, South Carolina (1969)

Waste Control Specialists Andrews, Texas (2012)

All 4 sites regulated by Agreement States 3

Rough Comparison between IAEA and US NRC Waste Categories 4

International Atomic Energy Agency Waste Categories U.S. Waste Categories High-Level Waste High-Level Waste Intermediate-Level Waste Greater-than-Class C LLW Low-Level Waste (LLW)

Class A, Class B and C LLW Very Low-Level Waste Class A Very Short-Lived Waste Material held for decay storage Exempt Waste Liquids/Air: Effluent releases Solids: Case-by-case analysis

Waste Hazard Considerations Wide Variety of Inventory

• Large scope of nuclear activities

• Wide variety of waste treatment methods Waste Form

• Durability

• Impact on retention and release of radionuclides Waste Volume Mix of Radionuclides of Interest 5

Cell Operations at Waste Control Specialists, Andrews County, Texas 6

Role of Engineering to Contain Short-Lived Radionuclides Most facilities rely on a combination of features to contain short-lived radionuclides, including:

• Site Characteristics

• Waste Form

• Disposal Cell Design

• Engineered Covers Concentrations in waste may be controlled by operational considerations 7

FEPs in Near-Surface Disposal 8

FEP Analysis coupled with Barrier Analysis is important in near-surface disposal Supports conceptual model development Supported by early regulations (e.g., 10 CFR 61.12 requires specific technical information)

Hazard profile with time along with being in the biosphere leads to different primary FEPs (vs geologic disposal facilities)

Lessons Learned from Early Experience in the U.S.

for Near-Surface Performance Issues Hydrology Issues

• Water Retention in Disposal Cells ->

Bathtubbing

• Unidentified Fast Flow Groundwater Paths Waste Inventory Concerns

• Appropriate Concentration Limits

• Waste Forms

• Presence of Hazardous Material

• Presence and Treatment of Liquids See NUREG-1853, History and Framework of Commercial Low-Level Radioactive Waste Management in the United States, https://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1853/index.html 9

Human Intrusion Scenarios Near surface more accessible for potential intrusion Loss of knowledge of sites still an issue with near surface disposal Larger variety of methods of disturbance 10

Human Intrusion 11

Community Outreach and Involvement Most of the outreach managed by the licensee/developer/operator

• May establish citizen advisory panels

• Work with local organizations Regulators focus

• Explaining regulations and allowing public comment

• Identifying hearing opportunities

• Discussing the decision-making process

• Announcing review findings and decisions 12

Regulatory relationship between U.S. Federal and Agreement States

• Establishing generic regulations and guidance

• Providing technical assistance, if requested by the State requests

• Evaluate general approaches to new waste streams

• Evaluate State programs for consistency

• License material not part of State agreements NRC

• License and oversight of material within their State

• Assist in evaluating other State and national program for consistency State programs 13

Conclusions Safety cases for near-surface have same range of considerations as high-level waste

• Inventory

• Site Conditions

• Engineering

• Need for Community Outreach Differences include

• Additional Focus on Inadvertent Intrusion

• Lessons Learned from Previous Sites Operations 14

Contacts Chris McKenney, US NRC Christepher.McKenney@nrc.gov

+1-301-415-6663 Tim McCartin, US NRC Timothy.McCartin@nrc.gov

+1-301-415-7099 15