Performance Assessment & Safety Case for US LLW Management Facilities

1. LLW Performance Assessment & Safety Casefor Licensing US RW Management Facilities Rateb (Boby) Abu Eid, Ph. D. (boby.abu-eid@nrc.gov) Senior Advisor Division of Decommissioning, Uranium Recovery, and Waste Management Office of Nuclear Materials Safety and Safegurds U.S. Nuclear Regulatory Commission, Washington D.C., 20555, USA IAEA Technical Meeting CRAFT Part II September 30, 2015

2. Radioactive Waste Categories in the US

3. 10 CFR Part 61 Subpart C Performance Objectives • §61.41 Protection of the general population from release of radioactivity: (annual doses not to exceed 25 millirems to the whole body, 75 millirems to the thyroid, and 25 millirems to any other organ and maintain effluent releases ALARA). • §61.42 Protection of individuals from inadvertent intrusion: (Design, operation, and closure of the disposal facility must ensure protection of individuals from inadvertent intrusion). • §61.43 Protection of individuals during operations: (Operation must be conducted in compliance with §Part 20 and effluent releases shall be governed by§61.41). • §61.44 Stability of disposal site after closure: (the LLW facility must be sited, designed, used, operated, and closed to achieve long-term stability) so that following closure, only surveillance, monitoring, or minor custodial care are required

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5. LLW Timeframe and Performance Period NUREG-1573

7. The Concept of IAEA Safety Case (SC) • NEA SC Definition: “The synthesis of evidence, analyses and arguments that quantify and substantiate a claim that the repository (i.e.; disposal facility) will be safe after closure and beyond the time when active control of the facility can be relied on”. • IAEA SC Definition: A collection of arguments and evidence to demonstrate the safety of a facility and to assist in key decision-making. • The SC has to be developed in the early phases of the development of a project. It constitutes the basis for internal decisions by the operator/licensee (e.g.; site selection, safety evaluation, design conceptualization and optimization, etc.…) as well as to establish a dialogue with the regulator and stakeholders.

8. A. Safety Case Context B. Safety Strategy C. System Description StakeholderandRegulatoryInvolvement Application of ManagementSystem D. Safety Assessment F. Management of Uncertainty E. IterationandDesignOptimization G. Limits, Controls and Conditions H. Integration of Safety Arguments IAEA Safety Case Components

9. Safety Case & Decision Steps

10. NRC’s Approach to Risk-Informed, Performance Based Assessments for LLW & Decommissioning • Facilitate application of risk-informed and performance-based implementation of the NRC’s rulemaking, licensing, and oversight functions for LLW, including waste incidental to reprocessing, and decommissioning on a case-by-case basis. • Staff engagement in development, maintenance, and evaluation of probabilistic environmental models and codes for risk/dose analysis. • Use of probabilistic distributions as inputs to uncertain physical and behavior parameters, particularly in independent staff reviews. • In review of DOE waste incidental to processing determination, the staff utilizes risk-informed performance-based approaches including uncertainty/sensitivity analyses and alternate conceptual models. The risk insights gained during the review are utilized to establish the monitoring areas for a site • Use of probabilistic tools with sensitivity/uncertainty analysis to demonstrate compliance with the dose criteria

11. NRC’s Integrated Risk Management Objective Manage the risks from the use of byproduct, source, and special nuclear materials through appropriate performance-based regulatory controls and oversight Goal Provide risk-informed and performance-based defense-in-depth protection to: • Ensure appropriate barriers, controls, and personnel to prevent, contain, and mitigate exposure to radioactive material according to the hazard present, the relevant scenarios, and the associated uncertainties • Ensure that the risk resulting from the failure of some or all of the established barriers and controls, including human errors, are maintained acceptably low

12. Decision-Making Process Use a disciplined process to achieve the risk management goal Identify issues Identify Options Analyze Implement Decision Deliberate Monitor Deliberation Process

13. A LLW Disposal Design Concept NUREG-1573

14. Intruder Scenario Used for LLW PA Intruder Construction Inhalation of dust Direct radiation from dust cloud Cap Direct radiation from waste volume Waste

15. Intruder Agriculture Scenario for LLW PA NOTE: Includes modified food pathways to account for non-equilibrium deposition and subsequent root uptake: (i) plant-human; (ii) plant-animal-human; and (iii) plant-animal product-human Direct radiation from dust cloud Plant-to-animal product-to-human Plant-to-animal-to-human Depositionofdust Inhalation of dust Cap Soil to root transfer Direct radiation from waste volume Waste

16. Scenarios and Pathways Used for 10 CFR Part 61

17. NRC Waste Classification Table for Long-Lived Radionuclides Note: If concentration is < .1 Table value, waste is Class A. If concentration is > 0.1 but less than or equal to Table value, waste is Class C. If concentration is > Table value, waste is greater than class C.

18. NRC Waste Classification Table for Short-Lived Radionuclides Note: If concentration does not exceed column 1, waste is Class A. If concentration is > col. 1 and < col. 2, waste is Class B. If concentration is > col. 2 and < col. 3, waste is Class C. If > col. 3, waste is not acceptable for near-surface disposal

19. Comparison of NRC’s vs. IAEA RW Management Systems

20. LLW Classification Scheme & Disposal Sites • Principal basis in deriving waste classification limits was protection of the inadvertent intruder. • Secondary bases: • Long-term environmental concerns • Disposal facility stability • Institutional control costs • Financial impacts to small entities

21. Steps in NRC NUREG-1573 PA Methodology Reviews • Data evaluation • Conceptual models & scenarios • Parameter distributions • Mathematical models & codes • Consequence modeling & analysis • Sensitivity & uncertainty analysis • Initial evaluation of site performance • R-evaluation of data & assumptions • Assessment of compliance with • 10 CFR 61.41 & §61.42

22. Infiltration • UZ Flow • Eng. Barrier Performance • Container Breach • Waste Form Leach • Source term releases • VZ Transport • SZ flow and Transport • Surface water transport • Exposure scenarios & • pathways transport • Dose to human • NUREG-1573 Specific Processes Considered in NRC LLW PA

23. Example of a Performance Assessment Process

24. Schematic Illustration of Examples of Exposure Scenarios for DU Disposal

25. GoldSim DU Disposal Model

26. PA Approach: Representation of LLW System, Conceptual & Mathematical Models, and Estimated Performance

27. An Approach to Uncertainty Analysis

28. Dose - Time PA Outputs D O S E TIME

29. Common Models/Codes Used In Reviews of Dose Assessments • Decommissioning & EIS Analysis • RESRAD Codes (RESRAD Onsite 6.5; RESRAD-Build 3.5; and RESRAD-Offsite (Beta Version 3.0) • D&D Screening Code (2.1 Updated Version) • FRAMES & GENII • LLW & WIR • GoldSim • RESRAD 6.5 and RESRAD-OFFSITE • FRAMES and GENII • AMBER • UR • MILDOS-AREA

30. PA & Integrated Risk Regulatory Issues • How to treat future site conditions, processes, events, and climate change • Exposure scenarios and compliance dose criteria • Performance of engineered barriers • Timeframe for LLW performance assessment • Treatment of sensitivity and uncertainty • Role of performance assessment during operational and post- closure periods • Overall integration of site characterization, facility design performance assessment, and safety analysis • Bench-marking and QA/QC issues • Stakeholders inputs

31. Trojan Reactor Vessel An Example of Predisposal Management • Disposal of the PGE Trojan Reactor Vessel Package at the US Ecology Low-Level Waste Disposal Facility near Richland, WA in August 1999 was the culmination of a unique combination of circumstances as well as hard work and dedication of hundreds of people in federal and state government and the private sector. • The ability to classify the waste as Class C based on concentration averaging guidance, the availability of a in-compact disposal facility, and the accessibility to water conveyance resulted in a unique first of a kind disposal opportunity. • Meticulous planning and implementation by licensees and their contractors coupled with scrupulous oversight by state and federal regulators led to successful, uneventful project completion. • Predisposal Planning & Management of Radioactive Waste is the Key.

33. Transporter, cradle, and RVP

35. Public Affairs Component • Media Management - National media attention while barging up river - Managed by USE media consultant - Local media afforded work observation opportunity • “Decontrolling” for the Show - Avoid bringing dignitaries into a controlled area - Eliminate need for visitor orientation • Public Event on August 19, 1999 featuring Congressman Hastings

36. Predisposal Management Cost/Time/Technology • The first large commercial reactor vessel to be segmented for disposal was in 2008. • In 2015 Energy Solutions completed the first segmentation of this type using an oxy-propane torch connected to a robotic fixture outside the vessel, a large-scale application of thermal cutting technology. • The vessel came from the Zion nuclear power plant. • The new procedure took only one month, significantly shorter than the seven months it took in the 2008 segmentation process using abrasive water jet technology.

37. Rulemaking for LLW Site Specific Analysis – Update of 10 CFR Part 61

38. Staff New Guidance on Technical Analysis for Part 61 Site-Specific Analysis

39. Technical Assessment

40. Stakeholders Involvement Public Meetings and Workshop

41. The EIS Process & Public Involvement • An environmental impact statement (EIS), under United States environmental law, is a document required by the National Environmental Policy Act (NEPA) for certain actions "significantly affecting the quality of the human environment". • The purpose of the NEPA is to promote informed decision-making by federal agencies by making "detailed information concerning significant environmental impacts" available to both agency leaders and the public. It involves a great deal of stakeholders participation in the decision-making. • An EIS is a tool for decision making. It describes the positive and negative environmental effects of a proposed action, and it usually also lists one or more alternative actions that may be chosen instead of the action described in the EIS. • The EIS document is considered a segment of the safety case.

42. What about risk management? Safety Case • Politics • Public Expectations • Competing Standards • Federal Regulations • Implementation Process • State Regulations Regulatory Flexibility

43. Disclaimer This presentation was prepared as an account of work sponsored by an agency of the U.S. Government. Neither the U.S. Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third party’s use, or the results of such use, of any information, apparatus, product, or process disclosed in this report, or represents that its use by such third party would not infringe privately owned rights. The views expressed in this presentation are not necessarily those of the U.S. Nuclear Regulatory Commission.