1. IAEA Technical Meeting on Future Human Actions at Disposal Sites IAEA, Vienna, Austria September 24-28, 2012 Overview of NRC Approach to Human Intrusion at LLW Shallow Land Disposal Facilities Boby Abu-Eid, Ph.D. Division of Waste Management and Environmental Protection Office of Federal and State Materials and Environmental Management Programs U.S. Nuclear Regulatory Commission

2. 10 CFR Part 61 LLW Disposal Concept Near-surface (<30 m depth) land disposal with specific technical requirements, performance objectives, and procedural requirements Cornerstone of safe disposal is stability: Stable wastes, designStable wastes, design Reliance on natural system isolationReliance on natural system isolation Reduced exposure to intrudersReduced exposure to intruders Stability of waste form & packagingStability of waste form & packaging Graded stability requirements using waste classes A, B, and C 2

3. 10 CFR Part 61.7 LLW Disposal Concept for Intruder Protection (3) ……Protection of such intruders can involve two principal controls: (a) institutional control over the site after operations by the site owner to ensure that no such occupation or improper use of the site occurs; (b) or, designating which waste could present an unacceptable risk to an intruder, and disposing of this waste in a manner that provides some form of intruder barrier that is intended to prevent contact with the waste. This regulation incorporates both types of protective controls. 3

4. LLW Timeframe and Performance Period 4 NUREG-1573

5. Waste Classification Table 1 Long- Lived Radionuclide (§61.55) RadionuclideConcentration Ci/M 3 C-148 C-14 in activated metal80 Ni-59 in activated metal220 NB-94 in activated metal0.2 Tc-993 I-1290.08 Alpha-emitting transuranic nuclides (t 1/2 > 5yr), nCi/g100 Pu-241, nCi/g3,500 Cm-242, nCi/g (If Concentration 0.1 and <1.0 of column value, Class C. 20,000 5

6. 6 2

7. A LLW Disposal Design Concept 7 NUREG-1573

8. Intruder Scenarios for Part 61 LLW & for Incidental Waste 8

9. 9 Cap Waste Inhalation of dust Direct radiation from dust cloud Direct radiation from waste volume Intruder Construction

10. 10 CFR Part 61 LLW Disposal Concept 10

11. 11 Cap Waste Inhalation of dust Direct radiation from dust cloud Direct radiation from waste volume Deposition of dust Soil to root transfer Plant-to- animal-to- human Plant-to- animal product-to- human 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 Intruder Agriculture

12. 12 Schematic Illustration of Examples of Exposure Scenarios for DU Disposal

13. PA Approach: Representation of LLW System, Conceptual & Mathematical Models, and Estimated Performance 13

14. 14 An Approach to Uncertainty Analysis

15. Intruder & Human Activity Issues How to treat future site conditions, processes, events, & climate change Intruder exposure scenarios assumptions, probability, and safety case (SC) stylized specific scenarios and realistic exposure pathways Timeframe for LLW performance assessment, Intruder dose criteria, compliance period & SR-SSR-5 Para 2.15 dose band optimization Performance of covers, engineered barriers & as a safty function to protect intruder Treatment of sensitivity and uncertainty and integration of uncertainties for intruder analysis & human activities Role of monitoring & safety functions during operational and post- closure periods; Passive & active institutional controls issues Source term assumptions, waste stability, and waste classification Overall integration of safety functions based on site characterization, facility design, scenario assumptions, and safety analysis during facility life cycle and update of the safety case Bench-marking and QA/QC issues Stakeholders Inputs 15