Lead Investigator: Craig H. Benson (Lead, University of Wisconsin-Madison)

Additional Investigators: Jiannan Chen (University of Central Florida), David Kosson (Vanderbilt University), Kevin G. Brown (Vanderbilt University)

Project Objectives:

In 2022-23, the CRESP Landfill Partnership undertook a complex-wide review with a broad range of DOE stakeholders to identify priorities for the next five years. These priorities fell into five thematic areas:

• Design & long-term performance of disposal facility final covers. Develop guidance for final cover design and performance assessment that reflects lessons learned from the last two decades of field and laboratory studies.
• Design to optimize waste acceptance criteria (WAC) and waste placement to maximize utilization of air space at disposal facilities. Examine strategies for waste placement and waste isolation in disposal facilities as well as innovative barrier solutions that provide greater control on release, allowing higher WACs.
• Significance of PFAS in disposal facilities. Understand the implications of PFAS in on-site disposal facilities, and whether disposal facility design and waste placement strategy need modification to address risks posed by PFAS.
• Optimizing design to manage mobile radionuclides (e.g., ⁹⁹Tc). Develop strategies to manage highly mobile radionuclides in on-site disposal facilities. These might include pre-treatment strategies, internal barriers, and liner modifications. Priority 4 ties closely with Priority 2.
• Adapting new technologies to facilitate design and performance assessment of on-site disposal facilities. Examine possible roles of using emerging technologies to facilitate design and performance assessment of on-site disposal facilities (e.g., AI calibrated based on monitoring network data).

Future LP activities will be formulated around these thematic areas.

Significance/Impact:
The research plans for the next three years will be tailored around each of the objectives identified in the site-wide review described earlier. A common theme in all plans will be outcomes that are directly applicable to activities at DOE facilities so that the findings have immediate significance and impact.

Public Benefit:
More effective and cost-efficient on-site disposal facilities will be developed based on cutting-edge research and lessons learned, providing significant public benefits. For example, CRESP demonstrated the service life of geomembranes in excess of 1000 yr. in LLW environments; this is critical information because the use of geomembranes is mandatory in some countries for facilities including hazardous waste landfills and liquid impoundments. CRESP also demonstrated field performance of engineering barriers for radon control showing sustained compliance with radon control requirements after decades of service. This work provides not only the foundation for more effective (reducing risks to the public) and cost-efficient (saving taxpayer money) but also builds confidence in the ability of landfills to reduce risks to the public over long periods of time.

References: (* indicates CRESP publication)

*Benson, C., Albright, W., Fratta, D., Tinjum, J., Kucukkirca, E., Lee, S., Scalia, J., Schlicht, P., and Wang, X. (2011), Engineered Covers for Waste Containment: Changes in Engineering Properties & Implications for Long-Term Performance Assessment, NUREG/CR-7028, Office of Research, U.S. Nuclear Regulatory Commission, Washington.  Appendix

*Williams, M., Fuhrmann, M., Stefani, N., Michaud, A., Likos, W., Benson, C., and Waugh, W. (2022), Evaluation of In-Service Radon Barriers over Uranium Mill Tailings Disposal Facilities, NUREG/CR-7288, Office of Research, US Nuclear Reg. Comm., Washington, DC.  Appx.