A New Paradigm for High-Level Radioactive Waste Disposal: Intrinsic Radionuclide Properties and Comparative Hazard

This paper develops a hazard- and pathway-based framework for high-level radioactive waste (HLW) disposal grounded in intrinsic radionuclide decay characteristics, geochemical behavior, and comparative hazard. We examine the physical and geochemical properties of key radionuclides and quantify lifetime cancer risk from chronic ingestion on a per-unit-mass basis using established regulatory models. Long-lived radionuclides are weakly radioactive and emit little or no penetrating gamma radiation; their hazards are therefore dominated by internal exposure pathways, analogous to those of chemical carcinogens commonly disposed of in the shallow subsurface. Actinides exhibit cancer risks comparable to dioxin but are strongly immobilized under reducing deep-geological conditions, while mobile long-lived radionuclides are associated with lower carcinogenic risk than typical persistent chemical contaminants. These findings support a paradigm shift in disposal strategies: (a) from heavily engineered containment systems toward nature-based approaches for ensuring long-term post-closure safety that explicitly leverage intrinsic radionuclide properties, along with slow release from waste forms and diffusion-limited transport, assuming appropriate site selection and geological stability; and (b) toward consideration of lifecycle perspectives and trade-offs between future hypothetical risks and present-day actual environmental impacts, including material use and fuel-cycle emissions. We further highlight asymmetries between radioactive and chemical waste stewardship. Public institutions and regulatory authorities are already responsible for actively managing large inventories of persistent chemical carcinogens in the shallow subsurface indefinitely. Increased efforts are needed to integrate radiological and chemical hazards within a unified environmental risk framework to establish more coherent, lifecycle-aware waste management strategies across industries.