Next-generation nuclear waste management: Geological repositories, emerging technologies, and global pathways

• Global nuclear waste exceeds 370,000 tons, projected to 400,000 tons by 2035 • Geological repositories analyzed: Onkalo (5,500 t) and WIPP (175,000 m³) • Emerging solutions: borehole disposal, transmutation, vitrification, Synroc • Risk models show <1% failure probability with IAEA and EPA compliance • Future innovations: graphene barriers, robotics, and AI-enabled monitoring • Integrated strategies support safe, adaptive, and net-zero aligned disposal The safe management of nuclear waste remains a central challenge for sustaining nuclear energy in the low-carbon transition, with a global inventory exceeding 370,000 metric tons and increasing by 10,000 tons annually. This review synthesizes advances in waste classification, repository design, emerging disposal technologies, environmental safeguards, and future directions. Nuclear waste is categorized into low-level (90% volume, <1% radioactivity), intermediate-level (7% volume, 4% radioactivity), and high-level wastes (2% volume, >95% radioactivity), alongside highly radioactive spent fuel (10¹⁰–10¹⁴ Bq/g). Current strategies emphasize geological repositories such as Onkalo (5,500 tons, 400–500 m depth) and WIPP (175,000 m³, 655 m depth), which employ multi-barrier systems but face challenges including high heat output (10–20 kW/ton) and material durability (10⁻⁵/year corrosion). Complementary approaches deep borehole disposal (3–5 km depth, 1–2 billion USD), partitioning and transmutation (>90% toxicity reduction), and immobilization via vitrification (leach rate ∼10⁻⁶ g/m²/day) are advancing the safety and sustainability of disposal. Risk assessments, supported by IAEA safety standards, demonstrate <1% failure probability over 10,000 years, while future innovations in advanced materials (e.g., graphene by 2030), robotics (RADBOT deployment by 2028), and AI-driven monitoring (20% predictive improvement by 2035) could reduce long-term risks by 30% by 2040. The findings underscore the critical role of geological repositories, enhanced by emerging technologies, and highlight the need for interdisciplinary collaboration to ensure secure, sustainable nuclear waste disposal aligned with global net-zero goals by 2050. By strengthening the scientific basis for next-generation disposal technologies, this study contributes on responsible management of hazardous materials