Nuclear Waste Could Provide Fuel for Fusion Energy

The United States may be sitting on a hidden energy resource. Researchers at Los Alamos National Laboratory have unveiled simulations showing how radioactive nuclear waste could be repurposed to generate tritium, the rare hydrogen isotope that fuels nuclear fusion. The work, presented at the American Chemical Society Fall 2025 meeting, suggests that decades of stored waste might help unlock cleaner, virtually limitless energy.

Why Tritium Matters

Fusion energy relies on combining hydrogen isotopes, typically deuterium and tritium, to release enormous amounts of energy. While deuterium is abundant in seawater, tritium is scarce and expensive. Current global supplies, largely sourced from Canadian heavy-water reactors, hover at around 25 kilograms, worth about $33 million per kilogram.

“Right now, the value of commercial tritium is about $15 million per pound, and the U.S. doesn’t have any domestic capability to create it,” said Terence Tarnowsky, a physicist at LANL.

Without a reliable tritium pipeline, commercial fusion plants cannot scale. A single 1 gigawatt fusion reactor would require more than 55 kilograms per year, far beyond current supply.

Recycling Waste Into Fuel

Tarnowsky’s proposal centers on accelerator-driven systems (ADS) that bombard spent nuclear fuel with particles. This process triggers reactions that generate neutrons, which can then be harvested to produce tritium through a series of nuclear transitions. Unlike a traditional chain reaction, the accelerator-driven model can be switched on and off, adding safety benefits.

Computer simulations suggest that a 1 gigawatt system could produce about 2 kilograms of tritium annually, rivaling the total yearly output of all Canadian reactors. Crucially, Tarnowsky estimates the design would generate more than 10 times the tritium of a fusion reactor at the same thermal power.

Molten Salt and Safety

One key design feature under consideration involves surrounding the waste in molten lithium salt. This coolant both stabilizes the reactor and complicates the diversion of materials for weapons production. The approach draws on established experiments in molten salt reactors but applies them in a new context for tritium generation.

• Destroys long-lived transuranic waste, reducing storage concerns
• Produces usable energy to offset operating costs
• Operates in a sub-critical configuration for greater safety
• Generates kilogram-scale tritium supplies to seed fusion plants

The Road Ahead

The project remains at the simulation stage. Tarnowsky is refining efficiency models and will next calculate projected costs. His ultimate goal is to give policymakers a roadmap for turning nuclear liabilities into strategic assets.

“Energy transitions are a costly business, and anytime you can make it easier, we should try,” Tarnowsky said.

If successful, the research could transform how the U.S. manages its nuclear waste while simultaneously advancing the long-sought promise of commercial fusion power.

Presented at the American Chemical Society Fall 2025 Meeting. Abstract: On-ramping the fusion economy with kilogram quantities of commercial tritium. LA-UR-24-33273.