The pursuit of practical nuclear fusion power promises a revolution in energy production that can offer a limitless and on-demand energy source. The scarcity of tritium is one of the technological hurdles as it is a heavy hydrogen isotope essential for current fusion reactor designs.
However, a potential solution has recently been proposed by a physicist at Los Alamos National Laboratory (LANL) that involves converting nuclear waste from fission reactors into fusion fuel.
Currently, fusion reactors mainly rely on deuterium and tritium. Despite being relatively rare, deuterium is still enough in the Earth’s oceans to meet future needs.
Meanwhile, tritium is exceedingly rare, with global reserves estimated at a mere 55 pounds. The current market price reflects this scarcity, with tritium retailing for approximately $15 million per pound. It can be seen that this limited supply poses a significant challenge, as it’s estimated that a substantial amount of tritium would be needed to power even a small economy.
To address this challenge, Terence Tarnowsky of LANL proposes using the thousands of tons of nuclear waste generated by fission reactors as a source of tritium. Although this concept is not entirely new, it has been revisited with the potential of modern technology to enhance its efficiency and practicality.
The process involves encasing nuclear waste, including uranium, plutonium, and other radioactive elements, in molten lithium salt. This mixture is then bombarded with high-energy particles from a superconducting linear accelerator.
This initiates spallation, a nuclear process that splits atoms and releases a shower of neutrons. These neutrons subsequently interact with the lithium, ultimately producing tritium.
A key advantage of this process is its subcritical nature. The nuclear reaction is sustained only while the accelerator is active, ensuring inherent safety. Tarnowsky’s simulations suggest high efficiency, estimating that a one-gigawatt reactor employing this method could produce enough tritium annually to power 800,000 homes. This is a tenfold increase compared to the amount a fusion reactor of the same thermal power could generate.
By transforming a problematic waste product into a valuable resource, this approach offers a dual benefit. It not only addresses the critical tritium shortage hindering fusion power development, but also provides a potential solution for managing existing nuclear waste. Therefore, it may be one step closer to realizing the promise of clean, abundant energy for all.
