Advocates of nuclear fusion have long envisioned generating virtually boundless energy on Earth by replicating the sun’s power source.
Today, the primary obstacle is ensuring that fusion power plants produce a net energy gain. The second challenge lies in securing sufficient fuel for sustained operation.
Deuterium Abundance vs. Tritium Scarcity
Many fusion reactors are engineered to operate on a mixture of two hydrogen isotopes: deuterium and tritium. While deuterium, found abundantly in seawater, is readily available, tritium is incredibly rare and must be artificially produced.
Marathon Fusion’s Potential Solution
“Globally, there are only around 20 kilograms of tritium,” Kyle Schiller, CEO of Marathon Fusion, revealed to TechCrunch. A single commercial fusion power plant would require several kilograms just for startup, implying the world has enough tritium for a dozen plants at best.
However, his previously undisclosed startup believes it has a solution to this critical fuel shortage.
Current Tritium Sources and Future Dependence
Currently, the world’s tritium supply is a byproduct of a limited number of nuclear fission plants, the type of nuclear power harnessed for energy since the mid-20th century.
Assuming scientists can achieve viable fusion power on Earth, initial fusion plants will rely on this existing supply.
Future reactors will then depend on the first generation of fusion power plants, which will be designed to breed additional fuel.
The Tritium Breeding Process
“Deploying fusion devices is a doubling process,” explained Adam Rutkowski, Marathon’s CTO. “You need to breed enough tritium to sustain the reactor’s consumption while also producing excess tritium to start up the next reactor.”
This breeding occurs when neutrons released during fusion reactions collide with a lithium blanket. The impact generates helium and tritium, which are subsequently extracted from the reactor core for filtration.
A portion of the tritium is re-injected into the reactor, while the remaining portion is reserved as fuel for future reactors.
Scaling Up Filtration for Commercial Viability
Existing equipment for this filtration process is suitable for experimental purposes, but it lacks the throughput required for commercial-scale power plants due to their short operational durations.
To meet the demands of continuous operation, filtration systems will need “several orders of magnitude improvement,” according to Schiller.
Source: TechCrunch