This has been true for decades Nuclear fusion as a great hope: almost unlimited electricity, hardly any CO2, no long-lasting nuclear waste like in classic reactors. But despite all the enthusiasm for high-tech and super temperatures, one very simple, crucial question remains: Is there even enough fuel?

Without enough tritium, the best reactor technology is of no use. There are only around 20 kilograms of this radioactive hydrogen isotope in the civilian sector worldwide. And it won’t be more, but less – because tritium decays with a half-life of around twelve years. Anyone who seriously talks about the energy supply of the future cannot ignore this material.

That’s why a report from Great Britain is now attracting attention. The company First Light Fusion explains that its “FLARE” power plant concept can generate significantly more tritium than it consumes. The calculations were checked and confirmed by radiation physicists from TÜV Süd UK, among others, it is said. If this proves to be the case in practical operation, a central problem of nuclear fusion would be defused – namely the question of where the rare fuel should come from in sufficient quantities.

Why fuel decides everything

Almost all serious concepts for nuclear fusion rely on the so-called deuterium-tritium reaction. Deuterium is not a problem – it is in seawater and can be obtained relatively easily from a technical point of view. The bottleneck is the second element of the reaction: tritium.

It practically does not occur in nature. It is only produced in very small quantities, for example in special nuclear reactors. This is far from enough for a future fleet of fusion power plants. In addition, new plants initially need large quantities of this substance before they can even produce any themselves. Large fusion power plants would require more tritium to start than is currently available in the civilian sector worldwide.

First Light Fusion has provided detailed tritium generation calculations for its FLARE power plant design. At the same time, the radiation physics team at TÜV Süd UK analyzed the concept using its own calculation models and independent databases. According to the company, both evaluations come to the same result: a tritium breeding ratio of 1.8.

At what point does a reactor produce more tritium than it consumes?

The so-called Tritium Breeding Ratio (TBR) describes how much tritium a reactor produces in relation to its consumption. For classification:

• TBR 1.0: The reactor replaces exactly the amount consumed.
• TBR around 1.2: Is considered the minimum value to compensate for losses and to work permanently self-sufficiently.
• TBR 1.8: Stands for a significant excess of your own needs.

TÜV SÜD UK stated that the analyzes carried out confirmed the value of 1.8 for the intended reactor geometry. “Solving the tritium question is crucial for nuclear fusion to grow on a large scale,” says company boss Mark Thomas. The validated design shows that a power plant can not only supply itself, but also provide additional fuel.

At the heart of the FLARE concept is a large bath of liquid lithium that surrounds the fusion reaction. The high-energy neutrons created during the reaction hit the lithium and create new tritium there. The more of these neutrons are captured, the higher the yield.

This results in a remarkable projection for the planned power plant design with 333 megawatts of electrical output: According to the company, a single plant could generate around 25 kilograms of tritium per year net – more than is currently available in the civil sector worldwide.

Billion dollar opportunity – with unanswered questions

Tritium is considered extremely expensive due to its scarcity. Market prices between 30,000 and 120,000 US dollars per gram are often quoted. Under these conditions, a significant surplus would have significant economic weight. According to the company, income from sales could theoretically even cover the construction costs of a reactor.

However, this calculation is based on the current shortage situation. If supply increases significantly, the market price is likely to fall. In addition, these are currently validated design studies and not a commercially operated system. Practical continuous operation is still pending.