How nuclear batteries can speed up the energy fusion race

Fusion power has always been a controversial subject. The fusion part is actually simple – an undergrad recently built a simple fusion device in his room, for example – but generating electricity in response is not.

“Fusion reactors that make energy — and there are a lot of them, already exist,” Daniel Velásquez, who leads materials science at Avalanche Energy, told TechCrunch. “A fusion reactor that makes electricity better.” That’s where the fledgling industry still stands.

Fusion reactions release large amounts of energy by fusing two lighter atoms into one heavier one. But harnessing that power has proven challenging. The most common method is to heat the water and circulate it with a steam turbine, but that method is very inefficient, using about 60% of the energy.

Avalanche Energy thinks it can capture more of that energy by developing new materials known as radiovoltaics. Radiovoltaics are similar to photovoltaics – traditional solar panels – in that they use semiconductors to convert radiation into electricity. They have been around for a long time, but they are not very successful. Existing radiovoltaics are easily damaged by the very radiation they use and do not produce as much electricity.

Today, Avalanche was awarded a $5.2 million contract from DARPA to develop new photovoltaics, the company exclusively told TechCrunch.

The Pentagon’s research agency is interested in using materials in a new class of nuclear batteries, which use the radioactive decay of elements such as polonium to generate electricity. Such devices could help power spacecraft and satellites for several years. They can also be used in ground military programs that take a lot of energy for days at a time – “especially in autonomous programs or missions where logistics are not allowed,” Velásquez said.

That’s not exactly what Avalanche is building for as a company, but the DARPA award aligns with its ambitions.

In both cases, the fusion of nuclear batteries produces alpha particles, a type of radiation that is so powerful that it can damage all types of equipment, including the walls of a nuclear reactor. Second, Avalanche is developing a small-scale fusion reactor that could replace diesel generators at remote military bases.

If a company can develop a new radiovoltaic for a nuclear battery, it can use that information in a new reactor part. Such sheathing can help capture alpha particles, protecting the reactor while increasing the amount of electricity produced. The Avalanche also won a $1.25 million award for the US Air Force’s AFWERX research lab to use computer advances to accelerate object detection.

Fusion reactors are all racing to achieve a milestone known as breakeven, in the scientific world known as iQ>1, where iQ is the ratio of the energy produced by the fusion reaction to the energy required to continue. Putting those alpha particles to work to generate electricity could make commercial fusion energy readily available.

Avalanche is not the only company with a reactor design that will produce alpha particles. If successful, the company could find itself supplying other fusion companies with the technology, an emerging trend in the industry.