Inertial fusion is a pulsed process. This means it works like an internal combustion engine where our target contains the fuel, and the fusion driver is the spark plug. Each target, when hit by the driver, releases a large amount of energy. Our pulsed approach gives great design flexibility, trading off energy per shot and frequency. Our aim is to to develop the lowest risk and simplest power plant design possible. By increasing the energy per shot, and reducing the frequency, we can achieve a smaller overall plant size with a much lower risk.
Our approach uses existing technology
In the power plant design, the target will be dropped into the reaction chamber. The driver will then be activated and, upon hitting the target, energy will be focused - achieving fusion and releasing energy*. That energy is absorbed by the liquid metal flowing inside the vessel, heating it up. Finally, a heat exchanger safely transfers the heat of the liquid metal to another coolant that turns a turbine and produces electricity.
The First Light amplifier technology operates within a plant design where the fusion reaction is surrounded by a liquid metal curtain. That serves to capture the energy as heat which is then passed onto the conventional island through a heat exchanger. The concept is very similar to a conventional fast breeder reactor of which a number have been built (using liquid sodium as the working fluid).
By having a high Lithium fraction in the liquid metal curtain, the neutrons that hit it convert Li7 into Li6 with Tritium as by-product which can be used to close the fuel cycle. Having the full reaction enclosed by this liquid metal greatly increases the ability to produce Tritium.
We intend to work with partners most likely from the nuclear sector to develop those systems.
This plant design avoids the three biggest engineering challenges of fusion: preventing neutron damage, producing the fuel that it consumes (self-sufficiency), and managing extreme heat flux.
Thick liquid metal is used to block the neutrons as it is a very good shielding material, and it also extracts the heat by blocking the neutrons. This means that neutrons do not reach the vessel, so it will last for the lifetime of the plant.
In addition, the liquid metal is a breeding material that generates the fuel that our targets need in order for the fusion event to take place. As a result, no external supply of fuel will be needed in operation.
There is a large amount of existing engineering that can be reused to realise this plant design. Fast breeder reactors, a type of nuclear plant, use liquid metal as the coolant, typically sodium or sodium-potassium mixture. The engineering from these plants can be ported over to fusion. After the heat exchanger, the plant is identical to many other already working facilities. Most of the cost is low risk engineering.