Denmark’s Seaborg Technologies, which is developing thorium-based Molten Salt Reactors (MSRs), has received funding from an investment coalition led by Danish innovation incubator PreSeed Ventures. This first round of pre-seed investment attracted “several millions” of Danish kroner.

Seaborg said investors included David Helgason, the founder of Silicon Valley-based game engine Unity.  The new funding will enable Seaborg’s team to increase its staff to 16 employees, making it the most significant reactor development start-up in Europe. The company will begin carrying out initial, small-scale experiments within the next few months. Seaborg previously received funding from the European Union and the Danish Innovation Fund and is seeking an additional €2m more from investors as soon as possible.

The company will use the funding to develop of its CUBE (Compact Used fuel BurnEr) reactor concept. The CUBE reactor would fit inside a 20-foot container, and could provide power for 200,000 homes, the company said.

Seaborg explained that conventional nuclear power reactors produce electricity from manufactured solid fuel pellets of low-enriched uranium, submerged in water which provides both cooling and moderation but risk melting down if coolant is lost. “In an MSR the molten salt itself acts as both the fuel and the coolant. In this way, should the reactor lose its cooling, it also loses its fuel, and the reactor process stops automatically. In any conceivable loss-of-coolant accident scenario, the reactor will therefore simply shut itself down.”  Following the shutdown, if the core reaches a threshold temperature, a plug of frozen salt melts at the bottom of the core and drains the warm salt to a dump tank where it cools down by itself.

Moreover, while conventional reactors operate at very large pressures, an MSR operates at only one bar atmospheric pressure. “All in all, this means that our MSR cannot explode nor melt down,” Seaborg noted. “Furthermore, the salt chemically binds volatile fission products or radioactive matter that can escape in the event of a very severe accident, and thus even in the most hypothetical accident scenarios, dangerous radioactive elements will never enter the biosphere.”

Seaborg said the CUBE reactor has “exceptional high thermal efficiency, a wide range of fuel options, excellent load power following capabilities (compatibility with variable renewables), a host of process heat applications and so on”. The use of thorium not only enables waste burning in a thermal spectrum reactor but also greatly improves the sustainability of nuclear power. “The waste salt remaining at the end of the reactor lifetime can be used to fuel new reactors operating directly on a closed thorium fuel cycle – and thus supply carbon-free energy to a rapidly developing global population for centuries to come.”

The investment will allow Seaborg to develop advanced simulation software that can be used by all developers and regulators within the licensing process, said Seaborg CEO Troels Schönfeldt. As well as accelerating its CUBE technology development, Seaborg hopes the new investment will pave the way to market for all MSR developers.

In particular, existing regulatory systems act as a barrier for thorium-based MSRs said Schönfeldt. Simulation of an MSR must include modelling the interdependence between neutron transport, fluid dynamics, heat transfer, and the associated chemical reprocessing, he noted, adding that existing tools are either not compatible with the current regulatory requirements, or not able to include these effects. “This represents an important barrier to the deployment of MSRs.”