What is so special about the floating nuclear plant of Copenhagen startup Seaborg Technologies? This power plant that has a similar size to a container has a power generation capacity of 200MW, and is adopted with a highly secure nuclear reactor that is affordable, easy to transport, and can be modularized. The power plant can be mass produced into several thousands of units before they are installed on ships, which transcends from the usual impression of power plants.
Traditional thermal power plants are gradually diminishing in the face of strict carbon emission targets, which has increased the focus on renewable energy. However, a segment of the population today is still focusing on the development of nuclear energy, and many are dedicated to the idea of developing new generation nuclear plants that are safer and more eco-friendly to use in the hopes of providing diversified energy configurations that uses cutting edge technology.
Unlike traditional nuclear plants, the new nuclear plant of Seaborg Technologies adopts a nuclear fuel mixed with sodium fluoride, which turns to liquid when the temperature rises to 500°C, and can be used as a coolant for the nuclear fuel. The nuclear fuel does not burst out instantaneously like steam when exposed in the air but is frozen into a solid form. Despite bearing radioactivity, the nuclear fuel is easier to dispose compared to radioactive gas and radioactive sewage, which has lower solubility. During temperature runaway, the frozen salt at the bottom of the nuclear reactor will first melt the nuclear fuel, and the core will be flown to the cooling storage tank at the bottom.
The startup believes that its nuclear power plant has a simpler and more essential safety mechanism than the other plants. It has established a total of four layers of protection at each area that impacts the operation of the system in order to minimize the possibility of accidents. Troels Schönefeldt, the joint founder and CEO of the startup, commented that it is impossible to reduce the possibility of the incidents to zero, but believes that the overall impact of these incidents could be minimized.
Seaborg’s plants also adopt a different moderator, which replaces graphite with another molten salt: sodium hydroxide (NaOH). Traditional graphite becomes weaker under strong radiation and repeated heating and cooling. The new plant design of Seaborg places the fuel salt pipe inside a bigger NaOH pipe, which make it the first plant of its kind to implement a fully liquid reactor.
This is why Seaborg has to not only resolve the high corrosive property of molten salt, but also the grain-boundary corrosion phenomenon derived from NaOH (strong base) and tellurium (a byproduct of nuclear fission), which imposes challenges to each component and parts. Pettersen commented that the core technology of Seaborg is a corrosion control based on moderate salt, and that the challenge also lies on the assembly, in addition to corrosion.
Seaborg commented that its team is currently implementing 20-30 test cycles in Copenhagen, including design, establishment, and experiment commencement. The conceptual design is now completed, with the basic design currently in the midst of execution, followed by a marching towards a full-scale prototype. The full-scale prototype is expected to initiate in 2025, and may be sent to a certain island in Southeast Asia. With tens of millions funded so far, Seaborg hopes to receive approval in 2026, and conduct commercial mass production in 2027 at the earliest. The startup is also seeking for shipyards in South Korea.
Seaborg believes that these floating nuclear plants are able to dock at sea, or various sized rivers, thanks to the scale of the reactor, and the ability of easy connection with the grid from the individual set up. The nuclear plants can operate for roughly 12 years without any fuel replenishment, and the more important thing is that this type of fuel cannot be used as a nuclear weapon.
(Cover photo source: Seaborg)