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Nuclear energy can lower emissions, create jobs and strengthen the economy – says the US Department of Energy (DoE). That is why it is boosting its nuclear industry: The US companies Terra Power and X-Energy will receive funding of 180 million dollars for their new reactor designs – with the option of receiving further billions of funds in the course of realisation.


The US wants to be a nuclear nation again: The government’s Advanced Reactor Demonstration Program recently selected two companies to receive generous financial support. The companies Terra Power and X-Energy are to build two different prototypes within seven years, which will supply reliable and shelf-ready electricity. National research institutions are to help with their development. “New nuclear energy is paramount to our clean energy strategy,” said energy secretary Dan Brouilette.

The selected reactor designs: different, but not new

The companies were awarded funding because the jury judged their plans to be feasible, swiftly realisable and competitive. The designs differ fundamentally from most modern-day reactors. There the energy of nuclear fission is used to heat water that circulates through the core to transport heat to the non-reactor unit of the plant. This works best when the water is pressurised. In the non-reactor unit the heat produces steam, which in turn drives turbines to generate electricity.

Instead of water, the TerraPower sodium reactor uses molten sodium as a coolant. Since sodium has a higher boiling temperature than water, the coolant would not have to be pressurised. With this challenging concept TerraPower hopes to reduce the plant’s complexity and cost. In contrast, the X-Energy design uses pressurised helium gas for cooling, which enables a high operating temperature of 750 °C. There are no fuel rods in the reactor core, but graphite “pebbles” containing uranium. Both principles might seem familiar to Germans: They have already been implemented in Germany before. So the selected designs are nothing new, and they have well known disadvantages: Sodium reactors require elaborate safety engineering because the handling of sodium is complex. Pebble bed reactors have a low power density.

Joe Biden also wants nuclear power to stay

Nevertheless: “The fact that the largest western democracy is once again turning to nuclear technology is a very important signal – even if the technologies being funded are not really new,” says Björn Peters, CFO of Dual Fluid. After all, the Department of Energy has announced that a further 50 billion dollars will be used to promote real innovations – i.e. reactors that has only existed as concepts so far. The companies that will benefit are to be announced in December.

Joe Biden also wants to hold on to nuclear power: By 2050, the American power grid is to become completely emission-free, for which he wants to use all low-carbon technologies. In his “Plan for a Clean Energy Revolution and Environmental Justice”, Biden promises to identify the nuclear power of the future – and explicitly mentions small modular reactors (SMR) as an option.


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