In the United States, decarbonization is not possible without nuclear power. But the nuclear power industry of the future must be different – portable, safe and mobile. To this end, US research institutes, with the involvement of budgetary funds, design not only modular microreactors with a capacity of up to 300 MW, but are also engaged in the development of safe and transportable microreactors with a capacity of up to 20 MW.

HolosGen nuclear microreactor project. Image source: HolosGen

Such microreactors can be used in a variety of areas: for charging electric vehicles along remote routes, for supplying power in sparsely populated areas, in the development of the Arctic and even in space… The dimensions of the reactors will have to allow them to be transported in standard 40-foot (12-meter) containers by trucks.

It is noteworthy that heat pipes will be used to transfer heat from the working zone of a nuclear microreactor to the zone of conversion into electrical energy, similar to the way it is done in the cooling systems of personal computers. Cooling and heat removal from the work area will become completely passive, ensuring system reliability and maintenance-free operation for decades.

Another important condition for the design of nuclear micro-reactors is the use of low-enrichment fuel. Such a substance, even if it falls into the wrong hands, cannot be used to create nuclear weapons. The technology for working with low-enriched nuclear fuel involves the process of “slowing down” neutrons. In conventional reactors, graphite is used for this, but in the case of microreactors, this is an unsuitable solution in terms of size and weight.

As an alternative to graphite to slow down neutrons in the reactor core, compounds of metals with hydrogen, hydrides, have been proposed, and the problem with the decomposition of hydrides at high temperatures has been proposed to be solved with the help of multilayer protective shells for such “moderators”.

Argonne National Laboratory is actively working in the area of ​​nuclear microreactors. Moreover, project participants are responsible not only for the development of reactors, but also cooperate with US regulators to develop a regulatory framework for the placement and operation of such power plants. A little more detail with links on this topic is available on the Argonne National Laboratory website.