Terrestrial Energy is rethinking energy. In this video, members of the Terrestrial Energy team explain the benefits of IMSR technology, and explore the business itself.
Atomic Insights took a recent look at Terrestrial Energy The main technical description from Atomic Insights is below.
Terrestrial Energy believe there are fundamental choices that can alter the competitive balance. TEI’s choice has been to design a reactor that is more akin to a chemical reactor, with fuel that is a dissolved reactant in a solution (in this case, a salt solution) where the solution provides the transport mechanism for the heat produced in a strongly exothermic reaction. Of course, the reaction in this case is not a chemical reaction; it is a fission chain reaction.
The hot reactor fluid is circulated through multiple redundant heat exchangers sealed into the same container as the reactor. Solar salt circulates on the other side of the primary heat exchangers to transport the reactor heat to a second set of heat exchangers where water receives the heat and boils into high temperature, high pressure steam.
The salt circuits operate at high temperature but low pressure. Low pressure enables containers that are simpler, cheaper and quicker to produce compared to the containers performing similar functions in a water-cooled reactor.
Terrestrial Energy has chose to operate its molten reactor on low enriched uranium — which it describes as a dry tinder — vice thorium, which is the frequently targeted molten salt reactor fuel. According to TEI’s web page explaining that choice, thorium is analogous to “wet wood” and needs a “torch” like plutonium-239 or highly enriched uranium (either 235 or 233) in order to be lit and sustained.
TEI knows there is plenty of available natural uranium at an affordable cost, and that there is plenty of capability to produce the correct enrichment with the ability to expand capacity as needed. Uranium fuel has a well-established supply chain; using it will simplify licensing. TEI is aggressive about commercialization; it is aiming to simplify both designs and related processes in order to drive down schedule-related costs.
TEI understands that graphite is a well-proven and understood moderator and structural material for high temperature, liquid-fueled reactors, but TEI also understands graphite’s characteristics of storing energy and changing dimensions under a sustained neutron flux. Replacing graphite components would be complicated; designing them to last the lifetime of the reactor would require research and development with uncertain results.
TEI has a solution for that issue in the form of producing sealed reactor/primary heat exchanger units with installed redundancy that will last for roughly seven years before needing to be replaced. Each unit will have a shielded space for two reactor modules, one will be in use and one will be cooling off. The design philosophy is similar to that used in staged rockets; the difference is that TEI will not throw away used reactors; they will contain useful materials that can be recycled when conditions are right for that activity to begin.
TEI has developed conceptual designs for three different power outputs aimed at various niches in the power market, ranging from 29 MWe to 290 MWe. Any of the basic power modules can be combined at a power station to provide a large total output power level.
Canadian has a performance-based nuclear reactor licensing process. That process should take several years less than the one that would be required for a US license.