Canadian Company Building Integral Molten Salt Reactor

          By Brian Orlotti

A Canadian company has secured $10Mln CDN in funding to develop an unusual type of nuclear reactor. Oakville, Ontario based Terrestrial Energy will use the funds to develop an integral molten salt reactor (IMSR) for industrial and commercial markets.

The general layout of an IMSR plant. As outlined in the Stopping Climate Change page on the "Terrestrial Energy Integral Molten Salt Reactor (IMSR)," the design is a small modular reactor (SMR) design based closely on a DMSR design from the Oak Ridge National Laboratory, but also incorporates elements found in the small, modular, advanced, high temperature reactor (SmAHTR), a later design from the same laboratory.  Graphic c/o Terrestrial Energy.

As outlined in the January 8th, 2016 Next Big Future post, "Terrestrial Energy gets funding for development for Game Changing Molten Salt Nuclear Reactor," IMSR reactors promise nuclear power that is far cheaper and greener than traditional methods.

IMSRs differ from traditional fission-based nuclear reactors in that they use fuel (in this case, denatured uranium) which has been dissolved in a molten liquid salt. Because an IMSR’s fuel is in liquid form, it functions as both fuel and coolant, transporting heat away from the reactor as it circulates. Thus, an IMSR cannot go into meltdown because a loss of coolant (the traditional cause of meltdowns) would also mean a loss of the fuel needed to drive the reactor.

In addition to being "melt down proof," IMSR technology offers other advantages:

• With the fuel and cooling systems essentially combined, IMSRs are a much simpler design than traditional fission reactors and so can be made smaller and cheaper.

• IMSRs use denatured uranium, a fuel that does not require extensive processing (i.e. lower fuel costs) and cannot be used to build nuclear weapons (no proliferation risks).

• IMSRs require only 1/6th the fuel needed annually by traditional reactors (lower operating costs).

• IMSRs can use recycled fuel.

For all of these advantages, IMSRs would still produce radioactive waste. However, this waste would be at far lower volume (kilograms versus tonnes) and be far shorter-lived (200-300 years versus millennia) when compared to traditional reactors.

Salt water reactors aren't new. From 1961 to 1965, this Tupolev-95LAL Russian bomber, using conventional engines and fuel, but also carrying a Russian designed and fully operational molten salt water reactor, performed a series of test flights designed to ascertain whether a nuclear reactor could be used to power an aircraft. The American equivalency was the Convair NB-36H "Crusader" program, created under the US aircraft nuclear propulsion program (ANP) to demonstrate the greatly extended range possible with nuclear-powered aircraft when compared to conventional designs. Both programs were cancelled as the benefits of ballistic missiles became clear. Photo c/o Stopping Climate Change.

Terrestrial Energy's IMSR builds upon research done in the 1960’s in the US at Oak Ridge National Laboratory (ORNL), where the molten salt reactor experiment test reactor operated from 1965 to 1969 and the denatured molten salt reactor was designed. In January 2015, Terrestrial Energy announced a collaboration with ORNL to commercialize its IMSR design. The design phase is scheduled for completion in 2017, with the company intending to have its first power plant commissioned somewhere in Canada in the 2020s.

Brian Orlotti.

With the debates over global warming and energy independence reaching a new crescendo, and off-world resource extraction steadily overcoming the giggle factor, Canada’s homegrown nuclear expertise could prove a great asset.

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Brian Orlotti is a network operations centre analyst at Shomi, a Canadian provider of on-demand internet streaming media and a regular contributor to the Commercial Space blog.