Monday, December 11, 2017

Molten Salt Reactors Catching On

          By Brian Orlotti

Oakville, ON based Terrestrial Energy has announced that it’s integral molten salt reactor (IMSR) design had passed the first phase of a pre-licensing vendor design review by the Canadian Nuclear Safety Commission (CNSC).

As outlined in the November 8th, 2017 Terrestrial Energy press release, "Terrestrial Energy IMSR First Commercial Advanced Reactor Assessed by Regulator," IMSR technology appears to be gaining traction in other nations for both civilian and military purposes.

In January 2015, Terrestrial Energy announced a collaboration with Oak Ridge National Laboratory (ORNL) to commercialize its IMSR design and secured $10Mln CDN in funding. With Phase One of the CNSC design review proces complete, the company will enter Phase Two. Requiring further design detail, phase Two will take 18 months to 2 years to complete. Terrestrial Energy anticipates completing Phase Two in 2019, then obtaining a customer and beginning the reactor’s construction in the 2020s.

IMSRs 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 the reactor’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.

IMSRs would still produce radioactive waste, but at far lower volumes (kilograms versus tonnes) and far shorter time spans (200-300 years versus millennia) when compared to traditional reactors.

Molten salt reactors are not new technology. Terrestrial Energy's design builds upon research done in the 1960’s in the US at ORNL. In addition, the Convair NB-36H "Crusader" aircraft, created under the US’ Aircraft Nuclear Propulsion program (ANP), flew a series of test flights from 1955-57 with a functioning salt-water reactor on board to ascertain whether a nuclear reactor could be used to power an aircraft.

From 1961 to 1965, the Soviet Union performed a series of test flights of a Tupolev-95LAL bomber, using conventional engines and fuel, but also carrying a Soviet-designed molten salt water reactor.

Both the US and USSR’s programs were cancelled due to the rise of ballistic missile technology.

As outlined in the December 6th, 2017 Next Big Future post, "Thorcon floating supertanker molten salt reactors starting with 2021 prototype," a US-based startup called Thorcon Power is developing a molten salt reactor based off of ORNL designs for use on oil supertankers.

Currently under development in the US, Thorcon intends to build the reactor in a yet-to-be-determined Asian shipyard, then float it to Indonesia, where testing will begin in 2021. Thorcon’s team includes several former ORNL engineers.

The US and China are also eyeing molten salt water reactor tech for use in warships and drones in order to greatly increase their endurance and capabilities.

As outlined in a 2012 Sandia National Labs paper under the title, "Project Accomplishments Summary, Cooperative Research and Development Agreement (#1714) between Sandia National Labs and Northrop Grumman Systems Corporation," from 2008-2011, Albuquerque, NM based Sandia National Labs and West Falls Church, VA based Northrop Grumman collaborated to design nuclear-powered unmanned aerial vehicles (UAVs) able to stay aloft for many months.

According to the December 5th, 2017 South China Morning Post, "China hopes cold war nuclear energy tech will power warships, drones," China will spend $3.3Bln USD ($4.4Bln CDN) to develop two molten salt reactors in the Gobi Desert in northern China by 2020. Aside from civilian energy production, China considers molten salt ideal for powering UAVs as well as warships in its steadily expanding navy.

In addition, molten salt reactors could be fueled by thorium, a material China has in abundance. Using thorium as a fuel would enable higher power generation efficiency, enabling aircraft carriers and submarines with greater speed and range than uranium-powered ones.

As ever, nuclear technology remains a double-edged sword, enabling new human capabilities for both war and peace. Let us hope such capabilities are used wisely.
Brian Orlotti.

Brian Orlotti is a regular contributor to the Commercial Space blog.


  1. Please change "salt WATER reactor" which is inaccurate to the correct term "molten salt reactor." This will avoid confusion with Zubrin's "nuclear salt-water rocket."

    Otherwise, interesting article.

  2. I've made the corrections. Thanks for the heads-up.

    Chuck Black - Editor


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