Terrestrial Energy Announces Upgraded IMSR400 Generation IV Nuclear Power Plant

Oakville, ON – September 14, 2021 – Terrestrial Energy today announced its upgraded Integral Molten Salt Reactor (IMSR) nuclear power plant design – the IMSR400 – a facility with a net 390 MW of electric generation capacity for grid supply from twin reactors and generators. This upgrade, in response to utility requirements, further increases the cost-competitiveness of the IMSR400 as a clean, safe and reliable source of energy.

“With our upgraded IMSR400 Generation IV nuclear power plant, Terrestrial Energy is raising the bar for innovative carbon-free technology in terms of cost-competitiveness, resilience, and scalability,” said Simon Irish, CEO, Terrestrial Energy. “The IMSR400 has the efficiency, economics and flexibility to play a major role in the clean energy transition including the production of clean hydrogen at industrial scale.”

Terrestrial Energy’s IMSR400 is one of three Small Modular Reactor (SMR) power plant designs under consideration for deployment at Ontario Power Generation’s Darlington Nuclear Generating Station. It is one of two Generation IV technology candidates, and the only Canadian technology candidate. Terrestrial Energy’s Oakville operation represents the largest SMR power plant technology development project in Canada.

The IMSR400 is a proprietary power plant design drawing on Generation IV reactor technology developed and demonstrated over many decades. Using Generation IV molten salt reactor technology, the IMSR400 generates electric power 50 per cent more efficiently than conventional nuclear power plants that use water cooled and moderated reactor technology. With this 50 per cent efficiency improvement, the IMSR400 has a reduced capital requirement and waste footprint, and improved economics per kWh of electricity for new nuclear power plants.

The Generation IV reactor technology class was defined in 2001 by the Generation IV International Forum (GIF), an agency created by international treaty and overseen by the Organization of Economic Cooperation and Development (OECD), to which Canada and the United States were founding signatories. The GIF identified as Generation IV six reactor technologies – of which the molten salt reactor is one – that offer improvements in cost, safety, versatility and waste, and embody the future of civilian nuclear power generation.

“With the commercial development of the IMSR power plant, we are realizing the breakthrough promise of Generation IV technology set out by the GIF 20 years ago,” said Mr. Irish.

Since early 2016, when it became the first Generation IV reactor developer to submit a power plant design to the Canadian Nuclear Safety Commission (CNSC), Terrestrial Energy has been committed to the CNSC’s Vendor Design Review process. It completed Phase 1 in 2017 and expects to complete Phase 2 by early 2022. Since late 2019, the company has also been engaged with the CNSC and the U.S. Nuclear Regulatory Commission (NRC), as the two regulatory agencies collaborate to develop licensing practices to support efficient reviews of Generation IV nuclear power plants.

The IMSR400 uses nuclear fuel at standard enrichment – the only Generation IV SMR power plant designed to do this today. This avoids the considerable cost and time of re-licensing uranium enrichment plants and removes hurdles to commercialization, hastening deployment. The company announced an agreement on August 17 with Westinghouse and the UK’s National Nuclear Laboratory to provide the IMSR’s nuclear fuel supply, the first Generation IV Small Modular Reactor (SMR) to have such an agreement.


Image: Illustration of the IMSR400 power plant in the configuration proposed for the Darlington site. The IMSR400 has the capacity to generate 390 MW (net) of clean, reliable and carbon-free electric power on a 7 hectare site.

About Terrestrial Energy

Terrestrial Energy is a developer of small and modular nuclear power plants that use its proprietary Integral Molten Salt Reactor (IMSR) technology. IMSR technology is non-Light Water Reactor and Generation IV technology and will generate electricity 50% more efficiently than conventional nuclear reactor technology. The IMSR represents a step-change improvement in economics, versatility and functionality of nuclear power plants that is possible only through Generation IV technology. IMSR power plants will provide resilient, reliable, dispatchable, zero-carbon and cost-competitive electric power, as well as high-grade industrial heat for use in many industrial applications, such as chemical synthesis, hydrogen production and desalination, and in so doing extend the application of nuclear energy far beyond electric power markets. IMSR power plants have the potential to make important contributions to industrial competitiveness, energy security, and economic growth. Their deployment will support rapid global decarbonization of the primary energy system by displacing fossil fuel combustion across a broad spectrum and can scale to meet net-zero policy goals of major industrial economies. Using an innovative design, and proven and demonstrated molten salt reactor technology, Terrestrial Energy is engaged with regulators and industrial partners to complete IMSR engineering and to commission first IMSR power plants in the late 2020s.