The Canadian Nuclear Safety Commission (CNSC) and the United States Nuclear Regulatory Commission (NRC) have selected Terrestrial Energy’s Integral Molten Salt Reactor (IMSR®) for the first joint technical review of an advanced, non-light water nuclear reactor technology.

The selection of Terrestrial Energy’s IMSR® for joint technical review follows the August 2019 Memorandum of Cooperation (MOC) between the CNSC and the NRC that further expands the agencies’ cooperation on activities associated with advanced reactor and SMR technologies. The MOC’s collaborative technical reviews are intended to increase regulatory effectiveness as well as reaffirm the agencies’ commitment to safety and security.

IMSR Conceptual Image

Terrestrial Energy’s IMSR® is an advanced reactor employing Generation IV molten salt technology with a power output of 195 MWe. It is currently the subject of regulatory engagement in both Canada and the United States. 

IMSR® submissions to the CNSC for Phase 2 of the Vendor Design Review (VDR) process commenced in December 2018; the IMSR® is the only advanced reactor in Phase 2 of that process. Since February, the IMSR® has been the subject of NRC pre-licensing activities supported by grant funding from the U.S. Department of Energy.

The CEO of Terrestrial Energy, Simon Irish, said: “We look forward to participating in joint CNSC and NRC reviews of IMSR® advanced reactor technology and to support the goals set by the agencies in the August Memorandum of Cooperation.” 

The CNSC-NRC Memorandum of Cooperation is intended to expand the cooperation provisions of the 2017 MOU between the two agencies to include activities associated with advanced reactor and SMR technologies, and to further strengthen the agencies’ commitment to share best practices and experience through joint reviews of advanced reactor and SMR technology designs. (CNSC statement) (NRC statement)

About Terrestrial Energy

Terrestrial Energy is a developer of Generation IV advanced nuclear power plants that use its proprietary Integral Molten Salt Reactor (IMSR®) technology. IMSR® power plants will provide zero-carbon, reliable, dispatchable, cost-competitive electric power and high-grade industrial heat for use in many industrial applications, such as chemical synthesis and desalination, and in so doing extend the application of nuclear energy far beyond electric power markets. 

They 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.  

The IMSR integrates the primary reactor components, including primary heat exchangers to secondary clean salt circuit, in a sealed and replaceable core vessel that has a projected life of seven years.  It will operate at 600-700°C, which can support many industrial process heat applications. The moderator is graphite.  

The fuel-salt is a eutectic fluoride with low-enriched uranium fuel (UF4) at atmospheric pressure. Emergency cooling and residual heat removal are passive. Each plant would have space for two reactors, allowing 7-year changeover, with the used unit removed for off-site reprocessing when it has cooled and fission products have decayed. Compared with other MSR designs, the company deliberately avoids using thorium-based fuels or any form of breeding, due to “their additional technical and regulatory complexities.”

Terrestrial Energy is engaged with regulators and industrial partners to complete IMSR® engineering and to commission first IMSR® power plants in the late 2020s.

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