US-based Terrestrial Energy has completed its siting study with Canadian Nuclear Laboratories (CNL) shortlisting a number of sites suitable for a commercial power plant that uses the company’s Integral Molten Salt Reactor (IMSR). The study recommended further detailed investigation of several sites within the Chalk River Laboratories property. Terrestrial Energy CEO Simon Irish said: “Completing the study of target sites at Chalk River for detailed planning is another step forward towards deployment of an IMSR power plant, a transformative clean energy technology for affordable and cost-competitive heat and power without greenhouse gases.”

Terrestrial Energy will pursue more detailed site work to further develop its plans. The company announced 19 February that it has progressed to the next stage of a CNL invitation process to evaluate siting a reactor at one or more CNL-managed campuses. Terrestrial Energy’s IMSR is the first Generation-IV reactor to complete the first phase of the Canadian Nuclear Safety Commission’s Vendor Design Review and is progressing through the second phase.

Terrestrial Energy says its IMSR technology represents true innovation in cost reduction, versatility and functionality of nuclear power plants. “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.

The IMSR design is based on the demonstrated molten salt reactor (MSR) design developed in the 1960s at the Oak Ridge National Laboratory, and through a series of subsequent programmes at other national laboratories. The Terrestrial Energy design makes full use of the passive safety benefits of MSR.

Molten salts are thermally stable and excellent heat-transfer fluids, ideal for capturing and dissipating heat from the fission process. The IMSR uses a graphite moderator and operates on a simple fuel cycle.  

The primary reactor components, including the graphite moderator, are integrated into a sealed and replaceable reactor core, which has an operating lifetime of seven years, and can be replaced simply and safely. The IMSR design uses standard assay low-enriched uranium fuel with the same level of enrichment (less than 5% U-235) as in conventional NPPs. Terrestrial Energy says the IMSR is a modular design and can be built in four years. Each module will be mass-manufactured in a factory, and transported by truck or rail for on-site modular assembly.