Skip to main content

Nuclear-reactor developer Terrestrial Energy has completed a prelicensing review by the Canadian Nuclear Safety Commission, an early milestone along the road to commercialization of its next-generation product.

The Integral Molten Salt Reactor (IMSR) is the first of its kind to finish the CNSC process known as a vendor design review. Whereas conventional reactors use solid fuel, this novel variety features liquid fuel dissolved in molten salt that’s heated to temperatures above 600 degrees.

The review, which began in 2016, is intended to provide feedback to reactor vendors in the early stages of development, but does not confer a licence to build one. CNSC staff found “no fundamental barriers to licensing,” signalling their willingness to entertain next-generation designs radically different from Canada’s aging fleet of Candu reactors.

“The reason it’s so important is because it answers the most important question that one needs to address when commercializing any reactor system – and that is: Is it licensable?” said Simon Irish, chief executive of the company, based in Oakville, Ont. “This allows us to focus on the commercial opportunity and the commercial aspects of our design.”

Yet the CNSC’s high-level findings, published Tuesday, highlight the challenges ahead. It called on Terrestrial to provide more information to confirm that the IMSR meets safety requirements. Sensors, monitoring equipment, instrumentation and control systems all need to be further developed.

The CNSC also sought tests to demonstrate how the reactor would behave at low power, as well as more evidence regarding systems that would control and shut down the reactor.

“It’s great that they got through vendor design review Phase 2,” said Akira Tokuhiro, a professor at Ontario Tech’s energy and nuclear engineering department. (The VDR process has an optional third phase, which no small modular reactor has yet completed.)

“But in the comments, you see a lot of engineering questions that have to be followed up on.”

Prof. Tokuhiro said answering those questions means Terrestrial (which currently employs about 100 people) will need to grow its engineering staff. NuScale Power, an early developer of small modular reactors (SMR) founded in 2007, stands alone in achieving certification from the U.S. Nuclear Regulatory Commission. It needed 500 staff and US$1-billion to accomplish that, said Prof. Tokuhiro, who previously served as an engineer at NuScale.

“There have been SMR startups – I won’t name names – where the company and investors quit when they got to the point of going from 50 engineers to 500 engineers on payroll,” he said.

Prof. Tokuhiro estimated that fewer than 20 people throughout North America possess deep experience with molten salt technologies, making it difficult to find qualified workers. Moreover, Terrestrial will likely need to build a demonstration unit – another expensive undertaking.

“It has to be a facility that’s quality assured and quality controlled,” he said. “And it has to be able to produce data that the regulator accepts.”

Mr. Irish said Terrestrial wasn’t surprised by any of the CNSC’s findings, having been engaged with the regulator for many years. (The company is also in preapplication discussions with the U.S. Nuclear Regulatory Commission.)

Initially developed in the 1950s and 60s, molten salt reactors never operated commercially but have lately enjoyed renewed interest. The U.S. Department of Energy funded two small demonstration projects, and the Canadian government provided tens of millions of dollars to each of Terrestrial and Moltex Energy, another startup, based in New Brunswick, that’s marketing a model known as the Stable Salt Reactor – Wasteburner (SSR-W).

According to a 2021 report about advanced nuclear reactors by the Union of Concerned Scientists, molten salt reactors are “even less mature” than other novel designs such as sodium-cooled and gas-cooled reactors.

That report – entitled Advanced Isn’t Always Better – concluded they were “significantly worse” than traditional light-water reactors in terms of safety and the risk of nuclear proliferation and terrorism, but acknowledged that some molten salt reactors would generate less hazardous waste than conventional models.

“MSR fuels pose unique safety issues,” the report concluded. “Not only is the hot liquid fuel highly corrosive, but it is also difficult to model its complex behaviour as its flows through a reactor system. If cooling is interrupted, the fuel can heat up and destroy an MSR in a matter of minutes.

“Perhaps the most serious safety flaw is that, in contrast to solid-fuelled reactors, MSRs routinely release large quantities of gaseous fission products, which must be trapped and stored.”

The nuclear industry has precious few small modular reactors available for sale today, but is under intense pressure to bring new ones to market quickly to capitalize on an anticipated surge in demand for low-carbon electricity. Yet recent reactors based on conventional technologies took longer than 30 years to develop, license and build, and some ran disastrously overbudget.

Terrestrial has said previously that it planned to build its first IMSR by 2030. It suffered a setback in late 2021 when Ontario Power Generation selected a competitor, GE Hitachi Nuclear Energy, to build an SMR at its Darlington Nuclear Generating Station. OPG says that reactor, known as the BWRX-300, will be completed by 2028, and other utilities have expressed interest in building additional units.

With the vendor design review complete, Mr. Irish said Terrestrial will focus on courting large industrial customers seeking to decarbonize energy-intensive processes. Potential applications include powering data centres, chemical plants producing ammonia or petrochemical facilities making low-carbon fuels.

“They have made commitments to decarbonize industrial activities in the 2030s,” he said. “And they need to start today to select and identify technologies that are capable of providing big solutions.”

Your Globe

Build your personal news feed

Follow the author of this article:

Follow topics related to this article:

Check Following for new articles