IMSR starts second stage of Canadian design review

17 October 2018

Terrestrial Energy's Integral Molten Salt Reactor (IMSR) has entered the second phase of a vendor design review by the Canadian Nuclear Safety Commission (CNSC). The design was the first advanced reactor to complete the first phase of the CNSC's regulatory pre-licensing review.

A rendering of a plant based on the IMSR (Image: Terrestrial Energy)

The CNSC's pre-licensing vendor design review is an optional service to provide an assessment of a nuclear power plant design based on a vendor's reactor technology. It is not a required part of the licensing process for a new nuclear power plant, but aims to verify the acceptability of a design with respect to Canadian nuclear regulatory requirements and expectations.

The review involves three phases: a pre-licensing assessment of compliance with regulatory requirements; an assessment of any potential fundamental barriers to licensing; and a follow-up phase allowing the vendor to respond to findings from the second phase. These findings will be taken into account in any subsequent construction licence application, increasing the efficiency of technical reviews, according to the CNSC.

Terrestrial Energy completed phase 1 of the vendor design review in November 2017. CNSC said the company had demonstrated an understanding of the regulator's requirements applicable to the design and safety analysis of the 400 MWt IMSR, known as IMSR400. Terrestrial Energy had also demonstrated its intent to comply with CNSC regulatory requirements and expectations for nuclear power plants, it said.

Terrestrial Energy announced yesterday that phase 2 of the review has now begun. This, it said, involves a detailed follow-up of phase 1 activities, and an assessment of the IMSR design's ability to meet all 19 focus areas of power plant licensing.

"This is a critical commercial step that precedes site selection and construction of the first plant," it said. Phase 2 is expected to take two years to complete.

Molten salt reactors use fuel dissolved in a molten fluoride or chloride salt which functions as both the reactor's fuel and its coolant. This means that such a reactor could not suffer from a loss of coolant leading to a meltdown. Terrestrial Energy's IMSR integrates the primary reactor components, including primary heat exchangers, to a secondary clean salt circuit, in a sealed and replaceable core vessel. It is designed as a modular reactor for factory fabrication, and could be used for electricity production and industrial process heat generation. The company aims to commercialise the modular reactor design in the late 2020s.

"We are making consistent progress towards commercial deployment of IMSR advanced nuclear power plants and are engaged with commercial partners interested in operating," said Terrestrial Energy CEO Simon Irish. "Successful completion of the final phase of design review will be a project green light to start site licence applications."

In June 2017, Terrestrial Energy began a feasibility study for the siting of the first commercial IMSR at Canadian Nuclear Laboratories' Chalk River site. In March this year, Terrestrial and US utility Energy Northwest agreed a memorandum of understanding on the terms of the possible siting, construction and operation of an IMSR at a site at the Idaho National Laboratory in southeastern Idaho.

Last month, Terrestrial Energy USA announced that it has partnered with utility Southern Company and several US Department of Energy national laboratories to investigate the production of hydrogen using its IMSR. The two-year research and development project will examine the efficiency, design and economics of using the IMSR to produce carbon-free, industrial-scale hydrogen using the hybrid sulfur process.

John Barrett, president and CEO of the Canadian Nuclear Association, said: "Small modular reactors using innovative technologies are a great new opportunity for the nuclear industry. In the race to develop them, Terrestrial Energy's next-generation design is leading the way to commercial deployment with its innovative IMSR design. Completing CNSC's phase 2 design review will be a major milestone."

Researched and written by World Nuclear News