Canadian university launches subcritical assembly project

23 February 2023

Ontario Tech University has begun pre-licensing activities for a new facility to support its undergraduate nuclear engineering programmes and for applied nuclear engineering research. The facility will be unique in Canada.

Graphite moderator rods and blocks will be part of the subcritical assembly (Ontario Tech Student Union)

A subcritical assembly - sometimes called a "teaching reactor" - is based on the same nuclear science principles as critical nuclear reactors but remains in a subcritical state, relying on an external source of neutrons to sustain the nuclear fission chain reaction. Unlike a nuclear power plant, which operates in a "critical" state where the nuclear chain reaction is self-sustaining, a subcritical assembly cannot sustain a chain reaction on its own, and stops operating unless the external source of neutrons is proactively supplied. It is incapable of generating power or electricity, or heat that requires cooling.

Ontario Tech - which runs Canada's only undergraduate nuclear engineering degree programme - says its Subcritical Assembly Project would enable enhanced hands-on, experiential learning opportunities for students, as well as supporting research to develop nuclear technologies and strategies to protect the environment and combat climate change.

The university said it expects to begin the full regulatory approval process shortly, and has already informed the Canadian Nuclear Safety Commission (CNSC) that it intends to apply for an operation licence during the 2023/2024 financial year. It will "actively engage with Indigenous communities and the broader public" as the project develops. The CNSC's licensing process also encourages public participation.

Canada currently has no operating subcritical assembly, although two such facilities have operated in the past at Polytechnique Montréal, one of which was dismantled in 1982. According to its notification to the CNSC, Ontario Tech acquired "assets" from the Polytechnique Montreal's other legacy subcritical assembly in 2022. These assets are currently in storage at Ontario Tech's campus and, although they could possibly be used "as is", the university intends to amend the original design to make it better suited to meet its intended training and research purposes and to further enhance safety.

"The addition of this equipment would be a timely game-changer for our students and provide Ontario Tech with a unique-in-Canada tool for clean energy research and teaching," said Hossam Kishawy, dean of the Faculty of Engineering and Applied Science at Ontario Tech. "Students in our Energy, Nuclear Engineering, and Radiation Science programmes would gain increased experiential learning opportunities, and be even further equipped for career readiness in their chosen fields," he added.

Researched and written by World Nuclear News