Small modular reactors (SMRs) are among the innovative nuclear technologies under development and starting to be deployed to help meet energy demand and net-zero emissions goals. More than 70 commercial SMR designs under development in 17 countries target varied outputs and different applications, such as electricity, hybrid energy systems, heating, hydrogen production, water desalinisation and steam for industrial applications.
SMRs are advanced nuclear reactors that have a power capacity of typically up to 300 MW(e) per unit, which is about one-third of the generating capacity of traditional nuclear power reactors. Given their smaller footprint, SMRs can be sited on locations not suitable for larger nuclear power plants, and they can be factory-assembled, shipped and installed on site, making them more affordable to build than large power reactors. Other innovative reactor designs include transportable SMRs, high temperature gas cooled reactors (HTGRs), lead fast reactors (LFRs), sodium fast reactors (SFRs), molten salt reactors (MSRs) and microreactors.
The emergence of these innovative reactor designs has led the IAEA to expand its Technical Safety Review (TSR) Service for nuclear power programmes, to incorporate the new guidelines for the conceptual design safety review that now covers the conceptual designs – the rough drafts in terms of function and form – of innovative reactors, including SMRs.
“We decided to revise the scope of the guidelines to add additional elements to make them more versatile, not only for water-cooled reactors but also for other types of technologies, such as HTGRs, MSRs and fast reactors,” said Alexander Duchac, IAEA Nuclear Safety Officer. “Because many innovative technologies are at an early design stage, we realized there was a need for design safety review guidelines for conceptual designs.”
The new guidance is included in the ‘design safety review’ section of the TSR, which is a service providing a tailored, independent evaluation of documentation and activities at different stages of a nuclear power programme development and deployment. The service is carried out by senior international experts and led by IAEA staff, and evaluations are against the application of IAEA Safety Standards.
Topics covered by TSRs include design safety review, review of a preliminary safety analysis report, review of periodic safety review documentation and review of a probabilistic safety assessment. To date, the IAEA has completed 114 TSRs in 29 countries, and four reviews are planned in 2022.
“The guidance indicates what level of detail is expected at the early stage of the design,” said Jozef Misak, Vice President of UJV Rez in the Czech Republic and contributing author. “Use of the TSR Service at the stage of the conceptual design helps to avoid difficulties complying with safety standards at later stages of development.”
