Small modular reactors (SMRs) are among the innovative nuclear technologies under development, 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."
Applying the Technical Safety Review Service
To present the experiences and lessons learned of recent TSR Services, the IAEA will host a webinar on 15 March for representatives of regulatory bodies, designer organizations, operators or technical support organizations that have received TSR Services or are interested in TSR assistance.
"With different reviewers coming from different countries, organizations and regulatory frameworks, the guidelines explain how to use the IAEA Safety Standards and how to perform the review service in a unified way. They also explain the technical contents of a submission needed for the review, Duchac said. "This webinar will provide a forum for information exchange on the current needs in relation to TSR services for operating and new reactors, including SMRs and other innovative designs. Additionally, the newly developed IAEA technical guidelines for the conceptual design safety review of SMRs and other innovative reactor designs will be introduced."
About the TSR Service
Since 1988, the IAEA has been providing safety reviews to support countries in the application of the IAEA Safety Standards. In addition to design safety, the TSR Service covers five other technical subject areas: generic reactor safety, national safety requirements, probabilistic safety assessment, accident management and periodic safety review.
TSRs are intended for regulatory bodies, plant operating organizations, vendors and other stakeholders, and the duration of the service depends on the scope of the review. The TSR Service Guidelines, IAEA Services Series No. 41, released in November 2019, provides guidance on how to request, prepare for and conduct the TSR.
Register for the TSR Service Webinar, and learn more about the IAEA's review missions and advisory services.
