The International Atomic Energy Agency (IAEA) has launched an initiative aimed at finding common ground among regulators, designers, operators and other stakeholders to support the safe deployment of advanced reactors, including small modular reactors (SMRs).

The Nuclear Harmonisation & Standardisation Initiative (NHSI), launched in 2022, is developing a series of tools and publications to support advanced reactors. NHSI includes 30 countries, 94 unique organisations with more than 200 contributors.

IAEA recently brought together more than 120 NHSI participants, in person and virtually, to assess progress and to set priorities for the coming year. NHSI aims to support the timely deployment of advanced reactors by making progress towards harmonising regulatory approaches and standardising industrial approaches. Technical publications and toolkits are expected to be available by the end of 2024.

NHSI participants work in two separate but complementary tracks: the NHSI Regulatory Track and the NHSI Industry Track. Both have topical working groups, and over the past year, each has held 16 working group meetings.

IAEA Director General Rafael Mariano Grossi, in his opening remarks to the meeting outlined the benefits of NHSI’s work, noting that harmonisation of the regulatory process reduces uncertainty and helps to lower the cost of building and deploying SMRs. “When it comes to the design of SMRs, working towards global standardisation of approaches – by developing international generic user requirements, for example – could increase trade and create economies of scale for manufacturing, construction and operation,” he said.

Regulatory Track participants have produced approaches that will help countries to work together in SMR regulatory reviews, sharing resources and knowledge. “The implementation of these approaches will help regulators to learn from each other, increasing their trust that other regulatory frameworks that may initially seem different, are able to achieve good results,” said Paula Calle Vives, Senior Nuclear Safety Officer at the IAEA. “The work we are doing is not necessarily aiming to harmonise regulatory requirements but to harmonize how the requirements are met and demonstrated,” said Anna Bradford, Director of Nuclear Installation Safety at the IAEA and Chair of the Regulatory Track.

“We are on track to develop approaches to enhance national reviews, enabling regulators to take maximum advantage of international work and efforts by other regulators, Grossi said. “This will lead to minimal repetition among regulatory reviews by different member states and minimal need for design changes arising from regulatory differences. Together we can establish a common basis for member states’ regulatory decisions while preserving their sovereignty.”

For the nuclear industry, NHSI is identifying common approaches on codes and standards used as a part of design, manufacturing, construction, commissioning and operation of advanced reactors, such as SMRs. “The SMR business model is often based on serial production, which means that after the deployment of the first-of-a-kind reactor, cost and time savings materialise under a standardised approach,” said Aline des Cloizeaux, Director of Nuclear Power at the IAEA and Chair of the Industry Track.

One of the main objectives of the Industry Track is to harmonise high-level user requirements. An international reference is under development to help regulatory bodies understand what future licensees expect and to help embarking or expanding nuclear power countries structure their specifications for prospective suppliers.

The Industry Track is also forming a network and associated platform for resource sharing on experiments and code validation for SMRs. The IAEA Network for Experiment and Code Validation Sharing (NEXSHARE) is expected to be launched next year, in conjunction with a workshop and publication on participating experimental facilities. “Sharing information on experiment and code validation does not necessarily mean sharing data but identifying what is available, what work is being conducted, what are the gaps and what facilities are currently available,” des Cloizeaux said.

Regulatory and industry representatives shared feedback and suggestions on the work that has occurred, thus far, and possible areas for enhancement going forward. The timeliness and relevance of NHSI’s work, which will be beneficial for both mature and embarking nuclear power countries, is underscored by the need to transition to clean energy and to meet energy demands. “NHSI can be a game changer if we all work together and commit our resources to bring it to a successful outcome,” Grossi said. The next NHSI plenary is planned for 2024.

Image: IAEA Director General, Rafael Mariano Grossi, delivers his remarks at the opening of the Nuclear Harmonization Standardization Initiative (NHSI) plenary meeting at the Agency headquarters in Vienna (courtesy of D Calma/IAEA)