International safety assessments of Finnish, French SMRs

The Finnish Radiation and Nuclear Safety Authority (STUK) conducted a preliminary safety assessment of the LDR-50 last year. In June, STUK said the draft concept assessment for Steady Energy's LDR-50 found that "nuclear and radiation safety, security arrangements, emergency arrangements and nuclear material safeguards solutions are such that they can be designed to meet safety requirements". Concept assessment is a procedure proposed in the new Nuclear Energy Act in which STUK assesses whether the power plant could meet safety requirements in general terms. It is separate to the construction permit process for the nuclear power plant. STUK said it used the draft concept as a basis for its assessment.

STUK is now coordinating an international safety assessment of the LDR-50, together with the Czech State Office for Nuclear Safety (SÚJB), Poland's National Atomic Energy Agency (PAA), the Swedish Radiation Safety Authority (SSM), and the State Nuclear Regulatory Inspectorate of Ukraine (SNRIU). Participating authorities will base their examination of the LDR-50 plant based on STUK's earlier work while conducting their own evaluations based on their national regulations.

As part of the review, experts will conduct a preliminary assessment of the key design assumptions of the LDR-50 reactor, such as the adopted design basis and safety objectives, the method of ensuring safety functions, the approach to defence-in-depth, and protection against internal and external threats. Solutions relevant to operation and emergency preparedness will also be verified.

Poland's PAA said a key element of the initiative was to examine the extent to which an assessment conducted by a nuclear regulator in one country can provide valuable support for safety assessments conducted by regulators in other countries, while maintaining the full autonomy of national regulatory competences. "These activities are part of broader international efforts to harmonise and standardise the regulatory approach to new nuclear technologies," it noted.

The Joint Early Review (JER) process began in October last year and is scheduled to run until May 2026. The first technical meeting under this project took place in December. The aim of the review is not to form a joint regulatory position - national findings will be compiled into a summary report, which will be delivered to Steady Energy.

"Early examination of the LDR‑50's safety solutions offers insight into how the design aligns with different national regulatory environments and helps Steady Energy and national regulators gain valuable experience in applying international expertise to national processes," Steady Energy said. "For Steady Energy, the project offers a chance to engage in structured dialogue with multiple nuclear authorities at once. Each participating country is highly relevant from both regulatory and market perspectives, making early feedback especially valuable. Every pre‑licensing step advances the path toward formal licensing process and strengthens overall project readiness in each country."

Steady Energy was spun out of Finland's VTT Technical Research Centre in 2023. The LDR-50 SMR, with a thermal output of 50 MW, is designed to operate at around 150°C. Unlike most SMRs being developed around the world, it is not designed to generate electricity - or electricity and heat. Instead, it is designed to only produce heat and is focused on district heating, as well as industrial steam production and desalination projects.

The company has already signed agreements for 15 reactors in Finland, with its reactor design currently being assessed by STUK. The aim is for construction of the first plant - to be the clean energy source for a district heating scheme - to begin in 2029.

"The Joint Early Review process allows Steady Energy to be better prepared for the formal licensing process in each of these countries once we get projects ongoing," said Juho Vierimaa, Steady Energy's Head of Licensing.

Nuward review progresses

France's Autorité de Sûreté Nucléaire et de Radioprotection (ASNR) has announced the launch of the third phase of the joint review of safety options for the Nuward reactor.

_{A rendering of a Nuward SMR plant (Image: Nuward)}

In June 2022, EDF announced that the Nuward design would be the case study for a European early joint regulatory review led by the ASNR with the participation of Finland's STUK and the Czech Republic's SÚJB. The six areas covered during the year-long joint early review were: the general safety objectives; the list of design basis conditions and design extension conditions; the use of passive cooling systems; the development plan for computer codes; the integration of two reactor units in a single facility; and the Probabilistic Safety Assessment approach. The three regulators published their report on the first phase of the review in September 2023.

A second phase of the review was joined by Poland's PAA, Sweden's SSM and the Netherlands' Authority for Nuclear Safety and Radiation Protection (ANVS). This second phase built upon the successes of the pilot phase - particularly the work of reviewing a specific project and establishing a direct dialogue with the designer - while evolving to address new challenges, notably broader participation. During the second phase, the scope of the assessment was extended to new technical topics, including: management of extended design conditions; assessment of containment and radiological effects; architecture of electrical systems and measurement, control and management systems; and criticality risk management. The final report of the second phase was published in December last year.

The third phase has now been launched. In addition to the participation of the Dutch (ANVS), Polish (PAA), Swedish (SSM), Finnish (STUK), and Czech (SUJB) authorities, the initiative now includes Belgium's Federal Agency for Nuclear Control (FANC) and Italy's National Inspectorate for Nuclear Safety and Radiation Protection (ISIN). The evaluation of regulators during this third phase will focus on new themes: the approach to preventing the failure of main components, the approach to classifying the safety of equipment and the approach taken to take into account scenarios of loss of external power supply.

The conclusions of this review, expected by the end of 2026, will inform the ASNR's deliberations on the harmonisation of safety requirements and authorization processes for new reactors.

The Nuward project - launched in September 2019 by the French Alternative Energies and Atomic Energy Commission, EDF, Naval Group and TechnicAtome - is for a pressurised water reactor with a thermal power of 1,150 MW, which can be converted into up to 400 MWe and 115 MWt.

In September last year, a pre-licensing assessment of the EAGLES-300 lead-cooled small modular reactor was launched by the Belgian, Italian and Romanian nuclear regulators. Four European nuclear technology organisations launched the Eagles Consortium in June 2025 to develop and commercialise the EAGLES-300 SMR with the aim of delivering a first demonstration by 2035.