The Radiation and Nuclear Safety Authority (STUK) is coordinating the international safety assessment of a Finnish small modular reactor. The project examines how cooperation could facilitate the evaluation of new nuclear facilities.

The Finnish company Steady Energy is developing its own small reactor (LDR-50), which it markets as a source of district heating for cities. STUK conducted a preliminary safety assessment of the LDR-50 last year. In the newly launched international cooperation project, STUK’s counterpart authorities will use the assessment prepared by STUK as support when conducting their own assessments. Nuclear safety authorities from Ukraine (SNRIU), Poland (PAA), Sweden (SSM), and the Czech Republic (SÚJB) are participating in the international review of the LDR-50.

Teemu Soukki, the inspector responsible for coordinating the cooperation project at STUK, notes that one goal of the project is to provide early feedback to the reactor designers on the safety solutions of the reactor concept and their suitability for the regulatory environments of different countries.

The other goal for the nuclear safety authorities is to gain experience on how international cooperation can be used to support national assessment work.

“STUK receives valuable feedback on its own assessment from counterpart authorities”, Soukki says. According to him, STUK is also gathering experience on how it can make use of assessments conducted by authorities in other countries in its own evaluation work.

The international safety assessment of the LDR-50 began in October 2025 and will conclude in summer 2026. Each authority will conduct its assessment independently based on its own regulations. The aim is not to form a joint regulatory position. National findings will be compiled into a summary report, which will be delivered to Steady Energy.