Safety of fast neutron reactor power units under operation and design in Russia Original Research Article

Fast neutron reactors have been designed and operated in Russia for over 40 years. The paper provides the story of the regulatory basis applied for designing, constructing and operating fast reactors. The increasing extent of the requirements of the supervisory authorities, and the issuing of modified regulatory documents, has increasingly led to the necessity of implementing difficult and expensive measures so as to provide appropriate safety levels for operating first and second generation power units built earlier. The main problems have been caused by the revision of the maximum evaluated earthquake level, standards for analysis of its consequences, and requirements for safety systems. This paper outlines modifications implemented in the first and second generation power reactor units. International efforts—reflected in the IAEA documents—on the improvement of approaches to safety assurance for NPPs of the new generation, leading expertsʹ presentations, and advanced design development have caused a significant shift towards the maximisation of usefulness of inherent safety features and safety systems based on passive principles. A brief description of the BN—800 reactor design using these approaches is given.