Deterministic analysis of internal hazards in substantiating the safety of the nuclear power plants

Deterministic analysis of internal hazards in substantiating the safety of the nuclear power plants.

Goryunov O. V., Lanin D. G.

The safety analysis of a nuclear power plant (NPP) in accordance with the requirements of NP-001-15 “General provisions for ensuring the safety of nuclear power plants” should take into account how internal hazards (for example, failures of systems/elements of the NPP, failures caused by fires, flooding, explosions, leading to the formation of flying objects, the spread of toxic substances, etc.), as well as external hazards (for example, earthquakes, hurricanes, man-made events, etc.). The requirements for accounting for external hazards in the safety analysis of nuclear power plants are set out in the NP-064-17 “Accounting for external hazards of natural and man-made origin on nuclear energy facilities”. At the same time, recommendations have not been developed on how to take into account internal hazards when justifying the safety of an NPP, which does not correspond to international practice in designing and justifying the nuclear and radiation safety of an NPP. For example, in the standards of the IAEA No. SSR-2/1, the Western European Association of Regulatory Authorities (WENRA), European Electricity Producers (EUR E) the requirements for accounting for internal and external hazards are supported by detailed recommendations in the relevant IAEA guidelines No. SSG-64 and SSG-77.
In order to highlight this problem, this article presents the results of a comparative analysis of the requirements for accounting for internal hazards in the NPP project based on consideration of international standards (IAEA, WENRA, EUR), as well as national requirements of some countries (Finland, Hungary, Canada, Great Britain, Russia). The results of a comparative analysis of Russian and foreign requirements regarding the consideration of internal hazards in the design of buildings, structures and systems, and in the implementation of the safety justification of the NPP showed that more attention is paid to these issues abroad. International experience in the design of an NPP shows that taking into account the results of a deterministic analysis of internal hazards, for which the relevant recommendations define the procedure for its implementation, provides a comprehensive and complete justification for the safety of the NPP (for example, the identification of previously undetected initial events and their accounting as part of the NPP project).

► Keywords: internal hazards, nuclear and radiation safety, nuclear power plant.

Article language: Russian. Pp. 24–35. [in Russian]. DOI: 10.26277/SECNRS.2024.114.4.002.