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on 6/17/25 at 9:29 AM
The Nuclear Energy Agency (NEA) Working Group on External Events (WGEV) was established by the Committee on the Safety of Nuclear Installations (CSNI) in June 2014 with the aim of improving the understanding and treatment of external hazards in order to support the continued safety performance of nuclear installations and improve the effectiveness of regulatory practices in NEA member countries. Based on its work with respect to different natural hazards, such as coastal flooding, riverine flooding and high winds, the WGEV identified a common challenge: uncertainties related to hazard assessments. Therefore, a two-phased task on “uncertainties in the assessment of natural hazards (excluding earthquakes)” was proposed to, and accepted by, the CSNI. Phase 1 of this task is intended to provide an overview of the types of uncertainties that need to be considered depending on the type of natural hazard, the data sources and the assessment approaches.
To facilitate the compilation of a report on the sources of uncertainties, it was decided to convene an international workshop shortly after the beginning of this activity. More specifically, the purpose of the workshop was to gather information on: i) sources of uncertainties affecting all assessments of natural hazards; ii) sources of uncertainties relevant to specific hazards; iii) sources of uncertainties related to the input data for the assessment; and iv) sources of uncertainties specific to certain assessment methods. The workshop was organised into three technical sessions, covering the spectrum of hazards within the scope of this activity (extreme temperatures, heat sink effect, lightning, snow, site flooding, and high winds), and an opening and wrap-up session. Each technical session consisted of a set of presentations followed by a panel discussion. In the wrap-up session, the rapporteurs and session chairs summarised the main insights and key messages from the technical session.
