Criticality accident intervention a slide-rule for dose estimation

International audienceFollowing the Fukushima-Daiichi accident in 2011, France initiated a process to reas-sess the safety margins of its nuclear installations; these Complementary Safety Evalu-ations have led to numerous in-depth studies related to various risks. In this context, consequences of a hypothetical criticality accident due to the usage of water as mean of intervention in connection to a catastrophic event (earthquake, flooding...) which would eventually lead to the ruin of buildings where fissile matter is handled were studied. The goal of these studies was to assess the dose potentially inflicted to the in-tervention staff in the event of a criticality accident, depending on the intervention technique chosen. Rather than conduct multiple studies for each intervention technique, it was chosen to build abacuses that would allow a quick estimate of doses. This paper describes these abacuses as well as a methodology of implementation. Ambient dose equivalent depending on the distance to the accident site and on ordinary concrete width crossed were calculated as a first approach. Next, parametric studies were con-ducted to estimate the impact on the dose of various important parameters such as the physicochemical form and the volume of the source, or the composition of the con-crete. These calculations were carried out with the deterministic one-dimension code SN1D to allow for fast exploration of parameters variabilities. Finally, an implementa-tion methodology, that allows to take into account these variabilities, as well as an ap-plicability domain, are discussed