The deployment of innovative nuclear systems (passive systems) requires the demonstration of their enhanced safety features with respect to traditional concepts. The innovative nuclear systems often operate at different neutronic and thermal-hydraulics conditions with respect to the traditional ones. Therefore, deterministic and probabilistic analysis are needed to verify the performances of the new systems.
In this view, on one hand there is the need to analyse the evolution of Design Basis Accidents (DBA) and Beyond-DBA by deterministic models, and on the other hand a re-elaboration of the classical Probabilistic Safety/Risk Assessment (PSA/PRA) approaches is required, taking advantage of new methods (e.g., functional safety, dynamic reliability, advanced deterministic and stochastic simulation, artificial intelligence).
The objectives include: a) to define innovative techniques for the design of new nuclear systems within a risk-informed framework even in the conceptual phases, as well as the adaptation of PRA/PSA analyses to such new plants; b) identify the important physical phenomena occurring during the accidental transients; c) to verify and qualify system codes (mainly developed for active systems) for the analysis of DBAs and severe accidents. The applications include innovative fission reactors, and fusion machines, as well as non-nuclear high-risk plants.
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