Integrated deterministic and probabilistic safety assessment of the cooling circuit of a superconducting magnet for nuclear fusion applications

In recent years, there has been a growing interest in nuclear fusion as energy source due to its several principle advantages over fission, which include reduced radioactivity in operation and in waste, large fuel supplies, and increased safety. The most promising configuration of a nuclear fusion system is currently the tokamak, the largest of which, called the largest of which (ITER), is under construction in Cadarache, France. The safety of nuclear fusion systems has to be proved and verified by a systematic analysis of the system behavior under normal transient and accidental conditions. One challenge to the analysis is that the operation of tokamaks presents complex dynamic features as it is based on the transformer principle: in particular, they employ superconducting magnets, a subset of which operates with variable current to generate one of the components of the magnetic field needed to confine the plasma in the chamber where nuclear fusion reactions occur. In the present paper, we apply techniques of Integrated Deterministic and Probabilistic Safety Assessment (IDPSA), which combine phenomenological models of system dynamics with stochastic process models, taking for the first time as reference system the cooling circuit of a superconducting magnet for fusion applications, subject to a Loss-Of-Flow-Accident (LOFA).