Safety analysis in the LBE-Cooled XADS plant through an integrated use of HAZOP, FAULT TREE and thermalhydraulic transient analyses

摘要

This paper illustrates the effectiveness of an integrated use of some risk analysis techniques, namely the HAZOP, Fault Tree and thermalhydraulic transients analyses, through the application in safety analysis of the XADS facility. Indeed, it can allow to perform an exhaustive study of the examined plant, identifying, by the classic HAZOP analysis, any process deviations, the relevant causes (IE) and possible consequences (TE), as well as, by performing subsequent thermalhydraulic simulations for each IE, to individuate if it is capable to really bring the plant to the identified TE. The results of the analyses show that various causes have the potential to bring to fuel cladding break occurrences. However, all these must be coupled with the failure of temperature control at the core outlet. Likewise, some of the above mentioned causes have the potential to determine the secondary coolant vaporization too, once more coupled with outlet core temperature control failure. In particular, evaluating the Fault Tree relevant to the TOP1, a TE frequency equal to 3.854-10~(-5) y~(-1) is obtained.