A methodology for the identification of the postulated initiating events of the Molten Salt Fast Reactor

The Molten Salt Fast Reactor (MSFR) with its liquid circulating fuel and its fast neutron spectrum calls for

a new safety approach including technological neutral methodologies and analysis tools adapted to early

design phases. In the frame of the Horizon2020 program SAMOFAR (Safety Assessment of the Molten Salt

Fast Reactor) a safety approach suitable for Molten Salt Reactors is being developed and applied to the

MSFR. After a description of the MSFR reference design, this paper focuses on the identification of the

Postulated Initiating Events (PIEs), which is a core part of the global assessment methodology. To fulfil

this task, the Functional Failure Mode and Effect Analysis (FFMEA) and the Master Logic Diagram (MLD)

are selected and employed separately in order to be as exhaustive as possible in the identification of the

initiating events of the system. Finally, an extract of the list of PIEs, selected as the most representative

events resulting from the implementation of both methods, is presented to illustrate the methodology

and some of the outcomes of the methods are compared in order to highlight symbioses and differences

between the MLD and the FFMEA.