European Commission JRC G.I.4 Task Force on Molten Salt Reactors (MSRTF) : safety analysis and assessment of molten salt reactors

Molten Salt Reactors (MSR) constitute one of the most promising designs seemingly able to solve the most challenging issues related to the use of nuclear energy for power generation: possibility of large radionuclide releases, nuclear waste and nuclear safeguards. However, MSRs also present a large set of novel features when compared to most of the nuclear reactors in operation whose technology is based on encapsulated solid fuel and water as coolant and moderator. Such large technology differences make the risk of non-compliance with the nuclear safety licensing framework increase. Bearing this aspect in mind, a careful, comprehensive safety evaluation parallel to the development of the design becomes key. This report presents the fundamentals of a safety-by-design approach to Molten Salt Reactors consisting of the integration of safety from the first steps of the design. Such integration is conducted through a dedicated methodology that starts by identifying and prioritizing the safety-related activities by means of a Safety Activity Ranking Table (SART) and planning through Safety Work Plan. Once the activities have been ordered upon dedicated importance criteria, each of them is analysed via Evaluation-Model Phenomena Identification Ranking Table (EM-PIRT) out of which safety is assessed and feedback to the design provided.