A sensitivity analysis of the factors that influence the hazard potential of fusion power plants

Abstract

• Hazard potential critically depends on plant design and radioactive source term. • Release height and weather conditions at time of release are crucial. • Ground level releases under DF2 conditions gave most limiting results. • Opportunity for plant designers to design out or minimise tritium and dust source terms. A robust safety case for a fusion power plant for electricity generation must demonstrate that the radiological risk to workers and the public under any credible accident scenario is as low as reasonably practicable (ALARP). Whilst the hazard potential of a fusion power plant is significantly less than that of a fission power plant, a fusion power plant will still contain radiological inventories. From the work done in previous fusion safety studies and the current work being undertaken for the ITER project, it has been established that there are certain accident scenarios in which a part of these radiological inventories can be released into the atmosphere, potentially posing a risk to workers and members of the public. The actual radiological risk to an exposed person depends on a multitude of factors including type of inventory released, quantity released, height of release, weather conditions and age of person exposed, amongst others. The aim of this paper is to assess the radiological dose received by an exposed population under a variety of conditions, to put these releases into context by comparing them with sheltering and evacuation emergency reference levels (ERLs) and to discuss the impact of siting a fusion power plant near local populations.