Speaker
Description
The UNITY (Unique Integrated Testing Facility) is currently under construction in Japan. The facility will be capable of performing integrated testing of components necessary for the primary and secondary thermal cycles used in power generation and fuel cycle of early fusion power plants. The thermal section of the facility will have heating capacity for blanket modules up to 0.1 m² of plasma-facing surface area. Of the three liquid coolants supported (Li, LiPb, FLiBe), the LiPb loop will be connected first, with an inventory of 100 litres. A uniform magnetic field of up to 4 T can be generated with a pair of NbTi magnets for liquid metal magneto hydrodynamics testing. A plasma exhaust pumping system for the inner fuel cycle, direct internal recycling, a fuel clean-up system, tritium extraction from the coolant, and storage will be integrated into one system, using deuterium as a proxy for tritium. As future iterations of UNITY will use tritium for fuel cycle demonstration, we conduct a safety evaluation of a hypothetical tritium release in accidental conditions, assuming the use of deuterium and tritium instead of only the deuterium proxy. The safety assessment goal for UNITY is to demonstrate that it can be easily sited in Japan (or another country), without public health and environmental concerns, or the need for any emergency planning. We employ proven risk assessment methodologies to select the most representative accident scenario in terms of potential consequences. From this scenario, we estimate the quantity of radioactive materials that could be released from a simplified loop. We also undertake a literature review of the likely tritium release fraction that is then used in the assessment. Finally, we perform a sensitivity analysis to identify the most impactful parameters, enabling us to make design-impacting decisions and proportionate safety systems.
