Fusion Neutron Source – Technical Meeting 1

The 1st Fusion Neutron Source Technical Meeting (FNS TM1) was held remotely on February 09, 2023, to share the status of the FNS Unit activities.

The first session was focused on the Lithium Target Facility activities (LF) that are the engineering validation activities in BA phase II (from 2020) aiming to perform additional R&D in order to improve the reliability of the individual systems from the viewpoints of long-term operation.

The progress of the construction of Li loop facilities were presented for both the 1:10 scale pilot plant (Japan) and the full-scale test loop (EU). The first experimental results of the erosion-corrosion of Target Assembly and ELTL (EVEDA Lithium Test Loop) material were discussed before being used to feed its modelling. The experimental setup for the study of the stabilization method of used/leaked Li including radioisotopes was completed and enabled the start of the experiments. Following the finalization of the Li fire experimental setup, the conclusion of the first experiments on Li fire risks identified the levels of humidity without ignition.

The second session was focused on the Engineering Design activities (ED) that are theactivities in BA phase II (from 2020) aiming to obtain relevant information for the design of an IFMIF-like Neutron Source concerning the safety reduction. Many modelling and experimental studies were presented. 

The possibility of storing the lithium after its stabilization was investigated within the tritium migration estimation. Experimental studies on a stabilization treatment are currently underway.

The erosion-deposition modelling in the target system for FNS enabled the evaluation of the absorbed dose rate of the primary heat exchanger oil due to the activated erosion-corrosion products. The modelling activities are now focused on the corrosion.

In order to complement the accident analysis in safety, an environmental impact assessment was performed using the PUFF code developed to study the tritium atmospheric release from FNS facilities. Additionally, the first draft of failure mode analyses activities is expected to be available in June 2023 including references to the top-level safety regulations.

The irradiation campaigns of the candidate oils for the heat transfer fluid in the primary heat exchanger were performed with simulations in JA using the dibenzyl toluene properties and experiments in EU using hydrogenated terphenyls to investigate the behaviour at different gamma dose rates. As main results, a good stability under gamma irradiation has been found up to 13 MGy (dose expected in DONES after 40 years of nominal operation).

Evolution of EU oil candidate colour due to the gamma radiation at NAYADA facility (CIEMAT, Spain) up to 13 MGy