LAUSR

Abstract The fusion neutron source is an advanced facility for scientific research, testing structural materials of future fusion reactors, nuclear waste utilization, fissile fuel production and control of sub-critical nuclear systems. Tokamak is one of the most promising systems to build fusion neutron sources with a fusion power over 10 MW. Plasma maintenance requires the injection of fuel mixture containing hydrogen isotopes (deuterium and tritium) into the vacuum chamber with subsequent fuel pumping and processing. To simulate hydrogen isotope flows in the fusion neutron source fuel system, the FC-FNS model of the fuel cycle has been developed. This paper describes the modification of FC-FNS model and includes the results of calculations of tritium inventories in the DEMO-FNS fusion neutron source with different T/D ratios in plasma. Fuel pellet injection (separately injection of D2, T2 and DT) from the HFS and LFS is the main method of fueling. Frequency of D/T pellet injection providing the stable plasma operation for different NBI gas supply scenarios was chosen. Tritium inventory in the fuel cycle depending on the scenario and D:T ratio in plasma was calculated. Use of the D + T beam is reasonable only when T fraction in plasma equals 0.5, while the D – beam is more effective with higher fraction values within the range of 0,6–0,7.