Activation of nuclides in a flowing fluid across a spatially varying neutron field

The EU-DEMO design is exploring several blanket models, including the Water Cooled Lithium Lead blankets. In this blanket model, liquid LiPb will be used as both the tritium breeder and multiplier. This liquid will experience a spatially varying neutron field as it moves across the tokamak. The production of radioisotopes would depend on the flow parameters of LiPb across this spatially varying neutron field. In this study, we have explored the production of radioisotopes in such a field and compared it with an equivalent, static, non-flowing simulation. While static calculations are simpler and computationally less expensive, we find that the predicted production of a radionuclide deviates from flowing fluid simulations to varying degrees, depending on the radionuclide’s half-life. We also demonstrate how the computational methodology developed can be used to explore online tritium extraction parameters and their impact on the End-of-Life tritium inventory. • Simulations of flowing fluid demonstrate that the production of a radionuclide can deviate from equivalent predictions without flow, depending on its half-life. • A computational methodology has been developed to explore the impact of tritium extraction parameters on the end-of-life inventory. • In LiPb, 210 Po is produced continuously via beta decay, and so its concentration is strongly influenced by the flow path • The short half-life of 207m Pb means that its predicted concentration is the same in both the static and flowing scenarios.