Outcomes of activation measurements and analyses of ITER materials during JET DTE3 operations
The 2023 JET deuterium–tritium (D–T) experimental campaign (DTE3) achieved record fusion energy output (69 MJ), providing a unique 14.1 MeV neutron environment for irradiation studies. A range of ITER material samples were exposed in a Long-Term Irradiation Station (LTIS) within the JET nuclear environment to neutron fluxes up to 2 × 10¹³ n/cm²/s, reaching total fluences of 7 × 10¹⁵ n/cm² — the highest achieved in a tokamak. Post-irradiation analysis using high-resolution gamma spectrometry across five laboratories identified a range of neutron-induced activation products present in these samples, which were quantitatively compared with neutronics simulation predictions. Complementary neutron fluence measurements with metallic dosimetry foils located in the LTIS enabled validation of the simulation approach via MCNP and FISPACT-II codes. The DTE3 results, combined with those from prior D–T campaigns, together provide a highly valuable dataset for ITER, supporting the validation of predictive modelling tools towards sustained high-power D–T operations.