The planned high-profile experiments during 2020 at the Joint European Torus (JET), notably including a deuterium-tritium (DT) experimental phase, are expected to produce large neutron yields, in the region of 10²¹ neutrons. The scientific objectives are linked with a technology programme, WPJET3, to deliver the maximum scientific and technological return from those operations. The data expected to be retrieved under this program will support, develop and improve the radiation transport and activation simulation capabilities via benchmarking and validation in relevant operational conditions. Such capabilities are important and are applied extensively to predict a wide range of nuclear phenomena and impacts associated with components and materials that will be used in ITER operations and more generally in fusion power plant design.

This presentation emphasises the progress on experimental activities conducted within the ACT subproject under WPJET3. The overall aim, now entering an important phase in 2020, is to take advantage of the significant 14 MeV neutron fluence expected during JET DT operations to irradiate samples of materials that will be used in the manufacturing of main ITER tokamak components, such as SS316L steels from a range of manufacturers, SS304B, Alloy 660, W, CuCrZr, OF-Cu, XM-19, Al bronze, NbTi, Nb₃Sn, and EUROFER. Experimental results include gamma spectrometry measurements of irradiated samples following the DD JET campaigns in 2015-16 and more recently in 2019. The samples comprise dosimetry foils (Ti, Mn, Co, Ni, Y, Fe, Sc, Ta) and various ITER material samples, exposed to JET neutrons in the long-term irradiation station or via the JET KN2 pneumatic transfer system. Measurements using a range of dosimetry foils have been used to derive neutron fluence and spectra as part of the effort to characterise these irradiation locations. Experimental results are compared to the latest simulations using MCNP6 with FISPACT-II performed with fusion-relevant nuclear data libraries.