International Fusion Materials Irradiation Facility
In fusion power plants, neutrons will be present at fluxes in the order of 1018 m−2s−1 and will interact with the material structures of the reactor by which their spectrum will be broadened and softened.
[7][8] Therefore, conventional fast fission reactors, which produce neutrons with an average energy around 1-2 MeV, cannot adequately match the testing requirements for fusion materials.
[9] Spallation neutron sources provide a wide spectrum of energies up to the order of hundreds of MeV leading to potentially different defect structures, and generating light transmuted nuclei that intrinsically affect the targeted properties of the alloy.
Ion implantation facilities offer insufficient irradiation volume (maximum values of a few hundreds µm layer thickness) for standardized mechanical property tests.
[12][13] In the 1980s, the rapid advances in high-current linear accelerator technology led to the design of several accelerator-driven neutron sources for satisfying the requirements of a high-flux high-volume international fusion materials testing facility.
The energy of the beam (40 MeV) and the current of the parallel accelerators (2 x 125 mA) have been tuned to maximize the neutron flux (1018 m−2 s−1) while creating irradiation conditions comparable to those in the first wall of a fusion reactor.
The Li screen fulfills two main functions: to react with the deuterons to generate a stable neutron flux in the forward direction and to dissipate the beam power in a continuous manner.
The control of impurities, essential for the quality of the liquid screen, will be done through a tailored design of cold and hot trap systems, and purities of Li during operation better than 99.9% are expected.
Based on numerical analyses carried out in the last three decades, the beam-target interaction is not expected to have a critical impact on jet stability.
The Post-Irradiation Examination facility, an essential part of IFMIF, is hosted in a wing of the main building in order to minimize the handling operations of irradiated specimens.
