RADAMES: RAdiation DAMagE in Structural material of fusion reactors under neutron irradiation: cross section measurements and material testing protocols.

The proposal aims to address the issue of radiation damage in structural materials within fusion reactors.

The exceptionally high neutron flux generated in the plasma is anticipated to significantly reduce the lifespan of various components, including the mantle and the divertor, in future fusion power plants. Beyond causing atom displacement and resulting in material structure defects, neutrons induce nuclear reactions leading to transmutation, thereby altering the material’s chemical composition. Additionally, these reactions produce gases, such as hydrogen and helium, which are responsible for bubble formation, leading to embrittlement and alterations in the material’s thermo-mechanical properties.

To estimate the lifetime of reactor components under neutron irradiation, an extensive range of nuclear data is required, particularly data on neutron-induced reaction cross-sections up to 14 MeV—the energy of neutrons produced in the D+T reaction. Experimental studies on radiation damage in structural materials for fusion reactors are expected to occur at dedicated neutron irradiation facilities like IFMIF and its intermediate step DONES, currently under construction. However, the neutron energy spectrum at these facilities includes a high-energy tail extending up to several tens of MeV, well beyond the energy of fusion neutrons. The contribution of this tail to radiation damage must be accurately evaluated and considered to correctly determine the lifetime of reactor components from irradiation tests at IFMIF-DONES. Presently, this can only be accomplished based on high-energy neutron reaction data, which is either entirely lacking or extremely scarce, posing a significant challenge in accurately assessing neutron damage in fusion.

The project aims to conduct measurements of neutron-induced reactions relevant to fusion energy at the n_TOF spallation neutron source at CERN. The unique characteristics of the neutron beam, including high flux and a wide energy range, coupled with the development of high-performance detectors and the use of highly reliable Monte Carlo simulation tools in data analysis, will provide much-needed data for assessing neutron damage in structural components of fusion reactors. Employing a multi-disciplinary approach, the project aims to define a protocol for testing material properties post-irradiation and to explore the feasibility of monitoring techniques based on variations in material physical properties. This final task of the project will establish the groundwork for the proponents’ future participation in the international effort to experimentally determine neutron damage in structural materials for fusion power plants.