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a b s t r a c tTorsion tests at high temperatures and high strain rates were conducted on a high nitrogen steel (HNS). Under these conditions, adiabatic heating influences its flow behavior. This work focus on a new algorithm for conducting the adiabatic heating correction of stress-strain curves. The algorithm obtains the stress-strain curves at quasi-isothermal conditions from those at adiabatic conditions. The corrections in stress obtained can be higher than 15% and increase with increasing strain rates and decreasing temperatures. On the other hand, an upper bound for the temperature rise was found using a dynamic material behavior approach. Finally, the influence of adiabatic heating correction on the Garofalo equation parameters of HNS was analyzed. High values of activation energy and stress exponent were attributed to reinforcement by dispersed particles and the high amount of alloying elements.

IFMIF-DONES is a powerful neutron irradiation facility for the study and qualification of materials planned as part of the European roadmap to fusion-generated electricity. Its main goal is to study properties of materials under severe irradiation in a neutron field similar to the one in a fusion reactor first wall. It is a key facility to prepare for the construction of the DEMO power plant envisaged to follow ITER. The decision to start the construction of IFMIF-DONES is expected imminent. In this paper we present and discuss several key technical studies and decisions to improve and optimize the engineering design of IFMIF-DONES which were carried out as part of the activities in the framework of the EUROfusion Early Neutron Source work package (2015–2020). The following topics are discussed in this paper: the new layout of the IFMIF-DONES SRF LINAC accelerator and high-energy beam transport line, 7Be impurity management approach for the lithium loop, a maintainable test cell concept, a revised layout of the access cell for the remote maintenance operations, and facilities for complementary experiments.

Isothermal stress-strain curves data from torsion tests conducted at high temperature (950-1200 ºC) and strain rates (2-26 s-1) were analyzed in a ultrahigh carbon steel (UHCS) containing 1.3%C. The sine hyperbolic Garofalo equation was selected as an adequate constitutive equation for the entire range of the forming variables considered. The Garofalo parameters were assumed strain dependent allowing the prediction of stress-strain curves under transient and steady-state conditions. The average relative errors obtained were below 3% in stress. In addition, the creep deformation mechanisms in the UHCS were analyzed from the Garofalo equation parameters. For this aim, the stress exponent of the Garofalo equation was, for the first time, related to that of the power law equation. The results show that the controlled deformation mechanism at steady-state is lattice diffusion-controlled slip creep.

The International Fusion Materials Irradiation Facility (IFMIF) is a projected accelerator-based, D-Li neutron source for fusion reactor materials qualification. LIPAc (Linear IFMIF Prototype Accelerator) is an accelerator aiming to generate a 125 mA, 9 MeV continuous wave deuteron beam, which is currently being commissioned in Rokkasho (Japan) with the objective of validating the IFMIF accelerator design. In LIPAc, a 10 m long High Energy Beam Transport line (HEBT) will connect the exit of the superconducting linac to the beam dump (BD). The HEBT line must accommodate the diagnostics for beam characterization and open the beam at the end to allow its stopping at the BD. The line contains several magnets to control the beam shape and its trajectory, maintaining beam losses below 1 W m−1 along the beamline to limit activation of surrounding elements and allow hands-on maintenance. In this work, the LIPAc HEBT line project is described since its origins. A summary of the beam dynamics calculations and other studies (vacuum, radioprotection, assembly, alignment) that led to the conceptual design of the line is done. After that, the detailed design of the line is presented, justifying the main design decisions taken and finally, the manufacturing and procurement process and the acceptance tests performed are summarized.