Materials Research for HiPER Laser Fusion Facilities: Chamber Wall, Structural Material and Final Optics

Abstract

The European HiPER project aims to demonstrate commercial viability of inertial fusion energy within the following two decades. This goal requires an extensive Research & Development program on materials for different applications (e.g., first wall, structural components and final optics). In this paper we will discuss our activities in the framework of HiPER to develop materials studies for the different areas of interest. The chamber first wall will have to withstand explosions of at least 100 MJ at a repetition rate of 5-10 Hz. If direct drive targets are used, a dry wall chamber operated in vacuum is preferable. In this situation the major threat for the wall stems from ions. For reasonably low chamber radius (5-10 m) new materials based on W and C are being investigated, e.g., engineered surfaces and nanostructured materials. Structural materials will be subject to high fluxes of neutrons leading to deleterious effects, such as, swelling. Low activation advanced steels as well as new nanostructured materials are being investigated. The final optics lenses will not survive the extreme ion irradiation pulses originated in the explosions. Therefore, mitigation strategies are being investigated. In addition, efforts are being carried out in understanding optimized conditions to minimize the loss of optical properties by neutron and gamma irradiation.

Effect of ion flux on helium retention in helium-irradiated tungsten

“…This is due to a number of features that it presents: low sputtering yield, low-activation, high melting point, high thermal conductivity and low thermal expansion [1][2][3]. In the case of inertial confinement fusion by laser (laser fusion) with direct drive targets (as it is the case of the European project HiPER) W is proposed as an armor material [4,5] with the function of protecting the underlying structural materials against the intense ion fluxes stemming from the target explosions. Furthermore, W is considered the material of choice for the first wall and divertor of future magnetic fusion power plants [6,7].…”

Neutronics and activation of the preliminary reaction chamber of HiPER reactor based in a SCLL blanket

“…It is considered to be composed of 1 mm of tungsten mounted onto 1 cm of EUROFER97. The survivability of this component has been addressed in other studies inside the HiPER project [7], and it is out of the scope of this work. The FW cooling is still under discussion in the HiPER project [8], but for this study it is assumed that the FW heat removal will be through the blanket cooling circuit.…”

Ultraintense Lasers as a Promising Research Tool for Fusion Material Testing: Production of Ions, X-Rays and Neutrons

“…A complete characterization of these noxious factors also requires the consideration of synergetic effects between the impinging radiation/species and their role in the mentioned processes. Thus, reactions between C and H isotope atoms, non linear high radiation flux effects (fluxes >10 20 /cm 2 /s), changes in the physical and chemical properties of the materials and their influence in the evolution of defects need to be studied in a reasonable time scale [4].…”

“…Ledingham et al [34] for the most recent results. According to Ledingham, the most promising nuclear reactions for generating neutrons using intense lasers are (gamma,n), (gamma, fision), (p,n), d(d,n) 3 He and d(t,n) 4 He. Based on those reactions, neutron yields of around 10 9 -10 10 neutrons per shot have been reported for large laser systems (pulses >100 J).…”