Potential common radiation problems for components and diagnostics in future magnetic and inertial confinement fusion devices

Abstract

Keywords: Nuclear fusion Inertial confinement Magnetic confinement Radiation damage Materials DiagnosticsThis work aims at identifying common potential problems that future fusion devices will encounter for both magnetic and inertial confinement approaches in order to promote joint efforts and to avoid duplication of research. Firstly, a comparison of radiation environments found in both fusion reaction chambers will be presented. Then, wall materials, optical components, cables and electronics will be discussed, pointing to possible future areas of common research. Finally, a brief discussion of experimental techniques available to simulate the radiation effect on materials is included.

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].…”

“…In both cases, laser (with direct drive target) and magnetic fusion, the most detrimental situations that W components must face are originated by intense ion pulses [4]. These pulses produce very high thermal loads [8,9] that may result in fatal thermomechanical response of the W components.…”

Object kinetic Monte Carlo simulations of irradiated tungsten for nuclear fusion reactors

“…From the thermomechanical point of view, the temperature at the PFM surface will approach 3000 K [10,11] in the case of edge-localized modes (ELMs) or pulsed irradiation with α particles and ion debris in ICF. In Table 1.1, the main characteristic parameters are compared [11] for a typical direct-drive target (yield per shot of 154 MJ) in the case of ICF and conditions assumed for ITER in the case of MCF.…”

“…In Table 1.1, the main characteristic parameters are compared [11] for a typical direct-drive target (yield per shot of 154 MJ) in the case of ICF and conditions assumed for ITER in the case of MCF. The heat flux parameter (H = E·Δt 1/2 ) Tungsten is proposed as a convenient PFM for both first-wall in ICF [13][14][15][16][17] and divertor regions in MCF [18][19][20][21][22][23].…”

“…In both cases, inertial fusion with direct drive target and magnetic fusion, the most detrimental situations that tungsten components must face are those originated by intense ion pulses [11] (see Chapter 1). Numerous studies [33,37] images reveal that swelling and pore formation take place, which eventually lead to W exfoliation with mass loss.…”