Application of dense plasma focus devices and lasers in the radiation material sciences for the goals of inertial fusion beyond ignition

V A Gribkov,E V Demina,V N Pimenov,M Paduch,I V Borovitskaya,T Laas,S V Latyshev,E E Kazilin,S V Rogozhkin,S A Maslyaev

doi:10.1063/5.0005852

Abstract

Specimens of materials for prospective use in chambers of nuclear fusion reactors with inertial plasma confinement, namely, W, ODS steels, Eurofer 97 steel, a number of ceramics, etc., have been irradiated by dense plasma focus devices and a laser in the Q-switched mode of operation with a wide range of parameters, including some that noticeably exceeded those expected in reactors. By means of 1-ns laser interferometry and neutron measurements, the characteristics of plasma streams and fast ion beams, as well as the dynamics of their interaction with solid-state targets, have been investigated. 3D profilometry, optical and scanning electron microscopy, atomic emission spectroscopy, X-ray elemental and structural analyses, and precise weighing of specimens before and after irradiation have provided data on the roughening threshold and the susceptibility to damage of the materials under investigation. Analysis of the results, together with numerical modeling, has revealed the important role of shock waves in the damage processes. It has been shown that a so-called integral damage factor may be used only within restricted ranges of the irradiation parameters. It has also been found that in the irradiation regime with well-developed gasdynamic motion of secondary plasma, the overall amount of radiation energy is spent preferentially either on removing large masses of cool matter from the material surface or on heating a small amount of plasma to high temperature (and, consequently, imparting to it a high velocity), depending on the power flux density and characteristics of the pulsed irradiation.

Highlights

Radiation resistance of materials intended for the plasma-facing components (PFCs) of the chambers of nuclear fusion reactors (NFRs) with inertial plasma confinement (IPC) is an important current area of fusion research, since this resistance is essential for successful operation of future reactors of this type
At the distances from the anode used in the experiments with the PF-12 device, the power flux densities of these streams were approximately equal and were lower than those to be expected in NFRs with IPC. % Fe and 2 wt. % Ni) and HPM1810 (W with 1.67 wt. % Fe, 3.33 wt. % Ni, and small amounts of Co and Cu in a binder phase)
It is almost impossible to find changes in the microstructure of the specimen irradiated by two pulses compared with the virgin one, except that there is a greater degree of micro-inhomogeneity on the surface of the latter [compare Figs. 15(a) and 16(a)]

Summary

Introduction

Radiation resistance of materials intended for the plasma-facing components (PFCs) of the chambers of nuclear fusion reactors (NFRs) with inertial plasma confinement (IPC) is an important current area of fusion research, since this resistance is essential for successful operation of future reactors of this type. Among the alternative materials considered for use in PFCs of NFRs with IPC are oxide-dispersion-strengthened (ODS) ferritic and ferritic–martensitic steels.. Among the alternative materials considered for use in PFCs of NFRs with IPC are oxide-dispersion-strengthened (ODS) ferritic and ferritic–martensitic steels.27,33–38 They have enhanced mechanical characteristics at high temperatures (>700 °C) as a result of their high content of dispersed inclusions of oxide particles (Y2O3, Al2O3, TiO2, etc.) of nanoscale sizes. These prevent movement of dislocations and help to increase the stability of grain-restricted structures and their resistance to creep.. Intense lowtemperature embrittlement and a loss of plasticity were observed in specimens of the ODS Eurofer at low doses of neutron irradiation (

Methods

Results

Conclusion