The system of diffusion filling with hydrogen isotopes for a batch of spherical shells up to pressures of 1000 atm at 300 K

Abstract: The current promising developments in controlled inertial fusion energy (IFE) are aimed at creating a power facility for mass fabrication of cryogenic fuel targets (CFT) and their high rep-rate delivery to the irradiation zone of a powerful laser. To ensure continuous operation of a IFE reactor, the thermonuclear burn region should be refilled with fuel at the rate of about 1 million targets per day. At the same time, handling an array of free-standing CFTs at each step of a closed operation cycle is a key requirement for the reactor technology design. The first step in the CFT fabrication is filling of hollow spherical shells with a fuel, which is deuterium or a deuterium–tritium mixture. The CFT shells are made of polymer, glass, beryllium, or high-density carbon. In world practice, it is customary to carry out the filling step either by diffusion of fuel gas through the CFT shell wall or by injecting liquid fuel through a thin capillary (several microns in diameter) built into the shell wall. The latter method is extremely problematic for future applications because it disrupts the integrity and symmetry of the shell and precludes rep-rate injection of the CFT into the laser focus. Based on data from many experimental runs, we present results on the optimization of a diffusion filling system first developed at the Lebedev Physical Institute (LPI) for filling a batch of free-standing polymer and glass shells (dia. 0.8 to 2.0 mm) with hydrogen isotopes to pressures of 1000 atm at 300 K. These results are unique and have no counterparts in the world.

Keywords: inertial fusion energy (IFE), cryogenic fuel target, batch of shells, diffusion filling system, hydrogen fuel.