International Thermonuclear Experimental Reactor Vacuum Research Articles

Non-stationary volume-adsorption model for pumping of vacuum chambers

The non-stationary mathematical model of pumping of gas, located in the volume and adsorbed on the inner surface of vacuum chambers is considered. A feature of the model is the use of variation of adsorption heat with respect to the logarithm of the degree of coverage obtained from the Frendlich adsorption isotherm. The relations between pressure, gas release, heat of adsorption, the amount of adsorbed gas and the pumping time are calculated. The existence of a regular pumping mode is shown. Experimental verification of the model confirms the theoretical calculations. The model makes it possible to specify the pumping time of International Thermonuclear Experimental Reactor vacuum chambers and to obtain a significant economic effect when selecting pumping means by reducing the safety factor.

Influence of Forming Residual Stresses on the Welding Distortions of Two Thick Plates

The manufacturing of the ITER (International Thermonuclear Experimental Reactor) vacuum vessel involves the welding of thick deformed plates. The aim of this study is to investigate the influence of forming residual stresses on the welding distortions of two thick plates. The plates are deformed using a three point rolling process. A first numerical simulation is performed to investigate the residual stresses induced by this process. The forming residual stresses are taken into account as initial conditions to perform the electron beam welding simulation of a deformed plate. This simulation first requires calibrating the heat source. Two welding simulations are then performed: the first one with residual stresses and the second one without. The comparison of the simulation results points out a low effect of the residual stresses on the electron beam welding distortions. As a result, in the next electron beam welding simulations of the vacuum vessel, no forming residual stresses will be taken into account.

Fusion reactor vacuum vessel cooldown

Abstract The paper discusses a new approach to the International Thermonuclear Experimental Reactor vacuum vessel (W) cooldown. The approach is based on equalizing temperatures of the inside and outside VV walls and securing approximately equal coolant flow rates through W components under normal operating conditions and in emergency situations. It is based on the coolant flow rate redistribution in clearances between the walls and the in-vessel steel/water shielding plates as well on the application of a two-circuit VV cooldown system with the use of an ebullience pipe.