Process for dissolving solids, particularly solid nuclear reactor fuels and dissolving vessel specially for this process

In order to increase the throughput, in a process for dissolving solids in a liquid, a rectification vessel with a sieve bottom column part is used as the dissolving vessel. The solid and the dissolving liquid are introduced into the sieve bottom column part and are taken together through the sieve bottom column part, while the gas flows in counterflow to the solids and dissolving liquid, and the dissolving liquid with the dissolved solids is drawn off from the sump of the rectification vessel. (orig./PW)