Abstract: The invention relates to a method and an arrangement for operating a system in which dismantling works are performed underwater in a liquid-filled vessel (10) of a nuclear facility, the liquid being guided in a circuit (20) and flowing through at least one filter device (26, 28, 30). The liquid in the circuit flows through at least a first filter device (26) in the form of a coarse filter and a second filter device (28), in which at least one device from the group of ion exchangers (1, 2, 3), reverse osmosis systems, ultrafiltration systems, activated carbon filters, zeolite filters, and biological filters is used for filtration.

Abstract: The invention relates to an arrangement for dismantling a container (10) which comprises a circumferential wall (20) and an opening surrounded by said wall and which has a screening cover (14) situated above the opening, and to a dismantling tool for cutting segments (42, 44, 46, 53, 56) out of the circumferential wall. The dismantling takes place in such a way that regions of the circumferential wall which have a hollow cylindrical geometry are successively cut into segments and these segments are then removed. After a segmented region having the hollow cylindrical ring geometry has been removed, an end edge of the remaining circumferential wall is available. The screening cover has a lowering device for successively lowering the screening cover onto a particular available end edge.

Abstract: The invention relates to a method for dissolving an oxide layer containing chromium, iron, nickel, and radionuclides by means of an aqueous oxidative decontamination solution, which contains permanganic acid and a mineral acid and which flows in a circuit (K1), wherein the oxidative decontamination solution is set to a pH value ?2.5.