Abstract: A bioreactor for culturing microorganisms which has a reactor vessel, a plurality of gas-introduction tubes and a gas-introduction system for introducing gas into a culture medium in the gas-introduction tubes via injectors, wherein the gas-introduction tubes are connected by their respective lower end, in the vertical direction, to the reactor vessel and by their opposite upper end to the upper end of an upright vessel which is likewise connected by its lower end to the reactor vessel, and at the upper end of the upright vessel an expansion vessel is arranged.

Abstract: A bioreactor for culturing microorganisms which has a reactor vessel, a plurality of gas-introduction tubes and a gas-introduction system for introducing gas into a culture medium in the gas-introduction tubes via injectors, wherein the gas-introduction tubes are connected by their respective lower end, in the vertical direction, to the reactor vessel and by their opposite upper end to the upper end of an upright vessel which is likewise connected by its lower end to the reactor vessel, and at the upper end of the upright vessel an expansion vessel is arranged.

Abstract: A method for the electropermeation of living cells between at least two electrodes over a predetermined interval with an electrical potential or a current, characterised by the following features:a voltage or current source which is not exhaustable over the interval is applied to the electrodes via a controllable power semiconductor functioning as a regulator;the course of the potential or of the current during the interval is predetermined by a setting value transducer which generates any selectable course of curve, and is inputted to a controller which is connected in front of the driver step for the power semiconductor;the controller receives a value, as an instantaneous value, corresponding to the actual potential or current applied at the electrodes;the interval has a time range of a few 100 ns to several minutes.

Abstract: A clay layer of low permeability and of a thickness of about 2 meters, depending somewhat upon the permeability, immediately covers and laterally surrounds the external concrete wall and roof structure of the nuclear reactor building, this layer extending at least down to a ground water draining or leading ground layer. Above it is a layer of gravel, sand or porous stone of relatively high permeability, typically somewhat less than a meter thick, and on top thereof an earth fill layer of less permeability than the intermediate layer is provided, which is typically 8 meters thick. The clay layer, which could also be a loam layer, prevents the emergence of radioactive materials in the event of cracking of the concrete structure by an accidental malfunction and absorbs aerosols and water-soluble fission products. The gravel layer converts the convective mass flow of the emerging materials into a diffusion flow and prevents the spreading of cracks in the covering layers.