Abstract: A method for the production of an electrochemical cell and an electrochemical cell stack is disclosed with annular electrolyte arranged in a pressure vessel. Such a cell is produced by providing an annular precursor already provided with the electrodes where the product is converted to the desired membrane/electrolyte by heating and oxidation. By using a pressure vessel, pressure can also be generated during the conversion. To this end the region outside the cell is provided with a fill material. A number of cells can be stacked on top of one another. With this arrangement, the anode of one cell can act as cathode of another cell by means of a Z-shaped configuration. Adjacent anodes/cathodes can be applied to one another by welding or can be of a Z-shaped design.

Abstract: Fuel cell stack in which anodes and cathodes, and preferably also the membrane separating these, are made of relatively brittle material. To prevent the risk of breakage, and thus leaks, these are enclosed with a tight fit in a pressure vessel and mechanical pressure is produced on raising the temperature. The pressure vessel is preferably of elongated construction and a number of fuel cells are arranged alongside one another. The opposite ends of the pressure vessel delimit compartments for the supply and removal of one of the reactants. The other reactant is supplied to the pressure vessel and removed therefrom close to the ends of the fuel cells.

Abstract: Fuel cell stack in which anodes and cathodes, and preferably also the membrane separating these, are made of relatively brittle material. To prevent the risk of breakage, and thus leaks, these are enclosed with a tight fit in a pressure vessel and mechanical pressure is produced on raising the temperature. The pressure vessel is preferably of elongated construction and a number of fuel cells are arranged alongside one another. The opposite ends of the pressure vessel delimit compartments for the supply and removal of one of the reactants. The other reactant is supplied to the pressure vessel and removed therefrom close to the ends of the fuel cells.

Abstract: A chimney which can be reconfigured or removed during refueling to allow vertical removal of the fuel assemblies. The chimney is designed to be collapsed or dismantled. Collapse or dismantlement of the chimney reduces the volume required for chimney storage during the refueling operation. Alternatively, the chimney has movable parts which allow reconfiguration of its structure. In a first configuration suitable for normal reactor operation, the chimney is radially constricted such that the chimney obstructs vertical removal of the fuel assemblies. In a second configuration suitable for refueling or maintenance of the fuel core, the parts of the chimney which obstruct access to the fuel assemblies are moved radially outward to positions whereat access to the fuel assemblies is not obstructed.