An external solar receiver, for a concentrating thermodynamic solar power plant of the type with a tower and heliostat field, has a wind tight modular inner structure, also called “casing,” and a plurality of heat exchanger tube receiver panels fastened to that inner structure. Each panel has a plurality of metal boxes supporting the heat exchanger tubes and assembled to one another by assembly means allowing the disassembly, each box being covered with thermal insulation via an anchor. The tubes are secured to the boxes by a removable and floating connector.