Reactor and Method for Carrying out a Chemical Reaction

A reactor has a reactor vessel and one or more reaction tubes. One or more power input elements are guided into the reactor vessel for the electrical heating of the reaction tube(s). The one or more power input elements each have a rod-shaped section, and the rod-shaped section(s) each run in a respective wall passage through a wall of the reactor vessel. A connection chamber into which the rod-shaped section(s) project is arranged outside the reactor vessel and adjacent to the wall of the reactor vessel through which the rod-shaped section(s) run in their wall passages. Gas feed means apply an inerting gas to the connection chamber, and the wall passages with the rod-shaped sections received therein in a longitudinally-movable manner are designed to be gas-permeable so that at least a portion of the inerting gas fed into the connection chamber flows out into the reactor vessel.