Abstract: In a method of inspecting heat exchanger tubes of a heat exchanger in which the heat exchanger tubes are fixed in position by spacers and serve to transfer heat from a first medium to a second medium that is fluid-tightly separated from the first medium, a measuring probe is introduced into an heat exchanger tube to be inspected. A wall section of the heat exchanger tube is subjected to an electromagnetic alternating field generated by the measuring probe resulting in local eddy currents within the subjected wall section. An eddy current sensor that is rotatable in the circumferential direction of the heat exchanger tube is guided in the longitudinal direction of the subjected wall section of the heat exchanger tube. A voltage signal induced by the eddy currents within the wall section is picked up with the eddy current sensor. The voltage signal varies locally as a function of the condition of the material of the wall section, the thickness of the wall section, and the presence of a spacer.

Abstract: Method and apparatus for avoiding potential accidents in water-cooled nuclear reactors of the type having an enclosing containment, due to the formation of an explosive gas mixture in the containment. Air is withdrawn from the containment and fed to at least one internal combustion engine as combustion air for the engine. The exhaust gases created by the internal combustion engine are then recycled back into the containment. The result is the lowering of the oxygen partial pressure in the containment to below the critical limit for oxyhydrogen explosion.