Abstract: A fuse device for an automatic emergency shutdown system in fast reactors provides a coupling between a casing tube placed within a fuel can and a series of neutron-absorbing masses held together above the reactor core under normal operating conditions but released in free fall to the lower portion of the casing tube at the level of the reactor core as a result of melting of the fuse when operating characteristics such as temperature or neutron flux attain a level which exceeds a predetermined threshold.

Abstract: The present invention concerns an improvement to the method for detecting a steam micro-leak in a heat-exchanger having circulation tubes surrounded by an alkaline/molten/metal (e.g. liquid sodium), said improvement consisting in using the normal operating fluid of the exchanger (in particular, water) as the hydrogenated tracer fluid, in injecting an inert gas successively into groups of tubes comprising at least detecting device (which is based on the measurement of hydrogen, in particular in sodium) until a zero reading, indicative of the leaking tube, is observed.

Abstract: In a fast reactor in which each cooling loop comprises the primary sodium circuit which exchanges heat with the sodium of a secondary circuit by means of an intermediate heat exchanger, each cooling loop comprises in parallel with the secondary sodium circuit an auxiliary secondary circuit in which a chemically inert gas extracts heat from the primary sodium, said secondary auxiliary circuit being equipped with at least one gas turbine which is supplied with the inert gas and operates in a closed energy-producing gas cycle.

Abstract: The present invention relates to a method of and apparatus for enabling the visualization of isometric physical condition maps of a three-dimensional test object, the physical condition being for example the amplitude of vibration of the test object or the contour of the object. The latter is studied by the striation method whereby flat parallel light beams on light on the object forming a system of striations thereon; there is superimposed on the image in a given direction of the illuminated object a corresponding image of a typical comparison object, the resultant superimposed image being a coded representation of the physical condition of the test object. A television camera is used to analyze the successive images of the system of striations formed on the surface of the object.

Abstract: In a method of widening the zone of stable operation of an axial-flow fan, and of attenuating noise generated thereby, a portion of the flow medium is drawn off upstream of the fan and is returned to a zone at the periphery of the fan rotor. The invention also includes an axial-flow fan for carrying out the method.