Abstract: The present invention relates to a standard fission product emission device, for detecting failed fuel elements in a nuclear reactor of the type cooled by pressurized water, said reactor comprising a pressure-resistant vessel and a core constituted by fuel element assemblies, wherein said device comprises a hollow rod, adapted to be inserted into said vessel and defining a chamber divided into a first chamber and a second chamber located at the end of the rod by a constriction creating a first drop in pressure, said second chamber comprising on its wall a deposit or a metal plate of radioactive material and communicating with the vessel of the reactor, when said device is in position, by a nozzle creating a second drop in pressure greater than the one created by said constriction, a first tube disposed in said rod and opening out at the end of the first chamber remote from the second chamber, said first tube being adapted to be connected to a source of pressurized water at a pressure greater than that of the