Leak detection system for a nuclear reactor

Claim 1

In a leak detection system for a nuclear reactor of the fluid cooled type and having an external leakage detection monitoring means, the improvement comprising a slide valve adapted to be supported internal of the reactor and having an elongated cylinder member with a plurality of equally spaced sampling ports aligned along a lower portion of the cylinder and a plurality of equally spaced flush ports aligned 180* removed from the sampling ports, a flushing port being positioned between each adjacent sampling ports, said sampling ports adapted to connect to various reactor fuel subassemblies through sampling tubes and said flushing ports open to the reactor coolant, a movable slide member fully positioned within the cylinder, said slide member cooperating with the cylinder to define an outlet chamber along the upper portion of the cylinder, said outlet chamber adapted to connect to the monitoring means via a throughgoing conduit and an annular chamber extending along the slide member and terminated by an enlarged sampling head, said head having a sampling duct therein for direct alignment with the sampling ports and communicating with the outlet chamber through a central duct in the slide member, said sampling head also including an annular peripheral chamber communicating with the sampling duct, said sampling head dimensioned to form a slight gap between the head and cylinder and to extend between adjacent flush ports when the sampling duct is in direct communication with a sampling port, whereby said sampling member alternately aligns with a sampling port and a flush port to sequentially draw samples from all the sample ports, said coolant from the reactor acting both as the flush and the seal for the slide valve.