Failed fuel location detector

摘要

An apparatus for detecting the location of a failed fuel assembly among a number of in-core fuel assemblies, which utilizes a combination of a tag gas system and a selector valve system. The fuel assemblies are divided into a plurality of groups and all the fuel assemblies in the same group are tagged with the same tag gas. Coolants flowing out from the respective fuel assemblies are individually sampled by sampling pipes and led into intermediate mixers wherein the coolants are mixed. The groups of fuel assemblies are mutually connected via the sampling pipes to the intermediate mixers such that each group of fuel assemblies has the sampling pipes extending therefrom and connected to each of the intermediate mixers. The group to which the failed fuel assembly belongs is identified by the tag gas system, and the selector valve system identifies which mixed coolant from the intermediate mixers contains fission products released from the failed fuel assembly.