Automatic failed fuel element detector

Purpose: To improve the detection accuracy and prevent radioactive exposure to reactor operators by the provision of a sampling vessel on a sampling tube attached to a shipper cap and by the detection of used filters of a filter device provided in a vacuum pump loop by a detector. Constitution: A shipper cap is detachably provided so as to cover the fuel assembly loaded in a reactor core. The shipper cap is connected with an air feed tube communicating a pressurized air source and with a sampling tube communicating a sampling vessel that incorporates a metering vessel. The lower end of the sampling tube is inserted within the channel of the fuel assembly to take out the samples in the channel and store them in the sampling vessel. The samples in the sampling vessel are passed through the filter device to deposit claddings contained in the samples on the filters of the filter device. The used filters are taken out for the radioactivity detection. (Moriyama, K.)