Neutron flux detectors esp. for gas cooled reactor - housed in retractable tubes inside liner tube in concrete vessel wall

摘要

Appts. for carrying out safety and/or operating measurements in a liner tube of a nuclear reactor pressure vessel, esp. a concrete pressure vessel contg. a gas-cooled reactor, comprises a first guide tube, constructed of one or more tube lengths, which can be introduced into the fixed liner tube. Inside this guide tube one or more single-component or multi-component guide tubes are fitted, each contg. a detector in the region of the inner wall face of the concrete vessel. Further out from these detectors, each of the smaller guide tubes contans a shielding plug. The detectors and shielding plugs can be inserted into these inner guide tubes. Pref. each detector is connected to the associated shielding plug by a flexible connection. The outer end of the outer guide tube pref. bears through a shelding ring and/or spacer ring against the closure cap of the liner tube. Electrical supplies to the detectors are by cables passing as helical coils through the shielding plugs. Used esp. for gas-cooled reactors, typically high-temp. reactors, housed in concrete pressure vessels.