Safety lock for mobile instrument trolley in reactor - arrests trolley automatically if subjected to blast of escaping coolant

摘要

A safety device for a measurement instrument unit in a nuclear reactor is designed for retarding and locking in position an instrumentation unit which can normally be driven to and fro by a chain drive mechanism within a guide tube. The moving trolley for the instrument unit comprises a guide and drive plate, this plate is connected to the chain drive via a wedge-shaped component attached to the plate by shear pins. In a fault case if a sudden blast of gaseous coolant occurs, tending to blow the unit and trolley out along the guide tube, the shear pins fracture and the wedge-shaped component immediately jams between the plate and surrounding guide tube, so that the unit is locked in position and not destroyed. Used typically, for a high-temp. gas-cooled reactor.