RESEARCHES FOR THE CANDU NUCLEAR REACTOR FUEL CHANNELS DECOMMISSIONING. PART 2 - FUNCTIONING AND OPERATING OF THE DECOMMISSIONING DEVICE

Abstract

The paper scope is to present the main functioning steps of the decommissioning device and to achieve the operating panel of the horizontal fuel channels decommissioning device and its operating presentation. The horizontal fuel channels decommissioning device from the CANDU nuclear reactors is a electromechanical system with many freedom degrees, capable to perform the internal components extraction of the horizontal fuel channels, operations performed under a control system equipped with a Programmable Logic Controller (PLC) and monitored by an operator panel, Human Machine Interface (HMI) type. The system is automated, each operation step shall be confirmed by the operator after its finalization, to preparing the next operation step. The system is designed to control the actuators and sensors, to supervise the proper performance of the operations execution. The operations performed from the operator panel (HMI) consists of platform positioning, coupling and locking the device at the fuel channel, unblock, extract and store the channel closure plug, unblock, extract and store the channel shield plug, block and cut the middle and the end of the pressure tube, block, extract and store the end fitting, block, extract and store the half of pressure tube, mounting of the extended closing plug. The operations are monitored by the internal sensors and transducers, by pyrometer for temperature during the cutting process and cameras for the dismantling components video surveillance. The operations steps are performed by the cutting and extraction device and by the extraction actuator from the device handling elements assembly. After each dismantling step is necessary the confirmation its finalization in order to perform the next operation step. The dismantling operation steps of the fuel channel components are repeated for all the 380 reactor fuel channels, from the front of calandria side (plane R) as well as the rear side (plane R'). The fuel channel decommissioning device shall provide radiation protection during the dismantling stages, ensuring radiation protection of the workers.