A novel encoding water level monitor system during and after LOCAs in a nuclear heating reactor Original Research Article

The water level in a nuclear reactor vessel is an important parameter during and after LOCAs. Nuclear safety specifications can not be carried out when the water level is measured using a pressurizer which does show the level in the vessel. It is difficult to monitor the water level in the vessel of a Daqing 200MW Nuclear Heating Reactor (NHR-200) using the present differential pressure transducers. Based on the heat transfer differences between water (or liquid) and steam (or gas), a novel level detector, which includes encoding heating shell thermocouples, has been developed and verified for use experimentally under pressures of 0.15–3.0 MPa. A novel encoding water level monitoring system was designed, made up of an assembly that contains several detectors, a signal encoder and an intelligent processor. Analysis and experiments have shown that the new system is correct in principle, reliable and feasible in structure for monitoring the water level in the NHR-200 reactor.