Three level Dashpot oil level monitoring system

Abstract

Nuclear reactors use free fall of control and safety rods (CSR) for a fast shutdown of the reactor in case of emergencies to prevent radioactive hazards. During the last 250mm of the total 1085mm of travel of the CSRs, there is a dashpot with oil to facilitate the smooth descent of the control rods. This oil prevents any shock to the system due to the sudden fall. Thus, there is a requirement to measure the level of dashpot oil to ensure the healthiness and smooth functioning of the system. The earlier systems involving a dipstick or a capacitor level probe can be more inaccurate due to temperature and noise effects with stringent software verification and validation requirements. In order to accomplish this, a novel optical sensor has been created.