Gauge Newsletter January 2020 | Page 41

Inside the reactor vessel, the fuel rods are immersed in water, which acts as both a coolant and a moderator. The moderator helps slow down the neutrons produced by fission to sustain the chain reaction. Control rods can then be inserted into the reactor core to reduce the reaction rate or withdrawn to increase it. The water turns into steam by the heat created by fission. The steam spins a turbine to produce carbon-free electricity. Radioactive materials that are used for the chain reactions are hazardous. Nuclear radiation can ionize chemicals in the cells, which changes the way the cells behave. It can also deposit large amounts of energy into the body within a few seconds, which can damage or destroy cells. The risk associated with radioactive materials depends on the amount of dose we get. In other words the time of exposure. Being exposed to highly radioactive materials or being exposed to radioactive materials for long periods or regularly, increase the dose received, which in turn increase the risk. The world witnessed the first nuclear power plant disaster in April 1986. The disaster happened at the Chernobyl nuclear power plant in Ukraine. It was the product of a flawed Soviet reactor design, coupled with serious mistakes made by the plant operators. It was a direct consequence of the Cold War. GAUGE Magazine University of Peradeniya Page 39