Gauge Newsletter January 2020 | Page 44

The main radionuclide released from Fukushima Daiichi was iodine- 131. It has a half-life of 8 days. Other than that, cesium-137, which has a 30-year half-life and Cs-134 was also produced and dispersed which has a two-year half-life. On 7 September 2011, TEP- CO president Toshio Nishizawa said that the four damaged reactors will be scrapped and it will take 30 years to finish. In 2021, they are planning to begin the removal of the melted fuel inside the reactors. It had been 9 years since the disaster and the cleaning of the neighboring area is still going on. Significant efforts are being taken to clean up radioactive material that escaped the reactor. Washing down buildings and scraping away topsoil is still happening. According to the plans, all areas with radiation levels above 1 millisievert per year would be cleaned. Radiation levels between 5 and 20 millisieverts should be cut down to 60% by 2013. On 22 February 2012, TEPCO started cementing the seabed near the plant to prevent the spread of radioactive materials into the sea. Some 70000 square meters of the seabed around the intake of cooling water would be covered with 60 centimeters thick cement. And it prevents the spread of contaminated mud and sand at that place for at least 50 years. The Japanese government introduced 3 zones according to radiation levels. 1. No-entry zones, with annual radiation exposure of 50 millisieverts or more. At these places, habitation would be prohibited. 2. Zones with annual radiation exposures between 20-50 millisievert. Here, former residents could return, but with restrictions. 3. Zones with exposures of less than 20 millisieverts per year. In these zones, the residents would be allowed to return to their houses. Six years after its evacuation, Namie is about to reopen. The cost of this disaster is already up to 202.5 billion dollars. And it could rise to 650 billion dollars. Nuclear energy is one of the cheapest and cleanest energy sources in the world. But, if something goes wrong, it can be a huge disaster and we have two such experiences until now. Therefore, we should try to make it safer and prevent disasters like Fukushima and Chernobyl. N.K.B.Lakshan Madhushanka Bandara, Third Year - Department of Electrical and Electronic Engineering, Faculty of Engineering University of Peradeniya. Page 42 University of Peradeniya GAUGE Magazine