Explained: How and where will Japan release the contaminated water from Fukushima Nuclear Disaster?
Fukushima Nuclear Disaster:
- A nuclear disaster happened at Fukushima Daiichi Nuclear Power Plant on Japan's coast in March 2011. An earthquake of magnitude 9.0 Ritcher scale caused a tsunami that flooded the critical control equipment of the nuclear power station and caused a meltdown.
- Now after 10 years too the plant workers cool the wreckage with water.
- The Tokyo Electric Power Company or TEPCO is now dealing with a new issue of radioactive water piling up at the site.
- Now Japan is planning to release the water into the sea . Tokyo Electric Power Company Holdings Inc would begin the process of pumping out the water in about 2 years after the treatment process is completed. The process is expected to take decades to complete.
- This move which has been made after a decade is actually a blow to the fishing industry of the country too. To deal with this the Government of Japan has come up with a premise.
- The water needs to be filtered again to remove harmful isotopes and will be diluted to meet international standards before any release.
How does the reactor work?
- The reactor consists of enclosed rods of uranium pellets. Uranium is naturally radioactive and undergoes fission. This means that the atoms of Uranium split at a specific rate releasing neutrons and heat.
- In the reactor fuel, the natural ability of Uranium is harnessed and it is split apart in a chain reaction. The heat that results from the process boils water which in turn drives the steam turbines to generate electricity.
- The fuel rods are surrounded by control rods to absorb extra neutrons and the fuel is immersed in water to keep it cool.
- Before the earthquake 3 of the reactors were in use and functioned smoothly to generate electricity.
- The tsunami flooded the critical operating equipment and cooling systems turned dysfunctional.
- The workers contained the meltdown and kept the smoldering site cool for 10 years by pumping water into the buildings but now a huge amount of radioactive water is left with nowhere to put it.
How were the 10 years managed?
- The company used a makeshift system of pumps and pipes to pour water into the damaged reactor vessels to keep melted uranium fuel rods cool.
- The water is contaminated as it is coming in contact with the fuel before the leaking into damaged basements and tunnels. It mixes there with the groundwater. The combination results in excess contaminated water pumped out and treated before being stored in huge tanks crowding the site.
- These tanks hold 1.3 million tonnes of radioactive water, enough for about 500 Olympic sized swimming pools.
How will the water be purified again?
The water will be filtered again to remove the isotopes leaving behind only tritium, which is a radioactive isotope of hydrogen hard to separate from water. Tepco would dilute the water until tritium level falls below the regulatory limits. It would be then pumped directly into the ocean. Tritium is considered to be less harmful to humans than other radioactive materials. Once released, the process would take 10 years to complete.