From UPSC perspective, the following things are important :
Prelims level : Heavy Water
Mains level : Nuclear pollution
In a controversial move, Japan has decided to dump the radioactive heavy water from the Fukushima nuclear power plant into the Sea. The dumping of nuclear waste is considered to be the easiest way to get rid of it.
What is Heavy Water?
- Heavy water (deuterium oxide) is a form of water that contains a larger than normal amount of the hydrogen isotope deuterium rather than the common hydrogen that makes up most of the hydrogen in normal water.
- Heavy water is used in certain types of nuclear reactors, where it acts as a neutron moderator to slow down neutrons.
- Slowed neutrons are more likely to react with the fissile uranium-235 than with uranium-238 which captures neutrons without fissioning.
Where is Fukushima waste?
- It is currently being stored in large tanks, but those are expected to be full by 2022.
- Almost 1.2 million liters of radioactive water from the Fukushima nuclear power plant is to be released into the ocean.
- The contaminated water has since been used to cool the destroyed reactor blocks to prevent further nuclear meltdowns.
Hazards of the nuclear contamination
- Radioactive pollution in the ocean has been increasing globally — and not just since the disaster at Fukushima.
- Radiation levels in the sea off Fukushima were millions of times higher than the government’s limit of 100 Becquerel.
- A single Becquerel that gets into our body is enough to damage a cell that will eventually become a cancer cell.
- Even the smallest possible dose, a photon passing through a cell nucleus, carries a cancer risk. Although this risk is extremely small, it is still a risk.
Who else dumped radioactive water into oceans?
The dumping of nuclear waste in drums was banned in 1993 by the London Convention on the Prevention of Marine Pollution. But discharging liquid contaminated with radiation into the ocean is still permitted internationally.
- The lion’s share of dumped nuclear waste came from Britain and the Soviet Union, figures from the IAEA show.
- By 1991, the US had dropped more than 90,000 barrels and at least 190,000 cubic meters of radioactive waste in the North Atlantic and Pacific.
- To this day, around 90% of the radiation in the ocean comes from barrels discarded in the North Atlantic, most of which lie north of Russia or off the coast of Western Europe.