At the crippled Fukushima nuclear power plant in Japan, scientists are running out of space for the plant’s enormous amounts of irradiated water. The radioactive water is being stored in thousands of tanks, and contains tritium, a substance that is hazardous to health. About 300 tons need to be pumped into the plant every day to keep its reactors cool.
Tritium can be removed from water in laboratories, but such an effort would be preposterously expensive, so scientists have another idea in mind: dumping the nuclear waste into the ocean.
The scientists say the risks are minimal, but many Japanese residents are understandably frightened and upset. The nation’s fishermen staunchly oppose the plan, fearing a release of the water could devastate local fish stocks. 
More important than the fish supply is the potential toll a release of tritium could have on human health. The substance goes directly into the soft tissues and organs of the body, potentially increasing the risk of cancer and other illnesses.
The Japanese government has been trying to downplay the risk to the public. Japan’s Parliamentary Secretary even sipped from a glass of decontaminated water taken from puddles inside the buildings housing reactors 5 and 6 in front of news cameras.
But there is a fine line between safe and unsafe radiation. Robert Daguillard, a spokesman for the EPA, said:
“Any exposure to tritium radiation could pose some health risk. This risk increases with prolonged exposure, and health risks include increased occurrence of cancer.”
Children are particularly at risk.
Rosa Yang, a nuclear expert at the Electric Power Research Institute, based in Palo Alto, California, isn’t worried. She says the amount of tritium that would be released into the water would amount to just 57 ml – about the amount of liquid in a couple of espresso cups. According to Yang, that amount would be barely a drop in a bucket compared to the size of the oceans.
Shunichi Tanaka, chairman of the Japanese Nuclear Regulation Authority, those couple of espresso cups-worth of tritium would be well below the global standard allowed for the substance in water.
“The substance is so weak in its radioactivity it won’t penetrate plastic wrapping.”
But the reassurances aren’t likely to calm the nerves of locals. There is so much distrust that Tokyo Electric Power Co. (TEPCO), the utility that operates Fukushima and oversees its decommissioning, has had little to say about the tritium. It is believed that the company is waiting for a decision from the Japanese government.
Privately, TEPCO officials say it will have to be released, but they can’t voice that publicly. 
In 2011, Fukushima was irreparably damaged when a 50-foot tsunami slammed into it following a 9.0 magnitude earthquake. It was the worst nuclear disaster since Chernobyl in 1986. The 2 are the only disasters ever to be given the most severe grade, 7, by International Nuclear and Radiological Event Scale (INES).
More than 18,000 people died in the disaster, and 450,000 people had to be evacuated when deadly radiation spewed from the plant. 
 Daily Mail
 ABC News