Radioactive water leak into sea stops at Fukushima

TOKYO (AFP) - A leak of highly radioactive water into the Pacific Ocean from Japan's crippled Fukushima nuclear plant was stopped Wednesday, the operator Tokyo Electric Power Co. (TEPCO) announced.

"Workers confirmed at 5:38 am (2038 GMT) that the water running off out of a pit had stopped," the embattled operator said in a statement.

TEPCO had on Tuesday injected sodium silicate, a chemical agent known as "water glass", to solidify soil near a cracked pit, from where highly radioactive water had been seeping through and running into the sea.

The water had been found to have a radiation level of more than 1,000 millisieverts and is believed to be the source of spiking radioactive
iodine-131 readings more than 4,000 times the legal limit in ocean waters. 

The pit, which has a 20-centimetre crack in its wall, is linked to the plant's reactor No. 2, one of those which had its cooling systems put out of action by the quake and tsunami of March 11, triggering the nuclear crisis.

Several unsuccessful attempts had been made to try to plug pipes that run to the pit, using a polymer and even newspapers and sawdust, and an effort to seal the crack with cement had also failed to stop the leak.

Separately, TEPCO has been pumping low-level radioactive water into the sea to free up urgently needed safe storage space for water so toxic that it is halting crucial repair work.

S. Korea concerned over Japan’s dumping of contaminated water

Winds expected to blow radioactive materials here by Thursday


Seoul objected to Japan’s discharge of some 11,500 tons of highly radioactive contaminated water into the ocean Monday amid fears that so much radioactive water could endanger marine life and contaminate the human food chain.

The South Korean Foreign Ministry said it expressed concerns through its embassy in Japan that unleashing the contaminated water with radiation levels 100 times higher than the legally permitted level could infringe on international law and inquired about Tokyo’s next steps.

The Japanese foreign ministry replied that it will leak the contaminated water in small amounts over five days and measure the radiation levels in nearby waters as it continues to discharge. Tokyo also said it will reconsider the discharge once the detected levels exceed the legally permitted amount and look into whether it is against international law, according to Seoul officials.

Tokyo Electric Power Co., which runs the crippled Fukushima Daiichi nuclear power plant, began releasing excess water that has collected at the nuclear facility into the sea Monday evening. Most of the dumped water, 10,000 tons, will come from the plant’s central waste treatment unit which will then be used to store highly radioactive water from the No. 2 reactor.

The concentration of radioactive iodine in the discharged water is about 100 times the legally permitted amount. The power company dismissed concerns, however, saying the amount of radioactive materials an adult could intake by eating fish and seaweed from around the plant every day for a year would be 0.6 millisieverts, lower than the 1 millisievert exposure level set by the government.

Experts around the world say that the radiation will be quickly diluted in the Pacific Ocean, although it could have some negative effect on the sea life near the nuclear plant.

The discharged water’s concentration of radioactive iodine-131 is 6.3 becquerels per cubic centimeter, which is more than triple the radioactivity permitted in food.

International law such as the United Nations Convention on the Law of the Sea and the London Convention ban pollution of the sea by dumping, but provides no set criteria for the amount of contamination allowed to be discharged.

The UNCLOS Article 210 stipulates that states “shall adopt laws and regulations to prevent, reduce and control pollution of the marine environment by dumping” and that such laws “shall ensure that dumping is not carried out without the permission of the competent authorities of States.”

South Korea and Japan have signed an agreement on the peaceful use of nuclear power last December, but the agreement contains no regulation on discharge of radioactive materials into the sea.

A top Japanese official apologized Tuesday for dumping the radioactive water into the sea, acknowledging the damage on fishermen but said it was a necessary evil to avoid even more problems and contamination outside the embattled nuclear facility.

“The water contains a high level of radiation,” Chief Cabinet Secretary Yukio Edano said of the liquid being dumped. “We are sorry for this decision we have to make.”

Meanwhile, winds containing radioactive materials from the Fukushima plant are expected to reach South Korea on Thursday accompanied by heavy rain although the concentration level of radioactive materials reaching Korea will be almost negligible, state-run agencies said.

By Kim So-hyun (sophie@heraldcorp.com)