Japan: Toxic leak plugged at crippled N-plant

Japanese workers at the tsunami-hit Fukushima nuclear plant on Tuesday plugged a crack leaking highly toxic water into the sea from a concrete pit, though authorities were concerned about a possible hydrogen blast due to the build up of gas at a stricken reactor. The leak of radioactive water from a seaside pit located near the No 2 reactor, which was detected on Saturday last, stopped at 5.38 hours (local time) after the plant operator, Tokyo Electric Power Company, injected some 6,000 liters of chemical agents, including "water glass" or sodium silicate.

The government's nuclear safety agency said it has ordered TEPCO to keep monitoring the pit to check whether the water leakage into the Pacific Ocean has completely stopped, nearly four weeks after quake and tsunami struck Japan's northeast leaving nearly 30,000 people dead or unaccounted for. There is a possibility that the water, which has lost an outlet, may show up from other areas in the plant's premises, it said.

The highly radioactive water is believed to have come from the No 2 reactor's core, where fuel rods have partially melted, and ended up in the pit. The pit is connected to the No 2 reactor's turbine building and an underground trench connected to the building, both of which were found to be filled with high levels of contaminated water. TEPCO also said that it may inject nitrogen into the No 1 reactor's containment vessel where hydrogen gas was building up.

Hidehiko Nishiyama, a spokesman for the Nuclear and Industrial Safety Agency, said the move is being considered in a bid to stop a possible hydrogen explosion "in advance" and that it does not mean there is an "immediate danger," Kyodo news agency reported. The nitrogen injection process is expected to take several days, and may lead to the release of radioactive substances in the air.

Blasts caused by a build-up of hydrogen gas took place earlier in three reactors in the aftermath of the earthquake. To make room to store the highly radioactive water that is hampering the plant's restoration work, TEPCO is also dumping into the sea massive amounts of low-level contaminated water from a nuclear waste disposal facility at the site, as well as from the No 5 and 6 unit buildings, a move which has triggered concerns among neighbouring countries. The move would be followed by some repair work to make sure the facility can keep highly radioactive water safely without fear of the stored liquid leaking outside.

Due to the March 11 mega quake and tsunami, the plant's power grid and most of its emergency diesel generators were knocked out, resulting in the loss of many of the reactors' key cooling functions, partial melting of reactors cores and hydrogen explosions. A seawater sample taken near the No 2 reactor water intake on Saturday showed a radioactive iodine-131 concentration of 7.5 million times the maximum level permitted under law. High levels of iodine -- about twice the legal limit for vegetables -- were found in launce, a small fish, which was caught off Ibaraki prefecture to the south of Fukushima.

Anxiety is growing about seawater contamination and safety of seafood, especially after TEPCO dumped water containing relatively low levels of radioactive materials into the sea this week. Chief Cabinet Secretary Yukio Edano acknowledged that the government should have informed the public and Japan's neighbouring countries in a more efficient manner in advance about TEPCO pumping out a massive amount of radioactive water into the Pacific Ocean, and expressed his apology.

The National Federation of Fisheries Cooperatives Associations issued a statement, lodging a strong protest with the utility and the government. It said that fishermen are "immeasurably angry" at the "irresponsible" conduct of releasing toxic water into the sea without any prior consultation with them.

The head of the federation, Ikuhiro Hattori, held talks with TEPCO Chairman Tsunehisa Katsumata, asking the company to compensate the losses incurred by fishermen due to the crisis, Kyodo said. Also, countries likes South Korea said they were dissatisfied with Japan's way of disclosing information regarding its efforts to contain the crisis at the nuclear plant. TEPCO had made an announcement about the release of radioactive water into the sea at the last minute on Monday.

Edano said fishermen, whose marine products have been affected by the release of radioactive particles from the tsunami-ravaged Fukushima Daiichi nuclear plant, should receive provisional compensation. He said, it is natural for marine products affected by the nuclear crisis to be part of the upcoming compensation programme in the same manner as agricultural products.

His remarks came a day after TEPCO unveiled a plan to pay provisional compensation, probably by the end of this month, to residents and farmers living near the crippled nuclear complex. The utility has said it will make tentative estimates of the amounts to be paid out in consultation with the government, though there are no signs that the nuclear crisis will end anytime soon.