Radioactive water removal hits snag, high iodine detected in sea

Kyodo News: Radioactive water removal hits snag, high iodine detected in sea
Efforts to remove radiation-contaminated water filling up at a troubled reactor building and an underground trench connected to it at the crisis-hit Fukushima Daiichi nuclear power plant have hit a snag, casting a shadow on restoration of the vital cooling functions at the site, the government's nuclear safety agency said Wednesday.

The evolving nuclear crisis also showed no signs of abating, as the agency said the same day the highest concentration of radioactive iodine-131 was detected Tuesday in a seawater sample taken near the plant's drainage outlets in the Pacific Ocean. The density was 3,355 times the maximum level permitted under law.

Workers rushed to pump out radiation-polluted water that has been filling up the basement of the No. 1 reactor's turbine building and the tunnel-like trench connected to it, but they found out Tuesday a tank accommodating the water from the building had become full, the Nuclear and Industrial Safety Agency said.

The engineers also newly spotted water polluted with low-level radiation at a building designed for radioactive waste disposal at the plant, where the trench water is meant to be transferred. They nonetheless finished laying hoses to discharge the trench water, according to the agency.

Despite the halt of water-pumping operations at the No. 1 turbine building, the depth of stagnant water was confirmed to have been halved to 20 centimeters, the agency said.

On Wednesday evening, smoke was temporarily seen rising from a power distribution panel at the No. 1 reactor of the Fukushima Daini nuclear plant, some 10 kilometers south of the Daiichi power station, but it soon disappeared.

No radiation leak was confirmed from the site and nobody was injured in the incident, the plant operator Tokyo Electric Power Co. said.

At the Daiichi plant, radioactive water has also been soaking the basements of the Nos. 2-3 reactor buildings and filling the underground tunnels linked to them. The operator known as TEPCO continued work to secure enough space to accommodate the polluted water at the plant's tanks.

Hidehiko Nishiyama, a spokesman for the governmental nuclear regulatory body, told a press conference that the stagnant water obstructs attempts by TEPCO to revive the key cooling functions at the plant, which were paralyzed after the March 11 magnitude 9.0 quake and ensuing tsunami.

TEPCO has been pouring massive amounts of water into the reactors and spent nuclear fuel pools at the plant as a stopgap measure to cool them down, because serious damage to fuel rods from overheating could lead to the release of enormous amounts of radioactive materials into the environment.

However, pouring the water is believed to be linked to possible radiation leaks from the reactors, where fuel rods have partially melted.

''This will not lead to a sustainable condition. We want to restore power and rebuild the cooling system, but such efforts are hampered by the stagnant water,'' Nishiyama said. ''We have to find a way out of the contradictory missions'' of the incoming water and the removal of contaminated water.

As steps to resolve the situation, a member of the Nuclear Safety Commission of Japan, a government panel, has suggested digging a pool outside the turbine buildings in case the pumped contaminated water exceeds the capacity of the tanks.

TEPCO Chairman Tsunehisa Katsumata told a news conference that the firm's attempts to bring the nuclear emergency under control will take a long time, saying it is ''difficult to stabilize the reactors within several weeks.''

As for the future of the crippled plant, Katsumata said the company sees decommissioning the Nos. 1-4 reactors as inevitable. Chief Cabinet Secretary Yukio Edano also indicated that all six reactors at the plant should be scrapped.

Experts had suggested that the emergency injection of seawater into the Nos. 1-3 reactor cores to cool them down would eventually lead to their dismantlement, as salt and impure substances in seawater causes equipment corrosion.

Nishiyama said it is expected to take at least 20 years to finish the procedures to decommission the six-reactor Fukushima plant. Katsumata said TEPCO considers it as an option to cover the troubled reactors with ''stone coffins'' made of concrete and iron, a solution adopted in the 1986 Chernobyl nuclear crisis.

Meanwhile, the nuclear agency said TEPCO will take measures to improve conditions for workers who have been battling to put the situation under control at the Fukushima plant by preparing a variety of meals and spacious rest stations equipped with tatami mats.