First victory at Fukushima: workers have sealed radioactive water leak

Sources from Fukushima have reported that the workers have managed to stop the water leak from reactor 2, thus putting an end to the flow of the highly radioactive iodine into the ocean. They had been working around the clock, struggling for almost a month to keep the damaged reactors from overheating. Nevertheless, the Japanese officials warned that the fight is still far from over.

Until Wednesday, radioactive liquid was flowing into the ocean from a cracked concrete shaft near the turbine plant's water intake. Workers managed to seal that breach on Wednesday morning, but officials say they still have other important problems to solve.

"Is it completely stopped? We cannot be optimistic, just because we were able to plug this one." said Yukio Edano, chief of the Secretary Cabinet. Hidehiko Nishiyama of Japan's Nuclear and Industrial Safety Agency said the now-contained water "may lead to more leakage somewhere else."

Precautionary measures have been taken to minimize the risk of any additional explosions at other reactors. TEPCO announced that "The possibility of a hydrogen explosion is extremely low, but more hydrogen could eventually develop in the containment vessel." Hydrogen buildup is a symptom of overheating fuel rods and can cause explosions like the blast that blew the roof off reactor 1 and 3. But Tokyo Electric said it did not believe any explosion was imminent.

Since the leak was discovered (on Saturday, April 2nd), concentrations of iodine-131 measured in the water near the reactor have been million times higher than the legal limites. After plugging the leak, they have dropped dramatically (to less than 4 percent of that amount) in 24 hours, according to figures released by Tokyo Electric. The level remained 280,000 times higher than the legal limit, but these concentrations are dropping fast. The levels of cesium-137 remained higher than those of the iodine (about 61,000 times the legal limit), but much lower than initially measured during the leak.

Samples from a monitoring point 20 kilometers South-East of the plant found iodine-131 levels down to 1.5 times legal limit, with no reading for cesium. Experts said that the existing releases should not pose any long-term health risks to humans or sea life, as most radiatioactive particles detected are iodine-131 which loses half of its radiation every eight days.

Nevertheless, the existence of this still significant amount of radioactive water around the facility suggests that there may be other leaks and other problems.