Japan stops highly radioactive leak into Pacific

Photo by Jason Tighe

Photo by Jason Tighe

TOKYO -- Workers stopped a highly radioactive leak into the Pacific off Japan's flooded nuclear complex Wednesday, but with the plant far from stabilized, engineers prepared an injection of nitrogen to deter any new hydrogen explosions.

Nitrogen can prevent highly combustible hydrogen from exploding -- as it did three times at the compound in the early days of the crisis, set in motion March 11 when cooling systems were crippled by Japan's 9.0-magnitude earthquake and tsunami.

Nuclear officials said there was no immediate threat of more explosions, and but the nitrogen plans were an indication of the serious remaining challenges in stabilizing reactors at the Fukushima Dai-ichi plant and halting the coastal radiation leaks that have cast a shadow on northeastern Japanese fisheries.

Nitrogen normally is present inside the containment that surrounds the reactor core. Technicians will start pumping more in as early as Wednesday evening, said Junichi Matsumoto, a spokesman for the plant operator. They will start with Unit 1, where pressure and temperatures are highest.

There was a rare bit of good news Wednesday when workers finally halted a leak of highly contaminated water into the ocean that had raised concerns about the safety of seafood. By Wednesday afternoon, radiation at a point 360 yards off the coast was 280 times the legal limit, down from a high of more than 4,000.