Explosion at Japan nuclear plant; radiation rises outside

Several workers were injured, authorities say, as damage from the quake and tsunami have left at least one reactor in danger of melting down.

Several workers were injured, authorities say, as damage from the quake and tsunami have left at least one reactor in danger of melting down.

TOKYO // An explosion rocked a quake-stricken Japanese nuclear plant this afternoon, sending a cloud of debris and smoke billowing from the facility.

Several workers were reported injured and radioactivity rose 20-fold outside at the Fukushima Daiichi No 1 nuclear reactor. The walls of a building at the power plant were demolished at the time of the blast, but it was not immediately clear whether the building housed the reactor itself.

Japanese TV warned nearby residents to stay indoors, turn off air-conditioners and not to drink tap water. Radiation immediately outside the plant was reported to produce exposure levels in one hour equivalent to that of an entire year of normal exposure. People going outside were told to aviod exposing their skin and to cover their faces with masks and wet towels.

Authorities had been working for the last day to contain the threat of a meltdown after yesterday's massive earthquake damaged the cooling system. Outside water was being poured into the reactor to cool it down.

“If the water level remains at this level, the reactor core might be damaged, but we are now pouring water into the reactor to prevent it from happening,” a spokesman for Tokyo Electric Power Co said. TEPCO is the owner of the plant, which is located 240 kilometres from Tokyo.

A portion of the reactor’s fuel rods, which create heat through a nuclear reaction, have become exposed due to the cooling-system failure. The spokesman for TEPCO said 1.5 metres of the 4.5 metre fuel rods were potentially exposed.

Loss of cooling water resulted in a near meltdown of the Three Mile Island reactor in Pennsylvania in 1979, the worst nuclear incident in US history.

If coolant is not restored, extreme heat can melt through the reactor vessel and result in a radioactive release. Reactors have containment domes to catch any release. But there is always the chance that an earthquake could create cracks or other breaches in that containment system.

Hideyuki Ban, the co-director of Citizens’ Nuclear Information Center, said, “The Japanese government’s Nuclear and Industrial Safety Agency has said that if the water level can be raised to cover the fuel rods, they can keep the situation under control, but if the water cannot cover the fuel, the damage will become more severe, and that means radioactive materials will be released.

“If damage expands, cesium or other radioactive materials may be released not only inside the containment dome but also into the environment."

-Dow Jones Newswires, Agence France-Presse