Workers Return To The Fight At Crippled Nuclear Plant

Tokyo -- Workers at the Fukushima Daiichi nuclear power station returned to the plant Friday after a strong aftershock forced them to leave a day earlier, the plant's owner said.

The quake forced crews at the plant to evacuate as it rattled northern Japan late Thursday night. They returned to the plant about eight and a half hours later, and no fresh damage to the facility had been reported Friday afternoon, the Tokyo Electric Power Company said.

Before the quake, engineers had been injecting non-flammable nitrogen into the No. 1 reactor containment shell to counter a buildup of hydrogen in the chamber. That process continued while the plant was evacuated, and so did the pumping of fresh water into that reactor and units 2 and 3, said Hidehiko Nishiyama, a spokesman for the Nuclear and Industrial Safety Agency.

Hydrogen buildup is a symptom of overheated fuel rods in the cores of the reactors, which plant workers have been struggling to keep under control since the earthquake and tsunami. The nitrogen injections are aimed at displacing oxygen in the reactor shell, reducing the possibility of an explosion -- a chance Tokyo Electric called "extremely low."