Steam, Nitrogen Leak
"Radioactive steam and nitrogen is escaping from the containment vessel at the No. 1 reactor and the company is checking radiation levels around the reactor, spokeswoman Megumi Iwashita said by phone today.
Tepco started injecting nitrogen into the vessel to reduce the risk of a hydrogen explosion. The pressure inside the vessel is rising more slowly than expected, indicating a leak, Iwashita said. Work continues at the reactor and other parts of the Fukushima Dai-Ichi power station, she said.
Earlier today, the company said a hydrogen explosion was unlikely at the No. 1 unit.
“The situation is getting messier, especially at reactor No. 1,” Lauri Myllyvirta, a campaigner for Greenpeace told reporters in Tokyo today. “It seems likely that re-criticality or chain reactions in the fuel are taking place in there. Water isn’t going to be a solution for cooling the extra heat that generates.”