Tokyo Electric Power Company (Tepso) has announced that Fukushima Daiichi 2’s reactor core isolation cooling system had failed after an increase in pressure in the containment vessel to some 700 kPa. Serious damage to the reactor core seems likely after coolant was apparently lost for a period. The company prepared to pump seawater into the reactor system, but the water level had already reached the top of the fuel. The water level continued to drop, at which time Tepco began preparations to open a valve to vent the containment vessel. Tepco has since advised NISA that it presumed some of the fuel rods were broken, based on radiation detected in the environment.