While the situation at reactors # 1, and 3 is stable with cooling by sea-water ongoing, the situation of the spent fuel pool at reactor no. 4 is still very serious and radiation leakage is still continuing. Reactor no. 2 suppression vessel is damaged and cooling is ongoing but the situation was not yet considered stable. Radiation levels are too high for technicians to get close to the reactor #4 pool to inject sea-water. The pool temperature was at 84°C and double the normal temperature of about 40 °C. The 20km zone evacuation around the plant was completed on Tuesday afternoon.
The option of trying to drop water by helicopter through a hole in the roof has been discarded since the pool is offset from the hole.
The use of specialised fire trucks with equipment which would allow water to be injected into the pool is being considered.
Getting fresh cooling water into the pool is now becoming very urgent and unless this is achieved the situation could become critical. As the temperature increases hydrogen could be produced and another hydrogen fire with an associated release of radiation becomes more probable.
Reuters reports that “Two workers are missing after Tuesday’s explosion at one of the reactors at a crippled Japanese nuclear plant, the country’s nuclear safety agency said.
The agency did not identify the missing workers, but said they were in the turbine area of the No.4 reactor at the Fukushima nuclear plant, which was damaged by last Friday’s earthquake and tsunami”.
The k2p blog 