UPDATE 1-Q+A-What's going on at Japan's damaged nuclear power plant?

"Japanese engineers are struggling to gain control of the Fukushima Daiichi nuclear power plant, 240 km (150 miles) north of Tokyo, which was seriously damaged by the March 11 earthquake and tsunami.

Two of the six reactors at the plant, operated by Tokyo Electric Power Co (TEPCO), are considered stable but the other four are volatile." Reuters