The government and Tokyo Electric Power Co. on Tuesday announced the start of Step 2 of the road map to bring the crisis in the stricken reactors of Tepco's Fukushima No. 1 nuclear power plant under control.

The most important goal in mitigating the crisis is to attain the cold shutdown of the reactors by mid-January 2012.

In Step 2, the government and Tepco hope to constantly keep the water temperature inside the reactors' pressure vessels at less than 100 C. At present, no means to gauge that temperature are available.