The operator of the stricken Fukushima Daiichi nuclear plant says dozens of power-generating trucks brought to the plant just after the March 11th disaster mostly proved to be useless. About 70 generator trucks from the Self-Defense Forces and other entities headed to the plant after the quake knocked out external power and the tsunami disabled the facility's backup generators.
But plant operator TEPCO says debris strewn across the compound and flooded switchboards hampered the trucks' set up. The utility says a switchboard for the No.2 reactor was finally wired to one of the generator trucks about 24 hours after the disaster. But moments later, a hydrogen explosion at the neighboring No.1 reactor fried the wiring and cut off the power supply from the truck.
Another hydrogen explosion 2 days later at the No.3 reactor damaged generator vehicles with chunks of flying concrete.
Electricity was finally restored to the plant through the regular power grid on March 21st --- 10 days after the quake and tsunami.
http://www3.nhk.or.jp/daily/english/17_11.html