This report outlines the use of fire engines in an attempt to inject water into the reactors at Fukushima Daiichi. After the tsunami much of the cooling function on site was lost. The slides below document what fire engines were on site at what time, and what sources of water were injected where. Later research shows that little of the injected water made it to the reactors due to the lack of backflow valves in the fire line systems. Most of the injected water flowed into the condensers in the turbine buildings.
The slides below came from the FDADA site for the decommissioning authority