Workers record the status of instruments at the power plant
Braving exposure to radiation, the engineers dubbed the 'Fukushima 50' are shown attempting to repair power lines and recording data in a darkened control room.
Other images taken on March 18, a week after the Daiichi nuclear plant was damaged by a huge earthquake and tsunami, show fire crews at work on the site.
Now, the country's nuclear safety agency said more workers at the plant had needed treatment after being exposed to radiation.
"Three workers who were laying cables in the basement of the turbine building were exposed to radiation between 170 to 180 milli-sieverts," a spokesman for the Nuclear and Industrial Safety Agency (Nisa) said.
Two were sent to hospital after they found themselves in a puddle of water. Although they wore protective clothing, the contaminated water seeped in and their legs were exposed to radiation."
Exposure of 100 milli-sieverts per year is considered the lowest level at which any increase in cancer risk is evident.
About two dozen people have been injured since the plant began leaking radiation after suffering tsunami damage on March 11.
Technicians have now restored power to the reactor number one control room.
The progress means workers can now use two crucial control rooms - at reactors One and Three - which they were earlier forced to abandon after a series of explosions and amid strong radiation and in darkness.
The quake and tsunami cut electricity to the plant and knocked out backup systems, causing the cooling systems to fail.
This left the fuel rods inside to heat up and evaporate water, threatening a full meltdown.
More than 20 people have been injured since the plant was damaged