Japan's government said Wednesday that it could take 40 years to clean up and fully decommission the Fukushima nuclear plant that went into meltdown after it was struck by a huge tsunami.

Under a detailed roadmap approved earlier Wednesday following consultation with experts and nuclear regulators, plant operator Tokyo Electric Power Co (TEPCO) will start removing spent fuel rods within two to three years from their pools located on the top floor of each of their reactor buildings.

After that is completed, they will begin removing the melted fuel, a process that is expected to begin in 10 years and be completed 25 years from now. The location and conditions of the melted fuel is not exactly known.

The process still requires the development of robots and technology that can do much of the work remotely because of extremely high radiation levels inside the reactor buildings. Officials say they are aiming to have such robots by 2013 and start decontaminating the reactor buildings in 2014.

The operator and the government would also have to ensure a stable supply of workers and save them from exceeding exposure limits while keeping the long process going.

They also have to figure out ways to access each containment vessel and assess the extent of damage, as well as locate holes and cracks through which cooling water is leaking and flooding the area.

The decades-long process also would place an enormous financial burden on TEPCO. The ministers said that the total cost estimate cannot be provided immediately, but promised that there will be no delay because of financial reasons.