TOKYO (AP) Workers started the difficult task Monday of removing nuclear fuel rods from a heavily damaged reactor building at the Fukushima Dai-Ichi nuclear power plant in Japan. It's the first major step toward decommissioning the plant, a decades-long process fraught with uncertainty and challenges.
Q: How many fuel rods are there, and how long will it take?
A: There are 3,106 fuel rod assemblies, each holding about 60-80 rods containing uranium-based pellets inside, in four reactors, Units 1-4. The goal is to remove them over the next five years. What started Monday was the removal of the 1,533 assemblies in Unit 4, which is the only one of the four reactors being decommissioned that didn't melt down. Units 4, 5 and 6 were offline for regular safety checks and maintenance at the time of the March 2011 earthquake and tsunami. Unit 4 had no fuel rods inside its reactor core. The rods have remained in a pool of cooling water 30 meters (100 feet) above the ground inside the reactor building, along with fuel that had been there previously, making them vulnerable to another major earthquake.
Q: How will the rods be removed, and what will happen to them?
A: A crane, mounted inside a massive steel structure built next to and partly over Unit 4, will pull the fuel assemblies one-by-one out of a rack that holds them and put them into a cask that can carry up to 22 assemblies for transport. Another crane, mounted higher up in the structure, will lift the cask out of the pool and place it on a trailer outside the building. Two casks will be alternated, and each cask will then be taken to a nearby pool just above the ground, a much safer storage place. The operation will run around the clock with 36 workers in six shifts. Each cask trip takes several days. The goal is to finish removing the fuel in Unit 4 by the end of 2014.
