Investigations continue at the Fukushima Daiichi nuclear power plant in Japan, and earlier this week the Tokyo Electric Power Company (Tepco) released photos of the first nuclear material that they’ve actually managed to get out of one of the reactors.
As a quick recap, the unit 4 reactor was shut down when a magnitude 9 earthquake and 14m tsunami struck the Fukushima Daiichi plant on 11 March 2011. It was actually in the middle of refuelling when the emergency struck, and as a result, its old fuel was in a pool atop the reactor, along with a fresh batch. Since the accident, many people have worried that the fuel in unit 4 constitutes a serious safety risk, particularly if there’s another earthquake.
All summer long, Tepco’s been busy demolishing the top of the unit 4 reactor to try and get at the fuel (the reactor was damaged in a fire that may have started as a result of the meltdown at unit 3). In July, the successfully extracted a single fuel assembly, and this week, they unveiled photos of the assembly under inspection.
An assembly is basically a lot of long little straws filled with pellets of uranium fuel. This particular one is filled with fresh fuel, so it’s not particularly radioactive (which is why everyone is standing around it). This one also does not appeared to be damaged at all, which is pretty remarkable considering what it’s been through. There is a little corrosion on the rods, but that could be precipitated iron from the water used to cool the pool, according to Margaret Harding, a nuclear engineer based in Wilmington, North Carolina. There is some debris from the fires and explosions in the bottom of the pool as well.
The condition of the rod is a positive sign: it means that it may be possible to begin unloading the roughly 1,500 fuel assemblies from the unit 4 pool and move them to a common storage area that will be considerably safer than the current location. In fact, workers have already removed the heavy lid of the reactor’s pressure containment vessel to make way for the unloading operation.