NHK: Scientists to use detectors ‘deep underground’ to look for Fukushima fuel; It’s ‘believed’ to have cooled down, but no one can check — Officials: We don’t know if water is covering fuel — Expert: Water must be circulating around fuel or it will melt again
NHK’s ‘Nuclear Watch’, Aug. 20, 2014: Looking Inside Fukushima Daiichi… One of the biggest hurdles they’re facing is how to remove melted fuel… First they need to know the condition of the fuel. Experts believe it has cooled down and turned into debris. But engineers with TEPCO have not been able to check the actual state of the debris… detectors will be used to track the behavior of muons… in a bid to determine the status of the molten fuel… Kenichiro Okamoto: Team members face big challenges… The molten fuel inside the reactors is believed to have sunk to the bottom of the containment vessels. So scientists must place the detectors around the vessels deep underground. The job is made even more difficult as the whole area is… flooded with contaminated water…An engineer I spoke to expressed some concerns… Haruo Miyadera, a scientist with Toshiba: “Taking [detectors] to the site and assembling them in a radioactive environment will be tough. We need to do more work.” Another obstacle is the extremely high radiation being emitted by the surroundings. This creates noise that could disrupt the study… If this happens, researchers won’t be able to correctly grasp the situation inside the reactors. These are just some of the issues that the studies must address.
TEPCO officials 2 months ago:
- Teruaki Kobayashi, Tepco official: “We cannot tell at this point if the fuel is entirely submerged or if part of it’s above the water.”
- NHK: Officials at Tepco… don’t know whether [the water] even covers all of the nuclear fuel… Nothing is known about the condition of the melted fuel in all 3 reactors.
What happens to when the fuel is uncovered?
Dr. Gordon Edwards, court-certified nuclear expert, Crystal Kids Radio, Aug. 8, 2014 (at 49:00 in): “If you don’t remove that heat by circulating water, by flushing water through the core of the reactor, then the temperature is going to go up and up and up. It goes up so high that the fuel itself starts to melt… They have to pump about 400 tons of water… to prevent them from overheating again. They’re going to have to do this for at least 7 or 8 years, maybe longer, maybe 10 years.”