Official: Fukushima fuel melted "on unprecedented scale" - French Gov't: Parts of the coriums have been dispersed - AP: It's location and condition are unknown
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NHK WORLD, Dec. 17, 2013: [...] The International Research Institute for Nuclear Decommissioning [established by Japan's government] [...] held a session in Tokyo on Tuesday [...] They are seeking technologies to examine the condition of the melted fuel [...] They are also looking for possible ways to remove fuel debris [...] The institute's managing director, Kazuhiro Suzuki, said the fuel melted on an unprecedented scale but that he believes there are numerous technologies in the world that can be applied to this work. [...]

AP, Dec. 15, 2013: Japan is incapable of safely decommissioning the devastated Fukushima nuclear plant alone and must stitch together an international team for the massive undertaking, experts say, but has made only halting progress [...] there is the daunting challenge of taking out cores that suffered meltdown, which is the most dangerous type of nuclear power accident. Their exact location within the reactor units isn't known and needs to be ascertained so their condition can be analyzed. [...] The lack of experts is worse at the regulatory level. The tally is zero. Japan's Nuclear Regulation Authority has no one devoted to decommissioning, said spokesman Juntaro Yamada [...]

IRSN (France), August 2013: [...] since the accident, the water used to cool [...] degraded nuclear fuel. It picks up radioactivity, particularly by leaching of the most mobile elements still contained in the corium. In this respect, although uranium and transuranian elements have very limited solubility, certain fission or activation products are more easily dispersible in water (caesium, strontium, antimony [...]