The long road ahead for Fukushima cleanup.
[Translated by the Japan Times]If the fuel debris is no longer underwater, which shields engineers from radiation, it is expected to be harder for them to retrieve it. Tepco is also concerned about the possible rise in radiation levels and dust laced with radioactive materials floating inside the containment vessel. JAEA research shows that, judging from the temperature and other conditions, the half-melted fuel debris fell off slowly, leaving the possibility that there still may be something that could trigger a chemical reaction. There have been cases in the past at nuclear power plants when metal caught fire, which was hard to extinguish. It is necessary for Tepco to consider ways to approach this, taking into consideration the possibility that it could trigger a meltdown again and other possible risks as well. It is also important to analyze debris samples to assess whether the concentration of components has changed while it slowly cooled down and solidified. “It became clear that what’s happening to the fuel debris largely differs with each reactor,” said JAEA’s Kurata. “It’s important to proceed based on the assessment of the samples taken instead of relying on past precedents that occurred before the Fukushima meltdowns.”