Time-Immemorial
Restricted
http://www.smirkingchimp.com/thread/greyraven/64981/fukushima-unit-1-the-corium-has-disappeared
Accordingly, 140 metric tons of corium are no longer in the reactor vessel. The temperatures measured by IRID in the PCV as per August 25. 2015, which generally range throughout the entire Unit 1 complex at around 30 degrees Celsius, appear to confirm this. All that remains is corium “residue” seen on the walls along which it flowed downwards, as described (see images) in the links above.
It should be understood, that when addressing the situation at the Fukushima Daiichi nuclear plant, what we are looking at is not just one catastrophic nuclear event but at four separate events, each harboring their own, distinct risks and dangers. Each of the remaining three units at the site will have to be separately dealt with; one confirmed complete core meltdown with a fully compromised primary containment, two (partial or complete) core meltdowns.
As things stand, there are now well neigh 100+ metric tons of highly radioactive nuclear corium located somewhere beneath Unit 1 at the Fukushima Daiichi site.