For those wondering just why TEPCO and Japan in general have been in such as scramble to cover up as much of the reactor in a concrete sarcophagus, after up until now the utility had been perfectly happy to come up with one after another useless idea of delaying the inevitable moment of sarcophagation, here is Arnie Gunderson from Fairewinds and Associates explaining that now there is definitive proof, courtesy of Tellurium 129 and a order of magnitude higher concentration of Iodine 131 in Reactor 1, that the reactor is now undergoing sporadic events of recriticality: in other words, the fission reaction is recommencing on its own, and without any supervision, emitting undetectable neutron beams which are irradiating any and all personnel still on location. For the time being these recritical events are isolated, although courtesy of the whole premise behind a nuclear power plant, all it takes is for some form of critical threshold to be reached, and for a full blown self-sustaining chain reaction to result in Chernobyl part 2. If nothing else, we now know why the authorities are desperate to bury everything literally under the sand. Because at least a few thousands tons of concrete will provide a modest buffer for unprecedented amount of radiation before these hit the surrounding environment. Lastly, all those hoping that natural rod cooling is sufficient, and if the plant is left along long enough on its own, things will get better, are now proven wrong. We can only hope the outcome this time will be a tad more favorable than all the previously disastrously aborted attempts at restoring order.