I called the R4 fuel pool down a couple of days ago. It certainly isn't on the 4th floor of the reactor anymore because the reactor building has been torn down. A large amount of dust was generated by this operation. The concrete in these walls have been subject to neutron bombardment for the past 15 months. This makes the chemical elements in this material radioactive. The main isotopes to be found in this dust, among others, would include cobalt-60, europium-152 and -154, cesium-134, scandium-46, zinc-65, barium-133, and manganese-54. There exists a huge mess which cannot be mitigated at this point. During the day you can sometimes see activity here:
The 'official' TEPCO camera has been offline since the MAG 5.2 EQ that occurred at Fukushima hours ago. In fact there have been several earthquakes, two very near the Fukushima plants..
4.6M, depth: 48km 28/6/2012 16:415.2M, depth: 42km 28/6/2012 14:514.5M, depth: 48km 28/6/2012 13:55
I am now able to postulate a potential extinction event. The cooling is inoperable at all of the reactors and I believe we will begin to see smoke from nuclear fires within a couple of days. Anyone in line-of sight to one of the reactors (that is – looking down into it) will die within an hour and will get a years' dose of radiation in about 20 seconds. Therefore the people who are still working there won't be for very long.
The reactors are probably generating in excess of a megawatt of heat which can no longer be controlled. This will increase as transient nuclear events continue. This is the April assessment, but I believe the situation has worsened considerably since 21 June, 2012 when there was probably a re-criticality at R2. R1 is probably critical again as well.
While the official TEPCO camera was on, it caught this yesterday.