A hole was drilled in the #2 reactor containment vessel for insertion of an industrial endoscopy camera on January 19th, revealing high gamma radiation, no water level or evidence of corium, and a steady dripping of water through the breached reactor vessel. Which was reported to have "melted through" in the early days of the mid-March 2011 disaster.
Today the "0" level gage at unit-2 is still hovering around 250ºC, after having gone as high as 275.9ºC on Monday. TEPCO has been issuing reassuring statements that they 'think' the gage is broken because two other temperature gages in the vessel aren't reading that high, although at least one of them has behaved as irregularly as the "0" gage has. TEPCO employees at the site say they doubt the gage is actually broken, and have increased the water being added to the vessel as well as injected boron to help prevent criticality. Analysts have suggested that recent changes in the coolant flow due to changes made when the endoscopy was done may have affected the amount of water reaching the molten corium (wherever it may be), causing it to crack or shift, thus possibly going critical again for short periods to cause the temperature rise. Also over the weekend [Feb. 11 & 12] cesium levels measured around unit 2 jumped from single digits to 98.2 MBq/km2 for Cesium 134 and 139 MBq/km2 for Cesium 137.


A temperature of 250ºC in what is basically an empty reactor vessel sitting in a basically empty containment over a mass of molten corium somewhere underneath is NOT a reactor in "cold shutdown." TEPCO had declared all three of its melted reactors to be in that state late last year, primarily to limit the corporations' continuing liability for damages and payments to evacuees. Whom TEPCO has claimed since New Year's should come on home because everything's fine now.
Some of us will recall the many reports during the fall of rising groundwater underneath the nuclear reservation, including boiling water and steam 'erupting' from the ground around units 1 and 2 through the extensive ground fissures and cracks that riddle the ground and widen with every 'aftershock' of the great earthquake that initiated the disaster nearly a year ago. In the last couple of days a new danger has reared its head with the release of a new study from the European Geosciences Union which issues the warning that the Fukushima Daiichi nuclear reservation is at increased risk of suffering a big earthquake epicentered essentially right underneath it, and that rising groundwater is an ominous sign that it could come very soon.
Could Fukushima Daiichi Be Ground Zero for the Next Big One? - from the Wall Street Journal blogs takes a look at the new study and explains some of the data. Geophysicists at Tahoku University in Sendai City analyzed more than 6,000 earthquakes that occurred in northeastern Japan since 2002 and used seismic tomography to create a detailed model mapping the below-ground activity.
The triggering activity has been traced to fluids (primarily water) rising from the Pacific tectonic plate to the crust of the Okhotsk plate on which northern Japan is located…
The plate's movement raises the temperature and pressure of minerals inside it, causing them to dehydrate. The fluids released are then able to move around the thick rocks toward the upper crust. Mr. Zhao and his team believe that if enough of these fluids accumulate, they could push fault zones apart, raising the risk for serious seismic activity. The rocks below where the 1995 Kobe earthquake occurred underwent a similar process, the report says.
In the Iwaki area ~25 miles south of Fukushima Daiichi, where a magnitude 7 'aftershock' last April 11 occurred, Japan's seismic monitoring network recorded more than 24,000 tremors in the seven and a half months after March 11. There were a mere 1,300 quakes in the same area over the nine previous years. The research paper notes that Daiichi sits atop fractured crust with the same traits as Iwaki's, and that the fault under the plants can be weakened and "lubricated" by the same rising fluids. The conclusion of these geophysicists?…
"Therefore, much attention should be paid to the FNPP (Fukushima Nuclear Power Plant) seismic safety in the near future."
Given that the most destroyed units (3 and 4) at Daiichi are precariously leaning and appear to be sinking into the ground, the obvious question becomes "what, exactly, could be done to strengthen "seismic safety" before the predicted next 'Big One' hits?" Remember that unit 4's spent fuel pool is crammed full of its entire core and ~30 years' worth of extremely nasty spent fuel assemblies. And has suffered at least two fires (that we know of). The pool itself was shored up last summer by workers who are most likely no longer with us, but it still leaks like a sieve and there appears to be no way to remove any of the fuel stored in it.
Given that the Japanese government went back on a whole series of "worst case scenarios" through the past year on what, exactly, might signal a need to evacuate the highly populous region of Tokyo and its suburbs, I do not think we have to wonder whether that evacuation will finally take place if there is a magnitude 7 or higher earthquake under Daiichi that brings the whole thing crashing down. It won't happen, but the "shared sacrifice" and "shared pain" of the disaster will become a lot more "shared" by the millions of Japanese citizens who have been led (falsely) to believe they were in relatively little danger from radiation being released. The population of the greater Tokyo area, by the way, is right around 39 million men, women and children.
This massive nuclear disaster is nowhere near over, nor are the melted reactors in "cold shutdown" no matter what self-serving stupidities TEPCO broadcasts to the public. Right now all but 4 of Japan's nuclear power plants are shut down, and it becomes more doubtful every day that they will ever be allowed to restart. This latest warning makes it clear that tens of millions more Japanese citizens are in imminent danger than has previously been acknowledged, as Daiichi and its neighboring Daiini facility (where at least one reactor containment has also been breached) may yet prove to be the nations' ultimate downfall.
At what point does the rest of the nuclear world intervene to put their entire collective expertise into stabilizing these facilities, and the Japanese government nationalize TEPCO to allow for it? It's their mess, they ought to do something about it. All TEPCO can do is lie - about anything and everything - and send low-level laborers (most supplied by various yakuza mobs) to their deaths just for a charade. It's time they were removed from the equation and forfeit the entirety of its corporate wealth toward paying for what needs to be done. Sooner rather than later, as the corium flows have been interacting with rising groundwater since last summer and may well contribute some rather spectacular hydro-geological fireworks to the coming mega-quake.
The Japanese people must insist, because their government is in bed with TEPCO and the mobs no matter who's holding the public PR positions. I hope they are paying close attention, and will do what needs doing before it's too late. But I am not holding my breath.