TEPCO did the second endoscopic examination of Reactor 2 Containment Vessel on March 26, 2012, and finally found water. It was 3 meters below where TEPCO had expected to find (which was at the grating), and only 60 centimeters deep from the bottom of the CV.
Mainichi Shinbun (3/26/2012) puts out this cartoon which well reflects what TEPCO said in the evening press conference on March 26:
Part of the corium is still inside the Reactor Pressure Vessel, and part of it is at the bottom of the Containment Vessel;
60 centimeters of water is sufficiently covering the corium at the CV bottom, and the corium is cooled;
The temperature of the water that's supposedly removing the heat is (incredibly) 48.5 to 50 degrees Celsius:
The Suppression Chamber is probably damaged and leaking the water being injected into the reactor (9 tonnes/hour).
This is strange, as TEPCO themselves admitted last year that part of the corium of Reactor 2 was on the concrete pedestal, outside the Containment Vessel. That would mean the Containment Vessel (drywell) itself had been breached, not just the Suppression Chamber.
You may ask "Why trust anything TEPCO says?" Well, TEPCO is still the only source of any information about the plant, no matter how flawed or inadequate.
TEPCO has some photographs of the water and inside the water. Water is clear, TEPCO says, but there is yellowish debris in the water.
TEPCO also measured the radiation levels inside the CV, according to the plan, but there is no information on the radiation levels.
It took about 3 hours for the work, 18 TEPCO employees and 16 Toshiba employees, with maximum radiation exposure of 5.29 millisieverts.
From TEPCO's Photos for Press:
Inside of Primary Containment Vessel of Unit 2 (above the water surface):
Inside of Primary Containment Vessel of Unit 2 (under the water surface):
Inside of Primary Containment Vessel of Unit 2 (pipe of power cable and grating):
Survey of Inside of Primary Containment Vessel of Unit 2 (working condition):
From TEPCO's Summary of Findings (3/26/2012):
30-Day free trial by following the link.
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12 comments:
When one sees this yellowish stuff under the surface one gets reminded about Urania. Urania is kind of yellowish-brownish. Another name for Urania (a ceramic color prior to 1960) would be Uranium oxide.
http://en.wikipedia.org/wiki/Uranium_dioxide
from wiki:
1. 'Water increases the oxidation rate of plutonium and uranium metals.'
2. 'Note that the thermal conductivity of uranium dioxide is very low when compared with uranium, uranium nitride, uranium carbide and zirconium cladding material. This low thermal conductivity can result in localised overheating in the centres of fuel pellets.'
Would be interesting to know the radiation level of that water, btw inside the primary containment.
They are due to measure the radiation level of the air inside containment tomorrow. I would think this number will be pretty high compared to the sorts of numbers we usually hear about.
Im not sure that the temperature or radiation level of the 60cm of water is that interesting, because this will be affected by how often that water is being replaced. i.e. how quickly the water is leaking down to the torus room, and being replaced by water that has recently been injected.
Im not really sure what I have learnt from this investigation, other than TEPCO making very poor estimates of the water level in the past. It could be seen as evidence that not very much of the core fell down to the drywell floor, but there are other possibilities, such as the melted core having spread out, or moved lower due to eating concrete or even blowing down into the torus room.
9 tonnes of water injected/hr (must be quite a lot of water) and 60cm of water in an unstated volume of containment vessel and three chambers (containment and suppression)...WHERE is the water "leaking" into? The groundwater?
At what point does "leak" become "gush". My faucet leaks. The npp leaks? Doubt it.
To answer the blog post question about contradiction with last years estimate that some of the core had eaten into concrete:
The concrete they were talking about was not outside of containment. It was concrete on the drywell floor, inside containment, not concrete even lower down. If it had eaten through all of this concrete and the steel containment liner then that it would be outside containment, but thats not what they estimated.
(you can see this in some diagrams later in this document, e.g. page 23, where you can also see the wrong water level that they previously assumed before these missions to look inside the containment)
http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_111130_04-e.pdf
Darth3/11:
Water is leaking into the basement (torus room) of the reactor building and the basement of turbine building. These spaces are quite flooded, and they are large. And TEPCO pump water out of these to be treated and reused.
So tarts where most of the water is, although its also possible that some leaks out into ground (and we know that early on some went into trenches and then the ocean). But this possibility is not needed to explain where the water is.
We know water is making it out of the reactor and turbine buildings due to unit 2's intake canal being a royal high radiation mess.
The old reactor data is all available here
http://www.houseoffoust.com/reactors/graphs.html
I have a hard time believing TEPCO's story 100% based on the known data of the past and yesterday's scope job.
Excellent post Arevamirpal! Thank you for sharing. These are also remarkable photographs. I imagine everyone at CERNS has their eyes peeled to the wonder of it all. It's the most remarkable pixie dust in the universe to be certain. A criticality documented in pictures is amazing to behold.
I agree with Anon at 12:10. It does bring to mind uranium oxide in appearance. Some lab samples are the next goal I imagine to determine what TEPCO is dealing with. Appearance can be deceiving at this point. The prospect of multiple smaller corium is interesting too.
Agree with everyone too on the water flow rate making it impossible to state that the corium is in a cooled state. Given I do see steam or acidic vapors it's current status is open for debate. Plus, 9 tonnes/hour is an environment impact that is not good.
I thank the workers who managed this work and those who completed it; because every piece of knowledge in solving this puzzle is vital for Japan.
Hopefully, they can rig a sampling device with a camera and take both corium and solution samples soon.
I wouldn't believe a single, solitary, piece of data coming out of TEPCO!
This data collection activity is just "busy work." NOTHING can be done about this situation but, watch Japan self-destruct.
Such an intelligent People. Such brain-dead politicians!
The new measurement of radiation inside reactor 2 containment is now available (only in Japanese as of this moment):
http://www.tepco.co.jp/nu/fukushima-np/images/handouts_120327_02-j.pdf
72.9 Sv/h at the lowest physical point they measured, which is still quite far away from the water.
Big numbers, but to be expected I suppose. Also demonstrates that although containment failed, if it had failed in a catastrophic way (e.g. explosive) then the radiation levels on site would have been much, much higher in places.
Anyway I believe that the fact that the radiation increases as they move lower in the vessel will be used to suggest that lots of the core is at the bottom, not still inside the reactor vessel.
Radiation levels in english now:
http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120327_02-e.pdf
As already mentioned by "elbows", "the concrete pedestal, outside the Containment Vessel" is not what Tepco said. Tepco mentioned the concrete pedestal inside the containment vessel.
Anon @1:37 Please, do not give up hope. While in college, I did a research project in which I used nitric acid to dissolve the pine needles of Frazier fur in order to study the effects of acid reign on Roan Mountain Tennessee. I used the resultant solution in a atomic absorption spectrometer or AA and was pleased with the definitive results indicating the sulfuric acid content of the rain had in locations were the soil had a sand content had in fact basically caused hardening of the arteries in young trees which had lead to their die off. While I used nitric to mainly study the Ca & Al concentrations. I do believe there is a good possibility to use this same technique.
The corium as evidenced here in the video is already in a sludge state. To change the water out for nitric acid and finish dissolving the corium will allow for it's removal through simple vacuum tubes into a safe storage configuration which will greatly cut the radiation levels and allow for the encapsulation of the material into a feldspar based glass structure. There is now a end game in site. Samples would be best to predetermine the concentration of nitric acid needed so that if perhaps a different acid would be more appropriate it may be chosen but for unit 2 at least there is now some hope.
LOL, I have to admit I thought the Japanese were crazy for insisting on this road to perdition; but it may be their culture heritage has taught us all something very important. Time will tell. One thing is for certain now of us can look our next generation in the eyes if we do not fight this thing with every piece of science we have available to us. This increased "Compton scattering" is becoming more and more dangerous every day. I for one have always been a big fan of Bruce Willis’s movie “Die Hard”. ;)
Who TF is Bruce Willi ?
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