Friday, February 24, 2012

#Fukushima I Nuke Plant Reactor 2 RPV: Temperatures at Bottom Seen Rising, Diverging

Something is going on inside or outside Reactor 2 Pressure Vessel. Either more thermocouples could be failing, or those that were deemed failed weren't failing.

Here's the latest temperature reading of the Reactor 2 RPV bottom from TEPCO (2/24/2012):


  1. Gradual temperature divergence between 69H2 (now the "official" temperature gauge of the RPV bottom after 69H1 at 0-degree supposedly "failed") and 69H3 (first 2 columns after the date and time column). Up till February 22, the temperature difference between these two thermocouples was 1 degrees Celsius. The difference started to widen on February 22, widened further on February 23, shrinking a little on February 24.

  2. Overall rising trend of temperatures at all thermocouples at "the bottom head" and "support skirt junction". At 6PM on February 18, all temperatures measured at this location was below 30 degrees Celsius; at 5PM on February 24, temperatures are in the upper 30s to mid 40s.

No insight from the media there as to why this may be happening. I'll watch TEPCO's press conference archive later to see what TEPCO had said while I wasn't blogging.


Karen Sherry Brackett said...

From what I understand they are trying to lower the water flow rate which is good. The temperatures will increase as the water empties out. Do not worry, the fuel can sustain temperatures over 2,350 C even without noble gas application as long as all of the water is gone. Uranium itself boils at around 3800 C however the fuel will not be safe to that high of a temperature. With the application of noble gas or other mixtures it will lower quickly once all water is gone and just as importantly as long as no oxygen comes in contact with the fuel. What is important is to deal as quickly as possible with whatever is left in these vessels. So, that the larger problem at hand being the corium may be reached and dealt with properly. These temperatures do not reflect the location of corium in the vessels. It appears only fuel fragments are left inside the vessel containments.

Anonymous said...

Correct me if I am mistaken but the reporting has to be over 100 degrees as boiling point.

Then if the pressure is contained it will be like a pressure cooker unless the steam is vented releasing radioacitive steam.

The rods are melted so there is radioactivity in the vessel itself outside of the rods.

If the pressure is contained can only reach 1.5 the standard pressure rating for the vessel irrespective of the rod temperature.

If it has melted though the containment vessel it is no longer self contained and the pressure is held in concrete secondary containment and this might not be so strong.

arevamirpal::laprimavera said...

Recap of Reactor 2

At least part of the corium of Reactor 2 is out of the RPV, and is now on the Containment Vessel floor. TEPCO already admitted that the corium ate into the concrete floor, 20 centimeter deep or so in case of Reactor 2 CV.

Pressure is not contained in Reactor 2. The RPV is broken, and Suppression Chamber is broken.

(and Robot Quince is somewhere on the upper floors.)

DD said...

I miss the robot! such a brave little creature.

Atomfritz said...

It's important to keep the temperatures low, as we don't know how much of the Zirconium still is present in unoxidized form. This stuff must not get hotter than 600-800 C at all cost.

And the nitrogen gas injection thing has a big flaw: as long as reactor 2 is open to the air via the blown-up torus (or whatever), Tepco cannot with certainty inert the atmosphere in the vessel.
Nobody knows details about the leak(s), and Tepco seems not to be curious enough to take a gas sample via their video show peephole to learn more.

Or maybe they secretly did so and consequently stopped any further videoing and metering because of the high risk to trigger an explosion, and instead massively increased water flow to quench the acute oxyhydrogen explosion danger by increasing the steam content of the vessel atmosphere?

Anonymous said...

It's quite a shell game, when Tepco is simultaneously in a state of utter incompetance and likely also taking clandestine steps to further assess and control the outcome of this disaster in a way that further covers their individual posteriors.

Their reputation for truthful, direct information is so very poor as to make virtually any statement they make questionable as to truth. The time has come for this to end, Japan needs to do the right thing for their people and relenquish control of the situation at Fukushima to groups more capable of not only acting responsibly but holding credibility with the world audience.

This may happen when hell freezes over, or the cores actually reach hell, whatever happens first.

Anonymous said...

Hello Arevamirpal. Tepco has an interesting press release

Tepco received instructions about temperature increase in unit 2 rpv from Nisa, but Tepco provides only the japanese text of these instructions. I can't read them. But you can... :)


Karen Sherry Brackett said...

The Zirconium cladding has already failed that is why a meltdown happened, why the fuel is so reactive to water and oxygen and also why it has already been exposed to temperatures greater than 600-800 C during the intial explosion. However, that said with the use of noble gases there is no need for it get anywhere near those temperatures. I was only giving these temperature reference points so that the public will not be too alarmed as a transition may take place. Given the amount of acidic condensation that was shown in those videos the system will sustain the gas though some solids may form and some gas may be lost through holes. The corium is the real problem and it is not being dealt with at all. That is the focus that has to happen to keep this under control. Water is a moderator. It slows the reaction down long enough for the fission to occur. It is a fuel and not a coolant in nuclear energy. The only way water can be used is when the Zirconium cladding is intact because it shields the fuel from the water and more importantly the oxygen in the water while helping the heat generating reaction to occur. Frankly, Zirconium and graphite should be the least of anyone's worries at this point. Although they are certainly a concern. The Corium is what has to be dealt with. Worrying over two lion cubs when the lioness is growling in your face is not really going to save anyone.

Anonymous said...

Brackett, please go start your own blog. Leave here.

Anonymous said...

Karen, you write comments assuming readers here don't know anything elementary like oxidation of the Zircaloy cladding is part of a meltdown.
This is stuff we discussed almost a year ago.

Anonymous said...

anon at 10:20PM, THANK YOU.

Karen or Brackett or whatever, go away.

Anonymous said...

As anon at 10:20 says, readers of this blog is more knowledgeable than somewhere else. If you want to educate clueless readers, Karen, I suggest you go somewhere else. Otherwise, you just make yourself look stupid.

And whatever your motive is for suddenly coming here, don't use this as a way to window-dressing your resume - that you educated clueless readers of a nuclear accident blog.

Anonymous said...

Karen Sherry Brackett said...
Water is a moderator. It slows the reaction down long enough for the fission to occur. It is a fuel and not a coolant in nuclear energy....

...and a lot of other bullshit.

No wonder Chernobyl exploded, the idiots filled the reactor with WATER instead of harmless air! And let's see, if the water was the fuel in Chernobyl 4, then the graphite must have been there to absorb any impurities, like activated charcoal, right? And of course the uranium was not fuel, as you said the water was, which means the only logical purpose of uranium would be to weight down the reactor and keep it from physically shifting, as uranium is primarily mined for it's function as ballast.

It all makes sense now! If they would have just put more uranium into the core at Chernobyl, being heavier it wouldn't have flown into the air as far, and more graphite to absorb radioactivity in case something bad happened, and once they notice something was wrong, and when they saw something was going wrong they should have simply removed the supply of reactor water, thereby removing the fuel and preventing an accident from happening at all!

Karen, I demand that you invent time travel technology and go back to April 1986 to prevent Chernobyl from happening. Clearly your intellect has quantified nuclear technology in a way that nobody, I mean nobody has dared to in the history of science, time travel should be a next logical step.

Come to think of it, I don't believe there was ever a problem with the pumps getting water to the reactors in Fukushima. Just as workers lied when they said they "tested" Chernoby's "coolant" system by shutting down feedwater the night it exploded, if the operators at Fukushima were really unable to keep the reactors and fuel pools filled with water then how do they explain the way that reactors devoid of fuel (water) melted down and exploded? Obviously Fuku I as well as Chernobyl's doomed reactors were filled to the brim with water and with an excess of fuel they failed.

We need to do something, we need to all demand of our governments that they drain all the water out of every nuclear reactor in the world, before another disaster happens with this highly volatile fuel!

Anonymous said...

LOL !!!!

Damn, that's some fine writing there 12:58 PM. Are you single?? Unlike Karen, I am physically a very fine looking specimen with a brain that works. If you are taken then maybe Atomfritz isn't.

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