Saturday, February 11, 2012

Just In: Reactor 2 RPV Temperature at 78.3 Degrees Celsius as of 10AM, Feb 12, 2012

From TEPCO's plant parameter - Reactor 2 RPV bottom hourly temperature table (Japanese, for now):

2/11 17:00 69.5
2/11 18:00 71.2
2/11 19:00 71.1
2/11 20:00 70.9
2/11 21:00 73.3
2/11 22:00 72.5
2/11 23:00 71.2
2/12 0:00 71.1
2/12 1:00 69.5
2/12 2:00 71.9
2/12 3:00 74.1
2/12 4:00 75.7
2/12 5:00 74.0
2/12 6:00 74.4
2/12 7:00 76.3
2/12 8:00 74.5
2/12 9:00 77.1
2/12 10:00 78.3 (at TEPCO's morning press conference, 2/12/2012)

2/12 11:00 74.9

TEPCO do not give morning presser on weekends any more, but today is the exception due to the concern over the Reactor 2 RPV temperature. Matsumoto is doing the press conference, instead of the usual junior manager of PR department.

Q: What happens if the temperature here exceeds 80 degrees Celsius?
A: Further increase of water to be injected into the RPV. But the cold shutdown state should take other parameters of the reactor into consideration.

Q: Possible causes?
A: Unstable cooling at the location. Some movement inside RPV of melted fuel, possibly, disturbing the flow of water. We don't think it's likely because we haven't been working near the reactor. Instrument failure is another possibility.

Q: What evidence to verify the accuracy of the thermometer?
A: Difficult.

Q: Containment Vessel's temperature?
A: Dry Well 39.5 degrees Celsius as of 5AM February 12. Other parameters about Reactor 2 is stable, trending down, except for this particular location at the RPV.

A: We're watching out for Xe-135 for any indication of recriticality, so far there is no detection from the gas management system of Reactor 2.

Q: Are municipalities around the plant informed?
A: Yes. We've been informing them of the temperature and the amount of water being injected.

Q: Which is more likely, the unstable water flow or the instrument failure?
A: Not sure. We're on the safety side (that there is actually a rise in temperature), so we're increasing the amount of water.

Q: Current decay heat?
A: We estimate it to be 0.6 megawatt, but we're not sure whether the temperature rise like this is possible, given the uncertainty of how the water flows through the reactor.

74.9 degrees Celsius at 11AM.

Q: Is this the only location that shows abnormality?
A: No abnormal numbers anywhere else.

Q: Amount of boric acid solution to be injected?
A: 1000 kilograms, as before.

Amount of water from feed water system 7.8 tonnes/hour (from 6.8 tonnes/hour), core spray ssytem 10 tonnes/hour.

If the temperature doesn't respond to increased water, then the instrument failure may be suspected.

Q: When are you going to decide on the cause - instrument failure or water flow?

Q: What does the manufacturer of the thermometer say?
A: Nothing so far.

Q: Why is it taking so long to figure out the cause?
A: The problem is that we cannot enter the Containment Vessel. So we do everything we can from outside the CV to figure it out.

(Press conference just ended.)


Nancy said...

Link goes to the old temp sheet that ends 2.11. Do you have the updated sheet anywhere?

arevamirpal::laprimavera said...

No. They haven't uploaded the sheet that includes 10AM number. I'm watching the press conference that is on-going right now.

arevamirpal::laprimavera said...

They updated the Japanese version, which I've just linked.

netudiant said...

It seems TEPCO has learned to project humility.
This is the first time that I remember a TEPCO spokesperson explicitly state that they do not know.
That said, it is surprising to me that the 'recriticality' concern keeps coming up.
The odds against such a development are huge, afaik, so the evidence that they are testing the water for indications of such an event is actually somewhat disturbing

arevamirpal::laprimavera said...

From what I have watched, TEPCO doesn't lie like the government officials. TEPCO don't offer information unless they are specifically asked.

I think more information is coming these days because reporters have 11 months to educate themselves and started to ask some serious questions in technical details.

Anonymous said...

Its about time TEPCO allowed the webcams to operate without adding "features" such as building images, etc. Citizens need to see the situation. Its not to cause a panic..its to see the actual physical reactors to allow reaction in emergency. In a major event, it will be difficult to get information out to they are kept informed. Assuming, of course, that both TEPCO and the Japanese Government plan to allow people to they say its not known if citizens have the right to "live without radiation"..per one government press conference early in the emergency. That attitude might also be the same world wide by controlling governments.

And if the webcam video was provided immediately without modification, then people would not be "talking" about what THEY see in the blurry/hazy and whiteout images. Reactor 4 situation comes to mind.

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