Japan Earthquake: nuclear plants

Gaffney

One thing I don't understand is how the amount of water has been multiplied 6x over February but there has been no change in the reactor water level. Is the gauge broken, is the water evaporating quicker or is the water escaping the reactor?

elektrownik

I think that this is the case.

Yamanote

Yes, there is absolutely no change. Either the gauge is broken, or there is a leak at this level, letting escape even the big amount of water they are adding now.

Borek

Regardless of what is happening, imagine the wave of criticism they would face if they ignore it.

rmattila

The main circulation pump seals have certainly leaked since mid-March, and if there's any hole in the shroud, water from the core region will escape that way. In addition, there most probably are holes in the RPV bottom penetrations caused either by molten core material or corrosion.

But as far as I know, we still haven't been told which pressure measurement locations the reported level measurement is actually based on.

Yamanote

You are right Borek and I really appreciate their precaution this time. So let's hope for the best.

etudiant

Seen that the water level in the reactor was too low to be seen by the borescope, one can assume the RPV has some leaks, maybe large ones and that any reported reactor water level may be invalid. Obviously the increased injections will gradually raise the water level in the plant basement, but with 80,000 cubic meters there already, it will take some time to make a substantial increase.
The JAIF used to publish daily, then weekly situation reports that included the water levels in the various parts of the facility, but that stopped about a month ago when a more generic summary was substituted. TEPCO was the source of their data, so it may still be available there if one knows where to look.

Yamanote

If this is what you mean:

-> http://www.tepco.co.jp/en/nu/fukushima-np/index-e.html

-> Scroll down to "Situation of water level, transfer and treatment of the accumulated water"

This information is also provided with the daily press conference report and every now and then there is a more detailed report:

http://www.tepco.co.jp/en/press/corp...s/120201e3.pdf

mheslep

is it possible that the water boiled/drained away?

etudiant

Thank you, that is exactly what I was thinking of.
A very helpful reference that also gives some insight into the functioning of the water decontamination effort.

zapperzero

It's great info from you as usual, jim. But it makes it sound to me as if the other thermocouples failing too is pretty much a given.

elektrownik

Strange temps in unit 2 (data from today):

Attached Thumbnails

   

zapperzero

More sensors on the fritz? Maybe because of the extra water?

gbettanini

Is a melt-through possible?

elektrownik

Interesting that all strange temperature data are from bottom of RPV or close to this part of RPV so it is possible that something bad is in progress.

jim hardy

Multiple sensors trending together is worrisome.

But do i see readings of 118, 251 and 4 ?
Those need to be cross checked against other indications such as visible steam, temperature and particulate analysis of air exiting building.

and ask the technnicians whether those tc's are wet.

swl

I'm guessing it will be difficult to pressurize that RPV much above one atmosphere. And if the TC is away from water, there need not be any pressure.