Japan Earthquake: nuclear plants

GJBRKS

Wouldn't then this be a perfect setup for dismantling the company known as TEPCO ?

Could this be part of the information war ?

If you can't control the situation , control the flow of information ?

Create confusion ?

Because this news amounts to the equivalent of several stun- tear - flash -and smokebombs combined ...

ESPECIALLY if they backtrack on this data ...

If not then I wonder about the state of ALL the other readings ...

zapperzero

I think the questions to be focused on in the case of reactor 1 are not "where is the water and where is it going" but rather "where is the corium and how hot is it" if we are to get a reasonable picture of what happens next.

"How can it be directed to where it would do the least amount of harm" seems also to be worthwhile question, but not for us, for those fighting this battle.

I for one am not optimistic, given that instrumentation on the bottom of the RPV has failed a long time ago. April 8? Who knew a meltdown could be so slow?

elektrownik

Unit 3 is 283C now and increasing...
Also 2nd unit 3 sensor jump from 156 to 203C

PietKuip

The water must have leached an enormous amount of radioactive isotopes from the fuel, so its path is also interesting. And if the outflow is in the bottom, the current could also have carried pieces of corium with it.

|Fred

I do not think that a rational approach is undermined by weak data. As I use to be told geometry is the art of thinking out of false drawing. The idea not to make the theory fit the data. Does the actual adjustment, makes more sens ? Explain a gray area in the formally postulated hypothesis leading to and other hypothesis or does it makes thicken the plot ?
I think better usually comes from decisions based on reasoning (although the reasoning might be wrong) rather than on a 50/50 bet.

GJBRKS

Could you please provide links to your source when announcing these data ? (As there are 13 temp readings per unit)


http://www.tepco.co.jp/nu/fukushima-...3_05121300.pdf

zapperzero

I could not care less. The sea is where the fishes and a couple dozen discarded nuclear reactors live (I'm not talking only subs, the Russians dumped massive amounts of effluent from their plutonium separation plants into the sea). Plankton won't die from a few pCi/l more, the whales could use a 60-year moratorium on fishing. We live on land. A big fire or steam explosion means China gets a sizeable dose, while Japan gets cut in half.

Corium flowing into that lagoon? Meh. Think corium coating 80% of the world's chip foundries.

AntonL

Evidence of Earthquake Susceptibility of the Reactors


Evidence 1
On 7th April there was a reported 7.1 (some say 7.4) north of Fukushima that also shook Tokyo. http://earthquake.usgs.gov/earthquak...usc0002ksa.php


and look what happened to the CAMS reading from 30 to 100 to 187

Now with all the information we have today leak sprung in the reactor vessel releasing very radioactive water.

Evidence 2
On May 1^st, 11.48AM A 4.8 earthquake struck 9.5km from Fuskushima NPP
http://neic.usgs.gov/neis/bulletin/neic_kjal.html


after that the temperature in the reactor 3 rose, something changed!


I believe two earthquake events and two changes from the steady state reactor parameters is proof enough to make the statement that the damaged Fukushima reactors are susceptible to earth quakes, and is a very worrying thought for trying to get fukushima under control.

Edit: After Borek's comment post #6831

clancy688

Unit 1 remains a mystery for me. During the last few hours, some questions popped up...

Here's the NHK news regarding the Unit 1 water leak: http://www3.nhk.or.jp/daily/english/12_23.html



I didn't thought about it first, but that means that not only the water level sensor is malfunctioning, but another sensor as well - the pressure sensor.
Stolfis Plots ( http://www.ic.unicamp.br/~stolfi/EXP...t-un1-full.png ) were showing contant water levels and rising pressure for Unit 1.
Now we've learned that Unit 1 is leaking, both RPV and containment. If there's a leak, the RPV pressure will very unlikely rise significantly over atmosphere level.

A user raised doubts that the whole molten core could relocate in the bottom of the pressure vessel. I have no idea how big (in m³) the area 1m below the bottom end of the fuel rods is, and I also have no idea how much space (in m³ again) the whole core in corium form needs. It would be nice if someone, who has the needed numbers, could calculate this.
Even if there would be enough space for a fully molten core, it would be impossible to cool it down. The water could only reach the corium's surface, not the hot core.

Moreover, TEPCO stated that the bottom of the RPV is only slightly over 100 degree °C hot. But if the core's really relocated to the bottom, there's nothing between the hot corium and the steel. And then it's only 100 degrees hot? I can't believe that.

Since today we know that the RPV and the containment are breached. Water's disappeared and TEPCO doesn't know where it went. Perhaps the Houdini Unit 3 is getting acquaintance. If it went to the sides, TEPCO would have discovered it, as with the water leaks from Units 2 and 3.
So in my opinion, that leaves the only direction where TEPCO has no eyes - down.
What, if part of Unit 1s fuel got uncovered and melted, dropping to the bottom and compromising the RPVs integrity. It burned a hole into the RPV, which's now leaking. Water is escaping and the overall water level is sinking, more fuel is uncovered and melts as well. But those parts are not settling down at the bottom of the RPV, but washed out with the water flow - since there is always water supply from above.
Parts of this fuel gather at some point in the containment and burn another hole in the bottom, sinking through the basement and into the ground. Now the water can escape into the ground as well.

There's also a probability of sudden fuel cladding failure. The fuel was uncovered for a certain amount of time, but did not melt. But the zircalloy was very severely damaged. It's highly oxidated and unstable. Everything seems fine, water flow is resumed. Then, a violent afterquake hits, shaking all assemblies.
This sudden stress could result in rupturing and breaking of the cladding, releasing the fuel pellets to the ground. And if that happens in enough places, it could trigger a chain reaction (mechanical, not nuclear... ^^;), leading to a similiar outcome as described above.


I don't find them anymore, but sometime during the last weeks I saw assessments of Mark I containments and BWR pressure vessels during accidents. They stated that the RPV would likely be breached by corium in less than one hour.

PietKuip

Interesting analysis. And that "100.0" reading, was not that a code for "off scale"?

elektrownik

I also think that core is in drywell sience radiation jump in drywell...

artax

Sorry... simple question but what does CAMS stand for?

MadderDoc

Find attached my assessment of the state of the roof structure of unit 3, after the explosion.

Based on visual inspection of photos, each field in a 16x24 matrix covering the entire roof structure was assessed to one of five categories of damage, see legend. The method used gives the assessment a resolution of about 1.5 meter.

Fragments found on the roof of unit 3 were assessed, as were fragments of the roof structure locatable to the south and the east side of the building. Due to poor photo coverage and their inter-mixture with other debris fragments which ended to the north of the building could not be inspected. Those parts of the structure from the N end and from the SE corner which could not be inspected were assessed based on plausibility, judging from visually inspected close-by or bordering fields.

Attached Thumbnails

 

jlduh

Just wanted to remember everyone that Tepco just recalculated 2 weeks ago the amount of fuel damaged in the cores:

http://www.powermag.com/POWERnews/3678.html

For Unit 1 it was revised from 70% to 55%...

All this gave the impression of precision and control of what was going on, isn't it?

Now it's 100%. Finally, we could call it a "50/50 bet" , after all. With much "scientific" (maybe pseudo?) reasoning though.

Which credit should we give to the numbers for the other units, now?

PietKuip

Indeed. Based on the CAMS readings (Containment Atmospheric Monitoring System). But Michio Ishikawa never believed it.

artax

Thanks Piet, have these images been discussed, particularly the ones of the surveying helicopter at the bottom?

http://cryptome.org/eyeball/daiichi-...i-photos14.htm

htf

If the temperature readings are correct then the corium is not at that location. This would be my conclusion. So, where is the core?