Japan Earthquake: nuclear plants

maddog1964

Robinson, Astronuc description is very though, I think everyone trying to figure the radiation and explosions would be better able to analize both sitituations if they were not just concentrating on the fuel as the only place that "particulates" (not sure that would be the correct technical term") of the radiation would be (It is the main sourcre).

Have been studying bld#1 equipment (japan) and drawings from a US plant. After many hours and still not enought research... the systems are quite complex and "appear" to go to many of the buildings... not just the reactor containment bld. One example is the off gassing system.. its job is to "scrubb" the air of the radiation. There are several other systems that "clean" the SFP water of by-products. As Astronic desribed some go through the core. But what level of contamination is carried along I do not know and have been looking for help on in this area.

Pipe will collect product on the inner wall, if its Radioactive fluid its my understanding that the pipe wall will absore it.. I belive, but am still working on the system that is used to minimize this (BUT have not finished)
hope this helps...

I have been quite surprised at the building construction and very numerous components that are exposed to at least a min. low level radiation. They usually would not have a tank inside a concrete room if there was no "danger associated" with it (again, some of this infor is from a plant here in the US.) but if only 50% of the systems and components were applipicable to the Japanese plant it would explain alot.

The diagrams you see on the tepco and news articles only show the "main flow" they are much more complex, it will take me quite some time to link all the drawings together. Then there is the variables as to what japan has and does not. Most of these drawings are from 84 and some in the 90's

I guess the question that remains is how "Hot" do these resin beds/sludge tanks and many filters get... that part is not my field. The equipment and components are! And What is now debrie around the plant.. you can clearly see that some items seem to have left some of the buildings.... were they came from and were they are now is the ???????

StrangeBeauty

Also, I've been wondering about the possibility that this is another reading that's actually >1000 mSv, not just "1000 mSv". It would be based on the upper limit of the measuring device, and it seems that a lot of their devices top out at 1 Sv.

Also I see they are finally trying to get readings directly above the reactor buildings:

http://www3.nhk.or.jp/daily/english/23_11.html
Much will depend on wind direction and strength in addition to the instrument placement. I'd like to see a measurement taken directly in the steam emanating from the building.

MiceAndMen

To me it looks like steel or metal with reinfoced webs, but you're probably right about it being plastic. There would indeed be exposed metal at the breaks.

As for the red stuff in the photo, I think they used a "dye bomb" or dropped some paint on the hot spot as a marker.

If I could ask a favor, in the future could you please try and limit the horizontal width of posted pics to 800 or so? Very wide pics make the rest of the page really hard to read!

ElliotLake

Highly doubtful it's brick; that's a wrong red for bricks, too bluish-red, too "red" for brick.
Appears too as though whatever the red is, it got there after the pile got pushed together.

Atomfritz

This sounds very plausible, thanks!

Oooops... apologizes to all..
I really didn't think of that. *slapping myself*

westfield

Tepco press releases often seem a bit like their plant releases, they do nothing to clear the air.

In this case, are they simply surveying the place, or perhaps looking for a failure point or are they looking to see what equipment can be made serviceable?

If they are looking for a failure point then SGTS ducting outside of primary containment but inside the building would be a good candidate (it's my "favourite" for how hydrogen made it throughout the RB's). The SGTS's projected failure during reactor overpressure "incidents" is what prompted the Direct Torus Vent System retrofit.

However, there are the SGTS ducts, HVAC ducts and others, who knows what the ducting system is in the pictures, who knows why tepco surveyed it and who knows why they showed it to us.


There are lots of docs on the net going into GE Mark 1 BWR "issues" in depth but this one does two of the more likely failures in brief -
Page 4 of this document has a brief section on the Brunswick plant stress test that revealed the BWR Mk1 containment dome lifting off it's seals at 70psi and also the SGTS issue as mentioned above.

jmelson

That green stuff may be Borotron, or similar boron-loaded plastic for neutron absorption. I see it at the accelerator labs I visit, you can get it in sheets and blocks to fabricate shielding from.

Jon

Atomfritz

Yes, this really disturbs me.
And a closer looking also makes me doubt that this is just dye.
See this zoomed-in image.



This discoloration of bricks is often caused by abnormal high temperatures, like with metals.
Over-heated red pottery often discolors into crimson-bluish if it gets burnt too hot.

Another known cause of brick discoloration are chemical contaminations.

And why are these bricks (or whatever this is) in such a bad shape?
If these are hard bricks (as commonly used in modern times), such a pulverization makes me think that they originally probably have been very near the epicentre of an explosion.

Or, maybe like damaged oven/furnace bricks. Like being burst by steam expansion when heating up a wet oven.
If you look at the bricks closely, you also can find blackish-looking discolorations.
Like the soot you find when you demolish an old not-perfectly-tight chimney. You see where smoke has passed/leaked through.

In fact, these bricks look to me very similar to rotten chimney bricks, decomposed by the effects of heavily changing temperatures, humidity, condensing as boilt out, and salts and acids.
Really not the sort of things I would expect in a NPP.

To me these discolorations seem a bit too dark just to be mortar.
Could it be earth, on this sandy site?
Or, could it be precipitated black smoke?

So, what I don't understand - where came these "bricks" from?
And why do they look so odd?

Could it be possible that an opening in the reactor building has been closed by putting masonry into it?

Maybe due an open hole for some heavy equipment that had to be put with a crane into a building floor after raw construction has been finished?
Or by some modification involving closing no-longer needed openings?

If so, then this could have a series of imaginable consequences.
First, it would have been a weak point in the side walls - possibly ripping them outward instead of relieving the pressure in direction to the ceiling, resulting in the peculiar shape of RB #3?
Second, as most initial pressure then would be relieved when this "structural breaking point" opens, maybe a contaminated equipment part could have separated and blown out of the building?
And so, finally, resulting in a radiation obstacle for the pumping teams, so it just got bulldozed into the next corner?

(Sorry for my long unqualified and scientifically unfounded post. I just have a bit of construction experience, nothing nuclear.)

Grumalg

Maybe the brick color is due to Iodine? Iodine-129 @ .84% fission yield and 15.7 million year halflife could surely still be around in quantity.

Atomfritz

Being curious, if i find a clue what the green broken thing could be, I collected the item details in a pic. Looks like sort of container to me.
maybe an expert here can recognize/identify this item?

MiceAndMen

The PDF on this page, "May 22, 2011 Dose-measurement points by gamma camera..."
http://www.tepco.co.jp/en/nu/fukushi...s/index-e.html

is this file http://www.tepco.co.jp/en/nu/fukushi...10522_01-e.pdf

The first page shows where the pictures were taken from. It looks like they drove the gamma cam bot in through the vehicle portal ("carry-in gate for large stuff") and took pictures straight ahead, and then turned right 90 deg and took some more. The electrical panel on the column with the door hanging off of it is in both pictures. The second picture, then, is from an area near the SW corner of the building with the camera pointing South, while it seems to be pointing East in the first picture.

@Atomfritz : Thank you for resizing that picture.

ElliotLake

I've no nuclear experience but have built & fired a lot of kilns, and that red substance is nothing like any brick (kiln or otherwise) I've seen. The weird blue red in overburnt bricks goes along with melting, slagging not crumbliness. Boiler bricks would be whitish to white, high duty (high temp/corrosive atmosphere) refractories don't include iron.

It is a puzzle, that largest lump does have a brickish outline, but I can't believe Tepco would have used bricks that way: Japanese knowledge/practice of ceramics is vast and ancient. "Dye bomb" or indicator powder gets my vote.

Maxion

Heh, remember occams razor. What would normal red bricks be doing as construction material at a nuclear powerplant? Laying bricks is not exactly easy on labor.. And that would be the only small pile of bricks we've seen on the entire site.

It's paint/dye/powder to mark the spot of high radiation.

MiceAndMen

My second reply to this... I adjusted the levels a little on the second picture (the one to the south) just to enhance the contrast a bit. It's a little more complex up there than I initially thought. There seems to be a jib crane mounted on a vertical pivot that is probably used to load and unload equipment and fuel from vehicles. Other than that, it looks like a rat's nest of pipes and other things.

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zapperzero

I like your analysis. I think the red is red marker powder.
Let me throw my $0.02 in the rubble debate, from a very different angle.

I had been looking for a way to avoid having to think of burning concrete and burning metals, because I didn't understand why such high temperatures would not also produce other observable effects. Seems I found it.

The yellow stuff is indeed insulating foam. To be more precise, it is polyurethane foam, widely used for insulation and as a fire retardant. If you are looking for an explanation for what generated massive amounts of black smoke on several occasions, this may be it. A small electrical fire in a cable duct (a la Browns Ferry) can be enough to get it going.

Diablo Canyon incidents:
http://www.nrc.gov/reading-rm/doc-co...in88004s1.html

LATER EDIT: the small orange-brown pieces you ask about are also insulating foam. It gets like this from being exposed to UV light.

tsutsuji

Thanks for unearthing this Kyodo news.

This blame-the-rain stance sort of rules out the possibility that any serious radiation was released into the air at the plant on March 20th or 21st.

I was thinking that at the very least by knowing where the hot spots are located they would know where they need to add shields to block the rays.

jlduh

Concerning this particular picture that you mention:


I remarked when i saw it first when it was released by digitalglobe that there were those very bright spots encircled with coloured lines, especially on some roofs but also around the reactors on the ground. AT first i thought that these could be some glowing parts of fuel or corium emitting a very intense light, as in digital photography, this kind of fringing appears around very bright spots in an image, in fact this comes from an overflow of photos in the adjacent pixels when the pixels receiving too much light are saturating (which is called BLOOMING).

I tried to see on all the other pictures i saw after from the plant if i could do a correspondance between these spots seen on this picture taken just after explosion of N°3 and some specific areas with remaining debris. In fact i didn't succeed in doing this: those spots didn't appear to me to be of special interest based on the later pictures.

So i don't know what to think. For sure these bright spots circled with color are surprising at first sight. On the other hand, we see in the sea area (on the same picture) that there are a lot of speculars coming from what looks to be like aluminum sheets reflecting in the sun. I don't know if there is something special on the water that makes it shining like that, or if it is just from the waves and the sun playing together (i think this second option is the good one). For sure, the picture is a little bit overexposed and the sun reflecting here and there doesn't help.

Now, even if the spots on the roofs for example are not "glowing corium" (which was not evidently) but reflections from shiny parts, we shoud find evidence of some of those parts on other pictures. I had a hard time to confirm this either... So i guess this needs maybe further look and analysis. But again maybe it's just speculars on some small shiny parts, we all know how bright this can be if just at the right angle!

Concerning the white dots in some pictures in areas with radioactivity: this is a different subject than above but to me this is clearly the effect of the radiations (gamma) on the sensor. This is very well shown in the experiment in the video posted. Some of these dots may be in fact dead pixels from a previous exposure (like in the experiment shown) or pixels reacting to some gamma rays i think.

CCDs are considered more proned to this than CMOS but CMOS are also vulnerable to this. There is a complete thesis available on this subject:

http://www.cse.yorku.ca/visor/pdf/MSc_thesis_Henok.pdf