Japan Earthquake: nuclear plants

etudiant

Unfortunately, I do not read Japanese, so the writeup eludes me.
However, one of the commentators on EX-SKF noted that the data released did not reflect the actual source terms, but rather an assumption of initial emissions.
So these results may not represent reality at all.
Can anyone who actually reads Japanese help clarify whether these are actual measurements or merely estimates from a simulation?

Uagrepus

Thanks. I came to that idea watching a remarkable aerial and what looks like prism effects there (near the coast line):

http://www.digitalglobe.com/download...17_2011_dg.jpg

zapperzero

Evening story time. Back when I was living behind the Iron Curtain, some medical doctors in my country, after Chernobyl, put paid to the gov't story ("all is well, no fallout here, blah blah") by just exposing radiological film to dust in the air, plants or even small animals.

Auto-radiography it's called. I saw one of those films. It had been exposed to just outside air, from a first floor window, for a minute or so. It looked badly speckled, almost foggy, there were a couple streaks across too, from betas I guess, or maybe cosmic rays or whatever.

But I don't see this thing with the cameras, now, as a source of very much useful info. Yea, the plant is hot. We knew that. It's hotter some places than others. We knew that too, we have nice rad-maps from TEPCO. The sensors get triggered by gamma or beta or whatever. It's impressive, but so what?

Later edit: I just took a look at bqscan and the EXIF info in that photo. No luck, the particular camera model isn't supported :(

zapperzero

It's interesting and also near-useless... the source term is assumed, not known...

EDIT: That's how I read the google-translated docs. I do not speak or read Japanese, though I'm beginning to think it may be worth investing the time to learn at least a bit, after all this crisis won't be over in less than a year.

zapperzero

Hey ho... when you say prism effects you mean the oddly coloured diffuse splotches in the water? What abot the two closely spaced shiny/white spots, violet on the edges, on the roof of #1 turbine hall? There's another similar one on the road in front of #4. Specular?

havemercy

Could anyone here explain what is occuring regarding the schoolchildren ? I read that some political men has quitted because of the limits raised by the ministry of eductation, that some new maps has been released with level of radioactivity of certain elements but nut all ? Could it be also possible to link the level of radioactivity of the maps with the "normal" annual limits for children ? Many thanks in advance. :)

robinson

That's what I am wondering. Does metal equipment outside the reactor core, or outside spent fuel ponds ever get that radioactive? I find it hard to believe that anything inside the reactor building has that level of radiation that isn't covered with a lot of water, or inside the containment.

Because how could anyone work around equipment that hot? I don't know if it's secrecy or my ignorance, but there seems to be very little published or commonly known about radiation levels inside a nuclear power plant. Or a spent fuel pond.

I'm pretty sure nothing in the workspace in a normal plant is 1 Sv/hr

robinson

As for the photo questions, it would have to be gamma rays causing any effect on the electronics themselves. Right? Alpha and Beta won't effect the inside of a cameras sensors.

MiceAndMen

I don't understand why they're so enamored with the Megafloat barge. They seem to take every opportunity to keep everyone updated on where it is, at all times. It is perhaps the singularly most uninteresting piece of equipment in the cleanup operation.

MiceAndMen

Regarding the Gamma Camera images at http://www.tepco.co.jp/en/news/110311/index-e.html

Does the fact that the Gamma Camera registers significantly on the (broken?) ventilating ducts imply that the electrically powered HVAC fans were actively circulating radioactive material before they lost electric power on 11 March?

zapperzero

The easiest explanation is there's some steel thing with a fresh thick coat of radioactive cesium. Could be anything, really, although spent fuel should be much hotter.

Does equipment get that hot? Hmm... the cooling loop is pretty hot with very short-lived stuff, but may also get contaminated with all sorts of activated junk from the reactor.

I'm pretty sure I read somewhere that turbine blades are rad waste by the time they're done with them.

zapperzero

I think you've just answered your own question there. TEPCO PR and Corp Relations at work, I'm afraid. Barge updates are a cheap, truthful way of saying "look, there's progress being made" every so often. Good news are scarce, they make the most of what they have.

Look up their first sitreps. A lot of things were happening in the first three days. Yet, TEPCO PR were just re-releasing the same stale info every two hours or so. When they stated "no changes from previous release", even when the situation had in fact changed, well, they meant there was no change in the content of the press release, and they were saying that, and it's true, sort of. The kind of true that stands up in court, just barely, if you have the best lawyers money can buy.

Astronuc

Basically, anything in or adjacent to the core gets activated, i.e., becomes radioactive.

Clearly the fuel becomes radioactive. The fission produces produces fission products, most of which decay by beta emission. In the neutron flux, some uranium is transmuted to transuranics. Core internals, most of which use stainless steel become activated, as does the steel core support plate, baffle and upper guide structure. Corrosion products that deposit on the fuel are also activated.

Materials outside of the core, really ouside of the neutron flux do not become activated, but some of the corrosion products do deposit on surfaces of piping outside of the core and RPV. The reactor coolant system or recirculating water system does have resin filters that are design to collect corrosion products. This is the reactor water cleanup (RWCU) system.

If fuel fails, i.e., cladding is breached, the some fission products, primarily Xe, Kr, I will readily escape into the coolant and travel around the primary system. In the case of a BWR, they travel into the turbine. Some will exit in an off-gas treatment system where filter catch radioactive gases or their decay products. If the breach is severe, then some loss of fuel and soluble fission product into the coolant will occur. Then the RWCU will collect some, and some will collected on the condensate polishers, which are also resin filters designed to remove impurities/corrosion products from the water.

Most Curious

Excellent Astronuc!! Thank you.

I have heard Cobalt is one of the nasties that accumulates in piping that carries coolant. Any comment?

Astronuc

Yes - over the last two decades, the industry has taken steps to reduce Co-58 and Co-60 in the reactor coolant. The use of Inconel in the core has been minimized and the compositions of stainless steels, principally SS304 and 316, have had restrictions on Co content in order to mitigate Co-60. Co-58 comes from an n,p reaction with Ni-58.

Zn has been added to primary water chemistries to reduce Ni dissolution in order to reduce deterioration of stainless steels and Inconels, and reduce Ni deposition in the core.

Any cobalt-bearing alloys have been eliminated from cooling systems connected to the reactor system.

Atomfritz

I think the green stuff scattered on photo is no metal. You would see the metal exposed at the breaks, but it is colored uniformly. Looks like plastic to me.

I read somewhere in this thread that functional groups in nuclear plants are "color coded", like the "FHM green".

But I doubt that a plastic box would be used in hot areas, for various reasons. It could just be a trash can been hit in the yard by the explosion. (just my unqualified 2 cents)

I am also curious. What could be radiating so much there?

Certainly this is not caused by a screwdriver.

So here my layman's analysis of the image and my thoughts and questions:





(Edit 2: re-uploaded smaller sized pic, see full resolution pic here: http://imageshack.us/photo/my-images...actorstain.jpg )


What could be this reddish stuff that appears to spread like pigment?

Any idea?

Edit: This stuff also could be bricks. But I doubt that bricks of apparently very low quality are used in NPPs... So I suppose this could be something other... but what?

Azby

Yes, this had me scratching my head a few weeks ago. It's not clear what weighting/conversion factors they are using.
As for whether this data reflects actual source term measurements, the answer is no. These are estimates produced by measuring actual dust and wind direction, and the exrapolating back. The data is not exactly worthless, but is difficult to place a high degree of confidence in. We need more information about how it was calculated, what the assumptions were, whether the estimates over time were generated by continuous radiation measurements during the time frame or assuming a constant release for the entire period and interating wind measurements, etc..

As has been the case most of the time, the data is suggestive enough to cause great anxiety among laypeople but not complete enough to allow outside experts to make sound conclusions.

The attached files are dated for March 23-April 25. Two show estimates for adult doses for all nuclides; the one for infant doses shows I-131 only, and explans the reverse-extrapolation and says "trial calculation." (I have renamed the files)

Attached Files

	SPEEDI 2011_0425_press.pdf (313.6 KB, 11 views)
	SPEEDI 2011 0410 22th doc_1_3.pdf (315.3 KB, 9 views)
	SPEEDI infant dose Eng 3-24 2011 0323.pdf (644.8 KB, 7 views)