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[Shinziril]

Radiation exposure really ought to be reported using a baseline of natural background radiation.  It helps to put things in perspective, particularly for those without significant knowledge of radiation physics (i.e. the majority of the public). 

Looking at Wiki, apparently worldwide average background radiation exposure is about 2.4 mSv/year, which works out to about 6.5 µSv/day.  A chest x-ray is about 60 µSv, or ten days normal exposure.  A little concentrated, but not really worth worrying that much about.  A CT scan varies significantly depending on which body part is scanned; a chest CT is about 6 mSv, which is more than 2 years worth of background radiation.  It's still useful enough that we're willing to continue using it, but you definitely don't want to have a CT scan unless you need to. 

Just for fun, there's also a town in Iran called Ramsar, which due to the presence of radioactive isotopes in its hot springs has a significantly elevated level of background radiation.  In the most extreme locations it actually exceeds the recommended safe limits for radiation workers!  Bathing in some of the hot springs is equivalent to having a chest x-ray every two hours or so (30 µSv/hr); they're nevertheless interestingly popular as spas. 

[Tellemurius]

http://www.reuters.com/article/2011/03/24/us-japan-quake-idUSTRE72A0SS20110324
latest news i guess, Reuters switched over to the Middle east right now.

[ChairmanPoo]

OH SHI-

http://blogs.nature.com/news/thegreatbeyond/2011/03/breaking_news_fukushima_radioa.html?utm_source=feedburner&utm_medium=twitter&utm_campaign=Feed%3A+nature%2FySfs+%28The+Great+Beyond%29&utm_content=Twitter

[Bouchart]

AP reporting that it was an inaccurate reading:

http://news.yahoo.com/s/ap/ap_on_bi_ge/as_japan_earthquake

[Kogut]

"We have somewhat prevented the situation from turning worse,"

Yeah, because it is hard to turn into anything worst, short of second (big) earthquake.

[Shinziril]

1000 mSv/hr in Unit 2?  Damn, that's actually pretty high.  Enough to give noticeable radiation poisoning within an hour, although they'd probably survive if they don't stick around any longer. 

EPA recommended dose limit for emergency workers in lifesaving situations is 250 mSv.  Can you get the power cables for restarting the cooling systems laid in fifteen minutes?  Better move fast, or find another option. 

[Nikov]

Ah, no. That's not a recommended dose. That's a "you can save a life IF it is under this level, otherwise we're saying our goodbyes over the intercom". I'm pretty sure they're finding another option as they seem to have the time to spare.  And I recommend everyone Netflix the movie K-19. Seriously, I can't say that enough.

[Wastedlabor]

Now they found 1 Sv water in a U shaped channel outside the turbine building. That channel is connected by pipes to the turbine building, which is flooded too by deadly water coming, through more pipes, from the reactor.

To be honest, at this point the only sensible thing would be to flood everything with lava.

[Kogut]

lava made of melted fuel rods?

[freeformschooler]

To be honest, at this point the only sensible thing would be to flood everything with lava.

Sounds good to me.

[Bouchart]

It looks like they're going to bury the plant, like at Chernobyl:

http://chronicle.augusta.com/latest-news/2011-03-31/srs-concrete-pump-heading-japan-nuclear-site

[Starver]

It looks like they're going to bury the plant, like at Chernobyl:

http://chronicle.augusta.com/latest-news/2011-03-31/srs-concrete-pump-heading-japan-nuclear-site

I get a 403 from that URL.  Pay-per-view, or some possibly transient problem at my end?

Anyway, thinking about their radioactive water problem (of course it's radioactive, they've been dumping a whole load of water all over the site and it's had to go somewhere) I've been wondering when they'd get around to putting up the equivalent of sand-bags, to stop it from overflowing (some might say it's too late).

Those thoughts came from hearing the reports, a few days ago, about the contaminated water almost lapping over the edge of somewhere or other.  (Never quite got the handle on that, I suppose it could have been similar in function to the 65m shaft at Dounreay, which was, IIRC, meant as access to the low-level waste-release pipes but ended up itself being used for some nastier bits of intermediate-level waste.  But the last time I was at Dounreay (apart from happening to drive straight past it, about five years ago) was in the '80s, and I've forgotten most of what I knew about it then.  And, anyway, since then an awful lot of new info about past leaks got... well, leaked...  But I didn't pay much enough attention to that, anyway, it all being more than a little hyped up and/or muffled, depending on who was saying what.)

Ideally, all they'd need is a giant screw, a pipe section, a block, assorted mechanisms and an entirely newly constructed storage tank, and they'd be able to drain the contaminated water and store it as drinkable stuff...

Failing that, build walls around the place, then work out the best way to lower the level of water.  Whether that's a slow and controlled release of filtered water into the sea (with some discharged radionuclides, but what you gonna do? Especially as a little of it normally happens on purpose and recently a lot has apparently found its way out due to the general chaotic situation), or 'fixing' or precipitating any of the more volatile nasty stuff with appropriate chemicals and then carefully evaporating the liquid to leave a particularly nasty (but at least less voluminous) sludge behind that can be canned up and then put somewhere very very safe for a very very long time.

And it isn't enough to just be able (if indeed they are) to stop pouring their own water on the plant, because there's always going to be rain to add to the internal water-levels, what with the loss of the buildings.  So they need a plan.  That may include roofing the place over again, rather than actually smothering the place.  (Actually, that is more or less what they did at Chernobyl.)

But, as I said, I don't know what that linked-to article actually said, so I may be completely on the wrong track, with all the above.

[freeformschooler]

Starver, I think that's a decent idea in an ideal world, but I was watching the news today and some of the reactors have already gone full meltdown (as in there's nothing more they can do). I think your idea might be implementable were the situation not preposterously chaotic, but they probably just don't have the time or resources to do any of that. Let's face it: a lot of things are going to be irradiated, possibly for a long time. We'll have to deal, but especially places in Japan. Many Japanese will over time get sick or die from all this, but eventually I have a feeling that they're going to recover. They're strong people.

[Starver]

I think you got the wrong idea about what I said.  Especially as I had already mentioned the situation being chaotic.

But let's just say, for arguments sake, that they just smother the site in concrete.  Now they've got fuel elements encased either directly within concrete or more likely in unmanagable voids, either way, heat builds up.  Whether that's enough heat to melt the materials (or melt them further), or not, you should still consider the old adage of P₁V₁/T₁ = P₂V₂/T₂.  If they've completely sealed the thing with any significant amount of gas, pressure builds up, catastrophic failure occurs.  If they've not completely sealed it up then escaping gas (itself radioactive or otherwise, I'm not too sure how much radon/etc there'd be from the given mix of fuel products, but it'd be there) is going to bubble radioactive liquids/particles in liquid suspension through the cracks.

Whatever happens, there's no way of getting in there and making any necessary adjustments to the system.

Encasing would require decent 'inspection hatches'-cum-venting systems and monitors at a bare minimum.  You couldn't even just get away with embedding monitor of various kinds (temperature, pressure, geiger, etc) and small-bore tubes for dumping extra moderating liquid in and controlled extraction of gasses, because the monitors could fail and tubes could block, so you need to be able to retrieve and replace the instruments and deal with structural deformations in the exhaust systems.

Chernobyl might be considered "overly open" (birds fly in and out of the central area, apparently... not sure how many times they'd be able to do that, though, I'm out of date on the internal conditions at that site) but it at least provides passive air-cooling.


Personally, I'd go for two things: emergency water-retaining structures (caps on potentially overflowing drains, and otherwise put a rim around the site) and then try to arrange to more or less permanently re-roof the reactors themselves to prevent indiscriminate rain entry, although with an integrated controlled water (and/or boric acid or whatever) delivery system for use when needed and infrastructure for delivering remotely controlled mechanical equipment to undertake a proper decommissioning.  But there are problems with that solution.

And not just related to the most basic difficulties of construction and the obvious flaw with the whole "roof the site off" plan.  Given that the place is still in a quake/tsunami zone you have to account for the distinct possibility for more shakey-shakey and wavey-wavey for... well, the centuries you'd have to expect the site to have to be maintained even after the last of the more troublesome fuel is removed.  Dounreay, sitting in a fairly geologically stable location (although as susceptible to tsunamis from random underwater sediment-slopes shifting as just about any other place facing out to sea, even without a handy quake zone) in a (IIRC) hard-rock area has been worried about this problematic disposal shaft of theirs (that I mentioned) being subject to coastal erosion over the coming 400 years...


And I personally think that there'll be no more than a "warm spot" of radiation-related illnesses.  There'll be over-exuberant banning of fishing and farming in the affected areas, the zone will be left unpopulated within at least the immediate vicinity (not to wish to sound so casual about any aspect, but there's a whole lot more population upheaval gone on due to the original quake/tsunami incident[1], so any locals permanently evacuated from the vicinity will be very much a drop in the ocean in the grand scheme of things.  On the border between statistically significant and not so...  It won't be such a complete an evacuation as the USSR could so easily achieve (mostly due to relative population densities and the different degree and nature of the authoritarian governments involved) but it won't be 3rd-world-like in that there'll be significant underclasses (or oppressed locals or dispossessed immigrants) who find themselves unwittingly/unwillingly/unconcernedly living next to a disaster zone like you might in cases such as Bhopal or down-river of toxic gold-digging operations and their unstable dams in the Amazon.


I also think that they will get over it psychologically and socially, although I must admit that my previous opinions that there wouldn't be mass protests about the nuclear power have already been overturned, so I'm perhaps now less inclined to go with the whole "they are a stoic people" assumption than I was.  Still, I maintain it'll never get anywhere near Libya-level protests, probably not even close to those we had over here, last weekend, regarding these stupidly regressive budget cuts being foisted upon us.  And I know I'm setting myself up for another fall by being so bold in saying so.


On the whole, though, regardless of what opinions I might have asserted above, I'm also one with Niels Bohr, when he famously said "Prediction is very difficult.  Especially about the future.  Time will tell, and there will be more facts that I don't know about this situation than ones I'm definite about (and I'd bet I'm even wrong about some of the latter).



[1] There'll be a mix of those (who survived) wanting to move back to "their land", much as everyone did after the Great Fire Of London, down to demanding that they have their exact same plots of land, and those who would never live on the 'coastal plains' again.  Together with the losses of life in some areas having significantly depopulated areas, it's entirely possible that the

[Kogut]

"it's entirely possible that the " the what?