Radioactive Water Found In Two Reactor Buildings 442
RedEaredSlider writes "Japan's Nuclear and Industrial Safety Agency said it detected several kinds of radioactive material in the water on the floor of reactor buildings at the Fukushima Daiichi nuclear power plant. The isotopes found in the water were cobalt-76, technetium-99, silver-108, iodine-131, iodine-134, four isotopes of cesium, barium-140 and lanthanum-140. All have half-lives measured in hours or days, with the exception of cesium-137."
plutonium was just found outside (Score:5, Informative)
This does not have a half life in days, but years
http://news.blogs.cnn.com/2011/03/28/3-types-of-plutonium-detected-at-japans-fukushima-daiichi-plant/
This is extremely bad
"half-lives measured in hours or days" (Score:4, Informative)
Technetium-99 has a half-life of over 200k years. Of course, it's still days, just a lot of them.
Re:"half-lives measured in hours or days" (Score:1, Informative)
Unless it's Technetium-99m, which has a half-life of 6 hours.
Re:"half-lives measured in hours or days" (Score:4, Informative)
Re:plutonium was just found outside (Score:2, Informative)
> You, uh, do realise that the longer the half-life the _less_ radioactive something is?
That rule of thumb fails if said element happens to decay into yet another radioactive isotopes. Like, say, uranium...
Re:I'm fine with nuclear power. (Score:4, Informative)
Re:plutonium was just found outside (Score:5, Informative)
.... not really no.
it ups it but if your isotope with a 20K year half life decays into something something with a halflife of say (for an example that would be easy on the math)5 seconds then you'll get twice as much radioactivity out of it (assuming the seconds products are as dangerous forms of radiation) with a little variation.
a isotope with a 20K halflife will still be utterly dwarfed in terms of radiation output by something with a halflife of a few decades even if the former has a decay chain 10 isotopes long because it can only add a linear multiplier, not an exponential increase in radiation output.
once you're into halflives in the tens of thousands be more afraid of heavy metal poisoning than radiation poisoning.
Re:plutonium was just found outside (Score:4, Informative)
From what I read, plutonium is pretty bad if you inhale or ingest it, otherwise not too much of a problem. If it gets into you it can stay in you for years, causing cancer and bone problems (it can get into your bones and bone marrow).
Outside of your skin, the radiation is too weak to cause much concern, but when it is inside you, the radiation is enough to cause reasonably serious harm (or at least the potential therein).
Re:"half-lives measured in hours or days" (Score:4, Informative)
As others pointed out, they're probably referring to Tc99m, which has a short half life. The fact that ground state Tc99 has a half life of roughly forever is probably why it's not mentioned... It's so long that you need a lot of it to get a lot of decays. It's also fairly unreactive and doesn't form any particularly soluble salts (as best as I can tell), so the exposure possibility is limited. Finally, it decays with a fairly low every beta (294keV) and only very rarely emits a low energy gamma (90keV @ 0.0006%).
Compare to Cs137 which has a 30yr half life, so it has the same decay rate as 7,000 times as much Tc99. It forms highly soluble salts and can be absorbed by the body and concentrated in plants. On top of that, it has a much higher decay energy, and usually emits a strong beta (514keV) and gamma (662keV). It makes the Tc99 look like so many bananas. So, they aren't technically correct, but Tc99 isn't really important.
For reference:
Tc99m: http://ie.lbl.gov/toi/nuclide.asp?iZA=430399 [lbl.gov]
Tc99: http://ie.lbl.gov/toi/nuclide.asp?iZA=430099 [lbl.gov]
Cs137: http://ie.lbl.gov/toi/nuclide.asp?iZA=550137 [lbl.gov]
Re:above post: example of techie vs public disconn (Score:2, Informative)
you don't cure techie jackasses of a bad attitude with a patient and courteous demeanour. they are blinded by smug self-satisfaction. you need to smack them in the face until they pay some fucking attention
Re:plutonium was just found outside (Score:2, Informative)
irrelevant strawman argument (proton) and wrong to boot (toxicity) http://www.ccnr.org/plute_tox.html
The chemical toxicity of plutonium used in these contexts is much smaller than its radioactive toxicity
http://www.nrc.gov/reading-rm/doc-collections/fact-sheets/plutonium.html
The point is that plutonium sticks around for a long time and when inhaled into the lungs in fine particle for the lethal dose is about 1/4 mg. T
Still not looking good (Score:5, Informative)
The best reports on reactor status are at Japan Atomic Industrial Forum [jaif.or.jp], which publishes a status table every day. This is addressed to people in the industry. They just list the facts, without explanation.
The good news for March 28 is that Unit 3's containment is now listed as "undamaged" instead of "possibly damaged". Unit 2 is listed as "damaged and leakage suspected", and that's now the most worrisome unit.
There's finally a fresh water supply for cooling. That's a big relief. Sea water cooling in a boil-off situation leaves tons of salt behind, and there was a real worry that the seawater cooling would stop working once too much salt accumulated. Fresh water cooling can continue indefinitely. It's not clear where the water is coming from. Hopefully they have a water line to a reliable source by now, and aren't just bringing in tanker trucks.
The cores in units 1,2, and 3 still have exposed fuel rods. Until water injection into the core is working again, the reactor can't be brought to cold shutdown. Remember, the reactor vessel is pressurized and contains a mixture of water and steam. Injecting water into a boiler is inherently difficult. Injecting water into a damaged boiler in a ruined structure in a highly radioactive area is very tough.
The spent fuel pool situation on reactors 3 and 4 is marginally under control. Seawater spray continues, but if they have to keep putting water in, the situation is still bad.
They're weeks from a stable emergency shutdown.
That's just the beginning. The situation isn't safe until there are again redundant closed loop cooling systems working. The current cooling hacks dump radioactive water into the ocean.
Then comes decommissioning. The spent fuel pools have to be cooled for three years or so, and then the fuel rods transferred from the wrecked buildings to dry casks. It will probably be necessary to build another containment building around unit 2, at least. Units 1,2, and 3 are all too damaged to ever de-fuel normally. It's not clear what will be done there. Unit 4 wasn't fueled, but it had a hydrogen explosion while cooling was lost, and will probably never be restarted. Units 5 and 6 can potentially be restarted, but it's doubtful that they will be.
Re:plutonium was just found outside (Score:5, Informative)
Plutonium in perspective [nextbigfuture.com].
As far as widespread release of Plutonium into our environment is concerned, consider this:
The most important effects of plutonium toxicity by far are those due to nuclear bombs exploded in the atmosphere. Only about 20% of the plutonium in a bomb is consumed, while the rest is vaporized and floats around in the Earth's atmosphere as a fine dust. Over 10,000 pounds of plutonium has been released in that fashion by bomb tests to date, enough to cause about 4,000 deaths worldwide. Note that the quantity already dispersed by bomb tests is more than 10 million times larger than the annual releases allowed by EPA regulations from an all breeder reactor electric power industry.
Plutonium is not good for you, but the sky has yet to fall, and seems unlikely to in the future.
Re:plutonium was just found outside (Score:4, Informative)
not to put too fine a point on it but there's no shortage of completely non-radioactive substances which will diddle with your DNA, get something planar which can bind between bases and you get a nasty little insertion mutation.
lead and it's friends bioaccumulate pretty badly as well.
Not to put too fine a point on it but radiation isn't very special.
plutonium leaking into groundwater is serious but so would be lead or arsenic getting into food or groundwater.
Re:Still not looking good (Score:5, Informative)
Great post. One issue with it:
Units 5 and 6 can potentially be restarted, but it's doubtful that they will be.
The history of nuclear power accidents does not support this. Three Mile Island No.1 reactor is still in operation in Pennsylvania. Chernobyl No.1, 2 and 3 reactors were operated for up to 14 years after No.4 blew up and contaminated Europe, and there are 11 other RBMK reactors still in operation elsewhere. The power reactor at the Windscale site was operated for 46 years after the graphite fire in the weapons reactor.
Nuclear reactors represent astonishing capital investments by their builders, and by that I mean the companies, governments and citizens. Japan is dealing with rolling blackouts. This is intolerable in a nation that relies on meeting the demands of the export market. The No.5 and No.6 reactors represent about 2GW of generation capacity they desperately need.
They'll bring those reactors up at some point.