8.9 Earthquake has struck Japan

Jim Saueressig said:
Via Kyodo News

Radioactive iodine 134 extremely high in water at No.2 reactor.

10 mil. times normal level of radioactivity in water at No.2 reactor :eek:

Radioactive iodine 1,850 times limit in sea near plant
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Assuming someone didn't garble the atomic mass of the isotope in question...
I-134 has a very short half life - 53 minutes! There 'should' be essentially none floating about, apart from what may arises from the decay of longer lived fission fragments.

This table http://www.meti.go.jp/press/20110327001/20110327001-4.pdf comes from the Japanese Govt., http://www.meti.go.jp/press/20110327001/20110327001.html
If accurate, it would strongly imply that reactor 2 (or perhaps its spent fuel pond?) has somehow regained criticality. It shows a number of short-lived 'topes: Te-99 6hr, I-134 53min, LA-140 1.6days.
 
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You beat me to it, Greg. My first thought when I heard the report about iodine in the seawater was, "Why are they reporting on a short half-life isotope that shouldn't be a long-term problem in the ocean?"

Put this together with the belated rush to replace seawater with fresh for cooling and the obvious conclusion is that the hot, damaged fuel assemblies have been corroding and crusting up like a coffee-maker. They're also still not saying much about the #4 spent-fuel pond which from all I've read is a serious problem.
 
B Ozanne said:
Do 6.5's generate tsunamis? My understanding was probably not in most cases, but maybe along the Japan coastline. Also, as a preliminary measurement that 6.5 could be bumped up.
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There are tsunamis and then there are tsunamis. Japan can have local and regional tsunamis that can only devastate nearby coasts, but can do so in only a few minutes, from earthquakes apparently as small as mag. 4.2. It isn't going to produce a long-lived wave, but if it is sufficently close to the coast line it can still be damaging. Obviously, it also has to be the right sort of a quake (that results in water displacement).

Ignoring tsunami potential, a quake has to be a mag 5 to be considered a serious quake, from a potential damage perspective, and it must be a mag 6 or greater to get a "bold red" treatment on the USGS "big quake" page.
 
Anybody following this thread (or this story) with any interest may recall the explosion of the supression pool to unit No. 3 (the one that used MOX fuel). I think most of us realized that this was a reactor breach, although I don't think I have heard anybody actually confirm that. There can now be no doubt: Plutonium detected in soil at Fukushima nuke plant

From a TIME magazine blog back when MOX was being explained:
there are four kinds of carcinogenic isotopes released when a nuke plant blows: iodine-131, cesium-137, strontium-90 and plutonium-239. Plutonium is not only the most lethal of the four ("extraordinarily toxic" is how Dr. Ira Helfand, a board member for Physicians for Social Responsibility, describes it), it also hangs around the longest. It's half life is a whopping 24,000 years, and since radioactive contamination is dangerous for 10 to 20 times the length of the isotope's half.life, that means plutonium emitted in Fukushima today will still be around in close to half a million years.
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Source: http://ecocentric.blogs.time.com/2011/03/17/mox-the-fukushima-word-of-the-day-and-why-its-bad-news/#ixzz1Hul6g58x

EDIT: It is still possible that the plutonium detected came from spent fuel rods that were uncovered, melted and burned and not from the reactor core of No. 3. Would love to hear if it was Plutonium-239 and in what concentrations, exact location(s), etc.
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People seem to have reached their level of boredom with this incident, so perhaps I should let this thread die.

Good new article: http://www.guardian.co.uk/world/2011/mar/28/japan-fukushima-nuclear-reactors-electricity
Officials at Tepco, who run the plant, say it is not clear where the radioactive water came from, but it escaped from the reactor core, either directly through a breach in the containment vessel or through a crack or hole in pipework.
Lahey believes that molten fuel inside reactor two has begun to leak out of its containment vessel, meaning it may be too late to save that reactor.
The troubles on site are compounded by fears that radioactive material, including plutonium, is leaching into the soil and has washed into the sea. So far, these problems are localised: most radioactive material leaked onto land will bind to soil and stay there, while radioactive material in the sea will be diluted and disperse. "They are doing all the right things now, but this is a tight horse race," Lahey said.
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Guy quoted is Richard Lahey, who was General Electric's head of safety research for boiling water reactors when the company installed them at Fukushima.

Mostly unrelated, but interesting:
 
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Hardly a surprise. They've been talking all around the fact that it's quite likely there's low-level fission going on in the deformed core -- hence all the radioactive iodine and the "difficulty cooling it", as they euphemistically put it. I guess it's only a "partial meltdown" if not all of the core has melted into a puddle in the basement. Jeez.

They also keep saying not to worry that it can explode like Chernobyl. True, but the Chernobyl explosion also made the fragments sub-critical, rather than leaving a fissioning blob in the cellar.:(
 
Good day all,

Basically a meltdown (partial or not) produces a molten material containing fuel and components of the reactor / containment (metal and concrete) mixed in a hot "lava".

Elephant_s+Foot+1996.jpg


Above: This is the melted "foot" under the Chernobyl reactor after their meltdown. Radiation levels were a staggering 3,500 REMs per hour (thats 35 Sv ... Or 35,000 mSv per hour) just being inside the building!

Mostly, the only way to prevent farther release is by simply burying it ;-(
 
I saw on the news tonight that they have rescued a dog that survived for 21 days on a rooftop in the flotsam well off shore. I fear that they will also find several bodies in the flotsam as well, but many will never be found.
 
The death toll from the quake/tsunami will never be known. It is on track to be one of the deadliest quakes to ever hit Japan, though. Between the confirmed dead (+11,000) and the missing, the toll will probably be over 27,000
 
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