Japan earthquake - contamination & consequences outside Fukushima NPP

[jlduh]

Cesium contamination levels up around 10 times at the bottom of the ocean in some points 1 to 3 km around Fukushima site in September, trend to be followed up:

http://fukushima-diary.com/2013/10/...-spiked-up-this-september-over-10-times-much/

http://www.tepco.co.jp/nu/fukushima-np/f1/smp/2013/images/ocean_soil_131025-j.pdf

 

[zapperzero]

http://www.scientificamerican.com/a...prove-plan-to-release-groundwater-from-plant/
Fisheries association approve plan for a groundwater bypass. As I understand it, the water is captured in drains uphill of the plant and dumped into the sea and as such it is only very slightly contaminated anyway.

 

[a.ua.]

http://www.asyura.us/bigdata/up1/source/22098.jpg
http://ex-skf.blogspot.com/2014/04/happy-april-fools-day-residents-back-in.html

 

[F X]

Anyone know if this article is accurate?

http://www.vice.com/read/no-one-wants-you-to-know-how-bad-fukushima-might-still-be-666

 

[Rive]

Anyone know if this article is accurate?

http://www.vice.com/read/no-one-wants-you-to-know-how-bad-fukushima-might-still-be-666

As I see that article is accurate in some details: but as the accurate pieces are seriously contaminated with many fear-mongering and lots of inaccurate speculation, it's inaccurate in the big picture it draws.

The author carefully selects the pieces of information fits with his preconception. That's not the way to write accurate articles.

 

[etudiant]

It seems that apart from the problematic subdrain freezing effort, TEPCO has made substantial progress in sealing off the site
http://www.world-nuclear-news.org/RS-Additional-measures-for-Fukushima-water-management-1408144.html

Of course the steel barrier only addresses the ocean side, so more needs to be done, but it has gotten very little
public attention. Is it a useful step or a waste?

 

[mheslep]

Anyone know if this article is accurate?

http://www.vice.com/read/no-one-wants-you-to-know-how-bad-fukushima-might-still-be-666

When I asked past Nobel Peace Prize nominee Dr. Helen Caldicott these questions, she was quick to respond: “Because money matters more than people.”

nominee Caldicott has spoken. The lure of money and fame apply to others, not her.

No the article can not be entirely accurate.

 

[Astronuc]

Caldicott's comment, “The problem is that TEPCO has hardly invited in the international community to help to try and solve the problem,” says Dr. Caldicott. “A huge company like [Florida-based engineering group] Bechtol, which makes reactors and is a very good engineering company, should have been invited in by the Japanese government to try and propose a way to deal with these problems in an engineering fashion,” or the statement attributed to her is incorrect.

Bechtel is a civil engineering and construction company based in San Francisco, although they have branches/offices in various locations. They do the civil/structural works at nuclear power plants, other power plants and process plants. They do not make reactors.

TEPCO has had foreign experts providing advice and assistance, although I do not know the specific outcomes of those interactions.

 

[Gary7]

I'm trying to understand a bit more about fission products of Fukushima Daiichi, their distribution as a result of the accident, etc. Specifically, I'm struggling to understand the details of Cesium 137 and Cesium 135.

The ANL Human Health Fact Sheet regarding Cesium (October 2001) mentions that both Cesium 135 and 137 are produced in relatively high yields of 7% and 6% (respectively). Yet Cesium 135 is rarely mentioned in soil or water analyses.

My questions are;
1. Shouldn't there be equally large amounts of Cesium 135 in the environment as there are of Cesium 137?
2. If so, does the comparatively low specific activity and energy yield of Cesium 135 mitigate its health risk to the point where it is negligible compared to the other radionuclides?
3. Or, is it the decay of Cesium 137 into Barium 137m that makes Cesium 137 so dangerous? (Again, meaning the health risk of Cesium 135 is negligible by comparison).

Any help in sorting this out would be appreciated.

 

[Gary7]

Since I'm in a confessional mood, I guess I should also admit I don't really understand how the various isotopes of cesium are produced: is it correct to say that Cesium 135 is the decay/daughter product of Xe135 (which itself is a fission product of U235), and that Cesium 137 and 134 are the direct fission products of U235?

 

[nikkkom]

I'm trying to understand a bit more about fission products of Fukushima Daiichi, their distribution as a result of the accident, etc. Specifically, I'm struggling to understand the details of Cesium 137 and Cesium 135.

The ANL Human Health Fact Sheet regarding Cesium (October 2001) mentions that both Cesium 135 and 137 are produced in relatively high yields of 7% and 6% (respectively). Yet Cesium 135 is rarely mentioned in soil or water analyses.

My questions are;
1. Shouldn't there be equally large amounts of Cesium 135 in the environment as there are of Cesium 137?
2. If so, does the comparatively low specific activity and energy yield of Cesium 135 mitigate its health risk to the point where it is negligible compared to the other radionuclides?
3. Or, is it the decay of Cesium 137 into Barium 137m that makes Cesium 137 so dangerous? (Again, meaning the health risk of Cesium 135 is negligible by comparison).

1 Yes
2 Yes. Cs135 specific activity is ~100 thousand times less than Cs137.
3 No, mainly it's reason #2 why Cs135 gets far less attention

 

[mheslep]

1. Shouldn't there be equally large amounts of Cesium 135 in the environment as there are of Cesium 137?

After 15 yrs, half the 137 will be gone. Not so the 135.

 

[Gary7]

Shouldn't that be 30 years?

 

[mheslep]

Shouldn't that be 30 years?

Yes, sorry.

 

[Astronuc]

Greenpeace - Radiation Along Fukushima Rivers Up to 200 Times Higher Than Pacific Ocean Seabed
http://www.ecowatch.com/radiation-f...her-than-pacific-ocean-seabed-1937971722.html

Riverbank sediment samples taken along the Niida River in Minami Soma, measured as high as 29,800 Bq/kg for radiocaesium (Cs-134 and 137). The Niida samples were taken where there are no restrictions on people living, as were other river samples. At the estuary of the Abukuma River in Miyagi prefecture, which lies more than 90km north of the Fukushima Daiichi plant, levels measured in sediment samples were as high as 6,500 Bq/kg.

It would be nice to have independent confirmation, but it makes sense that Cs (and other radionuclides) would find their way to rivers where they would concentrate in the sediment. Cs is more soluble in seawater, so it would be diluted much more rapidly.

 

[mheslep]

The beaches of Brazil measure as high as 83,245 Bq/kg. Greenpeace findings have become little better, I think, than Helen Caldicott findings.

 

[Astronuc]

The beaches of Brazil measure as high as 83,245 Bq/kg.

True, but as the abstract indicates, such values are above the limit of 370 Bq kg⁻¹ recommended for the safe use of building materials for dwellings by OECD. One would not want to dwell on a beach 83,245 Bq/kg, or rather, I would not recommend children or pregnant women dwelling for prolonged periods on those beaches.

Since I'm in a confessional mood, I guess I should also admit I don't really understand how the various isotopes of cesium are produced: is it correct to say that Cesium 135 is the decay/daughter product of Xe135 (which itself is a fission product of U235), and that Cesium 137 and 134 are the direct fission products of U235?

Concerning Cs-134, -135, -137, refer to the attached images.

Note the darker squares in the first image, which provides the fission yields for each radionuclide. The yield for Cs-134 and Xe-134 is rather low. The main source of Cs-134 is the precursor Te-134 (fis yield ~ 0.0622) with a trace from I-134. The successive chain is Te > I > Xe > Cs. Similar Cs-135 comes from decay of Te-135 and I-135. On the other hand, Cs-137 comes primarily from the decay of Xe-137 and I-137 (with yields of 0.0319 and 0.0262, respectively). These isotopes can also be produced by n-capture of their A-1 neighbors.

The second image shows the n-capture cross-sections for (n,γ) reaction. The third image shows the half-lives of the radionuclides. The half-life of Cs-135 is approximately 2.3 E6 years, which means is has a very low activity. Also note that Xe-135 has a high n-capture cross-section, and much of that is transmuted to Xe-136.

 

[swl]

Hello all,

I have a new question related to Cesium in the waste stream of a refuse incinerator located in Machida, western Tokyo.
The site began sampling for Cesium 134 and Cesium 137, in the Incineration residue, after the accident in 2011.
From the time they initiated sampling, until June of 2016, the Cs-134 activity was always equal to, or less than the Cs-137 activity. Starting in June of 2016 and on multiple occasions since then, the Cs-134 activity has been higher than the Cs-137 activity. With consideration to the much shorter half life of Cs-134, I would have expected the Cs-134 activity to fall more quickly than the Cs-137 activity, but the reverse seems to be true here.

Can any of you please kindly help me to understand why the Cs-137 activity would be falling faster than that of the Cs-134?

Also, if this could be a case of confusion between Cs-134 and Bi-214 in the measurement process, how might we be getting Radium into the Incinerator?

https://www.city.machida.tokyo.jp/kurashi/kankyo/gomi/shiryo/keikakutou/shisetu.files/zansa_housyanou.pdf

If you would like an English translation, please PM me and I'll be happy to email the translation to you.

Thank you for reading and helping me understand.
Scott

 

[Gary7]

I'm interested in this too.
My guess is that the values being measured lately are so negligible, the minuscule variances will be the result of the uneven concentrations to begin with. The initial dispersal was uneven, and the environment where these measurements are now being taken (the incinerator) would not produce predictable results, and so expecting a textbook decay ratio is probably a mistake to begin with. The more important takeaway from the data is the long-term trend. Both are dropping, and C134, when it is detected at all, is, on average, lower than the C137.
That is my gut feeling, but hopefully someone who knows more than I do will be motivated to provide a more accurate response. It does seem that the CS137 is falling very rapidly. Maybe there is a biological component to this also... what kind of trash is going into that incinerator. Household trash, or industrial trash? Are they now (or were they ever) accepting loads of trash from Fukushima? Maybe too many variables to get an accurate picture.