Thursday, March 22, 2012

Low-Level Plutonium of #Fukushima Origin Detected in Iwaki City, 40 Kilometers South of Fukushima I Nuke Plant

It was originally reported on a blog called "Alpha rays and metal plate (α線と鉄板)" on March 18, 2012.

Email from Professor Masayoshi Yamamoto, Institute of Nature and Environmental Technology at Kanazawa University about the analysis of dust off the metal plate that had been left outside since the March 11, 2011 accident, as reported by the blog:


Here's the result of the analysis. Frankly, I am surprised that plutonium was detected.


Plutonium has been spread and deposited at low densities in wide areas because of the atmospheric testing of nuclear weapons . The ratio of plutonium isotopes, Pu238/Pu239+240, of the atmospheric testing origin is about 0.03. But this time [dusts off the metal plate in Iwaki City], this ratio is higher at 0.8, indicating the dusts contain plutonium of the Fukushima I Nuke Plant origin.


The government estimate of the ratio of these plutonium isotopes is 3. Considering the plutonium of the atmospheric testing origin is not attached to the metal plate, I wonder why the ratio is lower than the government estimate. It is possible that not all plutonium isotopes released had the ratio of 3, and there were plutonium isotopes with the lower ratio (0.8) that were released from the plant.


Further, the ratio of Pu239+240/Cs-137 is 9.0E-5, which is 200 times the government estimate of 4.3E-7, showing more plutonium being detected than the government estimate indicates. It is probably because of fractionation.

現在ウラン、出来れば Am-241なども分析できればと考えています。

Right now, I am hoping to test for uranium, and Am-241 if possible.

The report by Professor Yamamoto, from the same blog:

Cesium detection:

Plutonium. Pu-242 is a tracer for chemical yield correction. [-- Don't ask me what it means. I translated as best I can.]

I am asking Professor Yamamoto to confirm that this is his analysis report.


Atomfritz said...

"Pu-242 is a tracer for chemical yield correction"

I'll try to explain it as far as I understand this (might be totally wrong as I am no chemist).

As plutonium's alpha radiation doesn't penetrate much, it has to be extracted chemically before measurement.

Depending on the specimen material and the chemical reactions used, the extraction is always inefficient to some degree.
Some of the specimen plutonium stays behind in the chemical process waste.

So you can have a better guess of the original plutonium content when you know how much of the added tracer plutonium-242 has made it through the extraction process.

Anonymous said...

Atomfritz is right. On the first picture you can see he is writing something about NHO3 it is easier to understand actually if you write HNO3 (which would be according to IUPAC nomenclature) - which means he used nitric acid (also called aqua fortis). So probably the sample was actually boiled in HNO3 for a few minutes (this is called an oxidative acidic digestion) and than the remaining solids (mainly silica = sand) were filtered off. Now all (more correct most of) the plutomium is in the solution and you can handle it easier. But as Atomfrizt pointed out, this chemical reaction is not always 100% so you need to add something to the sample prior to the acidic digestion as a reference.

I am still not sure why he used a Ge detector thou. Once you have the Pu in solution it would be more sensitive to use a scintillation counter. The only advantage I can see in using Ge detection is to be able to get the KeV of the gamma rays, thus to distinguish between PU 239/240 and 238.

Just a warning, do not do an oxidative acidic digestion at home, there are lots of nasty fumes coming out of the boiling solution (it will foam and bubble massively). You do not want to inhale all that, otherwise there IS AN IMMEDIATE EFFECT ON YOUR HEALTH. ;-)

Anonymous said...

Did it come through the air and land on the ground?
yes or no?

kintaman said...

But people just outside of the 20km mark do not need to evacuate. Just smile everyone....

How can this not been outright manslaughter or even murder on the part of the government and TEPCO? Enough is enough arrest all responsible already.

Anonymous said...

plutonium-239, half-life of 24,100 years
plutonium-240, half-life, 6563 years
plutonium-238, half-life of 87.7 years

But then they know that, don't they?

ChrisNoland said...

Please share on your wall and with friends!
"I would like to fund raise to finish this movie for release so I can start a fund to help people in fukushima affected by radiation and buy materials for people to rebuild who cannot afford it. It got really great reviews at SFU Vancouver! It has also been featured in CBC canada news channel.

You can support this project by placing pre-order for DVD, also we have the option for people or businesses or organizations to pledge their support and we will place their name in the credits of the movie!

The reason to make the movie is so people have better understanding of what happened and sale of movie is a big business which can generate a lot of funds to help with our projects, but we need your help so we can get the movie to film company to make it available to the world.

Can you please share this with your friends? If we all share it with our friends, it will reach many!

Thank you
Chris Noland

Anonymous said...

Even though there is tons of plutonium in both the MOX fuel and the spent fuel, the ratio of Pu to U in Global Dirts analysis cannot be explained by any reactions in known inventories, as no U was detected and only high levels of Cs137, Pu and Am 241 were. This is the kind of ratio you would see if an HE exploded in a nuclear weapon accidently, releasing unfissioned plutonium.

Food for thought

Atomfritz said...

@ anon 8:36

He didn't seem to have the opportunity to test for uranium yet:

"Right now, I am hoping to test for uranium, and Am-241 if possible."

Post a Comment