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:

測定結果をお送りします。
Puが検出され、正直なところびっくりしました。

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

Puは核実験ですでに広く，低レベルで分布しています。
このPuついて、Pu238/Pu239,240放射能比は0.03程度です。
今回のこの比は0.8で明らかに高く、原発由来のPuを含んでいます。

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.

政府の放出量見積もりでは3です。
野ざらしの鉄板には核実験のPuが付着していないと考えると、
何故比が低いのかと考えさせられます。
全て3ではなくて0.8の低い比を持つPuが放出された可能性もありますね。

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.

さらにPu239,240/Cs-137放射能比が9.0E-5で、政府の推定値4.3E-7の200倍になり、Puが多く検出されています．たぶんフラクショネーション（挙動の違い）が存在するためだと思われます。

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.

(中略)
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.

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