東京電力は28日、福島第１原子力発電所の敷地内の土壌５カ所でプルトニウムを検出したと発表した。このうち２カ所は原子炉から外部に漏れた可能性が高いという。検出されたのはごく微量としている。同社はこれとは別に２号機のタービン建屋の外で、高い放射線量を計測したと発表した。汚染水が屋外で見つかったのは初めて。同機の原子炉内の燃料棒に深刻な損傷が生じた結果とみられる。

　検出されたのはプルトニウム238、239、240の３種類の同位体。３月21、22日に敷地内の５カ所で土壌数百グラムを採取し、外部機関に分析を依頼した。５カ所すべてでプルトニウム239と240を土壌１キログラムあたり最大で約1.2ベクレル検出。このうち１～２号機から西北西500メートルにあるグラウンド付近と固体廃棄物貯蔵庫前の２カ所で238を最大0.54ベクレル程度検出した。

via 福島原発の土壌からプルトニウム　東電発表「ごく微量」　　：日本経済新聞.

TOKYO (Kyodo)–Plutonium has been detected in soil at five locations at the crippled Fukushima Daiichi nuclear power plant, Tokyo Electric Power Co. said Monday.

The operator of the nuclear complex said that the plutonium is believed to have been discharged from nuclear fuel at the plant, which was damaged by the devastating March 11 earthquake and tsunami.

While noting that the concentration level does not pose a risk to human health, the utility firm said it will strengthen monitoring on the environment in and around the nuclear plant.

Meanwhile, high levels of radiation exceeding 1,000 millisieverts per hour have been detected in water in a trench outside the No. 2 reactor’s building at the nuclear plant, with the contaminated water suspected to have come from the reactor’s core, where fuel rods have partially melted, authorities said Monday.

via Plutonium Detected In Soil At Fukushima Nuclear Plant (Tuesday, March 29, 2011, Japan time).

Related articles:

1. Plutonium Outside Reactor Signals Worse-Than-Expected Leak
   1. Plutonium, produced as a result of uranium fission, does not disperse easily because of its weight. It was likely released outside during the string of hydrogen explosions and fires at the Nos. 1, 2, 3 and 4 reactors….
   2. Plutonium is far more toxic than uranium. Exposure to plutonium-238, which emits neutrons, is known to increase the risk of cancer.
2. Plutonium detected in soil at Fukushima nuke plant
   1. the plutonium, the presence of which was confirmed for the first time in the ongoing nuclear emergency, could have been discharged from nuclear fuel at the plant hit by the devastating March 11 earthquake and tsunami, but does not pose a major risk to human health.
   2. Plutonium is more toxic than other radioactive substances such as iodine and cesium, but the levels confirmed from soil samples taken at the plant on March 21 and 22 were almost the same as those from the fallout detected in Japan following past nuclear tests by the United States and Russia, said the utility known as TEPCO.

The government’s Nuclear and Industrial Safety Agency said it remains unknown which reactor plutonium came from and that TEPCO and the science ministry will strengthen monitoring on the environment both in the plant and outside of a 20-kilometer exclusion zone set by the government

Tags: earthquake, Fukushima, Japan, Nikkei, plutonium, radioactivity