アリューシャン列島の上空で異例なウラン235検出: ずくなしの冷や水

2018年03月09日

アリューシャン列島の上空で異例なウラン235検出

MailOnline 2018/2/15
Mystery as 'highly unusual' radioactive substance enriched with the type of uranium used to make nuclear fuel and bombs is detected in Alaska
Particles enriched with uranium, used to make nuclear fuel and bombs, have been detected above Alaska - and their source remains a mystery.

The 'highly unusual' particles, containing the isotope uranium-235, were spotted in the atmosphere for the first time in 20 years of plane-based atmospheric observations.

Experts have discounted natural causes, although research suggests it originated in Asia.

They believe that the sample may have come from China, Japan or North Korea.

Scientists from the US National Oceanic and Atmospheric Administration (NOAA) detected the particles at an altitude of 4.3 miles (seven km) above Alaska's Aleutian Islands.

The atmospheric aerosol was measured by a Nasa WB-57 plane, used in high altitude research.

Uranium, the heaviest element to occur naturally on the planet, comes in the form of the slightly radioactive isotope uranium-238.

Trace amounts of uranium-235, specifically used for making nuclear fuel and bombs, do also occur naturally.

During millions of research missions using planes to capture atmospheric particles, experts have never before obtained a sample containing uranium-235.

Writing in a study on the finding, its authors said: 'The purpose of the field campaign was to obtain some of the first global cross-sections of the concentration of trace gases and of dust, smoke, and other particles in the remote troposphere over the Pacific and Atlantic Oceans.

'Analysis of wind trajectories and particle dispersion model results show that the particle could have originated from a variety of areas across Asia.'

Researchers believe the sample came from recently created reactor-grade uranium, perhaps from burnt nuclear fuel.

This rules out nuclear disasters like Chernobyl and Fukushima.

Dan Murphy, who led the study, oversees flights across the globe which sample the atmosphere for aerosols.

The tiny particles originate from fires, pollution, dust and other sources and can affect cloud formation and weather patterns.

Speaking to Gizmodo, Mr Murphy added: 'It's not a significant amount of radioactive debris by itself.

'But it's the implication that there's some very small source of uranium that we don't understand.

'One of the main motivations of this paper is to see if somebody who knows more about uranium than any of us would understand the source of the particle.'

The full findings were published in the Journal of Environmental Radioactivity.

・・・引用終わり・・・

"source remains a mystery" ?
明らかではなかろうか。

精製・濃縮されたウラン235は燃料棒の被覆が破れなければ出てこない。起源は、F1か下北半島か、西にある近隣国の可能性が高いこととなる。
posted by ZUKUNASHI at 11:47| Comment(0) | 福島原発事故
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