PNAS：科研人员在加州探测到来自福岛的科研放射性硫

2011-08-16 09:35 · diana

科研人员在加利福尼亚州的La Jolla发现了来自福岛第一核电站的放射性硫。

科研人员在加利福尼亚州的加州La Jolla发现了来自福岛第一核电站的放射性硫。今年3月日本发生毁灭性的探测地震和海啸之后，使用了成百上千吨的到自的放海水冷却这座受灾核电站的一个核反应堆。Mark H. Thiemens及其同事从2011年3月9日到4月1日在Scripps海洋学研究所位于La Jolla的福岛栈桥测量了核爆炸产生的放射性硫在含有矿物质的海水以及空气中的含量。这组作者报告说，射性与自从2009年2月起该地区记录到的科研背景水平相比，大气中的加州放射性硫离子和二氧化硫气体的浓度在2011年3月28日最高。通过一个建模分析，探测这组作者发现从这个反应堆中泄漏出来的到自的放中子产生了放射性的硫，后者很可能被强烈的福岛西风携带到了加利福尼亚南部。这组作者估计，射性在太平洋海洋边界层接近1%的科研放射性硫离子（在这里二氧化硫被迅速氧化成了硫离子）在烟羽中被携带到了加利福尼亚。这组作者说，加州尽管观测到的探测放射性硫浓度不太可能损害人类健康，这些发现表明了可以使用硫同位素作为空气传播的化学物质的转变和长距离输运的一个标记物。

 

生物探索推荐英文论文摘要：

Evidence of neutron leakage at the Fukushima nuclear plant from measurements of radioactive 35S in California

Abstract

A recent earth*** and the subsequent tsunami have extensively damaged the Fukushima nuclear power plant, releasing harmful radiation into the environment. Despite the obvious implication for human health and the surrounding ecology, there are no quantitative estimates of the neutron flux leakage during the weeks following the earth***. Here, using measurements of radioactive 35S contained in sulfate aerosols and SO₂ gas at a coastal site in La Jolla, California, we show that nearly 4 × 1011 neutrons per m2 leaked at the Fukushima nuclear power plant before March 20, 2011. A significantly higher ³⁵SO₄^-2activity as measured on March 28 is in accord with neutrons escaping the reactor core and being absorbed by the coolant seawater ³⁵Cl to produce ³⁵S by a (n, p) reaction. Once produced, ³⁵S oxidizes to ³⁵SO₂and ³⁵SO₄^-2and was then transported to Southern California due to the presence of strong prevailing westerly winds at this time. Based on a moving box model, we show that the observed activity enhancement in ³⁵SO₄^-2is compatible with long-range transport of the radiation plume from Fukushima. Our model predicts that ³⁵SO4^-2, the concentration in the marine boundary layer at Fukushima, was approximately 2 × 105 atoms per m³, which is approximately 365 times above expected natural concentrations. These measurements and model calculations imply that approximately 0.7% of the total radioactive sulfate present at the marine boundary layer at Fukushima reached Southern California as a result of the trans-Pacific transport.

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