美國科學家發現核廢料清理的新線索

　　華盛頓州立大學一項有關锝-99的化學研究，提升了我們對這種具有挑戰性的核廢料的認知，而且會讓我們找到更好的清理方法。

　　研究成果發表在《無機化學》期刊上。這項工作是在機械與材料工程學院副教授約翰 麥克洛伊與化學系研究生杰米 韋弗的領導下完成的。并且與太平洋西北國家實驗室（PNNL），河流保護辦公室、勞倫斯伯克利國家實驗室的研究人員進行了合作研究。

　　锝-99是武器級钚生產的副產物，它被認為是美國環境凈化的主要挑戰。位于華盛頓州的漢福德核設施，大約有2000磅的元素分散在177個儲罐大約5600萬加侖的核廢料里。

　　美國能源部正在漢福德建設廢物處理廠，想要將危險核廢料固定在玻璃中。但研究人員一直沒有成功，因為不是所有的锝-99都能納入到玻璃容器中，揮發性氣體也必須被回收到熔化系統里。

　　該元素易溶于水，當以某些形態存在時，很容易在環境中流轉，因此它被認為是一個重大的環境危害。

　　因為從事锝化合物研究是一項難度很大的工作，所以早期研究使用不易揮發的替代品來研究這種材料的特性。已經有50年時間，沒有人研究锝的一些化合物，麥克洛伊說，“該材料的物流管理過程難度相當大，”他說。

　　華盛頓州立大學的研究是在太平洋西北國家實驗室的高度專業化的放射化學處理實驗室及環境分子科學實驗室內完成的。

　　研究人員進行了基礎化學實驗，了解锝-99的特性及其存儲方面的獨特挑戰。他們確定元素的鈉形態相比于其他堿形態，表現出很大不同，這可能是與其揮發性相關，也與為什么它易于和水發生反應相關。

　　“這類化合物的結構和光譜特征，有助于我們加深將锝注入核廢料玻璃容器的理解，”麥克洛伊說。

　　研究人員也希望這項工作將有助于對其他陌生化合物的研究。（張微編譯）

　　以下為英文原文：

　　Researchers find new clues for nuclear waste cleanup

　　A Washington State University study of the chemistry of technetium-99 has improved understanding of the challenging nuclear waste and could lead to better cleanup methods.

　　The work is reported in the journal Inorganic Chemistry. It was led by John McCloy, associate professor in the School of Mechanical and Materials Engineering, and chemistry graduate student Jamie Weaver. Researchers from Pacific Northwest National Laboratory (PNNL), the Office of River Protection and Lawrence Berkeley National Laboratory collaborated.

　　Technetium-99 is a byproduct of plutonium weapons production and is considered a major U.S. challenge for environmental cleanup. At the Hanford Site nuclear complex in Washington state, there are about 2,000 pounds of the element dispersed within approximately 56 million gallons of nuclear waste in 177 storage tanks.

　　The U.S. Department of Energy is in the process of building a waste treatment plant at Hanford to immobilize hazardous nuclear waste in glass. But researchers have been stymied because not all the technetium-99 is incorporated into the glass and volatilized gas must be recycled back into the melter system.

　　The element can be very soluble in water and moves easily through the environment when in certain forms, so it is considered a significant environmental hazard.

　　Because technetium compounds are challenging to work with, earlier research has used less volatile substitutes to try to understand the material's behavior. Some of the compounds themselves have not been studied for 50 years, said McCloy."The logistics are very challenging," he said.

　　The WSU work was done in PNNL's highly specialized Radiochemical Processing Laboratory and the radiological annex of its Environmental Molecular Sciences Laboratory.

　　The researchers conducted fundamental chemistry tests to better understand technetium-99 and its unique challenges for storage. They determined that the sodium forms of the element behave much differently than other alkalis, which possibly is related to its volatility and to why it may be so reactive with water.

　　"The structure and spectral signatures of these compounds will aid in refining the understanding of technetium incorporation into nuclear waste glasses," said McCloy.

　　The researchers also hope the work will contribute to the study of other poorly understood chemical compounds.