کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1564701 1514168 2016 6 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thermodynamic studies of studtite thermal decomposition pathways via amorphous intermediates UO3, U2O7, and UO4
ترجمه فارسی عنوان
مطالعات ترمودینامیکی مسیر تجزیه حرارتی studtite از طریق UO3، U2O7 و UO4 واسطه های آمورف
کلمات کلیدی
UO2؛ Studtite؛ کالریمتری؛ آنتالپی تشکیل؛ تغییر سوخت هسته ای
موضوعات مرتبط
مهندسی و علوم پایه مهندسی انرژی انرژی هسته ای و مهندسی
چکیده انگلیسی

The thermal decomposition of studtite (UO2)O2(H2O)2·2H2O results in a series of intermediate X-ray amorphous materials with general composition UO3+x (x = 0, 0.5, 1). As an extension of a structural study on U2O7, this work provides detailed calorimetric data on these amorphous oxygen-rich materials since their energetics and thermal stability are unknown. These were characterized in situ by thermogravimetry, and mass spectrometry. Ex situ X-ray diffraction and infrared spectroscopy characterized their chemical bonding and local structures. This detailed characterization formed the basis for obtaining formation enthalpies by high temperature oxide melt solution calorimetry. The thermodynamic data demonstrate the metastability of the amorphous UO3+x materials, and explain their irreversible and spontaneous reactions to generate oxygen and form metaschoepite. Thus, formation of studtite in the nuclear fuel cycle, followed by heat treatment, can produce metastable amorphous UO3+x materials that pose the risk of significant O2 gas. Quantitative knowledge of the energy landscape of amorphous UO3+x was provided for stability analysis and assessment of conditions for decomposition.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Nuclear Materials - Volume 478, September 2016, Pages 158–163
نویسندگان
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