Author :
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ISBN 13 :
Total Pages : 3 pages
Book Rating : 4.:/5 (871 download)
Book Synopsis Chemical Decomposition of High-level Nuclear Waste Storage/disposal Glasses Under Irradiation. 1998 Annual Progress Report by :
Download or read book Chemical Decomposition of High-level Nuclear Waste Storage/disposal Glasses Under Irradiation. 1998 Annual Progress Report written by and published by . This book was released on 1998 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this project is to employ the technique of electron spin resonance (ESR), in conjunction with other experimental methods, to study radiation-induced decomposition of vitreous compositions proposed for immobilization/disposal of high-level nuclear wastes (HLW) or excess weapons plutonium. ESR is capable of identifying, even at the parts-per-million level, displaced atoms, ruptured bonds, and free radicals created by radiation in such glassy forms. For example, one of the scientific goals is to determine whether ESR-detectable superoxide (O2−) and ozonide (O3−) ions are precursors of radiation-induced oxygen gas bubbles reported by other investigators. The fundamental understandings obtained in this study will enable reliable predictions of the long-term effects of and decays of the immobilized radionuclides on HLW glasses. This report represents the results of an 18-month effort performed under a 3-year research award. Four categories of materials were studied: (1) several actual and proposed HLW glass compositions fabricated at Savannah River Technology Center (SRTC), samples of which had been irradiated to a dose of 30 MGy (1 Gy = 100 rad) to simulate decay effects, (2) several high-iron phosphate glasses fabricated at the University of Missouri-Rolla (UMR), (3) one other model HLW glass and several simulated natural glasses which had been implanted with 160-keV He ions to simulate-decay damage, and (4) an actual geological glass damaged by decays of trace amounts of contained 238U and 232Th over a period of 65 Myears. Among the category-1 materials were two samples of Defense Waste Processing Facility (DWPF) borosilicate glasses modeling compositions currently being used to vitrify HLW at SRTC. The ESR spectra recorded for the unirradiated DWPF-glass simulants were attributable to Fe 3 ions. The 30-MGy irradiation was found to change the Fe{sup 3+} concentration of these glasses by a statistically insignificant factor (0.987 \261 0.050) and not to create measurable numbers of other defects.