کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6335181 | 1620241 | 2014 | 15 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Rock alteration in alkaline cement waters over 15 years and its relevance to the geological disposal of nuclear waste
ترجمه فارسی عنوان
تغییرات سنگ در آب های قلیایی سیمان بیش از 15 سال و ارتباط آن با دفع زباله های زباله های هسته ای
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
چکیده انگلیسی
The interaction of groundwater with cement in a geological disposal facility (GDF) for intermediate level radioactive waste will produce a high pH leachate plume. Such a plume may alter the physical and chemical properties of the GDF host rock. However, the geochemical and mineralogical processes which may occur in such systems over timescales relevant for geological disposal remain unclear. This study has extended the timescale for laboratory experiments and shown that, after 15 years two distinct phases of reaction may occur during alteration of a dolomite-rich rock at high pH. In these experiments the dissolution of primary silicate minerals and the formation of secondary calcium silicate hydrate (C-S-H) phases containing varying amounts of aluminium and potassium (C-(A)-(K)-S-H) during the early stages of reaction (up to 15 months) have been superseded as the systems have evolved. After 15 years significant dedolomitisation (MgCa(CO3)2 + 2OHâ â Mg(OH)2 + CaCO3 + CO32â(aq)) has led to the formation of magnesium silicates, such as saponite and talc, containing variable amounts of aluminium and potassium (Mg-(Al)-(K)-silicates), and calcite at the expense of the early-formed C-(A)-(K)-S-H phases. This occured in high pH solutions representative of two different periods of cement leachate evolution with little difference in the alteration processes in either a KOH and NaOH or a Ca(OH)2 dominated solution but a greater extent of alteration in the higher pH KOH/NaOH leachate. The high pH alteration of the rock over 15 years also increased the rock's sorption capacity for U(VI). The results of this study provide a detailed insight into the longer term reactions occurring during the interaction of cement leachate and dolomite-rich rock in the geosphere. These processes have the potential to impact on radionuclide transport from a geodisposal facility and are therefore important in underpinning any safety case for geological disposal.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Geochemistry - Volume 50, November 2014, Pages 91-105
Journal: Applied Geochemistry - Volume 50, November 2014, Pages 91-105
نویسندگان
Elizabeth B.A. Moyce, Christopher Rochelle, Katherine Morris, Antoni E. Milodowski, Xiaohui Chen, Steve Thornton, Joe S. Small, Samuel Shaw,