蒙特卡洛法模擬玻璃固化體浸出行為的研究
發(fā)布時間：2018-12-18 00:09
【摘要】：高放廢物的處置關(guān)系到人類的健康和環(huán)境的安全,因而引起國際上廣泛的重視。目前最理想的方案為:將高放廢物玻璃固化處理,然后進行深層地質(zhì)處置。然而在長期的地質(zhì)處置過程中,玻璃固化體會受到地下水的侵蝕,發(fā)生化學反應并溶解,導致放射性核素的浸出,威脅到生物圈的安全。因此,研究高放廢物玻璃固化體在水中的溶解行為,對高放廢物深層地質(zhì)處置有重大意義。本文首先綜述了高放廢物玻璃固化體溶解行為模型的研究現(xiàn)狀,從這些模型的基本原理出發(fā),對它們在高放廢物玻璃固化體溶解行為方面的應用進行了詳細的論述,對它們的優(yōu)缺點進行了評價,分析了各種模型的適用對象和發(fā)展前景。在實驗研究中,使用固定成分的玻璃固化體配方,采用MCC-1靜態(tài)浸出實驗,研究了玻璃固化體在去離子水中長期的溶解行為。并通過XRD、FTIR、ICP等測試手段進行分析。實驗結(jié)果表明:玻璃固化體在長期的浸泡過程中,硅、硼和鋁的濃度都能達到一定的平衡,且達到平衡的時間分別為150天、180天和210天,其平衡濃度值分別為為21.5ug/m L、2.5ug/m L和6.5 ug/m L。在浸泡過程中玻璃固化體表面無析晶現(xiàn)象,受侵蝕后的玻璃固化體表面產(chǎn)物為無定型結(jié)構(gòu),玻璃固化體內(nèi)部主要結(jié)構(gòu)單元未發(fā)生明顯變化。同時根據(jù)玻璃固化體在水中的侵蝕機理,開發(fā)了簡單的蒙特卡洛模型,并運用該模型模擬了玻璃固化體在去離子水中的溶解行為。模擬結(jié)果顯示:隨著反應的進行,去離子水中硅的濃度會達到一個平衡狀態(tài)。這是由硅的溶解和析出的概率值所決定,在硅的溶解析出動力學反應過程中,玻璃固化體與水的接觸面會形成由硅組成的膠體層,對硼和鋁的浸出產(chǎn)生了阻礙效應。通過限制硼和鋁的濃度,最后各種成分的濃度都達到平衡狀態(tài)。實驗結(jié)果與模擬計算結(jié)果較為吻合。此外,我們在鈉硼硅三組分模型的基礎(chǔ)上引入了鋁原子,用新的反應參數(shù)來描述鋁原子的特征,進一步驗證了該模型的可靠性。
[Abstract]:The disposal of HLW is related to human health and environmental safety. The ideal solution is to solidify high-level waste glass and then treat it in deep geology. However, in the long-term geological disposal process, the glass curing experience is eroded by groundwater, chemical reaction occurs and dissolved, which leads to the leaching of radionuclides and threatens the safety of the biosphere. Therefore, it is of great significance to study the dissolution behavior of glass solidification in water for deep geological disposal of high-level radioactive waste. In this paper, the current research status of glass solidification behavior models of high level radioactive waste is reviewed. Based on the basic principles of these models, the application of these models to the dissolution behavior of glass solidification is discussed in detail. Their advantages and disadvantages are evaluated, and the applicable objects and development prospects of various models are analyzed. In the experimental study, the dissolution behavior of the glass solidified in deionized water for a long time was studied by using the fixed composition of glass solidification formula and MCC-1 static leaching experiment. And through XRD,FTIR,ICP and other testing means to analyze. The experimental results show that the concentration of silicon, boron and aluminum can reach a certain equilibrium in the process of soaking for a long time, and the equilibrium time is 150 days, 180 days and 210 days, respectively, and the equilibrium concentration is 21.5ug/m L. 2.5ug/m L and 6.5 ug/m L. In the process of soaking, there is no crystallization on the surface of the glass solidified body. The surface product of the glass solidified body after erosion is amorphous structure, and the main structural units of the glass solidified body have not changed obviously. A simple Monte Carlo model was developed according to the erosion mechanism of glass solidified in water. The dissolution behavior of glass solidified in deionized water was simulated by using the model. The simulation results show that the concentration of silicon in deionized water reaches a equilibrium state with the reaction. This is determined by the probability value of dissolution and precipitation of silicon. During the kinetic reaction of dissolution and precipitation of silicon, the interface between glass solidified body and water will form a colloidal layer composed of silicon, which will hinder the leaching of boron and aluminum. By limiting the concentration of boron and aluminum, the concentration of each component reaches equilibrium. The experimental results are in good agreement with the simulation results. In addition, on the basis of the three-component model of sodium boron and silicon, the aluminum atom is introduced, and the new reaction parameters are used to describe the characteristics of the aluminum atom, which further verifies the reliability of the model.
【學位授予單位】：西南科技大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ171.1
本文編號：2384982
[Abstract]:The disposal of HLW is related to human health and environmental safety. The ideal solution is to solidify high-level waste glass and then treat it in deep geology. However, in the long-term geological disposal process, the glass curing experience is eroded by groundwater, chemical reaction occurs and dissolved, which leads to the leaching of radionuclides and threatens the safety of the biosphere. Therefore, it is of great significance to study the dissolution behavior of glass solidification in water for deep geological disposal of high-level radioactive waste. In this paper, the current research status of glass solidification behavior models of high level radioactive waste is reviewed. Based on the basic principles of these models, the application of these models to the dissolution behavior of glass solidification is discussed in detail. Their advantages and disadvantages are evaluated, and the applicable objects and development prospects of various models are analyzed. In the experimental study, the dissolution behavior of the glass solidified in deionized water for a long time was studied by using the fixed composition of glass solidification formula and MCC-1 static leaching experiment. And through XRD,FTIR,ICP and other testing means to analyze. The experimental results show that the concentration of silicon, boron and aluminum can reach a certain equilibrium in the process of soaking for a long time, and the equilibrium time is 150 days, 180 days and 210 days, respectively, and the equilibrium concentration is 21.5ug/m L. 2.5ug/m L and 6.5 ug/m L. In the process of soaking, there is no crystallization on the surface of the glass solidified body. The surface product of the glass solidified body after erosion is amorphous structure, and the main structural units of the glass solidified body have not changed obviously. A simple Monte Carlo model was developed according to the erosion mechanism of glass solidified in water. The dissolution behavior of glass solidified in deionized water was simulated by using the model. The simulation results show that the concentration of silicon in deionized water reaches a equilibrium state with the reaction. This is determined by the probability value of dissolution and precipitation of silicon. During the kinetic reaction of dissolution and precipitation of silicon, the interface between glass solidified body and water will form a colloidal layer composed of silicon, which will hinder the leaching of boron and aluminum. By limiting the concentration of boron and aluminum, the concentration of each component reaches equilibrium. The experimental results are in good agreement with the simulation results. In addition, on the basis of the three-component model of sodium boron and silicon, the aluminum atom is introduced, and the new reaction parameters are used to describe the characteristics of the aluminum atom, which further verifies the reliability of the model.
【學位授予單位】：西南科技大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ171.1
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