核廢料地下處置場之岩石材料參數對工程障壁飽和度影響分析

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王梅因(Mei-yin Wang)

指導教授 ： 張瑞宏

國立中央大學/工學院/土木工程學系/碩士(2011年)

摘要

核能發電是我國電力供應鏈中不可或缺的一環。但核能電廠產生的核廢料具有高放射性及半衰期週期長等特性，對生活環境具有潛在危險。國際間相關研究認為深地層處置(deep geological disposal)是目前最安全的處置方法。
本研究以深地層處置之概念為基礎，並以有限元素軟體ABAQUS進行依序熱—水—力學之耦合分析。在分析理論上，熱傳導分析採用傅立葉熱傳導定律(Fourier’s law of heat conduction)。水─力學分析採用達西定律(Darcy’s law)、廣義虎克定律(generalized Hooke’s law)、有效應力理論(effective stress theory)。
考量國內文獻對處置場尺寸、初始溫度條件與熱源散熱強度的設計建設；並以國內現有之礦源─日興土，以及文獻SKB所使用之膨潤土作為本研究之緩衝材料，就二者性質進行觀察比較。
在處置場完成設置、回填與密封後，地下水入侵的速率將受到各材料之水力傳導係數與孔隙壓力邊界條件之影響。根據分析結果可知使用膨潤土為緩衝材料時，其飽和度到達90%的時間比日興土延長大約5年，處置場水力傳導係數之差異會導致緩衝材飽和度到達90%時之時間相差15倍。其結果顯示處置場之水力傳導係數將對處置場之飽和速度造成顯著的影響。

關鍵字

熱—水—力學耦合分析 ； 深地層處置 ； 飽和度 ； 緩衝材料

並列摘要

Nuclear energy power generation is major in Taiwan. But the spent fuel will produce higher temperature in nuclear power station. Deep geological disposal used worldwide for radioactive spent fuel, which needs to be completely isolated form human life cycle.
Based upon the concept of the deep disposal method. Our study uses finite element method and conducts analysis of the coupled thermo-hydro-mechanical calculations. The heat conduction analysis uses the Fourier’s law of heat conduction to obtain the temperature field. The temperature diffusion rate is consequently increased. Hydraulic calculation uses Darcy’s law, generalized Hooke’s law and effective stress theory.
In addition of considering the size of repository, initial condition and boundary condition of the internal paper. Consider the internal source, we used the buffer material is Zhishin clay. The effect due to water saturation is discussed and compared with experiment results of materials.
After the completion of the emplacement, filling and sealing, the invasion of the groundwater is not avoidable. The hydraulic conductivities of materials and pore pressure boundary condition will influence the rate of saturation. The study directed at the influences of the saturation histories on the hydro conductivity of the disposal.

並列關鍵字

Deep geological ； buffe ； Couple thermal-hydrological-mechanical analysis

參考文獻

【2】Bear, J., Dynamics of Fluids in Porous Media, American Elsevier Publishing Company, Dover, New York,1972.

【3】Elsevier Science “Thermal-mechanical FE-analysis of residual stress and stress redistribution in butt welding of a copper canister for spent nuclear fuel”, ISSN: 0029-5493.

【7】Nguyen, T. S.,” Coupled thermal-mechanical behaviour of sparsely fractured rock: implication for nuclear fuel waste disposal”,

【9】Selvadurai, A.P.S., and Nguyen, T.S., ”Scoping analyses of the coupled thermal-hydrological-mechanical behavior of the rockmass around a nuclear fuel waste respository”, Engineering Geology,Vol.47, p.379 -400 ,1996.

【10】SKB, ”Deep Repository for Spent Nuclear Fuel: SR 97 Post-Closure Safety”, KBS, Sweden, November 1999.