核廢料的處理，一直是各核能國家關切的問題。一般認為，核 廢料以深層地質處置(deep geological disposal)為較可行的方法。 本研究採用有限元素法，針對核廢料處置場的溫度與變形分佈 進行分析，根據處置孔之不同間距尺寸進行討論。為了模擬更真實 的處置場情形，本研究考慮了兩組參數，包括緩衝材料分層及熱間 隙。本研究首先針對此二變因進行參數分析，觀察此二參數對分析 結果之影響。此外，在邊界尺寸的分析方面，針對各貯存槽間之不 同間距進行分析，除瞭解尺寸變化對於處置場溫度之影響外，並從 其中選擇適合之間距尺寸，以供處置場設計參考。 熱應力分析方面採用依序耦合熱應力分析(Sequentially coupled thermal-stress analysis），根據分析結果可知處置場之位移主要為垂直 位移，而垂直位移之方向與處置場深度平行。處置場在熱源附近之 應力場變化較大且複雜，處置場未完全封閉前於隧道及處置孔處以 空氣模擬，則可能在處置孔及隧道周圍產生較大的應力變化，且在 剪應力較大的區域發生塑性區；將之處置場完全封閉後，以緩衝材 及回填材填滿，則產生之剪應力較小，相對地進入塑性的機會也較 小。 Decay heat generated by the decay of radionuclide in spent nuclear fuels is an important factor that could cause the undesirable environment- al effects. Most People make choice of deep geologic disposal as the best method to achieve the isolation and retardation of nuclide migrating by multiple barriers (made up of waste package, buffer material, backfill material and host rock). Based upon the concept of deep geological disposal proposed by Swedish research groups (SKB), this research is aimed to study of the thermal and mechanical properties of the bentonite material and backfill material. The three-dimensional finite element program ABAQUS was used to perform numerical simulation of the behavior of rock mass. The numerical results show the space influence of deposition hole inside the multiple deposition holes environment. The cross-section of repository (short direction (6m) ×long direction (40m)) is considered as a standard size. In this study, we consider that the buffer material was delaminated into three parts, and the gap is inside the repository (SKB, 1999). According to the results, the variation in the repository temperature caused by altering short direction is more significant than those caused by altering long direction. Also the vertical displacement is larger than the horizontal displacement. The plastic zone occurs in the near field of the tunnel and the deposition hole, where reinforcement should be ensure to keep the deep repository in safety.
