地下水及表面水程式篩選及國內資料之蒐集

Abstract

近年來，以天然障壁作為低放射性廢棄物的最終處置場，已經漸漸為大眾所接受。其中， 處置場址的選擇，為最重要的部分，包括：水文地質資料之調查評估、地震評估、場址區域背 景輻射調查與評估、及環境接受性調查與評估等。若低放射性廢棄物在掩埋後，因受環境因素 影響，廢料桶內的核種產生種外洩、遷移的問題時，會對生態環境產生衝擊。因此，在處置場 址設置之前，需先行處置場的環境安全評估，而進行環境安全評估時，相關的模式是不可或缺 的工具。若想較準確地模擬、預測低放射性廢棄物於處置場址的遷移與宿命，則需調查、蒐集 侯選處置場址之水文地質資料；接著，按照場址及低放射性廢棄物之特性，篩選合適的模式， 以進行情境模擬與安全評估。 目前國外展出來的地表水及地下水模式的種類繁多，且各有其優缺點及適用性。因此，本 研究計畫擬針對低放射性廢棄物與候選場址的特性，回顧國內外較常用之水文模式，介紹相關 的理論架構、功能、輸入數據，並做模式評比，進行功能測試和簡單的案例分析，並建議一套 模式選擇與評估之準則，以提供原能會物管局未來作環境安全評估的參考。

Recently, geological medium is being considered for the disposal of low level radioactive wastes. The selection of the disposal site is an important task. Before the installation of a disposal site, one should collect the hydrogeological data, assess the potential damage of earthquake, investigate background radiation, and survey the public acceptance. In addition, the radioactive nuclides released from the waste tank may leak or migrate to the environment due to the damage of waste tanks by some environmental factors after a long-term disposal. Therefore, the environmental impact and safety assessment is a crucial and important work in the site selection. The transport of radioactive nuclides in the medium using the simulation model would be more realistic if the hydrogeological data are properly obtained from the characterization. Then a suitable model can be chosen for the environmental safety assessment. There are huge amount of computer codes available among the surface water and groundwater models. Each model has its own assumptions, capability, advantages, and limitations. This study is first to review the most popular or widely used hydrology models, and then to understand the methodologies, functions, data requirement of the models. Moreover, this study will assess the applicability of the models and make a simple case study if necessary. Finally, a procedure with some criterion for choosing an appropriate model will be provided for the use in the environmental safety assessment and/or site selection.