用過核子燃料深層地質處置場之遠場場址效應分析

Influential Analysis of Far-Field Site Effects on Deep Geologic Repositories for Spent Nuclear Fuel

張瑞宏(Jui-Hung Chang)；席芊庭(Chien-Ting Hsih)；石哲愷(Jeh-Kai Shih)

用過核子燃料 ； 深層地質處置場 ； 遠場 ； 熱－水力－力學耦合效應 ； spent nuclear fuel ； deep geologic repositories ； far-field ； THM coupling effect

臺灣鑛業

76卷3期（2024 / 09 / 01）

3 - 17

繁體中文;英文

目前國際上多以深層地質處置作為高放射性用過核子燃料之最終處置設施；在處置過程中，衰變熱會使處置場溫度急劇升高，引發熱－水力－力學的耦合效應，造成障壁系統之劣化。同時，依據我國處置計畫設定之進程，目前尚在「候選場址評選與核定」的執行階段，本研究配合此階段目標，針對臺灣、瑞典、芬蘭及日本等四國共五個案例，考量各不同場址之遠場材料特性與狀況，藉由大尺度有限元素暫態分析，觀察比較各場址特性對遠場溫度、應力增量及孔隙水壓增量的影響。研究成果期能提供具指標意義的階段性評估方針，作為未來場址規劃及細部設計的整合參考，以確保處置環境之長期安全及穩定。

High-level radioactive spent nuclear fuels are deposited mostly based on the concept of deep geologic repositories. The heat generated by the spent fuels results in coupling effect between the thermal, hydrological, and mechanical process. As a consequence, the long-term ability of the barrier system is significantly reduced. The study in this paper is carried out in conjunction with the current staged goal of Taiwan's national disposal plan, which focuses on selection of the candidate sites. To this end, five cases are presented by including specific sites involving in four countries including Taiwan, Sweden, Finland and Japan. Varying on-site material properties and conditions were considered through large-scale finite element transient analyses. Influential effects due to different site conditions were compared by observing the corresponding distributions of far-field temperature, stress increment and pore water pressure increment. The numerical results are anticipated to be applicable for future reference in site selection and practical engineering design.