核能發電所產生之核廢料處置技術近年在各工業先進國家是極受矚目的課題。地質深層處置法利用穩定地質的天然障壁及人為的工程障壁，防止核種遷移已成為世界各國處理高放射性核廢的共同趨勢。工程障壁中的緩衝材料直接包裹核廢料桶，因此，對於各項工程性質的要求極為嚴格，也是工程障壁極為重要的一環。經壓實之緊密碎石-皂土混合物由於具有良好的阻絕性能、適當的自癒性及優良的力學、熱學性質，已普遍被各國學者選為緩衝材料之主要的候選材料。適切配比的碎石-皂土混合物構成的緩衝材料雖然性能上較純皂土為佳，但其性質與配比有密切的關連。過去包括晚近的國外學者在研究此一主題時常依賴大量的試驗，由於配比繁多，結論多為定性的描述，不易獲致定量化的預測模式，使得對其整體性質難有精確的掌握。回脹及熱傳導係數為緩衝材料重要的工程性質之一，過去學者在對此類問題的探討較少從理論與實驗並重的方式進行。本計畫第二年度擬針對碎石-皂土混合物之熱傳導行為進行探討，從實驗研究與理論分析並行的方式研究碎石-皂土混合物之複合行為。以複合材料力學組成之概念，推求不同碎石體積比、含水量條件下之熱傳導係數，以作為緩衝材料之篩選參考及處置場緩衝材料熱傳導問題之數值模擬的基礎。 The development of technique for disposing of radioactive wastes from nuclear power stations has recently become a significant subject in industrial world. The disposal facility is planned to be constructed under the ground. The emplacement of bentonite-base buffer surrounding canisters and overpack has long been a feature of disposal concepts adopted for high-level waste and spent fuel disposal programmes within a number of countries. Such barriers are constructed from well-defined and quality-controlled bentonite or sand-bentonite mixture. Sand-bentonite mixture is seen as an effective component of artificial barriers for repositories of high-level nuclear waste. In order to provide reasonable assurance that buffer materials will ensure long-term waste isolation, it is essential to understand the swelling characteristic under a variety condition. Since there are few studies about the swelling and thermal behaviors of compacted sand-bentonite mixture from both experimental and theoretical point views, it is first necessary to Clarify the fundamental swelling and thermal characteristics in detail. For this purpose various laboratory tests on the steady state and transit state thermal properties of sand-bentonite mixture will be performed. It is expected based on the experimental results, the appropriate composite model and micromechanics will be proposed. 研究期間：9101 ~ 9112
