依據歐洲核能總署（NEA）的統計資料，黏土緩衝材料與密封回填佔核廢料最終處置場全部經費（含選址作業）的14%~18%。高放射性廢料最終處置計畫所需的緩衝材料數量龐大，以我國核能研究所之初步概念設計推估，用過核燃料處置計畫所須之緩衝材料數量約達四萬立方公尺之多，因此各核能先進國家都傾向於在自己國家中尋找合適的黏土材料作為候選緩衝材料。國內早於民國七十四年起就對台東樟原日興土進行相關研究，由於日興土屬於鈣型蒙脫石，其回脹性質較國外鈉型蒙脫石遜色。本研究目的在於尋求可能的活化改良方法，藉以提昇日興土的回脹特性，以增加其作為緩衝材料的競爭優勢。本研究採用的活化改良方法包括物理方法、化學方法、熱處理法及離子交換法四大類 試驗結果顯示：（1）物理改良產物（乾篩及濕篩法）之最大回脹應變量不如原礦；（2）酸活化處理有助於提升日興土之比表面積；（3）熱處理溫度高於300℃後，日興土回脹行為已不具規則性；（4）添加Na2CO3改良方式可有效提升日興土之最大回脹應變量，且其回脹歷時曲線不同於原礦，屬於後期上升型；（5）NaCl改良雖可提升回脹量但處理程序繁瑣，不建議使用；（6）研究中，除以離子交換程序改良外，其餘改良方式雖可改變黏土礦物表面性質或礦物性質，或對其他工程性質（強度、吸附性）有所助益，然對回脹行為的影響有限。 According to the data of OECD/NEA,the cost of buffer material is 14%~18% of whole disposal program. The HLW disposal program needs enormous buffer material, so that every nuclear country prefers to use domestic bentonite as potential buffer material. Zhisin clay has been studied from 1985. Zhisin clay is Ca-bentonite and the swelling property is less than Na-bentonite. The objective of this study is aimed to search for possible activation methods to enhance the properties of buffer material, including physical modification, acid and base activation, thermal treatment, and cation-exchange method. The experimental results of this research show（1）the swelling potential of Zhisin clay modified by physical modification （or篩分析）is less than raw material；（2）the BET surface of Zhisin clay activated by HCl is increased with the concentration of acid solution；（3）thermal treatment could decreased the swelling potential of Zhisin clay, particularly when thermal temperature over 300℃；（4）base activation could erode impurity in raw material；（5）the swelling potential of Na2CO3-activated Zhisin clay is significantly increasing. The time-swell curve of Na2CO3-activated Zhisin clay is different from raw material.；（6）in this study, cation-exchange method could most affected promotion to swelling potential. But others shifting method can only change surface property of raw material and have refund to other mechanical properties In conclusion, Na2CO3 activation method could meet the swelling function of buffer material.
