放射性廢棄物的最終處置在國際上多採用多重障壁的概念，即以多層防護措施，將放射性廢棄物隔絕於生物圈外，其中工程障壁提供放射性廢棄物長期圍阻功能，而混凝土是最終處置場最為常用的工程障壁材料之一，因此其長期服務品質至為重要。國內最終處置場候選場址可能建造於濱海區域且採用淺地層處置，在此不良環境的長期侵襲下，障壁用混凝土的長期耐久性成為處置安全的關鍵。因此，持續針對容器混凝土尋求更高品質的配比，以及提升容器混凝土長時間服務於處置場環境下的耐久性，為發展高完整性混凝土容器所面臨的重要課題。 本研究針對高完整性容器發展混凝土配比，擬採用高品質活性粉混凝土設計概念，藉由添加鋼纖維來提升混凝土韌性，使其具有良好力學性質，並有效降低高完整性容器之混凝土厚度。此外，為提升盛裝容器混凝土之品質，採用高溫養護方式，以進一步改善活性粉混凝土內部微結構，並提升其品質與服務性能。針對活性粉混凝土的力學特性及體積穩定性製作多種配比之試體，一方面提出優化之活性粉混凝土配比，另一方面評估活性粉混凝土配比運在處置容器上的效益。同時，對於活性粉混凝土運用於高完整性容器方面建立耐久性數據及檢測標準，以提高未來使用者的信心。 ;Safety is the most important consideration in the development of concrete mix for highly integrated container for disposal of low-level radioactive wastes. The final disposal site may be located in the coastal area with shallow embedment. Under the long-term attack of the adverse environment, durability of the concrete container becomes the key to ensure the safety of disposal. Therefore, it is important to seek for high quality concrete for the manufacture of highly integrated containers. Also, the durability of concrete under long-term service in the environment of the disposal site needs to be assessed effectively to assure safety. This research develops the concrete mixture that may be used for the highly integrated container for final disposal of low-level radioactive wastes. In this study, reactive powder concrete is proposed to be used for fabrication of concrete container, as it is known to have good mechanical properties and enhanced durability that are beneficial as a barrier material. By adding steel fibers to the reactive power concrete, the tensile strength of the concrete is highly improved such that the thickness of the container can be significantly reduced. In addition, high-temperature curing is used to improve the internal microstructure of reactive powder concrete which, in turn, improves its quality and service performance. Based on testing results on the mechanical properties and olume stability of reactive powder concrete with various mixtures, it is expected that an appropriate mix design for highly integrated containers will be developed and the superior durability of reactive powder concrete will be demonstrated. On the other hand, testing data on durability and acceptance standards for reactive powder concrete for highly integrated containers can be established to improve user confidence in this application.
