Recent Trends in the Evaluation of Cementitious Material in Radioactive Waste Disposal

Abstract

Cementitious materials are essential parts in any radioactive waste disposal facility (either shallow or deep underground facilities). Despite these materials having been extensively used and studied, there is still a need to investigate and understand their long-term behavior due to the fact that disposal is a passive system and regulatory requirements for the safe disposal range from 300 to few thousands of years, so there is a need to ensure that the system will work as intended for this period. An extensive array of researches have been devoted to study the feasibility of using cement or cement-based materials in immobilizing and solidifying different radioactive wastes and the feasibility of its potential use as engineering barriers. In this work, the current understanding of cement hydration mechanisms and kinetics will be presented. Experimental and predictive trends to assess the long-term behavior of cementitious material will be reviewed, and recent researches on the utilization of cements or cement-based materials as engineering barriers in radioactive waste disposal will be summarized. Finally this work will examine how these researches contributed to the current knowledge of long-term behavior of cementitious materials in disposal conditions and analyze if this knowledge has provided required inputs to regulation.