Leaching behavior of cement-natural clay composite incorporating real spent radioactive liquid scintillator

Abstract

Handling, storage and final disposal of the generated radioactive liquid scintillator waste should be performed under controlled conditions to protect man and his environment. The significance of the present study is to evaluate chemical stability of cement-natural clay composite incorporating spent radioactive liquid scintillator waste. This waste is originated from daily counting and quantification of β-particles, weak gamma and x-ray. Increasing amounts of liquid scintillator waste immobilized in cement-natural clay composite were investigated. The obtained monolith solid waste forms were subjected to leaching characterizations under static or dynamic conditions. The factors that supposed to affect the leaching behavior of the final waste form, e.g. the amount of incorporated liquid scintillator waste, leachant type and leaching temperature were investigated. The leaching parameters namely cumulative fraction leached, effective diffusion coefficient and leaching index were evaluated under various experimental terms. Based on the data obtained and the leaching experiments performed for the proposed final waste form, it could be stated that the proposed composite formed from 3% natural clay related to the weight of Portland cement at ratio 0.3 of water/cement incorporating 15% of actual spent liquid scintillator radioactive waste could comply the required specifications for the disposal process at very exaggerating conditions.