Journal of Nuclear Fuel Cycle and Waste Technology

Boron concentrates are one of the common radioactive waste produced in pressurized water reactor (PWR) NPPs. Liquid waste is generated during the operation of NPPs, including in the normal process, fuel reloading, and maintenance. The liquid waste is composed of different concentrations of boric acids dissolved in the primary coolant as a result of core reactivity control. At the early stage of NPP operation, the boron concentrates are solidified using a cement material. Cement solidification offers high product stability and low cost and is considered a promising treatment technology for very low, low, and intermediate level boron concentrate radioactive waste. However, the waste loading in cement solidification of radioactive waste is usually lowered to obtain high quality cement solidified forms. In this study, a cement re-solidification process for historic cement solidified boron concentrates was systematically investigated. The composition of the cement solidified form was evaluated to obtain a suitable material composition with reasonable cost. A water immersion test and a thermal cycle stability test were performed to determine whether the solidified form is suitable for disposal. The ANS 16.1 test also was implemented to evaluate its chemical stability. It is reasonable to conclude that the fabricated solidified forms have sufficient potential to be applied for the re-solidification process for historic cement solidified boron concentrates.

Keywords

Cement solidified boron concentrates, Cement, Solidification, ANS 16.1, Disposal