Effect of mineral admixtures in concrete on biological shield wall radiation in APR1400

Although many researchers investigated the effect of radiation on concrete mechanical properties, a little attention was given to the effect of concrete mix design on the radio-activation of biological shield wall, which could be important on decommissioning of nuclear power plants. In this paper, to investigate the effect of concrete mix design, radiation in biological shield wall of the Advanced Power Reactor 1400 MWe (APR1400) was investigated with consideration of several concrete mix designs. As an analytical variable, three different concrete mix designs were considered according to mix proportions of Ordinary Portland Cement (OPC), Fly Ash (FA), and Ground Granulated Blast Furnace Slag (GGBS), which were broadly adopted on construction site. For irradiation analysis of concrete, the compositions of concrete mix were analyzed to obtain the mass of each element in each concrete mix design. Flux distribution along depth of concrete shield wall was evaluated from flux at the outside of the Reactor Pressure Vessel (RPV) which was obtained through regression analysis for flux distribution in the RPV. After 60 years of service life and 10 years of cooling period, the analysis showed that concrete mixed with FA was 9% more radio-activated than concrete in which OPC only or both OPC and GGBS were mixed. The result of this paper will be useful for design of concrete shield wall considering radioactive waste amount generated through decommissioning.