The Effect of Air Exchange Rate and Room Size on Dose Estimation of Partial Substitution of Tin Slag 2 on Fine Aggregate in Making Mortar in Buildings

Tin slag 2 is a by-product of the tin processing and smelting industry. Tin slag 2 contains radioactive from the uranium and thorium decay series with specific activity concentrations. The current condition of tin slag 2 is still stored in storage. This study aims to simulate using tin slag 2 as a partial substitute for fine aggregate in making mortar, used as a floor or wall plastering material. Dose analysis of the use of mortar–tin slag 2 using RESRAD-BUILD. Several radionuclides were measured in tin slag 2, such as 226Ra 5.72 Bq/gram, 228Th 14.29 Bq/gram, 228Ra 16.59 Bq/gram, and potassium 1.16 Bq/gram. According to the regulations, the activity concentration limit is 1 Bq/gram for the uranium and thorium decay series radionuclide and 10 Bq/g for the potassium. Simulations were performed using RESRAD-BUILD software with scenarios of 2 room sizes against one assumption of the building/air exchange rate. In 2 room size assumptions, namely 4x3x2.5 m and 4x5x2.8 m, the results showed that the larger the room size, the smaller the dose received. Assuming the same building exchange rate, because the sizes used are different, the amount of air exchanged will also be different and affect the dose received by the receptor. The challenge that must be considered is that the air exchange rate is greatly influenced by various factors such as design, ventilation systems, natural or mechanical, environmental conditions, etc. Keywords: tin, slag 2, partial, substitution, mortar