In this study, tungsten (W) powder, which is high atomic number element among inorganic maerials was considered as an alternative material for the lead (Pb) generally used as radiation shielding material. The shielding sheets were prepared by the complexation of tungsten powder and polyurethane (PU), and their optimization was carried out. The sheets were prepared by increasing the tungsten contents to the polymer where the composition was 1:1, 1:5, and 1:10 (polymer:tungsten). The morphology of sheet was investigated by using optical microscopy and scanning electron microscopy (SEM). The increases of both sheets density and their shielding efficiency were observed with increasing the contents of inorganic filler into composite. The weight of tungsten in the final shielding sheet was confirmed through a heat treatment and the optimized composition ratio was obtained by considering the total weight and mass attenuation coefficient of the sheet.

본 연구에서는 방사선 차폐물질로 사용되는 납을 대체하기 위하여, 무기금속 물질 중 원자번호가 큰 분말 상태의 텅스텐을 사용하였으며, 폴리우레탄(polyurethane, PU)과 복합하여 차폐용 시트를 제조하고 최적화를 진행하였다. 차폐시트의 구성은 고분자대비 1:1, 1:5, 1:10 비율로 텅스텐 함량을 증가시켜 제조하였으며, 광학이미지와 SEM으로 단면촬영을 진행하여 구조를 확인하였다. 또 질량감쇠계수와 차폐율의 변화를 확인하였다. 무기물의 함량이 증가할수록 시트의 밀도가 증가하였으며, 차폐율 또한 증가하는 것을 확인하였다. 열처리를 통해 차폐시트에 포함되어 있는 텅스텐의 양을 확인하였으며, 함량과 질량감쇠계수를 비교하여 최적화된 비율을 찾았다.

Keywords: tungsten, radiation shielding, shielding sheet, polyurethane, composition