Investigation of radiation and water impermeability attitudes of heavy concrete produced with hematite and chromite for nuclear reactor shielding structure

In this study, two different high performance heavy concrete (HPHC) (C40, C50) were produced using three different aggregates: limestone, hematite, and chromite. During fabrication of HPHC, 18 different concrete mixtures were obtained by using 3 different aggregate size (0-4 mm, 4-8 mm, 8-16 mm) in accordance with TS EN 802, 2016. The water/cement ratios were maintaned at 0.45 and 0.44 for C40 and C50 samples, respectively. Cube samples, 150 x 150 x 150 mm3 in size, and plate samples, 200 x 200 x 50 mm3 in size were produced. Ultrasonic pulse velocity (UPV), uniaxial compressive strength (UCS), water permeability and radiation attenuation tests were performed on these samples. In addition, the radiation shielding and water impermeability properties of HPHC in the nuclear reactor shield structure were investigated. According to the test results, the highest UCS in C40 samples is 63.4 MPa, attenuation coefficients are 0.23 cm-1 and 0.25 cm-1 for gamma, 0.16 cm- 1 , 0.17 cm- 1 and 0.21 cm- 1 for neutron in HHH-40-1. The maximum water absorption was detected in CCC40-2 with 12.3 mm. In C50 samples, the highest UCS is 72.6 MPa, attenuation coefficients are 0.25 cm- 1 and 0.3 cm- 1 for gamma, 0.16 cm- 1 , 0.19 cm- 1 and 0.23 cm- 1 for neutron in the HHH-50-1. The maximum water absorption was detected in CCC-50-2 with 10 mm. When all the data were examined, HHH-40 mixture demostrates the best value in UCS and radiation shielding, CCC-40 mixture gave the best value in water impermeability in the C40 class. The HHH-50 mixture demostrated the highest values in UCS and radiation shielding, and the CCC-50 mixture achieved the best values in water impermeability within the C50 class. Consequently, hematite mixtures were characterized by UCS and radiation shielding, while chromite mixtures were characterized by water impermeability.