Experimental and numerical investigation of radiation-induced volumetric expansion of concrete aggregates

Abstract

The radiation-induced volumetric expansion (RIVE) of concrete aggregates is the driving mechanism behind the degradation of the concrete biological shield (CBS) in nuclear power plants (NPPs). The RIVE of concrete aggregates, which are commonly used in NPP CBS, is investigated in this study. The cylindrical samples with the height of 1 and 2 cm and the diameter of 1 cm were manufactured from rocks (concrete aggregates). Prior to irradiation, the mineral composition of the aggregates was determined using X-ray diffraction analysis with Rietveld refinement. Also, the volume of the aggregates was measured before and after irradiation using water pycnometry and Vertex 251HM MicroVu with touch sensors and optical profilometry. The irradiation of the aggregates was performed in the LVR-15 research reactor. The temperature of irradiation was controlled and did not exceed 60 °C. The concrete aggregates were irradiated up to two different dose levels. Simultaneously, the Rigid-Body Spring Model was used in order to develop in-house software for prediction of RIVE of aggregates. The results of experimental investigation and numerical predictions in terms of RIVE showed good correlation. The obtained experimental and numerical data will be used for further development of the software for prediction of radiation-induced concrete deterioration.