The concrete biological shields used in light water reactors are exposed to high neutron and gamma irradiation doses over the long term. Irradiation deteriorates the physical and mechanical properties of concrete. Such effects must be investigated to predict the concrete’s performance in the event of a lifetime extension of a nuclear power plant. This work combines high-resolution characterization techniques with fast-Fourier transform (FFT)-based 2D simulations to evaluate the radiation-induced
volumetric expansion (RIVE) and damage in concrete microstructures under neutron irradiation. Two concrete microstructures from samples provided by the Japan Concrete Aging Management Program (JCAMP) were characterized using micro x-ray fluorescence (mXRF) to obtain elemental intensity maps, and energy-dispersive x-ray spectroscopy to complement mXRF with local elemental information for Na.
Minerals and cement paste are then identified based on the elemental composition to produce highresolution phase maps, resulting in a more accurate representation of the microstructures compared to that seen in previous work. Simulations of RIVE, creep, and damage in JCAMP concrete use the fast FFT-based code Microstructure Oriented Scientific Analysis of Irradiated Concrete (MOSAIC), combined with the irradiated minerals, aggregates, and concrete (IMAC) database, which contains mineral-specific RIVE models. Overall, the simulation results are in fair agreement with experimental data.