Irradiation Effects on Reactor Concrete Structures

As the US Light Water Reactor (LWR) fleet ages, irradiation and environmental effects may degrade concrete structures within the reactor cavity of nuclear power plants (NPPs). Concrete components provide structural support and serve as a containment barrier and radiation shield. Among the most important constituents of concrete are the aggregates and cement paste phases. These two phases deteriorate due to different factors, aggregates swell due to the presence of neutron irradiation, while the cement may lose water due to gamma-ray-induced hydrolysis. The authors will present a series of results from different characterization techniques (i.e. TEM, XRD, XRF, EBSD and ellipsometry) and Fast Fourier Transform (FFT) micro-mechanical simulations using MOSAIC that demonstrates the effects of irradiation, moisture, temperature, and constraint on reactor cavity concrete (RCC). The development of new numerical techniques and understanding of the irradiation effects in concrete are crucial for the assessment and life extension of the NPPs.