Research is supported by a $1 million, three-year Department of Energy grant

By Matthew Chin

A team led by civil engineers at the UCLA Henry Samueli School of Engineering and Applied Science has received a $1 million, three-year grant from the U.S. Department of Energy to study how radiation damages concrete – the primary structural material used in the construction of nuclear power plants.

Concrete, a mixture formed of cement, water and mineral aggregates such as sand and stone, is used to build structural walls and containment structures in nuclear power plants, including the reactor cavity that surrounds the reactor core.

Concrete had been thought to be immune to the effects of radiation. However, a UCLA team led by Gaurav Sant, associate professor of civil and environmental engineering, recently showed that the minerals calcite and quartz, which often form mineral aggregates in concrete, can be significantly damaged by radiation in the form of neutrons. Specifically, radiation alters the atomic structures of such minerals, which reduces their chemical durability and can lead to an expansion in volume. Such effects may reduce the durability of the concrete and compromise its structural integrity. The new Department of Energy grant will support research by Sant’s team to better understand such damage, and its long-term implications.

“Given the tremendous investment required for the deployment of nuclear power plants and the obvious need for safety – it is important to understand how materials and components used in power plant construction may degrade, and at what rates,” Sant said. “This research will provide new insights into such questions with respect to structural concrete, and the nature of aggregates embedded therein. New understanding is needed to predict concrete degradation in radiation prevalent environments, and the risks thereof over long periods – ranging up to 80 years –over which numerous nuclear power plants are expected to operate.”

The team will apply pioneering nanoscale analytics and molecular simulations to understand the mechanisms of the mineral alteration process, and create a suite of prediction tools to establish the physical and chemical manifestations of radiation damage to concrete. These studies will help power plant owners, operators and regulatory agencies understand, predict and address potential concerns regarding nuclear power plant operations, safety and licensing.

Other team members include Mathieu Bauchy, assistant professor of civil and environmental engineering at UCLA; and researchers from Arizona State University; Oak Ridge National Laboratory in Tennessee; the National Institute for Standards and Technology, the Idaho National Laboratory; the Electric Power Research Institute, based in Charlotte, N.C., and Headwaters Resources.

quartz-to-SiO2-flow

Image: A simulation of how the atomic structure of quartz silica can be deformed by exposure to radiation