Overview of Electric Power Research Institute’s Research on Irradiation of Concrete

摘要

The Electric Power Research Institute (EPRI) LongTerm Operations (LTO) Program has made significantprogress on the R&D to provide the technical basis fordecisions regarding extended nuclear plant life. Theseresults inform those considering long-term operation past60 years and beyond and the long-term impacts of aging.Much of the research is coordinated and/or collaboratedwith the U.S. Department of Energy and the U.S. NuclearRegulatory Commission.The focus of this paper is on the research anddevelopment that supports the technical bases for longtermsafe and reliable operation in the area of concretematerials. Specifically, the neutron radiation that exits thereactor vessel and comes into contact with the concretebiological shield and interacts with atoms in theaggregates, thus creating point defects. These pointdefects can agglomerate and cause radiation inducedvolumetric expansion (RIVE), which, in turn, can causemicrocracking in the cement paste and degrade thephysical properties of the concrete. The EPRI work inthis area has included review of relevant literature,estimation of 80-year neutron fluence in the U.S. fleet oflight water reactors, review of concrete biological shielddesigns, estimation of effects of radiation on structuralcapacity, estimation of the magnitude of gamma heating,gamma flux and dose calculations, and an integratedstructural model. This work has also contributed to agingmanagement guidance in order to support nuclear powerplants’ assessment of the aging of their concretebiological shield walls for long term operations.The topic of this paper deals specifically withdetermination of the effects of neutron irradiation on thestructural capacity of concrete biological shield.