Durability and structural integrity of nuclear power plant concrete: A critical review of materials, ageing, and assessment

Abstract

Multiple components in nuclear power plants are made of concrete, which provide structural support, confinement, and radiation shielding over multi-decadal service. This critical review synthesizes evidence on material selection, irradiation and internal swelling, thermal and chemical degradation, mechanical-property evolution, non-destructive assessment, structural health monitoring, and long-term operation frameworks, with particular attention to evidence transferability and coupled ageing. Stiffness and tensile-related properties generally respond to distributed cracking earlier than compressive strength. This pattern is evident across historical irradiation datasets, experimental degradation studies, operating experience, and structural analyses. However, structural significance depends strongly on aggregate mineralogy, temperature and moisture history, restraint, prestress, exposure gradients, and the credited safety function. The available evidence does not support a single universal irradiation or degradation threshold that can be applied without regard to aggregate mineralogy, exposure conditions and structural restraint. This review introduces a coupled-ageing convergence framework that maps diverse mechanisms (irradiation, alkali-silica reaction (ASR), delayed ettringite formation (DEF), thermal, chemical, corrosion) onto six structural state variables (dimensional change, cracking, stiffness/tensile degradation, transport, prestress evolution, embedded-steel deterioration) and demonstrates, through integrated evidence synthesis, that compressive strength alone is an incomplete condition indicator for long-term operation (LTO) assessment. A defensible long-term operation strategy therefore combines traceable material and exposure records, targeted multi-method inspection, selective destructive verification, uncertainty-aware structural analysis, and function-specific acceptance criteria.