Analysis of Fatigue and Crack Properties of High-Performance Concretes for Application in Nuclear Power Plants

摘要

The design of concrete structures used in nuclear power plants should be suitable to protect against accidents caused by different factors, one of them being temperature. Stress due to temperature can be classified as a secondary stress, which is different from the primary stress caused by an external load. This stress can create a bending moment as a result of a temperature gradient inside walls, which is caused by the difference of indoor and outdoor temperatures, or an axial force can be exerted depending on restraint conditions. In addition to seismic loads, the temperature load is a dominant factor in the design of concrete structures used in nuclear power plants considering their thickness should be at least 4 ft. to ensure radiation shielding. In particular, the tensile stress around large passing-through reinforced parts or the tensile strength at cylinder-foundation slab joints may induce concrete cracks at an early stage. Moreover, the use of high-strength concretes and rein-forced bars that can be designed with a relatively small amount of reinforced bars may lead to rapid reduction in rigidity after SSE. In addition, safety of nuclear power plant structures against accidents caused by high temperature and seismic loads is a mandatory permit and authorization issue that must be reviewed; moreover, the fatigue and crack properties of high-performance concretes must be determined. Thus, this study analyzed the fatigue and crack properties of high-performance concretes that can be used in nuclear power plants.