Objective The shield building, as a component of the third-generation new containment structural system, has been endowed with unique and innovative functions and roles. Building upon the original baseline design, the design philosophy of the shield building should be further optimized to address scenarios such as extreme load events, multiple defense failures, or beyond-design-basis accidents, thereby enhancing its defense-in-depth capability and safety margin.

Method By analyzing and summarizing shield building of AP1000, EPR and SMR, the unique functions of shield building were illustrated. And according to different functions and types of shield building, design-basis loads of shield building and containment were introduced in this paper.

Result In recent years, it has become an inevitable development trend that tornado, earthquake and tsunami are all taken into account for beyond design-basis design in the new projects of generation Ⅲ reactor technology.

Conclusion Combined with the working conditions of beyond design-basis design, the application of the beyond design-basis design of the shielded plant for nuclear power plant is discussed in detail, which provides a reference for the relevant engineering design.