Construction of realistic NPP containment wall mock-up for challenging NDE methods

The renewal of an operating license requires that nuclear power plants (NPP) demonstrate that their facilities are ageing under controlled conditions. Non-destructive examination (NDE) provides crucial support for ageing management programs, where the renewal of an operation licence generates new challenges for the condition assessment of NPP concrete structures. In addition, the inspection of NPP concrete structures present challenges different from those of conventional civil engineering structures. Finnish research on NDE for NPP concrete infrastructure (Research Project WANDA Non-Destructive Examination of Nuclear Power Plant Primary Circuit Components and Concrete Infrastructure) focuses on the evaluation, calibration and validation of the available NDE methods and monitoring systems for concrete structures. This is achieved through the design and construction of a real-scale mock-up of a reinforced concrete containment wall for NDE, monitoring, R&D and education purposes. The mock-up represents a NPP reinforced concrete containment wall with simulated defects such as dimensional errors, construction errors, honeycombing, cracking, delamination due to structure stresses or deterioration mechanisms, embedded foreign objects in the concrete, voids adjacent to liner, and defects in grouted tendon ducts for the post-tensioned structures. The aim of this paper is to present the conceptual design of the mock-up, and provide some insight into its recent construction.