Use of NEWS and MMM technologies for diagnostics of NPP components

Abstract

The paper provides information on the results of the R&D projects of the Research Centre Rez carried out between 2019 and 2022 for the Technological Agency of the Czech Republic as part of the "Perspective Diagnostic Methods" projects. In the first part of this paper, the development of the use of NEWS technology for the detection of cracks in pipelines is described. Results from development on half-pipe and pipe test pieces are presented, as well as results from measurements on the main circulation pipeline and connection pipes up to the first shut-off fitting at NPP Temelín. The method of certification and verification of the methodology is also described. The second part of this paper describes the development of the use of MMM technology to detect the state of tightening of bolts of flange joints. The development focused on determining the dependence of the tension in the bolt and the values obtained by the MMM method, determining the influence of the measurement location for the MMM method on the assessment of the condition of the flange joint, and determining the sensitivity of the method to unsatisfactory flange conditions such as undertightened bolts, overtightened bolts etc. is described. At the end, implementation plans are presented, either for specific applications at the NPP or in a subsequent R&D project.