No abstract

No abstract

No abstract

There are several sources of uncertainties which need to be considered in a probabilistic reliability and lifetime assessment of safety-relevant components. In addition to the probabilistic distribution of material properties, the size and properties of flaws present in a component contribute to uncertainties in the lifetime analysis. In a current reactor safety research project, a methodology for a probabilistic fracture mechanics assessment of reliability for components with austenitic and dissimilar metal welds will be developed using the combined results from statistical evaluation of material properties and ultrasonic inspection (UT). Dissimilar metal welds present a particular challenge for ultrasonic testing due to the effects of the material anisotropy on ultrasonic propagation and scattering. Evaluation of inspection results is typically done using image-based techniques. As there is no simple relationship between UT response and flaw size, criteria for image evaluation and flaw sizing have to be defined taking into account the influence of various factors such as material and flaw properties on the UT response. In this paper, we present results from a study of the influence of grain structure on the ultrasonic inspection results and discuss the challenges of extracting data for probability of detection (POD) analyses.

The increasing market share of highly volatile electricity generated from renewable sources like wind or solar energy, leads to enormous challenges in the energy sector. Since large-scale storage systems are neither currently nor in the near future available, the gap between electricity from renewable sources and current electricity demand has to be closed with flexibly operated conventional power plants. In order to be a viable, cost-effective option in tomorrow’s energy market future power plants must be highly efficient while having low CO2 emissions. Furthermore, they have to be highly reactive to counter instabilities in the electrical grid due to fluctuations in renewable sources. Current materials used in power plants are only within limits suited to experience extreme changes in operational loads. However, extreme changes of operational loads will become increasingly severe with a growing share of renewables. Our project team has developed a new concept for CMC-jacketed pipes to alleviate these issues. Recently, this concept was further developed and tested in laboratory as well as a large-scale application test at Grosskraftwerk Mannheim (GKM). All tests are still ongoing. Additionally, to the use in modern highly efficient power plants such CMC-jacketed piping is also suitable for other high-temperature applications, like e.g. solar power plants or industrial chemical applications.