In response to the need to reduce carbon dioxide gas emissions, Japan has been actively researching 700°C-class thermal power plants with a focus on improving overall plant efficiency. This technological advancement is fundamentally grounded in advanced materials development, encompassing the creation of high-strength alloys, fireside corrosion-resistant materials, and steamside oxidation-resistant alloys. A significant challenge emerged as some of the developed materials fell outside the scope of existing domestic technical standards. Moreover, the potential failure modes for advanced ultra-supercritical (A-USC) components operating at 700°C were anticipated to differ substantially from those observed in traditional ultra-supercritical (USC) components at 600°C. Consequently, researchers systematically examined and analyzed the potential failure modes specific to 700°C A-USC components, using these insights to establish comprehensive performance requirements. The research initiative, which commenced in June 2006, was strategically planned to develop a draft technical interpretation by March 2011. This paper provides a detailed overview of the investigative process, encompassing the comprehensive analysis of failure modes, the derivation of performance requirements, and the progression toward developing a new technical interpretation framework for high-temperature power plant components.

Thermoelectric (TE) power generation from waste heat is recently attracted much attention as one of energy-saving technologies. In this paper, Co-doped n-type iron silicide semiconductor was plasma sprayed under various spray conditions to find the optimum spray-forming conditions. Then Co-doped iron silicide TE device with thickness ranging from 3 to 5 mm and the area of over 100 cm square was produced in the form of a plate or on tube. The paper examines the microstructure and evaluates thermal and electric properties. Paper includes a German-language abstract.