Qualification is the evidence-based process through which confidence is established that a component will perform its intended function, in its intended environment, for its intended lifetime, with the required reliability. It is an owner-led activity that defines the type, quantity and quality of data required for codification and for the industrial deployment of components and their structural materials. This paper presents a structured qualification framework and applies it to a fusion machine breeder blanket structure as a representative component. It demonstrates that qualification, rather than material properties alone, dictates the use of fusion structural materials and the deployment of such materials under ASME BPV and AFCEN RCC codes. Current limitations in addressing irradiation synergy, liquid metal corrosion, and joint integrity expose gaps that these codes cannot yet prescribe. Two contrasting structural blanket material case studies: metallic-based ferritic-martensitic steel Eurofer97 and non-metallic-based silicon carbide fibre-reinforced composites (SiC_f/SiC) are used to illustrate the differing evidence requirements for each system type. Industrial scale-up considerations, including alloy specifications, manufacturing readiness, inspection reliability, and supply-chain maturity, are evaluated alongside the need for internationally harmonised datasets and design methodologies. Fusion programmes can use a phased qualification strategy in which early, time-limited operation under controlled conditions builds the evidence needed for codification and scale-up, with the required pre-operation qualification level depending on risk, component criticality and failure consequences, and with the pace of qualification ultimately setting how quickly industry can supply components for commercial fusion. Codification remains essential for commercial deployment because construction codes express codified material behaviour through allowable stresses and permitted fabrication routes, enabling designers to use advanced materials without disclosing proprietary data. In jurisdictions where ASME BPV compliance is mandatory, codification determines whether a material may enter pressure boundary service and must therefore form part of the fusion machine owner’s long-term strategy for deployment.

In pursuit of cleaner and more sustainable power generation, gas turbine power cycles using supercritical carbon dioxide (sCO ₂ ) as a working fluid have emerged as an option to meet emissions targets. The Allam cycle achieves emission reduction through high-pressure sCO ₂ in an oxy-combusted, highly recuperated cycle, operating at 300 bar and up to 800°C. Alloy 625, known for its high corrosion resistance, is used for high-temperature components, including heat exchangers, which can be manufactured traditionally or via additive manufacturing (AM) techniques, such as laser powder bed fusion (LPBF).This study investigates Alloy 625’s microstructural influence on resistance to simulated Allam cycle conditions; comparing as-built and solution heat-treated LPBF AM samples with conventionally manufactured wrought. Isothermal oxidation tests were conducted at 800 ^° C for 1000h in a CO ₂ rich environment (CO ₂ + 2.7mol% H ₂ O + 1.43mol% N ₂ + 0.17mol% O ₂ + 300ppm SO ₂ ). Wrought Alloy 625 demonstrated the lowest oxidation rate, attributed to its homogenized microstructure and fine grain size. Solution heat-treated AM samples exhibited a continuous oxide layer due to grain boundary changes, enhancing oxide scale formation. The K _p values of as-built, solution heat-treated and wrought Alloy 625 were 4.8 x 10 ^− 5 , 5.3×10 ^− 5 , and 4.0×10 ^− 5 mg ² /cm ⁴ respectively.Grain morphology and heat treatment influenced oxidation. As-built LPBF samples formed ridges on the oxide scale and with subsurface voids, while wrought samples displayed uniform oxide layers without subsurface voids. These findings highlight how manufacturing techniques and post-processing affect Alloy 625’s high-temperature performance, crucial for turbine casing and heat exchangers in a baseline Allam cycle environment.