DESC0023575

Methods are sought to improve creep-fatigue performance of materials formed using powder metallurgical hot isostatic pressing. By developing Powder Metallurgical-Hot Isostatic Pressing operational conditions and can removal approaches to build and validate 316H stainless steel boiler materials for enhanced creep- fatigue performance, large scale near net shape components can be built for next generation molten salt nuclear reactors. Molten salts enable more economical operation due to higher temperatures (>600°C), thermal energy storage, and ability to dissolve fuel in the coolant. New reactor material manufacturing methods require validation and testing of these material systems to prove that they can meet or exceed the safety and lifetime protocols of conventionally produced materials. The Phase I/II objective is to develop a near net shape Powder Metallurgical-Hot Isostatic Pressing method to build and demonstrate near net shape high quality, complex 316H stainless steel components for nuclear reactor systems, including pumps, valves, and pressure vessels. State-of-the-art manufacturing processes can provide more economical fabrication of near net shape homogeneous material that meet or exceed the structural properties of conventional materials. Process optimization and creep-fatigue material enhancement demonstration of Powder Metallurgical-Hot Isostatic Pressing formed 316H stainless steels. Specifically, Phase I will study the effect of grain size, molten salt corrosion, and the surface damage that may result during can removal on the high temperature creep fatigue performance. The results of the Phase I will lead to a manufacturing strategy to produce a large scale near-net shape Powder Metallurgical-Hot Isostatic Pressing components of 316H stainless steel boiler materials that will be of interest to the molten salt reactor community. Phase II will include the build of a large structure and extract creep-fatigue specimens to demonstrate structural performance uniformity. This approach could be used to build near net shape boilers, pumps, valves, and pressure vessels for use in high temperature application where boiler materials (per American Society of Mechanical Engineers standards) are required. This not only includes nuclear reactors, but also a wide range of large area boiler structures of interest to the chemical and aerospace industries, as well as many other commercial markets.