When it comes to advanced, high-temperature reactors—using working fluids such as molten salt, high-temperature gases, or sodium—there simply are not many qualified materials for nuclear component construction. Alloy 617 is not a new material, but it made the news after Idaho National Laboratory announced that it was recently added to the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (BPV) Code for high-temperature nuclear applications, bringing the total number of qualified high-temperature materials to six.
What is Alloy 617? Alloy 617 is a solid-solution, nickel-chromium-cobalt-molydenum alloy with an exceptional combination of high-temperature strength and oxidation resistance, according to the High Temp Metals (HTM) website. The alloy also has excellent resistance to a range of corrosive environments, and it is readily formed and welded by conventional techniques.
Read more: A team led by INL Laboratory Fellow Emeritus Richard Wright published an updated draft case for Alloy 617’s addition to the BPV code in September 2018. ASME’s balloting process was completed in fall 2019.