The American Society of Mechanical Engineers has approved the inclusion of "617 Alloy" in the "Boiler and Pressure Vessel Code". "617 alloy" is a mixture of nickel, chromium, cobalt and molybdenum, which means that this alloy developed by the Idaho National Laboratory in the United States can be used in the proposed molten salt reactor, high temperature reactor, gas cooled reactor or sodium cooled stack. This is the first new material added to the specification in the United States in 30 years.
The “Boiler and Pressure Vessel Code” stipulates the design rules for acceptable stress, and specifies the materials that can be used for power plant construction (including nuclear power plants). Compliance with these specifications ensures the safety and performance of components. The Idaho National Laboratory developed the "617 Alloy" in 12 years, and the US Department of Energy invested $ 15 million. Unlike light water reactors operating at around 290 ° C, the proposed operating temperature of molten salt reactors, high temperature reactors, gas-cooled reactors or sodium-cooled reactors is twice or higher than this temperature. Therefore, it is important to determine the change of "617 alloy" over time at a given temperature.
Now, designers of high-temperature reactors use the new material "617 alloy", which can make the reactor's working range larger. Allegedly, previously allowed high-temperature materials can not be used above 750 ℃, and "617 alloy" can be used up to 950 ℃. Therefore, "617 alloy" can meet the higher temperature reactor design.