New Material Makes It Into the Nuclear Code For the First Time in 30 Years

Researchers from the Idaho National Laboratory spent years on the project.
Fabienne Lang
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The right materials need to be selected and used when engineers construct new buildings. Hence, the American Society of Mechanical Engineers (ASME) has put together the "Boiler and Pressure Vessel Code", informally known as "the Code". 

A team of researchers from the Idaho National Laboratory (INL) has made history by getting its new material, called Alloy 617, into the Code — for the first time in 30 years. Alloy 617 will be extremely useful for the future's advanced nuclear power plants as it allows for a higher temperature operation. 


New material

It's extremely rare for a new material to make its way into the Code, which lays down the design rules for how much stress is permissible, and specifies which materials can be used for power plant construction, which includes nuclear power plants

New Material Makes It Into the Nuclear Code For the First Time in 30 Years
Electron microscope image of dislocation particle interaction in Alloy 617 put under stress at 750°C, Source: Idaho National Laboratory

The new material created by the INL team is a combination of nickel, chromium, cobalt and molybdenum. 

Alloy 617 joining the other materials in the Code gives designers working on new high-temperature nuclear power plants 20% more options of component construction materials to choose from. 

New Material Makes It Into the Nuclear Code For the First Time in 30 Years
INL has nine electromechanical load frames, four servo-electric frames, 11 servo-hydraulic frames, 21 different creep frames and two custom-built stress-relaxation systems for testing new materials like Alloy 617, Source: Idaho National Laboratory

It wasn't a short journey, though, as it took the team 12 years to reach this day. The reason it took so long is mostly due to something called creep, which is the tendency for a substance to change its shape over time. At very high temperatures, creep happens and could pose immense issues in new proposed nuclear reactors. So, determining what happens to Alloy 617 over a long period of time at a given temperature was no easy feat, and not one to ignore. 

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Once the tests on the new material were done, it took three years to get past the Code's balloting process. The final approval came in Autumn 2019

New Material Makes It Into the Nuclear Code For the First Time in 30 Years
Alloy 617 was subjected to repeated fluctuations in temperature or physical stress to provide data for the ASME code case, Source: Idaho National Laboratory

It's a great addition for engineers looking to build high-temperature nuclear power plants, as the new material offers an expanded operating range. The newly qualified material can be used in the design and construction of temperatures up to 950 degrees Celcius (1,750 degrees Fahrenheit), which could enable new high-temperature concepts to form.