Source: Power Engineering | Rod Walton, Clarion Energy Content Director | June

Alloy 617 has made heavy metal history and may play a role in a potential nuclear power revival.

For the first time in 30 years, the American Society of Mechanical Engineers added a new alloy to its Boiler and Pressure Vessel Code. Alloy 617 is a combination of nickel, chromium, cobalt, and molybdenum.

It was first developed for use in high-temperature gas reactors but can also be applied to molten salt and liquid metal reactor designs, according to the U.S. Department of Energy.

The elevation of Alloy 617 marks the end of a decade-long effort by the DOE and researchers from the Argonne, Oak Ridge, and Idaho National Laboratories.

“It’s a pretty substantial accomplishment,” said Richard Wright, project manager for the Idaho National Laboratory. “This means designers working on new high-temperature nuclear plants now have 20 percent more options when it comes to component construction materials.”

The ASME added Alloy 617 to the code last fall. It is the first high-temperature material cleared for commercial use since the 1990s.

The DOE invested about $15 million over 12 years in an effort to develop a high-temp supporting metal for advanced reactor concepts. Numerous companies and utilities are working on clearing regulatory hurdles for small modular reactors and other advanced systems of the future.

The new metal offers significant improvements over previously approved alloys in the code and can withstand operating temperatures of 1,750 degrees Fahrenheit—nearly 400 degrees hotter than the next-best material. The new metal also reportedly has high oxidation resistance.

The new designs could also open up new market opportunities for the nuclear industry by using its thermal heat to directly heat communities, drive industrial processes, produce hydrogen, and even purify water without emitting carbon.

(Rod Walton is content director for Power Engineering and POWERGEN International. He can be reached at 918-831-9177 and