For the first time in 30 years, high-temperature nuclear plants will be able to use a new metal.
Scientists at Idaho National Laboratory (INL, USA) have announced the approval of a new high-temperature metal after a 12-year search project with million in funding from the Department of Energy. Alloy 617 , a combination of nickel, chromium, cobalt, and molybdenum, is durable and can withstand temperatures higher than 926 degrees Celsius. Scientists say this means it can be used in high-temperature nuclear facilities, as well as advanced applications such as molten salt nuclear reactors.
The fact that Alloy 617 was shortlisted for ” Boiler and Pressure Vessel Code ” by the American Society of Mechanical Engineers (ASME) was like trying to qualify for the Olympics. It is the first new material series on the list in the last 30 years. And unlike the materials used in light-water nuclear reactors, high-temperature nuclear reactors have few options.
Alloy 617 is the first new material to hit the list in 30 years.
“In contrast to light water plants – commercial plants where you can see 50 to 100 materials – there are only five that can be used in high-temperature reactors,” said INL project leader. , said Richard Wright.
As a result, nuclear researchers and industry insiders have been observing Alloy 617 with great enthusiasm, and they have also created related materials with much stronger properties.
In an article in Materials for Ultra-Supercritical and Advanced Ultra-Supercritical Power Plants in 2017, metal scientist Jutta Klower explained the quality of several variants from Alloy 617, Alloy 617B and 617occ, inherent ” addition of boron and low alloying elements ” to enhance properties such as stress relaxation and long-term strength.
While it may sound a bit strange, ” stress slack ” is how materials redistribute internal forces in response to overload. But when subjected to very high or continuously varying temperatures, stress slack can cause cracking.
“creep rupture “ is similar. “Creep” is the movement of metals and other materials and will eventually deform over time. If the material is completely bent or broken, it is “yield” , not “creep” ; if it melts at high temperature, it is “melt”. But “creep” can take place in both situations before the material “yield” or “melt”.
As Engineer Edge explains: “At room temperature, structural materials have a tension that they will exhibit as soon as an upward pressure is applied. At high temperatures, things may not be (e.g., for example). , stainless steel above 1,000 degrees F or zircaloy above 500 degrees F). At high temperatures and under continuous loads, many materials continue to deform at low frequencies. This behavior is called creep”.
For technology like molten salt, where bringing the reactor up to the right temperature takes a long time, durable materials are paramount. How can the molten salt reaction be effective if the container melts or deforms? A 20% increase in the list of usable materials will also give researchers more options and new ideas, as they continue to test new models of high-temperature plants. .
In addition, this means we will have more and better materials for use in super high temperature nuclear fusion reactors.