Antinuclear

Australian news, and some related international items

Over time radiation causes damage to the structure of nuclear reactors

Fission reactions also produce intense radiation that causes a deterioration in the nuclear reactor‘s structural materials.

At the atomic level, when energetic radiation infiltrates these materials, it can either knock off atoms from their locations, causing point defects, or force atoms to take vacant spots, forming interstitial defects. Both these imperfections disrupt the regular arrangement of atoms within the metal crystal structure.

And then, what starts as tiny imperfections grow to form voids and dislocation loops, compromising the material’s mechanical properties over time.

How prolonged radiation exposure damages nuclear reactors, Phys org, 7 Nov 21, by Vandana Suresh, Texas A&M University.   New research from Texas A&M University scientists …By using a combination of physics-based modeling and advanced simulations, they found the key underlying factors that cause radiation damage to nuclear reactors,…..

“Reactors need to run at either higher power or use fuels longer to increase their performance. But then, at these settings, the risk of wear and tear also increases,” said Dr. Karim Ahmed, assistant professor in the Department of Nuclear Engineering. “So, there is a pressing need to come up with better reactor designs, and a way to achieve this goal is by optimizing the materials used to build the nuclear reactors.”

…………… fission reactions also produce intense radiation that causes a deterioration in the nuclear reactor‘s structural materials. At the atomic level, when energetic radiation infiltrates these materials, it can either knock off atoms from their locations, causing point defects, or force atoms to take vacant spots, forming interstitial defects. Both these imperfections disrupt the regular arrangement of atoms within the metal crystal structure. And then, what starts as tiny imperfections grow to form voids and dislocation loops, compromising the material’s mechanical properties over time.

While there is some understanding of the type of defects that occur in these materials upon radiation exposure, Ahmed said it has been arduous to model how radiation, along with other factors, such as the temperature of the reactor and the microstructure of the material, together contribute to the formation defects and their growth.

“The challenge is the computational cost,” he said. “In the past, simulations have been limited to specific materials and for regions spanning a few microns across, but if the domain size is increased to even 10s of microns, the computational load drastically jumps.”

In particular, the researchers said to accommodate larger domain sizes, previous studies have compromised on the number of parameters within the simulation’s differential equations. However, an undesirable consequence of ignoring some parameters over others is an inaccurate description of the radiation damage……..  https://phys.org/news/2021-11-prolonged-exposure-nuclear-reactors.html

November 9, 2021 - Posted by | Uncategorized

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