Nuclear fusion energy has the potential to be an effective clean energy source due to the reaction. enormous amount of energy. The fusion reactor aims to replicate what happens on Earth. at the core of the sunVery light elements merge and release energy in the process. Engineers can harness this energy to heat water and produce electricity through steam turbines, but the path to fusion isn’t entirely straightforward.
controlled nuclear fusion several merit First and foremost, the fusion reaction itself does not produce carbon dioxide. There is no risk of melting, and the reaction does not produce long-lived radioactive waste.
I am nuclear engineer Scientists study materials that can be used in nuclear fusion reactors. Fusion occurs at extremely high temperatures. So if nuclear fusion is to one day become a viable energy source, nuclear reactors will need to be built. Material that can withstand the heat inspection It is produced by a fusion reaction.
(Credit: xia yuan/Moment via Getty Images) 3D rendering of the interior of a nuclear fusion reactor chamber.
Fusion materials challenge
During a fusion reaction, several types of elements can merge. What most scientists prefer Deuterium + Tritium. These two elements are most likely to fuse at temperatures that a nuclear reactor can maintain. This reaction produces helium atoms and neutrons, which carry most of the energy from the reaction.
(Credit: Sophie Blondel/UT Knoxville) In a DT fusion reaction, two hydrogen isotopes, deuterium and tritium, fuse to produce helium atoms and high-energy neutrons.
Humans have successfully created nuclear fusion reactions on Earth. Since 1952– Some even garage. But the secret now is to make it worth it. You must gain more energy from the process than you put in to start the reaction.
fusion reaction rise at once very hot plasmaThis is a state of matter similar to a gas but made up of electrically charged particles. The plasma must remain extremely hot (over 100 million degrees Celsius) and condensed during the reaction.
Special materials that make up the reactor walls are needed to keep the plasma hot and condensed and generate reactions that can continue to progress. We also need a cheap and reliable source of fuel.
Deuterium is very common and obtained from water, while tritium is very rare. A 1-gigawatt-class nuclear fusion reactor is expected to burn 56 kg of tritium per year. But in the world there are about Tritium 25kg It is commercially available.
Researchers must find alternative sources of tritium before fusion energy becomes commercially available. One option is to have each reactor generate its own tritium through a system like this: breeding blanket.
The breeding blanket makes up the first layer. plasma room It contains lithium, which reacts with neutrons produced in nuclear fusion reactions to produce tritium. The blanket also converts the energy these neutrons carry into heat.
ITER’s fusion reaction chamber supplies electricity to the plasma.
fusion device You also need a transition periodThe heat and ash produced by the reaction are extracted. Diverters help the reaction last longer.
These materials are exposed to unprecedented levels of heat and particle bombardment. And there are currently no laboratory facilities that can reproduce these conditions and test materials in real-world scenarios. So the focus of my research is to bridge this gap using models and computer simulations.
From Atom to full device
My colleagues and I are working on building tools that can predict how materials in a fusion reactor erode and how their properties change when they are exposed to extreme heat and large amounts of particle radiation.
When irradiated, defects can form and grow in these materials, which affects how well they respond to heat and stress. In the future, the hope is that government agencies and private companies will be able to use these tools to design fusion power plants.
Our approach is Multi-scale modelingconsists of looking at the physics of these materials over a variety of time and length scales using a variety of computational models.
We first study what happens in these materials at the atomic scale through accurate but expensive simulations. For example, one simulation might investigate how hydrogen moves within a material during irradiation.
Through these simulations, we Properties such as diffusivityThis tells us how much hydrogen can spread throughout the material.
Information from these atomic-level simulations can be incorporated into less expensive simulations to explore how materials behave on a larger scale. These large-scale simulations are inexpensive because they model the material as a continuum rather than considering every single atom.
Atomic-scale simulations can take weeks to run. supercomputerContinuum only takes a few hours.
In a multiscale modeling approach, researchers use atomic-level simulations, then take the parameters they find and apply them to larger-scale simulations, and then compare the results with experimental results. If the results do not match, we go back to the atomic scale and study the missing mechanisms. Sophie Blondel/UT Knoxville, adapted from https://doi.org/10.1557/mrs.2011.37
All of this modeling work that takes place on the computer is compared to experimental results obtained in the laboratory.
For example, we want to know if there is hydrogen gas on one side of the material. How much hydrogen leaks to the other side of the material. If the model and experimental results match, we can have confidence in the model and use it to predict the behavior of the same material under conditions expected in a fusion device.
If there is a mismatch, we go back to the atomic-scale simulation and investigate what we missed.
Additionally, we can Couple large-scale materials models to plasma models. These models can tell us which parts of a fusion reactor are hottest or receive the most particle bombardment. You can evaluate more scenarios here.
For example, if too much hydrogen is leaking through the material during fusion reactor operation, it may be a good idea to make the material thicker in certain locations or to add materials that can trap the hydrogen.
new material design
As the quest for commercial fusion energy continues, scientists must design more resilient materials. The field of possibilities is very difficult. Engineers can manufacture elements together in a variety of ways.
You can create new materials by combining two elements, but how do you know what the correct ratio of each element is? And what if you want to try mixing? 5 or more elements together? Running a simulation for all these possibilities would take too long.
Thankfully, artificial intelligence We are here to help. By combining experimental and simulation results, analytical AI We can recommend combinations that are most likely to have the properties we are looking for, such as heat resistance and stress resistance.
The goal is to reduce the number of materials engineers need to produce and experimentally test to save time and money.
Sophie Blondel is a research assistant professor of nuclear engineering at the University of Tennessee. This article is republished from: conversation below Creative Commons License. read original article.
