Nuclear fusion energy has the potential to become an effective clean energy source as the energy source produced by the reaction. an incredible amount of energy. Fusion reactors aim to reproduce what is happening on Earth in the center of the sunvery light elements combine and release energy in the process. Engineers can harness this energy to heat water and generate electricity with steam turbines, but the path to nuclear fusion is not entirely straightforward.
Controlled nuclear fusion is some advantage Better than other power sources for power generation. First, fusion reactions themselves do not produce carbon dioxide. There is no risk of meltdown, and the reaction does not produce long-lived radioactive waste.
I nuclear engineer A scientist who studies materials that can be used in fusion reactors. Nuclear fusion occurs at incredibly high temperatures. Therefore, in order to someday make fusion a viable energy source, nuclear reactors will need to be built with: With materials that can withstand the heat, irradiation Produced by a fusion reaction.
(Credit: xiayuan/Moment via Getty Images) 3D rendering of the inside of a fusion reactor chamber.
Issues with fusion materials
Several types of elements may combine during fusion reactions. Most scientists prefer deuterium and tritium. These two elements are most likely to melt at temperatures that a nuclear reactor can maintain. This reaction produces helium atoms and neutrons, and most of the energy from the reaction is carried by the neutrons.
(Credit: Sophie Blondel/UT Knoxville) In a DT fusion reaction, two hydrogen isotopes, deuterium and tritium, fuse together to produce helium atoms and high-energy neutrons.
Humanity succeeded in creating a nuclear fusion reaction on Earth. since 1952– even some of them. garage. But what’s important now is to make it worthwhile. More energy must be taken out of the process than is put in to start the reaction.
fusion reaction happens in very hot plasmawhich is a state of matter similar to a gas, but made up of charged particles. The plasma must maintain a very high temperature, over 100 million degrees Celsius, and condense during the reaction period.
To keep the plasma hot and condensing so that the reaction can continue, special materials are needed to make up the walls of the reactor. Cheap and reliable fuel sources are also needed.
Deuterium is very common and obtained from water, while tritium is very rare. A 1 gigawatt fusion reactor is expected to burn 56 kilograms of tritium per year. However, the world has about 25 kg of tritium It is commercially available.
Researchers need to find alternative sources of tritium before fusion energy can take off. One option is for each reactor to produce its own tritium through a system called . Breeding blanket.
The breeding blanket constitutes the first layer. plasma chamber It contains lithium, which reacts with neutrons produced in nuclear fusion reactions to produce tritium. The blanket also converts the energy carried by these neutrons into heat.
ITER’s fusion reactor charges the plasma.
fusion device You also need a diverterextracting the heat and ash produced in the reaction. Diverters help the reaction last longer.
These materials will be exposed to unprecedented levels of heat and particle bombardment. And there are currently no laboratory facilities to reproduce these conditions and test materials in real-world scenarios. Therefore, the focus of my research is on bridging this gap using models and computer simulations.
From atoms to full devices
My colleagues and I can predict how materials in fusion reactors will erode and how their properties will change when they are exposed to extreme heat or large particle beams. We are working on creating a tool.
When exposed to radiation, defects can form and grow in these materials, which affects the material’s reactivity to heat and stress. In the future, we hope that government agencies and private companies will be able to use these tools to design fusion power plants.
Our approach is multiscale modelingconsists of investigating the physics of these materials over different 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 can examine how hydrogen moves within a material during irradiation.
From these simulations we find that: Properties such as diffusivityThis indicates how far hydrogen can spread throughout the material.
Information from these atomic-level simulations can be integrated into cheaper simulations that examine how materials react on larger scales. These large-scale simulations are less expensive because they model the material as a continuum rather than considering every single atom.
Atomic-scale simulations can take weeks to run. super computerwhile continuous ones only take a few hours.
In a multiscale modeling approach, researchers use atomic-level simulations, apply the discovered parameters to larger-scale simulations, and compare the results with experimental results. If the results don’t match, go back to the atomic scale and study the missing mechanism. Sophie Blondel/UT Knoxville, adapted from https://doi.org/10.1557/mrs.2011.37
All of this modeling work done on the computer is compared with experimental results obtained in the laboratory.
For example, I want to know if there is hydrogen gas on one side of the material. Amount of hydrogen leaking 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 materials under the conditions expected in a fusion device.
If it doesn’t match, go back to the atomic-scale simulations and investigate what you missed.
Additionally, you can: Coupling large material models to plasma models. These models can tell which parts of the fusion reactor will be the hottest or have the most particle collisions. From there, you can evaluate more scenarios.
For example, if too much hydrogen leaks out of the material during operation of a fusion reactor, it may be a good idea to thicken the material in certain places or add something to capture the hydrogen.
new material design
As the search for commercial fusion energy continues, scientists will need to design more resilient materials. The field of possibilities is mind-boggling, with engineers able to fabricate multiple elements together in many different ways.
You can combine two elements to create a new material, but how do you know the right proportions for each element? What if you want to mix it up? 5 or more elements together• Trying to run simulations for all these possibilities would take too much time.
Thankfully, artificial intelligence We’re here to help. By combining experimental and simulation results, analytical A.I. 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 create and experimentally test, saving time and money.
Sophie Blondel is an assistant professor of nuclear engineering at the University of Tennessee. This article is republished from conversation under Creative Commons License. please read original article.
