By Maya RectorMEng students Keyu Wang (left) and David Zhang (right) testing their prototype outside of Blum HallEach year, UC Berkeley Master of Engineering students work on a team of 3 to 5 students with the goal of engineering solutions using cuttin…
By Paaras Agrawal, edited by Maya RectorPhoto by Andreas Gücklhorn on UnsplashPaaras is a current UC Berkeley MEng Mechanical Engineering student in the class of 2018. His concentration within Mechanical Engineering is experiential advanced controls de…
By Kaleb Hatfield. Edited by Giselle Diaz
To say that Kaleb Hatfield has always had a passion for science would be an understatement. As a high school senior, he was already experimenting with ways of assembling a home made nuclear fusion device — in his own garage. Not much has changed. His passion for clean energy has taken him from a seventeen year old with a homemade nuclear fusion accelerator, to an intern at Tri Alpha Energy, and most recently, full time Nuclear Engineer. But despite his growing career, his work is not done. Kaleb not only hopes to contribute towards a clean energy solution, but also aims to spread awareness about Nuclear Engineering as a viable and necessary field that will benefit the environment and society for generations to come.
Tell us about your role at Tri Alpha Energy.
Currently, my primary role is to help study radiation production and transport using physical/computational analysis. Basically, I look at current and future fusion devices that Tri Alpha Energy is building and help engineers understand how radiation produced by the plasma (extremely hot gas) held inside the devices moves through and interacts with the various components and surrounding environment. Naturally, this work leads me to take on other roles in areas like design or diagnostics.
What do you enjoy most about working there?
Tri Alpha Energy is a truly unique company that allows me the opportunity to interact with a wide variety of professional individuals. Although my home is in engineering, I interact with physicists all the time. I particularly enjoy this because my first degree was in physics and I hope to someday acquire a doctorate in plasma physics. Tri Alpha Energy gives me a chance to meet highly motivated people who wish to see fusion succeed and network with a tight-knit community.
Are there any risks or drawbacks associated with your job?
Aside from the eventual carpal tunnel and declining vision that affects most people sitting in front of a computer for extended periods of time, I don’t experience any risks or drawbacks. Of course when I do eventually get asked to provide some hands-on assistance, I will experience the same level of risks that people who work around big machinery do. Tri Alpha Energy proudly maintains a fantastic safety record under the guidance of our Safety Officers.
Tri Alpha Energy has a very clear vision: produce clean fusion energy. If achieved, what would be the impacts of introducing clean energy on a commercial scale?
In order to understand what impacts the technology that Tri Alpha Energy will bring, fusion energy must first be understood. The best place to start would be with the most iconic work of 20th century physicist, Albert Einstein. He suggested that scientists should place their faith in two basic constructs: both the speed of light and the laws of physics must remain constant in any frame of reference. On paper, these ideas are easily accepted. But if you were to step off the page and look at how the world works around you, these ideas are very hard to accept.
For example, imagine you got onto the BART and needed to move to another compartment to find a seat. But BART starts moving as you walk toward the next compartment. From your point of view, you are moving at your usual walking speed, but to the people waiting for the next Bart on the platform, you are moving at the speed of the BART plus your walking speed. That is the classical understanding of relative motion. Now what if you traversed the compartments at the speed of light instead of your usual walking speed? According to Einstein, the speed of travel from your point of view would be the same speed as the on-lookers on the platform.
This dramatic change in the understanding of motion has drastic effects on the way we view the universe. Mass becomes tied to energy and if you apply these changes, atoms, nuclei and even the smallest elementary particles suddenly have stored energy. Nuclear energy would be the release of some of this stored energy. But there are several ways in which nuclear energy can be acquired, and the most energy dense method is fusion.
What is Fusion?
Believe it or not, everybody is very familiar with fusion. There could not be life on Earth without it because fusion powers the sun as well as all of the other stars. It occurs when the nuclei of very light elements like hydrogen or helium smash together and stick creating heavier elements. The heavier elements then whizz away with a small portion of the energy that was used to hold the original nuclides together. However, this ‘small portion of energy’ is rather large when compared to chemical energy. In fact, fusion energy is a million times greater than chemical energy produced by burning fossil fuels like gasoline, coal or oil, and the end products are usually more environmentally friendly.
I stress ‘usually’ because there are fusion processes that can produce harmful radiation called neutrons, but Tri Alpha Energy is working toward perfecting technology that makes use of a fusion process which does not create neutrons. When this technology becomes available, the world could be looking at a power supply that releases large amounts of steady power and uses very abundant fuel while producing negligible levels of harmful waste. Currently, there is not an energy source on the market that can meet these criteria. To use a cliché, it would be completely game-changing.
At the crux of Tri Alpha Energy is its C-2U machine. For the general public, what is the best way to explain the workings of this machine?
Tri Alpha Energy is attempting to produce reliable fusion energy in much the same way that most viable fusion technologies are: magnetic control of a plasma with an economically beneficial quantity of fusion reactions (i.e. magnetic confinement). To put this in simpler terms, a really low pressure gas containing the fuel is heated up to millions of degrees centigrade until it becomes a soup of electrons and nuclei (or plasma). In order to stop the plasma from immediately cooling off, it is confined by magnetic fields from reaching the walls of the physical container; it is important to keep the plasma as hot as possible because a fusion reaction requires a great deal of energy given to nuclei in order to occur.
The differentiating factor in how Tri Alpha Energy performs magnetic confinement is in the way plasma forms and the arrangement of the magnetic fields. We are investigating something called Field Reversed Configuration (FRC) which is when a plasma generates the necessary confining magnetic fields through self-organization. In other words, the plasma builds its own magnetic container.
The C-2U machine was the latest project of Tri Alpha Energy that demonstrated how to create and stabilize an FRC, a historically difficult task. If you were to picture a ring of plasma at the center of a long tube wrapped in magnetic coils, this would be the FRC in C-2U. This plasma ring (or compact toroid) is formed in the machine by ‘blowing’ two smaller opposing plasmas rings along the axis toward the center of the tube from each end. The rings merge in the center to create the FRC, and a current moving around the FRC produces a magnetic field that opposes the magnetic field of the tube. The resulting magnetic fields acting on the plasma completely contain it. Unfortunately, the FRC is rather unstable, but the C-2U machine produces most of the necessary stabilization from a clever arrangement of beams of directed heated fuel (or neutral beams) imparting their energy to the FRC.
An analogy can be drawn to the stability of a coin spinning on a table-top. After you spin the coin, it will continue to rotate until it eventually starts to wobble and falls down. However if you carefully flick the edges of the coin, it will continue to spin. This principle is relatively the same with the neutral beams and FRC. Tri Alpha Energy is currently in the next phase of construction by building a new machine called C-2W which will achieve the next steps of physics goals leading toward a commercial device.
Given that fusion energy is a relatively unfamiliar field to the public — along with a fear of nuclear disasters, what safety precautions does Tri Alpha Energy take to ensure reliability?
The main safety feature for fusion energy devices is the intrinsic difficulties that plague their operation. They require a great deal of energy to contain the plasma, and if the necessary input energy or magnetic containment was lost, the plasma performing the nuclear reactions would become unstable and extinguish itself. In fact, any substantial damage to the machine would never spell disaster for the surrounding community or environment.
This is a clear advantage that fusion energy holds over the currently existing nuclear energy. Nuclear power plants today use a process called fission. Unlike fusion, fission requires that large nuclei be split apart to release energy and in order to be economically beneficial, the splitting is done in a chain reaction. One atom splits and releases neutrons which cause another atom to split and so on like dominos falling onto other dominos. It is only when this chain reaction gets out of hand that it becomes dangerous. Too many reactions at a time can release a significant quantity of heat that could melt the solid fuel that contains all the reactions. The geometry of the solid fuel not only provides crucial control of the overall chain reaction, but also, containment of the radioactive by-products produced in fission. So melting the fuel causes the reaction to both runaway further and rapidly release radioactive material.
This event, referred to as “meltdown” is what caused the most well-known nuclear disasters at Three Mile Island, Chernobyl and most recently, Fukushima. Future nuclear power plants are hoping to avoid this event with promising technology like molten salt reactors, and UC Berkeley is a leader in this field. However, fission will still produce hazards like spent nuclear fuel that Tri Alpha Energy will never have to face with their fusion energy technology. Of course, there are always inherent risk factors with big electrical machines, but these are mitigated by compliance with the appropriate agencies and safety policies.
What are some common misconceptions that people have of nuclear engineering/nuclear power?
Instead of misconceptions people have, it would be better to recognize a fault in our (the collective nuclear community’s) education of the public on nuclear engineering and nuclear power. Misconceptions are always created by ignorance, and if they are rampant, then we are not doing a good job of providing the right information.
People fear nuclear power because of the lasting effects that meltdowns create, and that is a legitimate fear. Fission reactors have the capability of producing radioactive material that will remain radioactive long after the human race has either left Earth or died out. However, most people don’t realize the incredible levels of safety and precaution detailed in the maintenance of those fission reactors. The safety of nuclear plants is so thorough that regulations can be somewhat overbearing at times.
The Nuclear Regulatory Commission (NRC) is the governing body that controls U.S. nuclear operations, and it desperately needs adjustment. Entities trying to build advanced reactors do not seek asylum for their work in the U.S. because the NRC chases them out with crippling fiscal demands and a lack of recognition for concepts that do not apply to the existing nuclear reactor infrastructure in the Code of Federal Regulations (CFR). Of course, there are brave companies pushing forward with new fission reactor designs in the U.S. instead of retreating to less restrictive countries like China.
However, the public needs better education on the subject of radiation. Schools should be making an effort to include nuclear science in their science programs. If offered at all, the most physics a high school student will learn is from the 18th century.
Drawing free-body diagrams for ramps and springs will not help them decide if they want to live next to a nuclear power plant in the future. If more people understood at most the basics, they could discern for themselves the true dangers or benefits that nuclear science can bring.
What advice would you give to people interested in pursuing a career in nuclear engineering and what trends are you seeing in the field?
I prefer to avoid trends in possible career fields. A job today could be gone tomorrow. For me, a career worth building is one in which a problem has been identified that possesses me to solve it and spurs other people who want the answer too. If someone is contemplating moving into a career field like nuclear engineering, at the core of their being they like to solve problems.
Sure there are other motives for picking a career, but if you can choose your path, why not be driven daily to satisfy your curiosity?
As I see it, the largest issue in the nuclear field being spent nuclear fuel. My master’s work was focused on the end of the current nuclear fuel cycle. In particular, I tried to address the halt of the U.S. national geological repository (Yucca Mountain) by designing a centralized interim storage facility for spent nuclear fuel. Through the course of my work, I quickly came to realize that an engineering solution was great, but the issue would be better solved from a policy standpoint.
The U.S. needs some major policy changes. For one, they do not reprocess spent nuclear fuel. This is due to the policy that leaving plutonium in an irretrievable form will thwart malicious individuals from building dangerous weapons. Personally, I think that policy has too much oversight. If France reprocesses spent nuclear fuel with ISIS literally at their doorstep, there are tested secure pathways, and they do not need to be executed in the current manner. Better methods like plasma processing exist which can separate more useful elements than the plutonium into a safe form.
Or we can get at the root of the problem by building better fission reactors. Several companies have decided to take this challenge, with design philosophies like modular fission reactors that create less spent nuclear fuel (NuScale), fission reactors that use molten salts to mitigate the production of spent nuclear fuel (Transatomic Power Corp) or fission reactors that just use the abundant spent nuclear fuel readily available (TerraPower).
An even better approach could be to avoid fission altogether and work toward fusion with companies like Tri Alpha Energy. If you make it through that chain of thought and haven’t found a niche, several other problems emerge. For example if the current nuclear reactor technology becomes obsolete, where will medical radioisotopes come from? Or if less fuel is needed in fusion for the same power density of current nuclear reactors, could nuclear technology meet the weight requirements for space travel?
The nuclear engineering field is beaming with opportunity. The person facing the decision of “should I become a nuclear engineer” just needs to find that one problem that keeps them busy looking for a satisfactory answer until a true difference in the way the world operates is made.