Engineers at the University of Washington have recently published a paper detailing their plans to design a working nuclear fusion reactor that would be less expensive than a new coal burning power plant when scaled to full size. Bringing this concept to reality would mark an historic event in energy production.
It’s often been said that learning how to develop and perfect nuclear fusion technology would be akin to learning how to harness the power of stars.
Deep within the cores of stars the atomic nuclei of light elements merge together creating vast quantities of energy. Utilizing this power has been a holy grail for scientists here on Earth for quite some time. If scientists can figure out how to master this process, then we would all benefit from a seemingly limitless supply of clean energy.
Nuclear fusion does not emit carbon dioxide into the atmosphere and, unlike nuclear fission, it does not produce radioactive waste that would require storage for thousands of years. Another clear benefit is that the fuels used in nuclear fusion, hydrogen isotopes in water and lithium, are abundant and easily accessible resources here on Earth.
Until recently, scientists had struggled overcoming a few key obstacles in creating and maintaining the temperatures required to sustain nuclear fusion technology. For example, nuclear fusion occurs in the sun at a relatively low 15 million degrees Celsius due to the intense pressure at its core. In contrast, this type of pressure on Earth is unattainable. In order for nuclear fusion to occur, the fuel needed to power nuclear fusion technology has to be heated to a mind blowing 150 million degrees Celcius. In addition, once this temperature is reached, it would have to be sustained to allow for the reaction to take place, which can only be accomplished if the fuel (which at these temperatures would assume the status of plasma) is suspended in a magnetic field; the moment the fuel in the form of plasma makes contact with any surface, it would cool down dramatically and the reaction would fail.
Once initiated the energy released from the hydrogen atoms fusing into helium heats a coolant which in turn rotates turbines much like in traditional electricity production. For decades, fusion was achieved with limited success in the lab. Although fusion has been achieved previously, the energy required to sustain the reaction always exceeded the energy derived.
Fortunately, engineers at the University of Washington have found a way to address these set backs to viable nuclear fusion technology.
“Right now, this design has the greatest potential of producing economical fusion power of any current concept,” said Thomas Jarboe, a University of Washington professor of aeronautics and astronautics.
The reactor, called the dynomak, started as a class project taught by Jarboe two years ago. After the class ended, Jarboe and doctoral student Derek Sutherland continued to develop and refine the concept.
The magnetic field, which is imperative in maintaining a fusion reactor, can be addressed in several ways. The innovative design that the University of Washington team developed, re-dubbed a spheromak reactor, generates the magnetic fields by driving electrical currents into the plasma itself. This reduces the amount of required materials and actually allows researchers to shrink the overall size of the reactor.
“This is a much more elegant solution because the medium in which you generate fusion is the medium in which you’re also driving all the current required to confine it,” Sutherland said.
This spheromak concept (pictured below) is far more economical than traditional fusion reactors, such as the ITER project (pictured above) in France, which relies on massive electromagnets to maintain the field. And with a reported five times the energy output and one tenth the cost of ITER, the promise of the spheromak design is exciting.
In light of these breakthroughs, and given Earth’s dire energy needs, let’s remain hopeful that fusion power will arrive sooner than scientists had previously anticipated.