Research physicist Daniel Jassby, writing in the Bulletin of the Atomic Scientists recently, said that commercial fusion energy, long a supposed holy grail to solve all of the problems associated with generating electricity, is a flawed fantasy.
Jassby has standing. Now retired, he did major plasma physics research for 25 years at the Princeton Plasma Physics Lab. He writes, “Now that I have retired, I have begun to look at the whole fusion enterprise more dispassionately, and I feel that a working, every-day, commercial fusion reactor would cause more problems than it would solve.”
The current article is a follow-up to a Bulletin article a year ago, in which Jassby concluded, “The harsh realities of fusion belie the claims of its proponents of ‘unlimited, clean, safe and cheap energy.’ Terrestrial fusion energy is not the ideal energy source extolled by its boosters, but to the contrary: It’s something to be shunned.”
The 2017 article, Jassby writes, “largely involved the characteristic drawbacks of conceptual fusion reactors, which fusion proponents continue to insist will somehow, someday, be surmounted.” The current article takes on “a prototypical fusion reactor facility in the real world: The International Thermonuclear Experimental Reactor (ITER) under construction in Cadarache, France.”
The greatest challenge for fusion to become a practical energy source is containing the incredibly hot and unstable plasma needed to get hydrogen atoms to fuse into helium, producing an enormous release of energy. It’s much easier in a thermonuclear bomb, because the event occurs instantly and only once. Click, boom.
ITER uses a Russian concept for confining the plasma with magnetic forces in a donut-shaped device known by the Russian term “tokomak.” Most of the world’s attention on fusion has bet on the tokomak approach. But there are others, including using lasers as in the Department of Energy’s Lawrence Livermore National Laboratory’s National Ignition Facility, which appears no closer to commercial fusion than ITER. Less is known about the NIF project, as it has nuclear weapons implications and much is classified.
ITER, Jassby says, illustrates on a practical level the conceptual problems he pointed to in his first article: “Electricity consumption, tritium fuel losses, neutron activation, and cooling water demand.” The $20-$30 billion ITER project, which will not produce electricity, but only demonstrate that possibility around 2030, is using an enormous amount of power during its construction. ITER is served by a switchyard to handle up to 600 MW from the regional grid. The project needs power to run essential systems such as “cryostats, vacuum pumps, and building heating, ventilation and cooling….”
Then there is the power drain from the plasma itself. “For ITER,” Jassby says, “at least 300 MW(e) will be required for tens of seconds to heat the reacting plasma and establish the requisite plasma currents. During the 400-second operating phase, about 200 MW(e) will be needed to maintain the fusion burn and control the plasma’s stability.”
The fuel for the fusion reaction is a combination of deuterium and tritium, hydrogen isotopes known as D-T. Deuterium is abundant but there is no natural supply of tritium, which is in limited supply. On top of that, Jassby notes that fusioneers are “intensely afraid of using tritium for two reasons.” It is slightly radioactive and could be released to the environment. Another issue is the “unavoidable byproduct of neutron bombardment of the reactor vessel” from the D-T fusion, raising operator safety issues and radioactive waste disposal needs.
Then there is water. “Torrential water flows will be needed to remove heat from ITER’s reactor vessel, plasma heating systems, tokamak electrical systems, cryogenic refrigerators and magnet power supplies,” Jassby writes.
Bottom line for ITER? Jassby writes, “Rather than heralding the dawn of a new energy era, it’s likely instead that ITER will perform a role analogous to that of the fission fast breeder reactor, whose blatant drawbacks mortally wounded another professed source of ‘limitless energy’ and enabled the continued dominance of light-water reactors in the nuclear arena.”
In the mid-1950s when it was clear that fission was a viable technology for making electricity, engineers and scientists assured us that fusion was the next big thing. It was, they said with brimming confidence, about 25 years away.
That was 70 years ago. Today, the most optimistic assessments of fusion don’t expect it to be viable for another 30 years or so. Some estimates say fusion energy is 100 years in the future. Some, like Jassby, say, “Forget about it.”
— Kennedy Maize
I had a good friend from college who worked on plasma fusion most of his adult life. His career was in one of the many small DOE- and NSF-funded fusion physics research cottage industries. He modeled and studied thermal transfer properties of plasma. He had a little consulting firm of 3-or-4 people that did this, grinding out and publishing papers. I often wanted to ask him if he really thought it would eventually come to something substantial, but I refrained, not wishing to challenge his life’s work.
Fortunately, his life’s work was raising his three beautiful and intelligent daughters and creating music. But unfortunately he passed away this past year after two brief but devastating illnesses. He passed on his research and little consulting firm to his colleagues.