Photograph Source: Lawrence Livermore National Laboratory – CC BY-SA 3.0
There was great hoopla—largely unquestioned by media—with the announcement this week by the U.S. Department of Energy of a “major scientific breakthrough” in the development of fusion energy.
“This is a landmark achievement,” declared Energy Secretary Jennifer Granholm. Her department’s press release said the experiment at Lawrence Livermore National Laboratory in California “produced more energy from fusion than the laser energy used to drive it” and will “provide invaluable insights into the prospects of clean fusion energy.”
“Nuclear fusion technology has been around since the creation of the hydrogen bomb,” noted a CBS News article covering the announcement. “Nuclear fusion has been considered the holy grail of energy creation.” And “now fusion’s moment appears to be finally here,” said the CBS piece.
But, as Dr. Daniel Jassby, for 25 years principal research physicist at the Princeton Plasma Physics Lab working on fusion energy research and development, concluded in a 2017 article in the Bulletin of the Atomic Scientists, fusion power “is something to be shunned.”
His article was headed “Fusion reactor: Not what they’re cracked up to be.”
“Fusion reactors have long been touted as the ‘perfect’ energy source,” he wrote. And “humanity is moving much closer” to “achieving that breakthrough moment when the amount of energy coming out of a fusion reactor will sustainably exceed the amount going in, producing net energy.”
“As we move closer to our goal, however,” continued Jassby, “it is time to ask: Is fusion really a ‘perfect’ energy source?” After having worked on nuclear fusion experiments for 25 years at the Princeton Plasma Physics Lab, I began to look at the fusion enterprise more dispassionately in my retirement. I concluded that a fusion reactor would be far from perfect, and in some ways close to the opposite.”
“Unlike what happens” when fusion occurs on the sun, “which uses ordinary hydrogen at enormous density and temperature,” on Earth “fusion reactors that burn neutron-rich isotopes have byproducts that are anything but harmless,” he said.
A key radioactive substance in the fusion process on Earth would be tritium, a radioactive variant of hydrogen.
Thus there would be “four regrettable problems”—“radiation damage to structures; radioactive waste; the need for biological shielding; and the potential for the production of weapons-grade plutonium 239—thus adding to the threat of nuclear weapons proliferation, not lessening it, as fusion proponents would have it,” wrote Jassby.
“In addition, if fusion reactors are indeed feasible…they would share some of the other serious problems that plague fission reactors, including tritium release, daunting coolant demands, and high operating costs. There will also be additional drawbacks that are unique to fusion devices: the use of a fuel (tritium) that is not found in nature and must be replenished by the reactor itself; and unavoidable on-site power drains that drastically reduce the electric power available for sale.”
“The main source of tritium is fission nuclear reactors,” he went on. Tritium is produced as a waste product in conventional nuclear power plants. They are based on the splitting of atoms, fission, while fusion involves fusing of atoms.
“If adopted, deuterium-tritium based fusion would be the only source of electrical power that does not exploit a naturally occurring fuel or convert a natural energy supply such as solar radiation, wind, falling water, or geothermal. Uniquely, the tritium component of fusion fuel must be generated in the fusion reactor itself,” said Jassby.
About nuclear weapons proliferation, “The open or clandestine production of plutonium 239 is possible in a fusion reactor simply by placing natural or depleted uranium oxide at any location where neutrons of any energy are flying about. The ocean of slowing-down neutrons that results from scattering of the streaming fusion neutrons on the reaction vessel permeates every nook and cranny of the reactor interior, including appendages to the reaction vessel.”
As to “additional disadvantages shared with fission reactors,” in a fusion reactor: “Tritium will be dispersed on the surfaces of the reaction vessel, particle injectors, pumping ducts, and other appendages. Corrosion in the heat exchange system, or a breach in the reactor vacuum ducts could result in the release of radioactive tritium into the atmosphere or local water resources. Tritium exchanges with hydrogen to produce tritiated water, which is biologically hazardous.”
“In addition, there are the problems of coolant demands and poor water efficiency,” he went on. “A fusion reactor is a thermal power plant that would place immense demands on water resources for the secondary cooling loop that generates steam, as well as for removing heat from other reactor subsystems such as cryogenic refrigerators and pumps….In fact, a fusion reactor would have the lowest water efficiency of any type of thermal power plant, whether fossil or nuclear. With drought conditions intensifying in sundry regions of the world, many countries could not physically sustain large fusion reactors.”
“And all of the above means that any fusion reactor will face outsized operating costs,” he wrote.
“Fusion reactor operation will require personnel whose expertise has previously been required only for work in fission plants—such as security experts for monitoring safeguard issues and specialty workers to dispose of radioactive waste. Additional skilled personnel will be required to operate a fusion reactor’s more complex subsystems including cryogenics, tritium processing, plasma heating equipment, and elaborate diagnostics. Fission reactors in the United States typically require at least 500 permanent employees over four weekly shifts, and fusion reactors will require closer to 1,000. In contrast, only a handful of people are required to operate hydroelectric plants, natural-gas burning plants, wind turbines, solar power plants, and other power sources,” he wrote.
“Multiple recurring expenses include the replacement of radiation-damaged and plasma-eroded components in magnetic confinement fusion, and the fabrication of millions of fuel capsules for each inertial confinement fusion reactor annually. And any type of nuclear plant must allocate funding for end-of-life decommissioning as well as the periodic disposal of radioactive wastes.”
“It is inconceivable that the total operating costs of a fusion reactor would be less than that of a fission reactor, and therefore the capital cost of a viable fusion reactor must be close to zero (or heavily subsidized) in places where the operating costs alone of fission reactors are not competitive with the cost of electricity produced by non-nuclear power, and have resulted in the shutdown of nuclear power plants,” said Jassby.
“To sum up, fusion reactors face some unique problems: a lack of a natural fuel supply (tritium), and large and irreducible electrical energy drains….These impediments—together with the colossal capital outlay and several additional disadvantages shared with fission reactors—will make fusion reactors more demanding to construct and operate, or reach economic practicality, than any other type of electrical energy generator.”
“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,” declared Jassby.
Earlier this year, raising the issue of a shortage of tritium fuel for fusion reactors, Science, a publication of the American Association for the Advancement of Science, ran an article headed: “OUT OF GAS, A shortage of tritium fuel may leave fusion energy with an empty tank.” This piece, in June, cited the high cost of “rare radioactive isotope tritium…At $30,000 per gram, it’s almost as precious as a diamond, but for fusion researchers the price is worth paying. When tritium is combined at high temperatures with its sibling deuterium, the two gases can burn like the Sun.”
Then there’s regulation of fusion reactors. An article last year in MIT Science Policy Review noted: “Fusion energy has long been touted as an energy source capable of producing large amounts of clean energy…Despite this promise, fusion energy has not come to fruition after six decades of research and development due to continuing scientific and technical challenges. Significant private investment in commercial fusion start-ups signals a renewed interest in the prospects of near-term development of fusion technology. Successfully development of fusion energy, however, will require an appropriate regulatory framework to ensure public safety and economic viability.”
“Risk-informed regulations incorporate risk information from probabilistic safety analyses to ensure that regulation are appropriate for the actual risk of an activity,” said the article. “Despite the benefits of adopting a risk-informed framework for a mature fission industry, use of risk-informed regulations for the licensing of first-generation commercial fusion technology could be detrimental to the goal of economic near-term deployment of fusion. Commercial fusion technology has an insufficient operational and regulatory experience base to support the rapid and effective use of risk-informed regulations.”
Despite the widespread cheerleading by media about last week’s fusion announcement, there were some measured comments in media. Arianna Skibell of Politico wrote a piece headed “Here’s a reality check for nuclear fusion.” She said “there are daunting scientific and engineering hurdles to developing this discovery into machinery that can affordably turn a fusion reaction into electricity for the grid. That puts fusion squarely in the category of ‘maybe one day.’”
“Here are some reasons for tempering expectations that this breakthrough will yield any quick progress in addressing the climate emergency,” said Skibell. “First and foremost, as climate scientists have warned, the world does not have decades to wait until the technology is potentially viable to zero out greenhouse gas emissions.” She quoted University of Pennsylvania climate scientist Michael Mann commenting: “I’d be more excited about an announcement that U.S. is ending fossil fuel subsidies.”
Henry Fountain in his New York Times online column “Climate Forward,” wrote how “the world needs to sharply cut [carbon] emissions soon…So even if fusion power plants become a reality, it likely would not happen in time to help stave off the near-term worsening effects of climate change. It’s far better, many climate scientists and policymakers say, to focus on currently available renewable energy technologies like solar and wind power to help reach these emissions targets.”
“So if fusion isn’t a quick climate fix, could it be a more long-term solution to the world’s energy needs?” he went on. “Perhaps, but cost may be an issue. The National Ignition Facility at Livermore, where the experiment was conducted, was built for $3.5 billion.”
The Lawrence Livermore National Laboratory has a long history with fusion. It is where, under nuclear physicist Edward Teller, who became its director, the hydrogen bomb was developed. Indeed, he has long been described as “the father of the hydrogen bomb.” The hydrogen bomb utilizes fusion while the atomic bomb, which Teller earlier worked on at Los Alamos National Laboratory, utilizes fission. The development of atomic bombs at Los Alamos led to a nuclear offshoot: nuclear power plants utilizing fission.
