There was great hoopla -- largely unquestioned by media -- over the just-announced claim 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.
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