For fusion energy enthusiasts, hope seems to spring eternal each spring, as the Congressional money machine begins to gear up. That evergreen story holds true again this year, as reported in Science magazine on Feb. 19.
The magazine article relied on a new report by the National Academies of Sciences, calling, no surprise here, for the U.S. to start constructing a fusion pilot plant by 2035 and have it running five years later. That means big funding from the U.S. Department of Energy, which provides the deep pockets for high-priced energy research.
The Science article said, “Enthusiasm has been growing among U.S. fusion researchers to build a prototype power plant that would finally harness nuclear fusion, the process that powers the sun, to generate electricity.” Fusion enthusiasts have been pushing for development of the technology since the early 1950s, with little to show except for empty wallets.
There are important skeptics. Bob Hirsch, an early researcher who developed the only working example of fusion, the tiny fusor, along with television pioneer Philo T. Farnsworth in the 1960s, and later led the fusion programs at the Atomic Energy Commission and the Energy Research and Development Administration, predecessors to the DOE, is one. Hirsch is an engineer and PhD nuclear physicist.
He told The Quad Report that the current approach to fusion, a deuterium (heavy hydrogen) and tritium (even heavier water) fuel cycle, the basis of most current research, including the massive, multi-billion-dollar 35-nation International Thermal Energy Project in France, and most other programs, has an inherent problem.
ITER and most other approaches to fusion rely on a reaction between deuterium and tritium, known as the D-T cycle. The conventional approach also relies on a magnetic confinement technology, developed by the Russians and known as a “tokomak” reactor, to contain the incredible high temperatures of a fusion reactor long enough to produce heat to make electricity. It has never worked, but ITER is founded on the concept that it can.
According to Hirsch, a stumbling block is the supply of tritium. Deuterium is common, occurs naturally. Tritium, on the other hand, “does not exist in nature and is produced primarily in nuclear reactors,” most today from the Canadian Candu reactor technology. Candu’s “heavy water” technology is far from the mainstream of modern light-water nuclear reactor technology. Hirsch said, “The assumption worldwide has been that there will be enough tritium to do whatever anyone wants, anytime.”
That assumption may be false. Hirsch sites the NAS report that was the basis of the Science article. The academy report says, “A D-T fusion reactor cannot function without a closed tritium fuel cycle, and this represents a fundamental feasibility issue for D-T fusion power production. Tritium provides a difficult species for control, accounting, and safety, yet it is critical to the fusion fuel cycle. In order for fusion to realize its maximum potential for safe operation and benign environmental impacts, high fidelity understanding of all processes involving tritium is required.”
Hirsch notes that the NAS report suggests “that if one is planning a fusion pilot plant based on D-T, it is imperative to line up the needed tritium supply in advance” or it might not be available. “That’s for a pilot plant. For a demo or commercial reactors, there will not be enough unless major R&D programs make tritium management more efficient.”
Hirsch also points to a June 2020 article published by the International Atomic Energy Agency, by a team led by Mohamed Abdou of the University of California Los Angeles. The article concludes, “The tritium aspects of the D-T fuel cycle embody some of the most challengimng feasibility and attractiveness issues in the development of fusion systems.”
Hirsch concludes, “In the extreme these reports imply that unless there is some kind of miracle, there will not be enough tritium for world D-T fusion plants unless more Candu reactors are built. Try to sell that to the environmentalists and the public.”
–Kennedy Maize