Guest essay by Eric Worrall
The last few weeks has seen a crescendo of nuclear fusion clean energy hype, as proponents pitch for a share of Biden’s promised climate cash giveaway. But practical nuclear fusion, if it is even possible, is still many decades away.
Fusion reactors: Not what they’re cracked up to be
By Daniel Jassby | April 19, 2017
Daniel Jassby was a principal research physicist at the Princeton Plasma Physics Lab until 1999. For 25 years he worked in areas of plasma physics and neutron production related to fusion energy research and development. He holds a PhD in astrophysical sciences from Princeton University.
Fusion reactors have long been touted as the “perfect” energy source. Proponents claim that when useful commercial fusion reactors are developed, they would produce vast amounts of energy with little radioactive waste, forming little or no plutonium byproducts that could be used for nuclear weapons. These pro-fusion advocates also say that fusion reactors would be incapable of generating the dangerous runaway chain reactions that lead to a meltdown—all drawbacks to the current fission schemes in nuclear power plants.
As we move closer to our goal, however, 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 in solar fusion—which uses ordinary hydrogen—Earth-bound fusion reactors that burn neutron-rich isotopes have byproducts that are anything but harmless: Energetic neutron streams comprise 80 percent of the fusion energy output of deuterium-tritium reactions and 35 percent of deuterium-deuterium reactions.
Now, an energy source consisting of 80 percent energetic neutron streams may be the perfect neutron source, but it’s truly bizarre that it would ever be hailed as the ideal electrical energy source. In fact, these neutron streams lead directly to four regrettable problems with nuclear energy: 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.
In addition, if fusion reactors are indeed feasible—as assumed here—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.
…Read more: https://thebulletin.org/2017/04/fusion-reactors-not-what-theyre-cracked-up-to-be/
I love the idea of nuclear fusion. But Tritium fusion is anything but clean and economically viable – in its current form it releases far more neutron radiation than fission, an intense blizzard of atom smashing radiation which within months of starting operation would cause massive structural damage and severe secondary radioactivity in the physical components surrounding the fusion core.
There are fusion processes which are cleaner than Tritium, but these processes require even more extreme conditions than Tritium fusion, or exotic ingredients like Helium 3, the nearest abundant source of which is the surface of the moon.
Nuclear fusion’s day will come; one day fusion reactors will power our civilisation and open the way to colonising other star systems. But I doubt any of us will live to see it.