Early atomic bombs like the ones used at Hiroshima and Nagasaki were based on nuclear fission – the splitting of heavy radioactive atoms like plutonium and uranium. A few years later in the 1950s, these “atomic” bombs were used as the trigger for even more powerful “hydrogen” or “thermonuclear” bombs that release energy from “fusing” two or more light atoms like hydrogen together into one slightly heavier atom like helium.
Nuclear fusion is the same source of power that is used by our Sun and all stars. If we could ever figure out how to release nuclear fusion energy slowly in a reactor of some sort, instead of all at once in a nuclear explosion, then humanity would have an effectively endless supply of energy. All the technological countries of the world have spent the past 50 years building ever-more complicated (and gigantic) reactors to generate usable levels of fusion energy, a goal which always seems to remain just out of reach. If they ever succeed, humanity is set for energy. After we ran out of deuterium fusion fuel in the Earth’s oceans after a few million years (one out of every few thousand molecules of water contains a special type of hydrogen atom that’s a great fusion fuel), then we might finally have some reason to move on to harvesting Helium-3 from lunar soil…
On the other hand, making a “small” fusion reactor about the size of an internal combustion engine in a car for “local” use has remained in the realm of crackpot inventors. A legendary pair of these in the saga for tabletop fusion would be Fleischmann and Pons (F&P), who claimed in the late 1980s to have discovered ” cold fusion” that worked by sticking a special palladium electrode in deuterium-rich (“heavy”) water. F&P’s cold fusion work has been mostly discredited and ignored, although a few lone (and lonely) inventors continue in their footsteps.
Perhaps the “secret sauce” to achieve desktop fusion is not palladium electrodes but do-it-yourself sonoluminescence. In this process, a bubble of gas is made to “hover” in a beaker of fluid while concentrated sound waves are focused on the bubble. The sound literally causes the bubble to “dance“, making it expand and contract its diameter very rapidly – and for unknown, incredible reasons, to generate flashes of light in the process. Explaining the source of this light is a mystery that scientists still debate. Everybody agrees that the “compression” stage of the bubble causes the gas inside to heat up and produce the glow – but just how hot CAN it get in there? The jury is still out on THAT question.
However, nuclear engineer Rusi Taleyarkhan thinks the inside of a sonoluminescent bubble can get hot enough to generate spontaneous fusion. In 2002 he claimed to have measured just that in experiments performed at Oak Ridge National Laboratory in Tennessee. Others felt his measurements of telltale resulting neutrons and tritium gas were suspect. Taleyarkhan seemed poised to join Fleischmann and Pons as footnote names in science.
Now Taleyarkhan is back. A series of new experiments jointly announced by Rensselaer Polytechnic Institute and Purdue University (where Taleyarkhan is now) apparently show much more convincing levels of neutrons and tritium coming from sonoluminescent bubbles. The details are set to be published in Physical Review E. Will Taleyarkhan’s latest paper be jeered – or take its place as a classic paper in the history of science? Stay tuned.
Fusion will also potentially create as much energy from a gallon of sea water, as compared to 300 gallons of a regular grade fuel.
Isn’t that wild?
Also, something referred to as the Z-machine, which helps create the conditions that cause fusion, resides not far away here in nm. What I would really like to know, is what might happen if the process went awry and the machine could not for some reason contain the reactions?
-cal
Around 1991 the Joint European Torus ran tests which produced 10% as much output energy, in the form of neutrons, as was input in the form of electricity.
Not sufficient, if your goal was to produce several times of the input energy. But I thought “Holy cow, a 10% efficient neutron generator!” Neutrons can be used to promote uranium-238 to fissile plutonium-239. I had a fantasy of – don’t laugh – an orbiting solar-electric station running a fusion torus to produce fission fuel for spaceships.
Quite the Rube Goldberg contraption. Its only advantages over the classic neutron source – a breeder reactor – were that it would not flirt with fission criticality the way a breeder does, and it wouldn’t entail such a mass of fission product radioisotopes.
Well. It looks like we may not need the torus to enrich uranium. Which would mean that our country, or extremist network, would only require sonofusion expertise, some natural uranium, and nuclear weapons skills in order to create a bomb. Heck, if we’re really keen, the sonofusion process makes tritium too – we could try for thermonuclear!
I’m not about to panic; we’ll have to wait and see if sonofusion is confirmed, and whether it scales up practically. But if it were to hit the jackpot, we’d have some serious proliferation issues, along with a new avenue in nuclear power generation … and the solar system would be in our hands.
Rejoice beware!