You may be thinking about He-3. It is extracted during maintenance from tritium in nuclear bombs (tritium is a neutron source but He-3 a most efficient neutron absorber). I think now there is also a spallation plant at Oak Ridge. Yearly production is a few kilograms. Interesting stuff.
It does, but only in rather small quantities. In fact it seems that most He-3 that's used is produced in Tritium decay reactions rather than extracted.
> According to a 1996 report from Institute for Energy and Environmental Research on the US Department of Energy, only 225 kg (496 lb) of tritium had been produced in the United States from 1955 to 1996.[a] Since it continually decays into helium-3, the total amount remaining was about 75 kg (165 lb) at the time of the report.
FWIU most synthesized tritium is from TPBAR rods (and also separated from drained reactor fluid); so it is possible, there just aren't many research institutions or indeed any production operations that do isotope separation from water?
FWIU evaporation doesn't work because Tritium/He3 crawls up the walls of the container it was in, because gravity.
Presumably nuclear research scientists have already considered centrifugation, titration, pressure / heat / boiling and other phase state transitions, Laser Nuclear Transmutation (*), reuse in a reactor with TPBAR rods designed to collect Tritium for later processing, and as fuel for peaceful civilian e.g. a D-T + (He3, He4) nuclear fusion electricity generation.
Fusion that takes heavy water as an input e.g. at a first stage facility that processes radioactive material and yields nonradioactives for a 'second stage' (?) facility would be great.
FWIU, that is what Helion does; though there aren't yet separate stages.
Do old casks of heavy water (dangerous nuclear waste from an old-gen nuclear reactor) contain significant amounts of recoverable Helium-3 due to the 12.3 year typical (*) half-life of Tritium?
Again, Helium-3 is a viable nonradioactive input to nuclear fusion reactions.
Production of He-3 is actually a major concern in the nuclear industry. It's pretty much the best medium to make a neutron detector out of because it has an enormous probability to capture a neutron. Neutron detectors are rather important for many reasons, but mostly because they're the best way to detect nuclear weapons.
He-3 is rather rare naturally and was only really produced in quantity as a byproduct of nuclear weapons fabrication. Basically nobody is making nuclear weapons these days (at least in significant quantities) and there's not really any viable source of He-3. Alternative detector media like BF3 is crappy by comparison and the only other way to make He-3 en masse is via fusion, which isn't yet feasible.
So nowadays a tube full of He-3 about the size of a typical fluorescent light can run into the $100000 range (ish, it's so rare that it isn't really sold by anybody).
Yes, by absorbing neutrons. It’s a good use for the neutrons, but neutrons (and any source of them) are both a hazard in themselves and a proliferation risk.
Here a nice thing of nuclear warhead maintenance/decommisioning of nuclear warhead. The article discuss mostly about the plutonium cores, but modern weapons uses triutium to boost the yield, see https://en.m.wikipedia.org/wiki/Boosted_fission_weapon. Tritium is faintly radioactive, and it decays over time in the stable helium-3. This is a quite rare isotope of helium, in comparison to the much abundant He4. He3 is much needed in dilition refrigerators, the big machines often seen in advestisment of quantum computer. So such activities on nuclear weapons are the source of a critical and scarce ingredient for quantum computing!
This seems a little crazy given that if you can do He3 fusion, you can also do D-D fusion, which makes He3 (half the time directly, otherwise it makes tritium which decays to He3). Fusion startup Helion is aiming to do it that way, saying only 6% of the energy would be released as neutron radiation.
Also of course, plain old fission reactors can produce He3, probably much more cheaply than attempting to harvest it from the moon.
Well, actually, a nice source of a large number of neutrons is a HUGE proliferation thread: weaponizable Pu-239 is produced out of easily-available U-238 by neutron capture. Only generation 2 (or 3) fusion, when we move past deuterium, will be proliferation-safe.
It's somewhat generous to call it a He3 generator though, since the half life of tritium is 12 years, you'd need to make sure you made most of the He3 you need over a decade in advance.
He3 has uses besides as a fusion fuel though, so maybe they can overshoot their estimated consumption rate by an order of magnitude and sell or stockpile the surplus 10 years later?
Extracting tritium between pulses seems to be the key approach to reducing degradation. One of the company's patents [1] explains:
"The D-3He fusion reaction produces no neutrons as well (D+3He?4He (3.6 MeV)+H (14.7 MeV). However the D-D side reaction, while not as frequent, can generate 14.1 MeV neutrons through one of its fusion product reactions (D+T?4He+n+14.1 MeV). There is also the D-D reaction itself that produces a lower energy neutron (2.45 MeV) which is below the threshold for activation of most nuclear materials and is thus far less detrimental...Example systems and methods described herein may employ a 3He fuel cycle which may reduce or suppress a dangerous D-T side reaction by extracting the tritium ions as they are created. The extracted tritium is unstable and may beta decay in a relatively short period of 11 years to 3He, a primary fuel for the D-3He reaction. Accordingly, example systems, reactors and methods described herein may enjoy a self-sustaining fuel cycle where the required 3He to operate the reactor may be generated by the decay of tritium ions extracted from the reactor itself..."
The FAQ on the website [2] acknowledges their process "does create some 'activated materials' over the operating life of a power plant. Helion’s plants have been specifically designed to only use materials that would result in low activation, similar to what might be created by medical devices or other particle accelerators.
Our expectation is that a Helion plant could be fully decommissioned within a week without any lasting environmental impact."
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