The Glade 4.0

That said, liquid hydrogen will get you down to around 20k, which should be enough for even the current magnets, I would think. Not positive, though. You might lose some resolution with the rise, but it's not like the technology will no longer work, it will just have to be tweaked.

I love that you use "exothermic reaction," "the process that fuels stars," and "almost no danger of a runaway reaction" in the same sentence, TheRiov.

The very nature of its being an exothermic reaction that will self-sustain means that there is a danger of a runaway reaction. Otherwise, you know, the stars would stop on their own before running out of fuel, and it wouldn't be an exothermic reaction.

The problem has very little to do with the fidelity of the image. You may have a mistaken impression of how an MRI works.

? ok. I'll bite.

In a theoretical fusion reactor?

I love that you use "exothermic reaction," "the process that fuels stars," and "almost no danger of a runaway reaction" in the same sentence, TheRiov.

The very nature of its being an exothermic reaction that will self-sustain means that there is a danger of a runaway reaction. Otherwise, you know, the stars would stop on their own before running out of fuel, and it wouldn't be an exothermic reaction.

Accident potential

There is no possibility of a catastrophic accident in a fusion reactor resulting in major release of radioactivity to the environment or injury to non-staff, unlike modern fission reactors. The primary reason is that nuclear fusion requires precisely controlled temperature, pressure, and magnetic field parameters to generate net energy. If the reactor were damaged, these parameters would be disrupted and the heat generation in the reactor would rapidly cease. In contrast, the fission products in a fission reactor continue to generate heat through beta-decay for several hours or even days after reactor shut-down, meaning that melting of fuel rods is possible even after the reactor has been stopped due to continued accumulation of heat.

There is also no risk of a runaway reaction in a fusion reactor, since the plasma is normally burnt at optimal conditions, and any significant change will render it unable to produce excess heat. In fusion reactors the reaction process is so delicate that this level of safety is inherent; no elaborate failsafe mechanism is required. Although the plasma in a fusion power plant will have a volume of 1000 cubic meters or more, the density of the plasma is extremely low, and the total amount of fusion fuel in the vessel is very small, typically a few grams. If the fuel supply is closed, the reaction stops within seconds. In comparison, a fission reactor is typically loaded with enough fuel for one or several years, and no additional fuel is necessary to keep the reaction going.

In the magnetic approach, strong fields are developed in coils that are held in place mechanically by the reactor structure. Failure of this structure could release this tension and allow the magnet to "explode" outward. The severity of this event would be similar to any other industrial accident or an MRI machine quench/explosion, and could be effectively stopped with a containment building similar to those used in existing (fission) nuclear generators. The laser-driven inertial approach is generally lower-stress. Although failure of the reaction chamber is possible, simply stopping fuel delivery would prevent any sort of catastrophic failure.

Most reactor designs rely on the use of liquid lithium as both a coolant and a method for converting stray neutrons from the reaction into tritium, which is fed back into the reactor as fuel. Lithium is highly flammable, and in the case of a fire it is possible that the lithium stored on-site could be burned up and escape. In this case the tritium contents of the lithium would be released into the atmosphere, posing a radiation risk. However, calculations suggest that the total amount of tritium and other radioactive gases in a typical power plant would be so small, about 1 kg, that they would have diluted to legally acceptable limits by the time they blew as far as the plant's perimeter fence.[12]

The likelihood of small industrial accidents including the local release of radioactivity and injury to staff cannot be estimated yet. These would include accidental releases of lithium, tritium, or mis-handling of decommissioned radioactive components of the reactor itself.

I've taken apart and rebuilt NMRs, I'm quite familiar with how they work.

I can see where you were coming from, but you're assuming the need for a particular magnetic field strength necessary for the instrument to function- in fact, you can have much weaker magnetic fields than are currently used, you just get a lower resolution. So in my point, is that with temperature dependent superconductors, you lose some conductivity in the rise from 4 K to 20 K, which assuming the same input of power, will lower your magnetic field strength and thus your resolution.

In comic strips the person on the left always speaks first. - George Carlin

Lots of people on this board take apart and rebuild computers. Maybe three actually understand how they work, and that estimate is rounded up.