Z-Machine at Sandia Labs Aims for More Power

Vexar writes "Memorable for its Back-to-the-Future room of electric arcs in 1998, Sandia Labs' Z-Machine is getting $61.7 Million in new funding. In addition to more physics textbook-worthy photos, the scientists at this lab intend to hit the all-important, fusion-ready 2.0 million degrees C."

Comments

Re:Weapons research

[merlin_jim]

Amazing research, though when they talk about reaching fusion temperatures, it looks to me like they're talking about modeling the fusion reaction of a Hydrogen Bomb, not creating a safe, clean power source.

They recognize as a side effect that they are refining plasma physics models and if you look at their experimental logs (troll around on their site a little and you'll see it), you can find experiments being run that are definitely designed to measure the physics of fusion temperature plasmas, with the stated goal of developing control algorithms for tokamaks.

ok now onto the <rant type=biased>

Tokamaks are fundamentally stupid ideas for two reasons. First off, ALL of the designs that are currently being discussed for funding and prototyping suffer transmutation of structural members. It takes a huge energy cost to get a tokamak started, and the designs that're being discussed undergo transmutation due to neutron and proton bombardment. Structural elements that are vital to the safe operating of the reactor will have to be replaced on a regular (6-18mo) basis to prevent a failure mode.

Which brings us to the second reason. You've got a big ring of extremely high-temperature, high-pressure, high-charge fluid material. Due to that charge, that ring is going to be fundamentally unstable. They're talking about controlling that with dynamic feedback electromagnet rings. The problem being that there's a stability jumping problem. And at the energies involved, quantum effects are very nearly on the scale necessary to jump to different stability modes.

Of course all the alternative stability modes result in the plasma stream contacting the reactor wall. Which will result in burn-through. I don't think the behaviour will be bomb-like (unlike a fission reactor, this failure mode is self-quenching), but it's still a catastrophic failure mode and probably will spread radioactive material all over the place. Think chernobyl-style quarantine without the explosion at the beginning.

Combine the two and I think you'll see why I say that a tokamak is a fundamentally stupid idea.
</rant>