Sandia’s Z Machine Could Mean Fusion in 20 Years
It's kind of a running joke that practical fusion power is always 20-30 years away, but this recent advancement with "Linear Transformer Driver technology" on Sandia's Z Machine causes some to make the 20 year claim once again:
April 26th, 02007 at 1:04 pm
Q: How many nuclear engineers does it take to change a light bulb?
A: 50: one to change the bulb, and 49 to figure out how to safely dispose of the old one.
I was once a nuclear engineering major all set to go into grad school and fusion research, but it quickly became clear that the bulk of fusion research in our country - and perhaps the world - is being used "to gather data to aid in computer modeling of nuclear weapons", as the Wikipedia article states.
While I do believe we will one day have fusion power - within the next hundred years, assuming peak oil, global warming, and the shift in global dominance to China don't distract us - I think we have some serious problems to overcome before then, mostly dealing with reactor materials and fuel confinement. Tritium, in addition to being extremely radioactive, is also extremely hard to keep bottled up, and we still don't have a good solution to managing the waste.
However, I still think getting fusion power working is more important than manned missions to the moon or Mars.
April 26th, 02007 at 3:56 pm
Z-pinch is promising, the article does fail to dsicuss two difficult problems. 1st is how you time getting the pelletized fuel in exactly the correct position at exactly the correct moment, 2nd, how do you extract the energy in a useable way. I'm pretty sure tho, that in this system you use a deuterium-based pellet (D-D reaction), not deuterium-tritium(D-T). Deuterium-Tritium reaction is easier, but is most commonly associated with magnetically confined concepts rather than inertially confined systems like Z. Tritium isn't even that big of a problem, as it is water soluable so it doesn't build up in a biological system, and when it decays it's a low energy beta (maximum energy of 18.6 keV and an average of 5.7 keV) that you could shield with a piece of paper, or simply the top layer of dead skin everyone carries (and with a half life of 12yrs, it won't be around that long). The primary concern radioactivity wise is design of the reactor vessel with low activation materials to withstand neutron bombardment, otherwise it's pretty darn clean. Most designs use a lithium blanket to absorb the neutrons and breed more tritium fuel. It's a holy grail, and Z has gone farther on less than any of the other efforts (NIF).