Search found 144 matches

by rnebel
Mon Sep 22, 2008 5:50 pm
Forum: News
Topic: ITER Costs Double
Replies: 34
Views: 10672

Jmc: I should have clarified this, but my comments apply to the US market and structure. I am in favor of nuclear fission power and back in the 70s I used to do a fair amount of nuclear advocacy. Although most of what the anti-nuclear people said was fear mongering, the local group we had was actual...
by rnebel
Sun Sep 21, 2008 6:40 pm
Forum: News
Topic: ITER Costs Double
Replies: 34
Views: 10672

Classicpenny: Back in the 1970s “nuclear optimists” predicted that nuclear power would comprise 20% of the US electrical market by 2000. Guess what. That happened. How can that be even if a lot of plants were cancelled and no new plants have been ordered since the 70s? The answer is that the project...
by rnebel
Mon Sep 15, 2008 11:02 pm
Forum: General
Topic: Focus Fusion
Replies: 7
Views: 3132

The Plasma Focus has been around for a long time. The usual criticism is that the fusion comes from instabilities (much like happened in Zeta in the 50s) and it won't scale. However, these machines can produce a lot of neutrons and I don't know what the new wrinkle is that is being proposed here.
by rnebel
Thu Sep 11, 2008 8:29 pm
Forum: News
Topic: TOKAMAK Instabilities
Replies: 25
Views: 10254

2. Mass power density has to do with the mass of the structure, not the fuel. The cost of electricity is based on how much stuff it takes to produce a given amount of power. There are two primary drivers for the COE: the mass power density and recirculated power fraction. My point is that if ITER-li...
by rnebel
Tue Sep 09, 2008 11:05 pm
Forum: Fund-Raising
Topic: T. Boone Pickens
Replies: 31
Views: 19888

I've had some contact with Mr. Pickens in the past. In the mid 80s, Phillips Petroleum was making some investments in fusion. Mr. Pickens, who is a corporate raider, decided that they had two much cash on hand and that their assets were larger than their stock price. Consequently, he tried to make a...
by rnebel
Tue Sep 09, 2008 12:07 am
Forum: News
Topic: TOKAMAK Instabilities
Replies: 25
Views: 10254

Josh: I've heard those statements and I'm not convinced. I asked Najmabadi (who heads the ARES conceptual design program) how well they could do on mass power density with their most advanced designs, and the answer I gotwas a factor of 10 worse than an LWR. Put a picture of an LWR power core (to sc...
by rnebel
Mon Sep 08, 2008 11:32 pm
Forum: News
Topic: TOKAMAK Instabilities
Replies: 25
Views: 10254

I have three questions for JMC: 1. If the mass power density of ITER is several hundred times worse than it is for a light water reactor power core (which it is), how do you expect to compete with them? Or with any other power source? 2. If all magnetic confinement D-T systems have inherently poor m...
by rnebel
Fri Sep 05, 2008 9:58 pm
Forum: Design
Topic: Muons
Replies: 19
Views: 8224

Muon fusion was tried experimentally at Los Alamos in the 1980s. The targets weren't plasmas, but rather were cryogenic. The problem was that a muon couldn't induce enough fusions to make up for the energy required to make the muon (Q<1). I believe the person who ran the experiments was Steve Jones,...
by rnebel
Thu Sep 04, 2008 6:35 pm
Forum: Theory
Topic: The question of scaling
Replies: 42
Views: 12767

I wouldn't recommend doing a lot of modelling of the arcing right now. We've been looking at it, and it's complicated. It's not just a Paschen breakdown to the chamber wall. However, rather than sticking my foot in my mouth (by saying something that's not correct) let me say that we don't understand...
by rnebel
Thu Sep 04, 2008 12:51 am
Forum: Theory
Topic: The question of scaling
Replies: 42
Views: 12767

Art: Lower Hybrid drift modes have been reported in earlier cusp experiments (Dolan's paper has some references), but they haven't been looked for in Polywells. I think the earlier machines were line cusp devices. Krall has stated that it is consistent with the observed "Magrid" scaling, b...
by rnebel
Wed Sep 03, 2008 4:35 pm
Forum: Theory
Topic: The question of scaling
Replies: 42
Views: 12767

Hanelp: The collisionless limit is actually where turbulence is the most likely to dominate. In fluids, for instance, viscosity is what damps turbulence. The drivers are anything nonlinear. In fluids, that's usually convection. In plasmas, there are many nonlinearities. Any nonlinearity will cascade...
by rnebel
Tue Sep 02, 2008 9:56 pm
Forum: Theory
Topic: The question of scaling
Replies: 42
Views: 12767

Aero and TallDave: My comments were primarily to give you an idea of the nature of the beast. The problem is that in order to experimentally study scaling you need to vary one parameter at a time. That is virtually impossible to do in a plasma. Secondly, all of the profiles have to be self-similar. ...
by rnebel
Tue Sep 02, 2008 5:41 pm
Forum: Theory
Topic: The question of scaling
Replies: 42
Views: 12767

Art: I have two favorite papers on Tokamak scaling. The first was by Taylor and Conner where they showed that all of the empirical tokamak scaling laws were inconsistent with any known plasma physics model. The second was a paper by Wayne Houlberg where he put the empirical tokamak scaling laws into...
by rnebel
Fri Aug 29, 2008 4:49 pm
Forum: Theory
Topic: The question of scaling
Replies: 42
Views: 12767

Art's right on this. The output power scaling for the Polywell is essentially the same scaling as for any magnetic confinement machine. The real physics issue is the input power required to keep the Beta constant. This has to balance the losses. In other words, the issue is how good the confinement ...
by rnebel
Fri Aug 29, 2008 4:37 pm
Forum: News
Topic: TOKAMAK Instabilities
Replies: 25
Views: 10254

Simon: I wouldn't put a lot of stock in this. The codes that Garabedian is using are inadequate, too. Among other things, they don't have plasma flow. I don't think that the ITER equilibria are a huge extrapolation from the equilibria in either JET or C-Mod. Those machines work pretty well, so I sus...

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