Friday, June 15, 2007

CAD Drafting Programs

Over at the IEC Fusion Newsgroup and also at the NASA Space Flight Forum I'm looking into the design of a test reactor with the following specifications.

Do we have enough expertise here to design WB-7x ?

Here is my general specification: LN2 cooled truncated cube coil configuration. Minimum size feasible for coil of reasonable dimensions and cost. 60 KV driver supply 10A, 100 V ripple maximum (10V much better). Capable of moderate levels of modulation (+/- 2 to 5 KV at 10 KHz) Vacuum pumps capable of 12 hr draw down or better. Vacuum chamber custom designed for coils and insulators. Updated 23 June 007: 75 KV driver capable of 25 Amps. Alternatives: (provision needs to be made in the lab to install bigger power supplies if a smaller one is chosen) 40 KV at 13 Amps. 20 KV at 7 amps.

My ideal would be a D-D Polywell - LN2 cooled magnets - well radiation shielded and instrumented - laser diagnostics - run continuously in an automated data collection mode for runs of at least a few minutes and preferably an hour at a time. HV power supply of 75KV so low levels of p-B11 fusion can be done. There is a p-B11 resonance that needs to be explored that is in that region. If the power density was sufficient in that region it could be a big advantage Bremms wise. The fusion cross section peaks at .1 barns there.

An electrostatically or piezoelectrically operated gas injection valve must be designed. B11 injection needs to be figured out. Decaborane might be the answer from a safety perspective. It boils at 213 C. Electrically heat a container of it to maintain a certain gas pressure and then valve it. Or perhaps a boron block heated by an electron beam or laser.

From the wiki on Decaborane:

In aneutronic fusion research, decaborane is used to boronize the tokamak plasma to research the proton-11Boron reactions.

All very interesting. However, what I want to do is suggest a CAD drafting program for use in the above project. First off the price must be zero for a 2D version. Upgrades to a full 3D engineering version must be reasonable. The 2 D version must not be in any way crippled. It must be easy to learn.

I have settled on Solid Edge Free 2D drafting package for now. I'm going to test it and see if there are any problems. If so I will report back. If not I will report that. Expect news in a day or less.

Any comments or suggestions would be appreciated.

Solid Edge Testimonial


NobobyExpects said...

What will be the B field strength?

I have installed Solid Edge 2D drafting, built a nice parametrized hexahedral magrid model, and done some quick and dirty calculations considering solid copper coils at 80 K.

For the conditions of WB-6, (0.13T) I found the LN2 requirements to be about 82 kg/s.

I could send you the spreadsheet I used and the dft file.

NobobyExpects said...

Sorry, I forgot. Those thermo calculations don't take in account the heat produced by the impingement of the fusion products in the coils.

NobobyExpects said...

As a collateral, I found that with 500 turns per coil (an arbitrary number), the power supply has to provide about 52A @ 10V, so the supply alternatives are:

All the coils in series:
52A @ 60V
All the coils in parallel:
312A @ 10V
3 branches in parallel of 2 coils in series:
156A @ 20V
2 branches in parallel of 3 coils in series:
104A @ 30V

Seems preferable to connect all the coils in series.

M. Simon said...


I hadn't run the numbers (thanks!), but I was thinking electrically in series and in parallel for LN2 flows.

So I think we are in agreement.

An 800 W power supply (to give some margin) is not very big. Even 8KW for 10X the field is not bad. If it turns out to be 80KW actual I could live with that.