Fusion Message Board

In this space, visitors are invited to post any comments, questions, or skeptical observations about Philo T. Farnsworth's contributions to the field of Nuclear Fusion research.

Subject: Re: Secondary Neutrons
Date: May 26, 4:38 pm
Poster: Richard Hull

On May 26, 4:38 pm, Richard Hull wrote:

>Now that we are making neutrons, what about using them to fission U238? Depleted uranium is fairly available (actually, almost free, in multi-ton (>40) lots, because there is a huge surplus). Using the n from the DD or DT reaction, you can hit a piece of U and generate 2 more n's, etc.


Nice idea, I have had this thought also about a year ago. I can have these thoughts as I am not afraid of the outcome if sucessful. Fusioneers are out for clean fusion only. To sully the beauty of the fusion process with a dirty, fission based, hybrid, hanger-on process is blasphemous. Farnsworth would has called us out into the alley for fisticuffs on this one!! Long term, and with big systems, we would be makin' more nuclear waste along with fissile material!!!! Sort of a fusion-fission breeder.

There are a few problems, which while not project killers are major engineering hurdles.

1. Even a rip roarin', hot fusor of 10e6 neuts/sec if surrounded with a U-238 blanket would not be have a big flux working the Uranium.

2. Placing the Uranium in the fusor near the focus would indeed give us the flux we need. There is a problem here in that the fusor is an ion/electron optical device and huddling unused junk in and around the inner grid is not allowed. This is why the simple introduction of a tiny langmuir probe into the system upsets it to the point that the data taken with it is skewed. A natural thought is to make the inner grid construction out of U-238 and that is the best of the lot. Here, it would be in an intense field of FAST neutrons

3. The really big problem is that the U-238 fission bit is best accomplished with THERMAL or SLOW neutrons. This puts us back, way outside of the fusor, on the other side of a big blanket of borated water or parafin, where the fulx is almost microscopic.

So, this idea kinda' looks grim with amateur fusor output levels. Nonetheless, it appears neato on the surface and shows we are thinkin'.

Richard Hull