FICS Fusion Live Stream on Youtube

[Sesselmann]

Hi Guys,

I did a 45 minute livestream on Youtube today. The objective was to test my new reactor design live for some other enthusiasts.

It didn't quite work out as planned, but some of you you may find it interesting anyway.

Warning: There are some rather slow passages where I struggled with the streaming software, so just fast forward where it gets too boring.

https://youtu.be/-Hmz3rdMVk8

Steven

[Rob Tayloe]

Perhaps you have discussed this elsewhere, but have you estimated your dose effective exposure (in Sv or Rem) from the fast neutrons? The lead will not stop the neutrons and you only have distance to reduce your dose. I was a bit surprised that you did not have some significant neutron shielding (e.g., borated poly, water, concrete, etc.) between the fusion reactor and yourself.

[Sesselmann]

Rob,

Thanks for your concern, the fast neutron exposure during short runs at a distance of 4-5 meters from the reactor is negligable at this stage.

We can work it out (4 x (pi) * 400^2) = 2,010,619 cm^2, so if the reactor was generating a very respectable 2 x 10^6 n/s isotropic the neutron flux would be about 1 neutron/sec.
To put this in perspective it takes a total of 28,000 n/cm^2 to give an exposure of 1 milliRem (equivalent to an uninterrupted 8 hour run).

If and when I get the reactor working reliably above 10^6 n/s I will certainly start adding some borated shielding and more lead as well, because neutrons cause all kinds of unwanted x-rays and gamma rays.

I actually made an online calculator many years ago and it is frequently used by many in the fusion research business.
https://www.gammaspectacular.com/fusion_calculator.html

Safety is always my #1 priority, which is why I have spent a lot of time on the Faraday cage and remote control components.

Steven

[Rob Tayloe]

Good to see that you are well aware of the potential hazards from the fast neutrons. When I had access to the Ohio State Univ. research reactor I found it interesting to activate different materials (generally I used metals or oxides in small quantities) to create sources for student labs. One of our labs was gamma spectroscopy. If you are producing adequate neutrons you could similarly activate stuff and obtain interesting sources. You might need something to thermalize the fast neutrons to obtain better activation.

For example tellurium can be used to produce I-131 which yields an interesting gamma spectrum. Below are links to an on-line calculator for neutron activation and an I-131 spectrum that I measured using the LaBr detector that you made for me.

http://www.wise-uranium.org/rnac.html
https://en.wikipedia.org/wiki/Iodine-131

[Sesselmann]

Rob,

So far my fusion effort has focused on making a better reactor, and so far I haven't had anything working steady enough to do any neutron activation experiments.
I have friends with regular Farnsworth fusors who have built neutron ovens and are doing cool activation experiments.

Neutron activation experiments are on my list of things to do, but first I have to get get the machine to output a steady, hands off 10^6 n/s , easier said than done 😝

Steven