Can someone explain to me how this guy: [url]http://en.wikipedia.org/wiki/David_Hahn[/url] built his own homemade nuclear reactor?
[editline]24th August 2014[/editline]
Apparently something called a Breeder reactor.
I posted this over on 4chan.org/sci/ but the only response I got was a shitposter, so I'm here bumping this thread for the discussion:
[quote]I don't know much about what /sci/ thinks of LFTR as I don't come here often. I personally think LFTR is greatly superior to conventional solid fuel reactors and think liquid fuel is the only financially viable way to build a breeder reactor. The design does currently have a few unknowns, but so does everything else before you've actually built a full-sized prototype and these are things that can be solved.
The core and moderator of the only molten salt reactor (MSR) built in the 60s was made from graphite. They took a massive tank of high purity long chain hydrocarbons (some sort of tar or bitumen as I understand it) and baked it in an oven at high temperatures. The hydrocarbons converted into graphite and hydrogen gas leaving a massive block of porous carbon.
Porosity wasn't desirable (don't want all those radioactive elements soaking into it, do we?) so they then vacuum impregnated the carbon block with more hydrocarbons and baked it again, repeating this process until it had a very low porosity. This block was then taken to be machined into the required shape and the fuel channels for the fuel to flow through were drilled.
At the time of the MSR Experiment, this was the single most difficult-to-make piece of nuclear graphite ever made and the reactor was only 7.4MW-thermal. In a commercial reactor you would need AT LEAST 500WM-thermal for a small 200-250MW-electrical reactor and 2000-2500MW-thermal for a 1GW-electrical reactor. This means when you start getting into commercial sized reactors you'll need to start manufacturing massive blocks of nuclear graphite that weigh several hundreds of tonnes and transport them to your reactor.
This isn't even the start though, neutron induced swelling of the graphite moderator will become a serious issue as your core gets larger. Depending on the unevenness of the swelling and core size this may become a very serious issue very fast, causing cracking of the core. Swelling against the reactor vessel would also be a problem though easier to solve from an engineering perspective.
Now, given the difficulties in manufacturing single-piece two-hundred tonne blocks of nuclear graphite, it would be reasonable to think they might make these cores in parts and piece them together. Large flat plates for example could be stacked to form the core, or the cylinder that makes up the core could be sectioned into quarters. None of these however are particularly good solutions to the swelling issue; presumably the pieces would be bolted together or stacked on top of each other meaning very large surfaces rubbing against each other as the parts swelled.
This of course could be overcome, but in my mind there is a much more simple solution; a pebble-basket core. The design would be similar to the pebble-bed reactor design in which piles of graphite spheres with small bits of fuel in them were stacked to make reactors, only in this design they would just be graphite spheres with no fuel in them.
The reactor vessel would be filled with these graphite spheres stacked in either and FCC or HCP lattice to make up the core. When activated, the spaces around the spheres would allow to fuel to flow while the very small contact areas would reduce rubbing. The spheres themselves could be anything from marble to basket-ball sized and their small size would encourage even swelling of each sphere reducing cracking. To further reduce the risk of cracking they could even be encased in thin metal shells of a suitable metal.
On top of that, the spheres would be fucking cheap to manufacture and easy to transport.
Sound reasonable, /sci/? Did I miss any obvious flaws in this?[/quote]
So, anyone see any flaws in the idea?
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