
DIY heavy water reactor - stenl
https://groups.google.com/forum/m/#!topic/can.general/cfAh7ldu3vk
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brandmeyer
I don't believe him.

1kg of uranium spread into 10x ingots, suspended in a pool of heavy water ...
I don't think this is sufficient to actually maintain criticality, even if he
had a startup neutron source. There isn't nearly enough mass. A commonly cited
figure for a CANDU reactor is ~8 kg, in a well-designed geometry, with a
properly designed reflector in addition to the moderator.

He used metallic uranium instead of uranium oxide. Therefore, I don't think he
had a sufficient neutron source to get the chain reaction started. For
example, modern power reactors rely on (alpha + oxygen -> neon + neutron)
reaction, with the alpha decay of the fuel as the alpha source.

"Should the reactor run away" Water-moderated reactors have a negative
temperature coefficient of reactivity. So if he actually achieved criticality
and generated enough power to produce heat, the reactor would be self-
regulating.

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madaxe_again
Ditto - there's quite a bit here that suggests it's a fabrication, as had
someone done this they'd want to talk about the gritty technical challenges
they overcame, not gloss over them.

That said, if you want to play nuclear physicist, there are plenty of fun home
projects. Farnsworth fusors can be built cheaply by a dedicated amateur, and
you can build your own particle accelerator (cyclotron or synchrotron, take
your pick) if the fancy takes you. Easier yet is making a cloud or bubble
chamber, and you can use all sorts as a particle source.

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outworlder
The bullshit-o-meter is off the scale on this one. So this individual left
centrifuges for two years separating heavy water, and went around the
countryside, geiger counter on hand, picking up uranium ore?

And then, after the experiment was done, he just filled the room (which had to
be built by himself, no contractors here) with concrete, casually picked up
with a truck and dumped far offshore?

That's something you would do in Minecraft, not real life.

~~~
dalke
Regarding heavy water separation, the BS article says:

> All the water in the world contains light water H20, heavy water D20 and
> very heavy water T20. ... The thing we need to know is that in every 5
> liters of tap water there is 1 cc (cubic centimeter) of heavy water. Now
> heavy water is 17% heavier that light water. ..

That leaves out HDO, or semi-heavy water. Quoting now from
[https://en.wikipedia.org/wiki/Heavy_water#Semiheavy_water](https://en.wikipedia.org/wiki/Heavy_water#Semiheavy_water):

> In normal water, about 1 molecule in 3,200 is HDO (one hydrogen in 6,400 is
> in the form of D), and heavy water molecules (D2O) only occur in a
> proportion of about 1 molecule in 41 million (i.e. one in 6,4002). Thus
> semiheavy water molecules are far more common than "pure" (homoisotopic)
> heavy water molecules.

The 1:5000 ratio (1cc in 5L) is much closer to the 1:3200 ratio for semi-heavy
water, not the 1:41 million for D20.

The BS article also says:

> [Heavy water] is considered a munition so you can not just go and and buy
> some without all kinds of legal documentation and permits

United Nuclear says there are no restriction. See
[http://unitednuclear.com/index.php?main_page=product_info&cP...](http://unitednuclear.com/index.php?main_page=product_info&cPath=16_17_69&products_id=135&zenid=54e1ed0c477416c600a4dd7dba62c247)
. Also, a kilo costs $725.

Sigma-Aldrich sells it at
[http://www.sigmaaldrich.com/catalog/product/aldrich/151882?l...](http://www.sigmaaldrich.com/catalog/product/aldrich/151882?lang=en&region=US)
. 4 kilos @ 99+% pure costs about $4,000.

~~~
ElCampesino
I was thinking the same. I remember looking when considering building a Fusor
and found that deuterium gas was relatively affordable. Why not simply react
high purity deuterium gas and oxygen to form the heavy water? Or just buy
heavy water directly as you have noted.

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sakopov
Wasn't there a graduate student who wrote thesis about building an atomic bomb
from readily available resources. I don't remember if his work was ever
published, but I certainly remember reading about this.

Update:
[https://en.m.wikipedia.org/wiki/John_Aristotle_Phillips](https://en.m.wikipedia.org/wiki/John_Aristotle_Phillips)

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vonnik
If this is phony, then it shouldn't be on the front page of HN. And if it's
true, it should not be on the front page of HN. Humanity as a whole doesn't
need more people building reactors in their garage... Svetlana Alexievich's
book "Voices of Chernobyl" is an excellent explanation why.

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ScotterC
This is really impressive and shows that the basics of nuclear technology
aren't all that complicated in small scale. Just like fire requires a spark
and oxygen, a fission reaction really only requires a fissionable metal and an
appropriate moderator.

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2old2randr
Interestingly, given the right conditions, chain reactions can take place with
very little effort. There is one known example of a natural nuclear reactor
that was in operation for a few hundred thousand years (2 billion years ago).
[https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto...](https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor)

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Beltiras
This just has to be a hoax. It's too conveniently packaged to be true. Bad
spelling and grammar make it less believable.

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sithadmin
Horrifying. Hope this is a joke.

~~~
NegativeK
This feels more like "I read the Wikipedia article about CANDU and wrote a
story from it."

~~~
gozur88
That's what I was thinking. The author glosses over years and years worth of
tricky engineering problems, particularly regarding heavy water production.

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PeekPoke
Sheldon? Is that you?

