Chemical Forums
Specialty Chemistry Forums => Citizen Chemist => Topic started by: billnotgatez on March 04, 2013, 03:28:41 AM
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I was perusing the channel on YouTube about science and enjoying it until this video -
http://www.youtube.com/watch?v=tzecE6XDFgg
Does anyone see some inaccuracies?
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I noticed he said He-3 is formed when Tritium decays. That's wrong, isn't it?
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Beta decay to He-3, this is listed in wikipedia.
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Oh yes, beta decay. My bad
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1. Used in the manufacture of liquid crystal display? Why? Maybe he is thinking of plasma displays.
2. Used to pressurize NASA rockets? Makes no sense. Maybe he is talking about the cabin area. Maybe they use an oxygen and helium mix for the people.
3. Nuclear bombs don't have tritium. I guess he is talking about hydrogen bombs and I hear these use LiD (lithium deuteride). Neutrons from the first stage split the lithium atoms into tritium and helium. The tritium fuses with deuterium and makes He 4). If they do actual use tritium in some form, it would have to be replaced every few years that's why LiD is better.
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From
Helium Resources of the United States – 2003 Technical Note 415 June 2004
Figure 4. Uses of helium in 2002.
24.4% Cryogenics
16 % Controlled Atmospheres
18 % Welding
20 % Pressurizing and Purging
6 % Leak Detection
13 % Other
3.1% Breathing Mixtures
I know it does not add to 100% but that is the best I could find on short notice.
@vmelkon
So for your 2.
The above implies that they use it for purging the NASA rockets and leak testing them.
I assume a lot is vented and lost to the atmosphere.
I am guessing that other inert gasses do not work as well due to them not being similar enough to Hydrogen in some physical properties.
It may be used for cabin air but I am thinking that it is not the major use.
For your 1.
I assume it is used as an inert environment during production of some electronics.
How much is lost during this process I would have no clue.
I bet with the cost going up they are recycling.
For your 3.
Someone in the nuke field will have to chime in
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If the electronics industry needs it for an inert atmosphere, they would likely use argon. They would not even buy argon. It is cheaper to buy a argon liquifier (from air).
Leak testing? I guess helium is a good choice.
The video also mentioned NMR. From a quick search, I see that the research scientists use liquid helium surrounded by liquid nitrogen. I use to think they used nitrogen but I guess it is hard to make a coil with ceramic barium titanium copper stuff. If someone can make a metal that becomes a superconductor at 77 K, they could change the industry.