Energy From Thorium Discussion Forum

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PostPosted: Dec 05, 2015 5:38 pm 
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Location: Iowa, USA
http://science.slashdot.org/story/15/12 ... e-solution

Saw a discussion on Slashdot claiming that is we are going to find a solution to the global warming problem then we must go to the moon to find it. This plan to mine the moon for helium-3 to fuel fusion reactors on earth does sound problematic to me.

To begin talking of the problems with this plan I'll start with the engineering challenges. We haven't had a rocket capable of bringing tons of material to the moon for decades. Manned spaceflight is largely limited to low earth orbit. Even getting a satellite to high earth orbit, or a probe beyond orbit, requires extensive planning and engineering to make the cargo as light as possible and the rocket as efficient as possible. This is also ignoring that no one has been able to demonstrate a working fusion reactor using any fuel, while He-3 might make that easier to achieve it has not been shown to work. I do believe that fusion power is possible but it will take a very large reactor. That reactor size will grow with the reduced tolerances in materials, meaning the smaller you want to make it the more expensive and fragile it becomes. I believe we could build a working fusion reactor with what we know today but it would have to be far too large for anyone to even consider building outside a World War II kind of threat. Again I'll restate my usual disclaimer, I am a computer engineer, not a nuclear engineer, so I may not know what I'm talking about.

I also see political problems with this. I'll give Iran as an example. What would the international community say or do if Iran stated an intent to mine the moon? They'd be building heavy lift rockets capable of carrying many tons beyond orbit and return cargo to the earth. This would also involve training people in the operation of devices that handles radioactive materials. It doesn't have to be Iran, consider the reaction if it was North Korea, China, Russia, Venezuela, Cuba, or any of a number of nations not so friendly to the USA. I can also turn this around. What if it was South Korea, Japan, India, Israel, or any of a number of nations with neighbors with less then amicable relations. The politics of building the capability of launching anything that can reach what is defined as "outer space" can no doubt be problematic for nations that do not currently have that capability.

In the comments many people brought up how much easier it would be to produce He-3 on earth with existing nuclear reactors. This brings to mind the question of what is the rate of production one might expect of He-3 (from decayed tritium most likely) given current and Gen IV nuclear fission reactors? I recall tritium production is a problem that comes up in many MSR designs, how much can be expected to be produced? Even if this is not a potential source for fusion fuel I can expect that there are many people interested in a new source of helium that it would be economically feasible to collect this byproduct for sale.

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Disclaimer: I am an engineer but not a nuclear engineer, mechanical engineer, chemical engineer, or industrial engineer. My education included electrical, computer, and software engineering.


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PostPosted: Dec 06, 2015 4:47 pm 
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Joined: Aug 15, 2011 2:16 pm
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Location: Pickering, Ontario
CANDU reactors produce tritium in their heavy water moderators, which is then distilled out at the Darlington Generating Station's Tritium Removal Facility. The stored tritium containers there probably house the largest supply of He-3 in the world.


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