this post was submitted on 17 Sep 2023
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Couldn't we have a lead box lined with these radiation to electricity converters with a small amount of radioactive material in the center, and have an energy generating device that would last for thousands or even millions of years? Imagine putting the sun in a box lined with solar cells, but on a much smaller scale.

Is there a reason this wouldn't work?

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[โ€“] [email protected] 24 points 1 year ago (2 children)

This article has a good breakdown. The biggest issue is efficiency. RTGs are around 5-9% efficient. Standard steam cycle generators are around 30% (see this article ) . You get much more usable energy from fuel used in a commercial reactor vice a RTG.

[โ€“] [email protected] 5 points 1 year ago (1 children)

From the article it looks like RTGs are just converting the heat energy into electricity. Seems like there's a lot unused potential being missed.

[โ€“] [email protected] 7 points 1 year ago

Yes, I don't think RTGs are really what you're asking about. It's just a solid state way of turning heat into energy instead of using steam.

[โ€“] [email protected] 1 points 1 year ago (2 children)

Can you ELI5 why the efficiency is so low on the RTGs?

[โ€“] [email protected] 8 points 1 year ago (2 children)

RTGs aren't radioactive-specific, they are just a solid state way of turning a temperature difference into electricity. The better way to do this (at scale) is e.g. a steam engine, which is what big power plants do.

[โ€“] [email protected] 2 points 1 year ago

Wow! I think is a subject that Iโ€™d going to occupy my downtime for awhile. Thanks for the in depth info, also relevant username?

[โ€“] [email protected] 2 points 1 year ago (1 children)

Thank you so much. I think Iโ€™m kind of getting but you have some to ing I can do some more research on.

[โ€“] [email protected] 2 points 1 year ago (1 children)
[โ€“] [email protected] 2 points 1 year ago

Very much so! Guess Iโ€™m going down this rabbit hole before bed tonight haha. Thanks for the extra info.

[โ€“] [email protected] 3 points 1 year ago

They take the waste heat from nuclear decay and convert it to electricity through the use of a peltier device. Those work off of differential temperature and are pretty inefficient to begin with. Unmderated Nuclear decay doesn't produce a lot of heat at one time, which is why reactors use a moderator to increase the power output.