/sci/ - Science & Math » Thread #11686468

14KiB, 700x700, radiation.png

View Same Google iqdb SauceNAO

non-critical nuclear reactors

Anonymous Mon 18 May 20:09:08 2020 No.11686468 View Reply Original Report

Quoted By: >>11686538

Are there any uses for them? My friend was talking about how it might be plausible to build a nuclear reactor with over the counter radioactive materials that would not reach criticality, which could be charged up and used similar to normal battery but be far more durable. Likewise we were discussing uses of lasers and supposed that you could have a sort of heat engine built from legal radioactive materials, which could react with heavy water using a laser. Not that it'd be very efficient, but at least plausible to get useful amounts of heat from such a device that (through a turbine) would create electricity.

Not talking about RTGs either, I guess it'd be a sort of "stimulated" RTG.... a crappy nuclear reactor.

Anonymous

Anonymous Mon 18 May 2020 20:28:08 No.11686538 Report

Quoted By: >>11686555

>>11686468
First of all, all reactor are technically designed to be sub-critical, it's up to the retarded neutrons to make the coefficient go up to 1.

This pedantic tehcnicality apart, the only way I see to make a subcritical reactor as you imply it would be to have something that have an effective coefficient below 1 but that looses its neutron flux density slow enough so that the reactor consume all its material before it shut down. This is practically very hard: you're trying to consume a whole match with a vanishing flame.

In any case, the kind of reactor you describe looks a lot like the first reactors (50-60's exeperimental generation, althought they were critical) with a very low output power that basically worked like batteries. The problem is that they were not economically viable, having the size and cost of a regular nuclear power plant but with 1/1000th or less of its output power.

In any case, it's still not as easy to be charged like a battery: fuel rods in such reactors are usually less radioactive and longer to be depleted, but they are still nuclear waste which require to be handled with care and that will take thousands of years to desactivate. Moreover, without reaching criticallity you'd need a very big source of neutrons to reach the designed neutron density at the start of cycle of your reactor, since your reactor is not creating enough neutrons to account for the ones it looses. For a big reactor, this is practically impossible, unless you want to detonate a neutron bomb inside your reactor at each start.

...hence, crappy RTG indeed.

Anonymous

Anonymous Mon 18 May 2020 20:35:26 No.11686555 Report

Quoted By:

>>11686538

Interesting. Do you think it's plausible to have such a "reactor" be a big tank of heavy water with some uranium in it, which is then agitated/heated to a useful level by a laser? The laser would obviously require an auxiliary power source, similar to how a car battery starts a combustion cycle. Energy would be released by the uranium and absorbed by the water, which is then (theoretically) put through a heat exchanger to push a turbine.

It wouldn't be efficient or even produce net power, again the application I'm thinking of is a high endurance battery not an actual power generator.

Capcode	All Only User Posts Only Moderator Posts Only Admin Posts Only Developer Posts
Show Posts	All Only With Images Only Without Images
Deleted Posts	All Only Deleted Posts Only Non-Deleted Posts
Ghost Posts	All Only Ghost Posts Only Non-Ghost Posts
Post Type	All Only Sticky Threads Only Opening Posts Only Reply Posts
Results	All Grouped By Threads
Order	Latest Posts First Oldest Posts First

Your latest searches