NASA Testing New Nuclear Reactor for Space Missions

DooKey

DooKey

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NASA is testing a new technology for nuclear reactors that promises to significantly reduce their size, increase capacity, and longevity. The reactor is called KRUSTY or Kilopower Reactor Using Stirling TechnologY and It uses uranium instead of plutonium. The fission reaction (AKA heat) activates a piston assembly that can run a generator. It produces enough power to run a small home and if you set up a few or these as a farm they could run a human settlement on the Moon or Mars. This is pretty cool technology, but I wonder what the radiation output is and what kind of clear zone is needed around them?

Watch the video here.


NASA and the U.S. Department of Energy say they have successfully tested a new type of nuclear reactor that could one day provide juice to colonies on other worlds. The reactor can power several homes and appears able to operate in harsh environments.
 
2014%2F09%2F29%2Fd0%2Fkrustythecl.63b41.jpg
 
Montu said:
NASA is testing a new technology for nuclear reactors that promises to significantly reduce their size, increase capacity, and longevity. The reactor is called KRUSTY or Kilopower Reactor Using Stirling TechnologY and It uses uranium instead of plutonium. The fission reaction (AKA heat) activates a piston assembly that can run a generator. It produces enough power to run a small home and if you set up a few or these as a farm they could run a human settlement on the Moon or Mars. This is pretty cool technology, but I wonder what the radiation output is and what kind of clear zone is needed around them?

Watch the video here.


NASA and the U.S. Department of Energy say they have successfully tested a new type of nuclear reactor that could one day provide juice to colonies on other worlds. The reactor can power several homes and appears able to operate in harsh environments.
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I am sure it will be shielded.
 
Montu said:
I wonder what the radiation output is and what kind of clear zone is needed around them?
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kju1 said:
I am sure it will be shielded.
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https://beyondnerva.wordpress.com/2...of-a-new-breed-of-reactors-kilopower-part-ii/

In order to shield the rest of the spacecraft, including the power conversion system and the radiators, from the reactor core, stacked depleted uranium and lithium-hydride plates are placed in between the reactor and everything else. In total, 40.4 kg of LiH and 45.3 kg of DU are used for shielding the reactor.
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There's lots of great info about the design on that blog.
 
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https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator

Pretty common, the Russians use them in remote lighthouses for example. Not dangerous unless you disassemble them. The things that are new here are using a Sterling engine and using Uranium instead of Plutonium.

Edit: Googling more, it looks like this really is a fission reactor design, not an RTG. But it contains a lot of RTG elements in its design.
 
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Always wondered how traditonal power could work in "0g", since most work on the idea that steam rises because it is less dense, that doesnt happen when gravity doesnt pull denser air down though
 
Compddd said:
Yep we'd have made a lot more advances in space and down here if not for them.
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We'd probably have nuclear powered vehicles by now. Whatever happened to the Thorium powered vehicle craze from several years back? My guess is that the tree huggers crushed the idea.
A nuclear reactor in every home, and a nuclear powered car in every garage!
 
mynamehere said:
We'd probably have nuclear powered vehicles by now. Whatever happened to the Thorium powered vehicle craze from several years back? My guess is that the tree huggers crushed the idea.
A nuclear reactor in every home, and a nuclear powered car in every garage!
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yep I remember reading about that in popular science, or popular mechanics magazines / online years ago, Thorium powered jet engines.... things were looking interesting.... then......nothing....
 
DigitalPanhandler said:
yep I remember reading about that in popular science, or popular mechanics magazines / online years ago, Thorium powered jet engines.... things were looking interesting.... then......nothing....
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Cadillac even built a concept vehicle for their 100th anniversary.
 
sfsuphysics said:
No I get those, but those arent "traditional"
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That's because you can't run a "traditional" one in space for the very reasons you mentioned. Doh. That's my bad.

Sorry, I didn't realize that's what you meant by "traditional", so I just linked other reactor types meant for space thinking you didn't know about them.

The one NASA seems to be working on also seems to be more of an evolution of both types. Instead of free-flowing steam through pipes, you have liquid metal going through heatpipes to run a stirling engine.
 
Am I the only one who gets annoyed at how NASA reaches for these acronyms? I guess they think it necessary for public outreach, but it comes off as stupidly childish to me.
 
tbonepat11 said:
Isaac Asimov predicted this about 60 years ago. Sad the green movement set this sort of development back decades through fear mongering.
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Nope. NERVA was killed off in 1972 by Republicans in Congress as part of the post-Apollo NASA spending cuts, it had nothing to do with the 'green movement.' They just didn't want to spend money on a Mars program. Multiple NERVA sizes/designs had already been heavily tested out in Nevada, including worst-case meltdown situations. More recently there was a proposal for a nuclear powered Jupiter/Europa probe back during the Bush Jr. admin but they axed that, too.
 
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mynamehere said:
We'd probably have nuclear powered vehicles by now. Whatever happened to the Thorium powered vehicle craze from several years back? My guess is that the tree huggers crushed the idea.
A nuclear reactor in every home, and a nuclear powered car in every garage!
Click to expand...

once you get past the sensationalist crap and examine the technology, it wasn't a good idea. the tree huggers (heavily influenced by gas and oil) have done a great job at slowing development of nuclear technology to a crawl, but this one they didn't have to.

allow me to explain. typical uranium reaction is done one of two ways. natural uranium contains two isotopes, U-238 and U-235. it's the U-235 that is the nuclear fuel. its far more unstable and tends to eject neutrons quite readily. so traditionally, you need a moderator to create the right conditions for the neutrons to collide with other uranium atoms and sustain chain reaction. you can either use a crappy moderator such as regular water and increase the concentration of U-235 in the fuel (this is enrichment) or use a good and very expensive moderator such as heavy water and forget enrichment.

thorium is very different in that it isn't a nuclear fuel on its own much like U-238 isn't initially either. thorium is only a mild beta radiation emitter, not a fissile fuel. but if you expose it to a neutron source....say high enriched uranium (U-235)....something interesting happens. it turns into uranium 233. yeah thorium becomes uranium fuel. U-233 is rather short lived but is extremely unstable and therefore makes a wonderful fissile fuel.

so now the problems. the first one is evident. you need a neutron source in the vehicle. those are tightly controlled since they are not only dangerous but also create more radioactive material. U-235 is a major component in weapons also...

the next problem is one of radioactivity. you'll need shielding. doesn't sound so bad, but remember how i said that U-233 is very energetic? well it also gives off more radiation as a result. a lot more. so much so that this is a barrier to creating thorium fueled power plants....and we're talking about putting this in a car.

i'm not saying that it's impossible and i'd love to see it. i'm very much a nuclear enthusiast and i also work in the industry. just trying to clear a few points up ;)
 
Sure is krusty alright...
 

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DeathFromBelow said:
NERVA was killed off in 1972
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Yeah, nuclear propulsion for spacecraft is nothing new. The name eluded me, but that's the one.
What is new is the engine NASA has designed.

I think there's still the issue of what happens when one of these new KRUSTY nuclear engine blows up in the atmosphere.
 
MrDeaf said:
Yeah, nuclear propulsion for spacecraft is nothing new. The name eluded me, but that's the one.
What is new is the engine NASA has designed.

I think there's still the issue of what happens when one of these new KRUSTY nuclear engine blows up in the atmosphere.
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They're different tools. KRUSTY is a reactor for generating electrical power. NERVA was a line of nuclear-thermal rockets, where the heat from a nuclear reactor was used to heat/expel a propellant. It could have been used directly as an upper stage replacement and/or a cycler for lunar/interplanetary missions:

nasaNAS9961818165665a.jpg


With KRUSTY, NASA will presumably leave the reactor off until it's in orbit or on the surface of the Moon/Mars. It doesn't generate thrust on it's own. You could use them to generate thrust with some sort of electrical propulsion like an ion engine or VASIMR.

5826ad58afa753e8d5d346c8ac565648_L.jpg


Flying up the fuel in a cask of some sort shouldn't be too big of a security risk. The RTG aboard the unused Apollo 13 lunar lander fell into the ocean off South America and ended up on the sea floor intact.
 
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Maybe they should fix the augmented reality and masking layer mishaps before they try to pull off something even bigger.
 
CaptNumbNutz said:
That's because you can't run a "traditional" one in space for the very reasons you mentioned. Doh. That's my bad.

Sorry, I didn't realize that's what you meant by "traditional", so I just linked other reactor types meant for space thinking you didn't know about them.

The one NASA seems to be working on also seems to be more of an evolution of both types. Instead of free-flowing steam through pipes, you have liquid metal going through heatpipes to run a stirling engine.
Click to expand...
Yeah that seems to be the one mentioned here, steam still expands, but if you can force it through pipes due to pressure you got something. I guess the big problem is finding a way to keep a pressure differential for it to continue working.
 
DigitalPanhandler said:
yep I remember reading about that in popular science, or popular mechanics magazines / online years ago, Thorium powered jet engines.... things were looking interesting.... then......nothing....
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Yeah those magazines are great, but they are almost by definition vaporware magazines, similar to all those "home of the future" shows they had back in the day. I wouldn't exactly blame the "treehuggers" on why you don't see 90% of the junk that's shown in them.
 
tbonepat11 said:
Isaac Asimov predicted this about 60 years ago. Sad the green movement set this sort of development back decades through fear mongering.
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That and psychotics trying to get their hands on them for a dirty bomb. On a side note, storage of the used fuel needs to be blasted into space. Not stored here on earth IMO.
 
If it were not for the occasional rocket/shuttle disaster, launch all that nuclear waste into the sun Superman 4 style. Though having an explosion in the upper atmosphere allows us to play Fallout 4 IRL.

Oh well, lets leave it to Deadpool to gather up all the Gluten in the world and launch it into space where it can't not hurt us ever again.
 
THRESHIN said:
once you get past the sensationalist crap and examine the technology, it wasn't a good idea. the tree huggers (heavily influenced by gas and oil) have done a great job at slowing development of nuclear technology to a crawl, but this one they didn't have to.

allow me to explain. typical uranium reaction is done one of two ways. natural uranium contains two isotopes, U-238 and U-235. it's the U-235 that is the nuclear fuel. its far more unstable and tends to eject neutrons quite readily. so traditionally, you need a moderator to create the right conditions for the neutrons to collide with other uranium atoms and sustain chain reaction. you can either use a crappy moderator such as regular water and increase the concentration of U-235 in the fuel (this is enrichment) or use a good and very expensive moderator such as heavy water and forget enrichment.

thorium is very different in that it isn't a nuclear fuel on its own much like U-238 isn't initially either. thorium is only a mild beta radiation emitter, not a fissile fuel. but if you expose it to a neutron source....say high enriched uranium (U-235)....something interesting happens. it turns into uranium 233. yeah thorium becomes uranium fuel. U-233 is rather short lived but is extremely unstable and therefore makes a wonderful fissile fuel.

so now the problems. the first one is evident. you need a neutron source in the vehicle. those are tightly controlled since they are not only dangerous but also create more radioactive material. U-235 is a major component in weapons also...

the next problem is one of radioactivity. you'll need shielding. doesn't sound so bad, but remember how i said that U-233 is very energetic? well it also gives off more radiation as a result. a lot more. so much so that this is a barrier to creating thorium fueled power plants....and we're talking about putting this in a car.

i'm not saying that it's impossible and i'd love to see it. i'm very much a nuclear enthusiast and i also work in the industry. just trying to clear a few points up ;)
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I remember them claiming that the required shielding was quite minimal (something akin to sheet metal) due to the low radioactivity of Thorium. Seems there was a bit more to it than what they claimed.
 
mynamehere said:
I remember them claiming that the required shielding was quite minimal (something akin to sheet metal) due to the low radioactivity of Thorium. Seems there was a bit more to it than what they claimed.
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Remember how I said that thorium is a beta emitter? That shielding would work fine for beta. Gamma goes through everything. If your intention is to split the atom, you'll have the entire range of radiation. Neutron while at power to do the work, and plenty of gamma, beta and alpha after the fact.

Once an atom is split, it becomes unstable. This emitting radiation is how they stabilize themselves. How much and what it is depends on the isotope.
 
THRESHIN said:
Remember how I said that thorium is a beta emitter? That shielding would work fine for beta. Gamma goes through everything. If your intention is to split the atom, you'll have the entire range of radiation. Neutron while at power to do the work, and plenty of gamma, beta and alpha after the fact.

Once an atom is split, it becomes unstable. This emitting radiation is how they stabilize themselves. How much and what it is depends on the isotope.
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Tis but a trifling matter. /s
I wonder how they neglected to mention such an important aspect. It sure would be awesome if it weren't for little details such as that.
 
tbonepat11 said:
Isaac Asimov predicted this about 60 years ago. Sad the green movement set this sort of development back decades through fear mongering.
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It wasn't just the Green movement, a hysteria of all things nuclear was created in hopes of helping to fuel unilateral disarmament.
 
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