Nuclear salt-water rocket propulsion

[Kopykat99]

Ive read about Nuclear salt water rockets on wikipedia but my brain () did not understood it. can anybody explain in a nutshell what is the Nuclear-salt water rocket about?

[magnemoe]

Basically you use water mixed with uranium salt of weapon grade uranium.

Tanks contains moderators or spacing who keeps it subcritical, however then injected into the engine you get an chain reaction who turn the water into plasma. Unlike an nerva type engine you use up the uranium.

Benefit is good isp and very high trust that is higher than an orion and continuous not pulsed.

Downside its very radioactive, probably hard to control the reaction in the engine and you have an real danger of fuel tanks going critical if salt settles

[Pyre]

Not to mention the fact that you have to build a spacecraft that can withstand a continuous nuclear explosion.

[lajoswinkler]

This rocket would not use nuclear explosions at all.

[magnemoe]

This rocket would not use nuclear explosions at all.

Depending on definition, it would use fusion of weapon grade uranium but it would not be an actual nuclear explosion.

Rather it would use the very high radiation you get then you get an critical mass without having the parts hit each other fast.

You will face some control issues, the amount of uranium salt in the fuel is important for the energy release but it should be possible to measure this at the intake and hopefully adjust the pumps fast enough.

However overall I think that an orion would be considered safe and environmental friendly compared with the nuclear salt water rocket

[Wesreidau]

Fission. You just have to build a spacecraft capable of withstanding the G's produced by that kind of engine. Since you're producing a constant thrust, you can engineer to a constant standard. I will say it seems easier to withstand a constant force than repeatedly getting hit again and again. That's the difference between slowly accelerating up to 60mph or just being hurled by a catapult.

Environmental concerns are only of importance within an environment. You can start the NSWR after getting high enough the hippies can't scream at you.

[Bacterius]

Environmental concerns are only of importance within an environment. You can start the NSWR after getting high enough the hippies can't scream at you.

Arguably, space could be considered an environment. There's a lot of space to pollute, but that's ok - we'll just find more debris. And.. well.. space hippies? Green satellites using ionized weed as reaction mass?

Edited August 26, 2013 by Bacterius

[lajoswinkler]

Depending on definition, it would use fusion of weapon grade uranium but it would not be an actual nuclear explosion.

Rather it would use the very high radiation you get then you get an critical mass without having the parts hit each other fast.

You will face some control issues, the amount of uranium salt in the fuel is important for the energy release but it should be possible to measure this at the intake and hopefully adjust the pumps fast enough.

However overall I think that an orion would be considered safe and environmental friendly compared with the nuclear salt water rocket

Nuclear explosion is a sudden catastrophic fission/fusion. This engine would not use it, but instead it would balance on constant criticality, and would heat water and throw it outside the nozzle, together with volatile fission products which are highly radioactive. The fuel would stay in the rocket. It's an interesting concept, but it puzzles me how would it avoid the precipitation of the salts which would cause hotspots and destruction.

I have no idea if it would release more fission products than the nuclear pulse engine. Maybe it would. After all, nuclear pulse engines throw everything out, whether this doesn't.

Arguably, space could be considered an environment. There's a lot of space to pollute, but that's ok - we'll just find more debris. And.. well.. space hippies? Green satellites using ionized weed as reaction mass?

I wouldn't care about it. Even our solar system is incredibly huge. Fission products would disperse.

[zekes]

Tanks contains moderators or spacing who keeps it subcritical

lol moderators "who" keep it? There are people in tanks

[Kopykat99]

Thanks for the feedbacck you guys are awesome

[Cheaterman]

However overall I think that an orion would be considered safe and environmental friendly compared with the nuclear salt water rocket

Considering we're talking about an engine causing a series of nuclear explosions and forces its dampener to withstand several dozen G's every 3 seconds or so, not mentioning most of my KSP rockets built with this fall apart on takeoff, this is one of the best quotes ever. If you don't consider the extra isp.

[magnemoe]

Considering we're talking about an engine causing a series of nuclear explosions and forces its dampener to withstand several dozen G's every 3 seconds or so, not mentioning most of my KSP rockets built with this fall apart on takeoff, this is one of the best quotes ever. If you don't consider the extra isp.

Thanks.

I prefer the: We are proud to announce our first Mun base as an mission extension of our first Mun landing. The landing legs, engine and fuel tank worked well as crumble zones.

[Mr Shifty]

Tanks contains moderators or spacing who keeps it subcritical

Point here: neutron moderators are used to make the reactor more, not less reactive. Neutrons produced by fission are high-energy. Unmoderated they would quickly escape the core and be useless to further the chain reaction. Moderators slow down the neutrons (by presenting a high neutron collision cross-section) to "thermal" energies so that they remain in the core area and can cause more fissions.

[DerekL1963]

Nuclear explosion is a sudden catastrophic fission/fusion. This engine would not use it, but instead it would balance on constant criticality, and would heat water and throw it outside the nozzle, together with volatile fission products which are highly radioactive. The fuel would stay in the rocket. It's an interesting concept, but it puzzles me how would it avoid the precipitation of the salts which would cause hotspots and destruction.

Keep in mind something that the Wikipedia article does not make clear, this engine has not been studied or analyzed in any detail or with any seriousness. It's pretty much among the ultimate of 'paper' rockets.

[Zaeo]

Why are you worried about "polluting" space with radiation when our star "pollutes" Constantly, and at a much higher degree than what we could even dream of producing at this point in time?

Its a problem with earth, because normally, our atmosphere absorbs and disperses most of the very harmful radiation, and nuclear explosions/radiation emitters cause that number to jump FAR above average for that area because it isn't being absorbed completely.

In space, its only creating a temporary and tiny fluctuation in the radiation levels, that just get blown away by solar wind.

[Kryten]

An NSWR isn't going to be emitting 'radioactivity', it's going to be pumping out fission products that are intensely radioactive in themselves. While still not an issue in interplanetary space, it's going to make any kind of rendezvous with orbital infrastructure quite hazardous.

[magnemoe]

Point here: neutron moderators are used to make the reactor more, not less reactive. Neutrons produced by fission are high-energy. Unmoderated they would quickly escape the core and be useless to further the chain reaction. Moderators slow down the neutrons (by presenting a high neutron collision cross-section) to "thermal" energies so that they remain in the core area and can cause more fissions.

You are right, you either want the neurons to escape as fast as possible or absorb them. Letting them escape is probably easier.

Still the problem with salt who concentrates and increase radiation would be an major headache, uneven salt concentration in the fuel who reach the engine probably more so.

An NSWR isn't going to be emitting 'radioactivity', it's going to be pumping out fission products that are intensely radioactive in themselves. While still not an issue in interplanetary space, it's going to make any kind of rendezvous with orbital infrastructure quite hazardous.

My issue to, radiation itself is not an huge issue, the only benefit is that the exhaust will probably have solar escape speed so as long as you don't point it at anything you should be good.

[Mr Shifty]

An NSWR isn't going to be emitting 'radioactivity', it's going to be pumping out fission products that are intensely radioactive in themselves. While still not an issue in interplanetary space, it's going to make any kind of rendezvous with orbital infrastructure quite hazardous.

The metals and other materials that the ship is made out of will also be activated by the neutron flux. You can mitigate this, to some degree, with shielding, but shielding is heavy, the anathema of spacecraft designers. And whatever the vessel is rendezvousing with will have to have shielding as well.

[lajoswinkler]

Why are you worried about "polluting" space with radiation when our star "pollutes" Constantly, and at a much higher degree than what we could even dream of producing at this point in time?

Its a problem with earth, because normally, our atmosphere absorbs and disperses most of the very harmful radiation, and nuclear explosions/radiation emitters cause that number to jump FAR above average for that area because it isn't being absorbed completely.

In space, its only creating a temporary and tiny fluctuation in the radiation levels, that just get blown away by solar wind.

Hmmmmmm, that's not exactly true... It's true that our Sun puffs out more radiation than Earth could ever produce, but the amount of radioisotopes it emits is poor, even considering its huge size.

One thing is correct - solar wind woud blow rocket's tiny particulate solids and gases away. Care should be taken so that such rockets are turned on at appropriate distances, away from Earth. Amount of stuff that would fall on Earth is not worth mentioning, but for things like space stations... I don't know. This requires heavy calculations and simulations.

[SunJumper]

Also worthy of consideration is how high up on Kerbin one could safely activate one of these engines tangential to the surface...

[tom1499]

Sometimes I kinda think Atomic and Nuclear physics were at a much higher level in the tech tree than the human race could unlock, but by some twist of fate we ended up with it.

[Fuzzy Dunlop]

An NSWR isn't going to be emitting 'radioactivity', it's going to be pumping out fission products that are intensely radioactive in themselves. While still not an issue in interplanetary space, it's going to make any kind of rendezvous with orbital infrastructure quite hazardous.

The radioactivity of the exhaust isn't an issue for two reasons.

1) The exhaust is moving so fast that it won't stick around long enough to cause any issues.

2) The exhaust is moving so fast that most of the nuclei in it will have more kinetic energy than your average alpha particle. Anything that gets in the way of the exhaust will be utterly obliterated.

[TheSaint]

In addition to all of the other downsides listed above, also consider this: One micrometeoroid strike on your fuel tank, one fuel leak, one throttle failure, or one of countless other possible mechanical failures could release enough fuel to start a chain reaction, which would release more fuel, which would make you bunkmates with an uncontrolled nuclear explosion. I wouldn't ride in the damn thing.

Sometimes I kinda think Atomic and Nuclear physics were at a much higher level in the tech tree than the human race could unlock, but by some twist of fate we ended up with it.

Unfortunately, no. Nuclear weapons are frighteningly easy to design. Remember, the Manhattan Project didn't have access to computers, they designed all of their weapons (including the very complex implosion weapons) with pencil, paper, and slide rule. This is why non-proliferation efforts stopped focusing on design knowledge and are instead now focused on limiting access to nuclear material. And even that is failing miserably. We need to stop trying to prevent folks from getting nuclear weapons and instead try to figure out how we'll keep the world safe when everyone has nuclear weapons.

[-Velocity-]

Environmental concerns are only of importance within an environment. You can start the NSWR after getting high enough the hippies can't scream at you.

The major flaw in your assertion here is the assumption that the anti-nuclear extremists respect any form of logic and reason.

[-Velocity-]

Unfortunately, no. Nuclear weapons are frighteningly easy to design.

Yup, the only thing you need to do to make a basic nuclear bomb explode is to rapidly assemble a supercritcal mass of weapons-grade fissile material. The natural decay, creating neutrons, will get the reaction started, and since its supercritical, it will rapidly go out of control. That's IT.

It can be challenging assembling the supercritical mass quickly enough, however; if you do it too slowly, the very start of the runaway reaction will blow the components apart, and the weapon will fizzle as a very low yield dud. So the key is to assemble a supercritical mass very quickly, before it can blow itself apart. High explosives are necessary in all the designs that I'm aware of, but the designs are still very simple.

This is why Iran is such a worry. Having the ability to produce highly enriched uranium makes you a defacto nuclear weapons state.

Edited September 12, 2013 by |Velocity|