Quote from: john smith 19 on 08/10/2017 06:48 am....IOW in principal going LEU saves a lot of money ...... a cost claim without argument.
....IOW in principal going LEU saves a lot of money
That doesn't make any sense. Please elaborate and/or correct your comment.
You're talking about HEU systems, which this is not, and contradicted your desire for efficiency by proposing a low temperature generator and associated systems.
Another contradiction, and a cost claim without argument.Based on your previous posts, I'd request the old JS19 reply
-- Previous quote --Re1) Why have you proposed tungsten will be part of the core and not part of the rocket - ie; the throat and upper nozzle? Isotopic requirements on neutron absorption/reflection would be much more applicable to the rocket architecture or core's casing than the core's matrix.
Re2) Agreed, but a LEU fast reactor still doesn't produce the heat desired for NTP without reflecting (W?), or otherwise encouraging, neutrons back into the matrix to accelerate fission and temperature. This is why I asked about creating higher temps or use of tungsten around the throat - the LEU doesn't cut it otherwise. And there's still the issue of keeping propellant in contact long enough to extract temperature - conflicting with keeping it moving and building velocity. I don't see how that's solvable without a working fluid. Thoughts?
You could probably make an NTR on LEU if you use heavy hydrogen (deuterium) as the remass. maybe even heavy Methane.You'd lose a some Isp from the heavier element, but fuel would be denser.CANDU reactors can run on natural uranium because of the use of heavy water as moderator.
Combine nuclear thermal propulsion with water from the Moon as reaction mass, and you could tool around the solar system at a high rate of speed. Get water from the Moon, drop to Earth orbit and pick up passengers, and get to Mars orbit in a month maybe?
I'm confused by this article. It states among other things that the NTP engines have higher thrust than chemical engines.
haha tricky is exciting Fast spectrum with LEU is going to have a pretty large fissile start-up charge. I'd bet this is going to a pretty heavy rocket. It's too bad we don't have a better infrastructure for the production of U233.
Humanity will never do anything truly substantial in space until it uses NTR of some type.I have always been an avid supporter of NTR technology so this is really good news.
what do "HEU" and "LEU" mean here?
Quote from: clongton on 08/06/2017 07:42 pmHumanity will never do anything truly substantial in space until it uses NTR of some type.I have always been an avid supporter of NTR technology so this is really good news.Really?As long as you are not able to simply refuel at destination it will not open the Solar System.And expendable architectures will not get us anywhere in the long run.
Quote from: clongton on 08/06/2017 07:42 pmHumanity will never do anything truly substantial in space until it uses NTR of some type.I have always been an avid supporter of NTR technology so this is really good news.I support nuclear propulsion research, but do you really think nuclear thermal will be a gamechanger? Merely doubling the specific impulse (while also making the engine heavier and more complex) does not sound like a big advance to me at all. It may not even be worth the added complexity. I do think future will belong to fusion drives or advanced nuclear drives like this:https://en.wikipedia.org/wiki/Fission-fragment_rockethttps://en.wikipedia.org/wiki/Nuclear_salt-water_rocketBut in the medium term, for inner solar system, I dont really see chemical propulsion as insufficient or a limiting factor. Especially with propellant depots.
Quote from: bradjensen3 on 08/19/2017 09:01 pmI'm confused by this article. It states among other things that the NTP engines have higher thrust than chemical engines. They don't explicitly say which chemical engines they are using for the comparison.
Quote from: bradjensen3 on 08/09/2017 06:03 amCombine nuclear thermal propulsion with water from the Moon as reaction mass, and you could tool around the solar system at a high rate of speed. Get water from the Moon, drop to Earth orbit and pick up passengers, and get to Mars orbit in a month maybe?seems obvious to me, but there is a whole thread where I get beaten to a pulp suggesting it.
Quote from: gongora on 08/19/2017 09:57 pmQuote from: bradjensen3 on 08/19/2017 09:01 pmI'm confused by this article. It states among other things that the NTP engines have higher thrust than chemical engines. They don't explicitly say which chemical engines they are using for the comparison. I think they mention being twice as much thrust as the Shuttle Main Engine.