A low-energy-barrier exothermic fission reaction which releases D could potentially do so at high enough particle energy to result in 6Li + D fusion with decay of the resulting 8Be to 2 4He at 22 MeV. Such a fuel could be mixed into the 6Li saltwater and serve as the trigger for the more energetic reaction.3He + T gives 4He + D and 4He + p + n to about 50% each (plus 9.5 and 12.1 MeV respectively).
Various endothermic reactions have a probability to release D.
Where is the point?
In short, NO! One is leaving out a lot of details, e.g., the stream in which the He is present. Extracting/collecting the He, if used in a propellant stream, would defeat the purpose of using it for propulsion.Can the helium-4 exhaust be collected(MHD) to power the neutron generator?
Thanks for the reply, Astronuc.In short, NO! One is leaving out a lot of details, e.g., the stream in which the He is present. Extracting/collecting the He, if used in a propellant stream, would defeat the purpose of using it for propulsion.
This discussion is about 4.5, almost 5 years old, and I had forgotten about my participation. There is a lot wrong with the discussion on the part of the original poster, who seems not to have a good grasp on engineering or physics.
The discussion is a prime example of someone who takes an reaction equation or concept (single piece of physics) and builds a faulty case for a complex system (multiphysics).
A single reaction, e.g., 6Li + n => T + α + energy is a single reaction that would take place in a population of 6Li, depending on the atomic density of the Li and the neutron flux. The physics and engineering get very complex depending on the various aspects such as propellant mass flow rate (thrust) and power generation. Note that the propellant is consumed, so somewhere, there is a mass of stored propellant that must be introduced into the neutron flux.
In nuclear systems, only a tiny fraction of the fuel (target material) is consumed at any given time. So one cannot simply take a single reaction equation and declare, Voila!, we have thrust. Rather, one must consider that reaction takes place in the presence of other atoms that do not experience the same reaction so that the energy of the one reaction is distributed to billions, trillions, . . . . 1014 - 1020 other atoms, depending on the density of the matter (in an engineered system) in which the reaction takes place. Natural systems like stars can achieve conditions (i.e., pressures, and mass and energy densities) well out of reach of human engineered systems.
Nuclear salt water systems are not practical for propulsion, period!
No, it's not feasible. By invoking Dr. Strangelove, is one implying 'fictional'. If so, I would agree.I was under the impression Zubrin's NSWR was feasible, but too Dr. Strangelove to be made.
I found the link through the Wikipedia page on the NSWR.
It doesn't claim an anisotropic flux, it claims there are more neutrons in one place (downstream) than another (upstream).This is insane! The neutron flux will not be concentrated downstream, but will be more or less an isotropic source, with some fraction streaming upstream to the source.
What's the specific problem here? Sure, controlling that will be a challenge.The 427 MWt is equivalent to 122 3500 MWt LWR nuclear plants! Into 196 kg/s?!? Really!?