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Warpspeed13
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So depleted uranium is mostly U-238 which can't sustain a chain reaction. If you were to compress depleted uranium to a thousand times it's normal density could it then sustain a reaction?
Warpspeed13 said:Wouldn't compressing it to 1000 times it's normal dentistry effectively make it an almost 100% chance that the atom compleatly fissions while also dropping the probability that the neutron loses all it energy to Inelastic scattering?
QuantumPion said:In order for a chain reaction to occur, the probability of the nucleus fissioning and releasing 2.5 neutrons after absorbing one neutron must be at least 1/2.5=40%. In other words, for every neutron absorbed, you need at least one new neutron produced. This is possible with fissile isotopes U-233, U-235, Pu-239, and Pu-241. However for U-238, the probability of fission occurring after absorbing a neutron is much less than 40% (more like 2%).
Warpspeed13 said:Ok so you wouldn't increase the probability of a fission. Would it decrease the probability of a neutron escaping the mass without interacting with a nucleus in some way, wether that be Inelastic scattering, total fission, partial fission ect ect?
snorkack said:So little?
I had picked up the notion that the effective neutron multiplication factor in uranium 238, although below unity, is appreciable.
snorkack said:The density of your critical mass starts to matter if it is spread over millions of kilometres.
QuantumPion said:No you are backwards. In an effectively infinite system, density is irrelevant because the neutrons will be absorbed eventually.
Warpspeed13 said:So if you had a system in which you were using an external neutron source to fission u-238 you could get higher efficiencies for the same number of source nutrons, because the chances of neutron escape were vastly reduced due to the u-238 being compressed to 1000 times it's normal density?
snorkack said:Density will become relevant if the extent of the system is in millions of kilometres because then free neutron decay becomes an appreciable factor in criticality. Fast neutrons, with energy in MeV range, have speed in region of 10 000 km/s; neutron lifetime is in region of 600 s; so if your critical mass is in millions of kilometres then free neutron decay will matter.
QuantumPion said:First, you can't compress uranium to 1000 times its natural density. The natural density of uranium is ~95% theoretical density. Second, I don't understand what you mean by "higher efficiency", you have to define what the goal of the apparatus is to know how good it is at it.
Warpspeed13 said:Would the neutrons be less likely to hit if the uranium was imploding into the neutron source and that was causing the change in density?
snorkack said:Yes - it does! The only thing which is affected by change of density is the external surface and thus escape probability of neutrons.
Depleted uranium is a byproduct of the process used to enrich uranium for nuclear weapons or fuel. It is about 40% less radioactive than natural uranium and is primarily composed of the isotope uranium-238.
Depleted uranium is used in various industries, including military applications such as armor-piercing ammunition and shielding for tanks and other vehicles. It is also used in some medical equipment and as a counterweight in aircraft and other machinery.
Depleted uranium is mildly radioactive and can pose health risks if ingested or inhaled. However, the level of risk depends on the amount and duration of exposure, as well as other factors such as the form of depleted uranium and the individual's overall health. Proper handling and disposal of depleted uranium can minimize potential health hazards.
Depleted uranium is a heavy metal and can have toxic effects on the environment if not properly managed. Its use in military applications has raised concerns about contamination of soil and water sources. However, studies have shown that the environmental impact of depleted uranium is relatively low and can be mitigated through proper disposal and monitoring.
In response to concerns about the potential health and environmental impacts of depleted uranium, many countries have put regulations in place to control its use and disposal. The International Atomic Energy Agency (IAEA) also provides guidelines for safe handling and disposal of depleted uranium. Further research is ongoing to better understand the effects of depleted uranium and to develop better methods for its management.