Plutonium-239 and Uranium-235
Sub Critical
Something consumed to produce energy, especially:a. A material such as wood, coal, gas, or oil burned to produce heat or power.b. Fissionable material used in a nuclear reactor.c. Nutritive material metabolized by a living organism; food.
Yes, this isotope is very fissionable and is used in nuclear reactors and nuclear weapons.
is the most common isotope of uranium found in nature. It is not fissile, but is afertile material: it can capture a slow neutron and after beta decay become fissile plutonium-239. U-238 is fissionable by fast neutrons, but cannot support a chain reaction because inelastic scattering reduces neutron energy below the range where fast fission is probable.
In light water reactors the new fuel has about 4 to 5 percent U-235, which is the fissionable part, the rest being U-238. In some countries mixed oxide fuel is used (MOX) which contains some Plutonium as well as U-235, but the fissionable content is much the same. Heavy water or graphite reactors can use natural uranium, which contains 0.7 percent U-235.
Sub Critical
A breeder reactor
Essentially, a core of fissionable material is impacted to such a degree that it will begin to undergo fission because of loose neutrons impacting the nuclei of the fissionable material. There are two methods, the first is by firing a bullet of fissionable material into a larger mass, and the second is by using conventional explosives to simultaneously concuss the material on all sides.
Sub Critical
The smallest amount of a fissionable material that will produce a self-sustaining chain reaction is called the critical mass. This mass of affected by geometry and other factors such as temperature, pressure, and moderator.
Critical Mass is that minimum amount of fissionable material needed to maintain a chain reaction
Either highly enriched uranium-235 or reactor produced plutonium.
Because in small samples the probability of a neutron escaping the sample without inducing another fission is bigger. Actually, what matters is the mass of the sample, especially if this mass exceeds the critical mass. Thus, the chain reaction in a smaller sample with sufficiently higher density of fissionable material might not die out, while it dies out in a larger sample with albeit a sufficiently smaller density of fissionable material.
Something consumed to produce energy, especially:a. A material such as wood, coal, gas, or oil burned to produce heat or power.b. Fissionable material used in a nuclear reactor.c. Nutritive material metabolized by a living organism; food.
To make a nuclear bomb, you need the fissionable material such as a Plutonium239 isotope, an explosive to start the nuclear chain reaction, a detonator, and a pusher.
Yes, this isotope is very fissionable and is used in nuclear reactors and nuclear weapons.
Uranium 235 is the most important isotope of uranium; it is a fissionable isotope used in HWR, PWR, BWR, research reactors and other types of reactors. But it is rare, only 0.72% of natural Uranium is this isotope.The more plentiful Uranium 238 isotope is only fertile not fissionable; it can only be used in fast reactors to breed Plutonium, which is fissionable. Isotopes of plutonium 239Pu and 241Pu are highly fissionable and importants for nuclear fuels.