Uranium-238 is fissionable only by bombardment with fast neutrons.
Neutrons; but the cross section area is not so important.
By neutrons; bu the cross specific area is very small for thermal neutrons.
a free neutron can trigger the split of a particle like uranium 238. It will produce a smaller atom (eg. proctantium), a beta particle and energy.
Uranium atoms are split during nuclear fission. Uranium-235 and uranium-233 are fissile with thermal neutrons and uranium-238 is fissile with fast neutrons.
Uranium-238 has 146 neutrons.
Pure Uranium is radioactive; thus harmful. Inside a nuclear reactor, atoms get split. When the Uranium atom is split, it releases a huge amount of energy. This energy is called nuclear energy. Also the normal Uranium is not used in reactors. The Uranium that is used is enhanced; it is an isotope of Uranium. Uranium-237 and Uranium-238 are used in nuclear reactors. I hope this answer was useful for you.
Uranium 238 is transformed in thorium 234 by alpha decay.
Uranium 238 has 146 neutrons.
The main difference between uranium-235 and uranium-238 is their atomic masses. Uranium-235 has 235 atomic mass units (AMU) while uranium-238 has 238 AMU. This difference in mass is due to the number of neutrons in the nucleus of each isotope.
Uranium-235 and uranium-238 are isotopes of uranium, meaning they have the same number of protons but different numbers of neutrons. Uranium-235 is used in nuclear reactors and weapons due to its ability to sustain a nuclear chain reaction, while uranium-238 is more abundant in nature but less useful for these purposes.
The only nuclei which are split are Uranium-235 in new fuel, and plutonium-239 which is formed during operation from U-238.
There are 3 major isotopes of uranium: Uranium-238, 235, and 234. These numbers are the amount of neutrons in the nucleus. Since Uranium only has 92 protons, this makes these isotopes VERY neutron-heavy!Uranium-238 is the most common in nature, followed by 235, then 234. All these are radioactive isotopes. Because there are so many neutrons in Uranium, it makes it fissile -- easy to split.