Fission reactions start naturally if the proportion of U-235 is high enough; there is evidence this has happened in places in Africa in the distant past of Earth's history.
Fusion reactions require more heat and pressure than we really know how to provide so as to keep a reaction going.
Fusion reactions require much higher temperatures and pressures to overcome the Coulomb barrier between atomic nuclei and achieve fusion. Additionally, controlling and sustaining the high temperature plasma for fusion is technically challenging and expensive compared to the relatively simpler process of inducing fission reactions with neutron bombardment.
It isn't, in general. Thermonuclear bombs use a fission bomb to generate the heat and pressure required to start the fusion process, but there are other ways of doing it (stars do so by gravity, for instance).
Fusion reaction combines isotopes of hydrogen to make helium and release energy. This requires temperatures in the millions of Kelvins to start.Fission reaction breaks up isotopes of heavy elements (Uranium & Plutonium) into lighter elements (fission fragments, a major part of fallout) and release energy. This can start a normal temperatures.
No way has yet been found to reach break-even in a controlled fusion reaction and get as much energy out as was needed to put in to start the reaction. To make a reactor you need to go past break-even and release extra energy.
Neutrons are required to start a fission reaction as they can initiate the splitting of uranium or plutonium atoms. In the process, additional neutrons are released which can go on to trigger more fission events. So, while neutrons are necessary to begin a fission reaction, they are not typically produced as a product of the reaction.
Fusion reactions require much higher temperatures and pressures to overcome the Coulomb barrier between atomic nuclei and achieve fusion. Additionally, controlling and sustaining the high temperature plasma for fusion is technically challenging and expensive compared to the relatively simpler process of inducing fission reactions with neutron bombardment.
It isn't, in general. Thermonuclear bombs use a fission bomb to generate the heat and pressure required to start the fusion process, but there are other ways of doing it (stars do so by gravity, for instance).
Only beacuse of starting trouble. Any way we need billion kelvin temperature to start with for which we have to rely on fission reaction. One more important point we cannot have a controlled fusion reaction as we do so in fission ie nuclear reactor using control rods.
If you are asking which has the maximum danger, a hydrogen bomb is one type of nuclear bomb. In general, nuclear bombs can be fission (called atomic) or fusion (hydrogen) A fusion bomb is larger than an fission bomb, and actually uses a fission bomb to start the fusion reaction.
Nuclear fission is used in nuclear weapons to create what some might call an atomic blast (nuclear blast). Nuclear fission used this way can also be applied in special complex designs to generate enough thermal energy (heat) to initiate a fusion reaction. This creates an even bigger nuclear blast.
Fusion. Fusion requires very high temperature and pressure. So on earth we usea critical mass of weapons grade uranium to start a fission chain reaction whichenables a fusion reaction in hydrogen. Fusion is of course more powerful than fission
In actuality, a spontaneous fission event begins a nuclear chain reaction. It kick starts a nuclear chain reaction. And a neutron from that fission will initiate another fission to continue and rev up that nuclear chain reaction.
Fusion reaction combines isotopes of hydrogen to make helium and release energy. This requires temperatures in the millions of Kelvins to start.Fission reaction breaks up isotopes of heavy elements (Uranium & Plutonium) into lighter elements (fission fragments, a major part of fallout) and release energy. This can start a normal temperatures.
No way has yet been found to reach break-even in a controlled fusion reaction and get as much energy out as was needed to put in to start the reaction. To make a reactor you need to go past break-even and release extra energy.
Collapsing matter and gasses get denser and denser until nuclear fusion and fission start.
Neutrons are required to start a fission reaction as they can initiate the splitting of uranium or plutonium atoms. In the process, additional neutrons are released which can go on to trigger more fission events. So, while neutrons are necessary to begin a fission reaction, they are not typically produced as a product of the reaction.
Good question. A fusion bomb combines (fuses) light nuclei (hydrogen) into larger nuclei to get its energy. But it needs a fission bomb to start it. A fission bomb breaks up (fissions) heavy nuclei (uranium/plutonium) into smaller nuclei to get its energy.