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Nuclear Fission
Nuclear fission is the phenomenon in which an atomic nucleus splits into lighter nuclei. This reaction can be spontaneous in some isotopes, but usually is the result of heavy nuclei absorbing a neutron. Because fission often results in the emission of multiple neutrons, this reaction can be self-sustaining, making such things like nuclear reactors and nuclear weapons possible.
488 Questions
To sustain a fission chain reaction, each fission reaction must result in one more fission reaction. And that one should result in one more, and so on.
Why is a nuclear reactor dangerous?
Components in the reactor inside the primary shielding will be radioactive, even after all the fuel has been removed. Provided everything is monitored and assessed properly and health physics advice followed by the operators, there should be no need for anyone to be exposed to dangerous levels during decommissioning.
Compare and contrast nuclear fission and nuclear fusion?
The process of combining two nuclei to form a heavier nucleus and thereby releasing energy is nuclear fusion. When a neutron strikes an atom of uranium-235, the atom captures the neutron, becoming an atom of uranium-236 with an excited nucleus. The U-236 nucleus vibrates rapidly and cannot hold itself together; it splits into several pieces (smaller atoms, free neutrons, etc.) in a process called nuclear fission (fission means "division"), releasing an enormous amount of heat energy and gamma rays.
Where does the released nuclear energy come from during fission?
A combination of the strong nuclear force and the electromagnetic force. The strong nuclear force provides the initial energy to split one large nucleus into two small ones, but once the smaller nuclei have separated by a short distance because both are positively charged the electromagnetic force repels them and rapidly accelerates them to very high velocity (i.e. high kinetic energy aka high temperature).
The end products (fission fragment nuclei and neutrons) have a slightly smaller mass than the mass of the original nucleus. If you plug the amount of lost mass into the equation E = M c**2, the result calculated will be exactly equal to the kinetic energy gained by the end products. So the energy came from a small part of the original mass.
So wording it another way, the energy release is driven by the strong nuclear force and the electromagnetic force, but the energy itself was released by the conversion of matter to energy.
BTW, the energy released in chemical reactions also come from matter to energy conversion, but as the energy is much smaller the lost mass is also much smaller (and usually undetectable).
What are the products of nuclear fission and fusion?
The nuclear fission and/or fusion results in loss of mass (or mass defect) that transforms into energy according to formula E = mc2 (c is light velocity). The resulting energy manifests itself as heat energy that produces steam. The steam spins the turbines that spins electric generators and hence producing electricity.
What particle is used to start nuclear 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.
What happens to a nucleus during nuclear fission process?
They just stay around, being stopped in the fuel rod material. Some are highly radioactive and constitute the high level waste, but if the fuel rods are stored intact, as normally happens with commercial reactors, they just remain in the rods indefinitely.
What is the starting material for nuclear fission?
You must not ask "what element", but "what isotope". Uranium-235 is one example of an ISOTOPE that is appropriate for nuclear fission. Uranium-238 is the same for chemical reactions, but for purposes of nuclear reactions, different isotopes must be considered to be different types of atoms.
Nuclear fusion compared to nuclear fission?
Nuclear fusion is the process of combining two light atomic nuclei to form a heavier nucleus, releasing large amounts of energy. Nuclear fission is the process of splitting a heavy atomic nucleus into smaller nuclei, also releasing energy. Fusion powers the sun and hydrogen bombs, while fission is used in nuclear power plants and atomic bombs. Fusion reactions produce less radioactive waste than fission reactions.
What is the impact of plutonium when nuclear power is made?
It is not entirely clear from your question what it is you really want to know about.
- Standard water moderated power reactors are not usually fueled with plutonium, but they produce plutonium as a byproduct of their operation. They can burn some of the plutonium that they produce but are not very efficient at it.
- Work has been done on adding limited amounts of plutonium to the fuel used in standard water moderated power reactors (mostly to help consume the excess plutonium from dismantled weapons), but as stated above these reactors are not very efficient at this.
- To most efficiently use plutonium for nuclear power purposes we would need to use a different type of reactor called a "fast neutron reactor" which has no moderator at all. One thing about these reactors that tends to frighten people is that their initial fuel load is "weapons grade" material (whether they are fueled with uranium or plutonium), however during their operation they quickly convert this fuel to a form totally unsuitable for weapons. But neither these unmoderated power reactors nor standard water moderated power reactors is in anyway capable of undergoing a nuclear explosion!
Do uranium nuclei split during nuclear fission?
if the fission was of uranium, then yes. but many transuranic elements (e.g. plutonium, americium) also fission.
What is the use of homolytic fission?
In a heterolytic fission, both the electrons shared in the bond go to one atom (almost always the more electronegative atom). In homolytic fission, the electrons go to the two separate atoms.
In a nuclear fission reaction what is converted into energy?
In fission, the mass of the resulting atoms is slightly less than the mass of the original atom that was "split" -- this matter has been converted into energy. A tiny amount of matter is the equivalent of an enormous amount of energy, according to the formula E=Mc2.
Why are there extra neutrons produced in nuclear fission?
Because usually during nuclear fission the nucleas is being split by colliding with a another unstable particle like a neutron, and in this case absorbing the neutron to become a more unstable nucleaus with a higher mass, for instance uranium 235 colliding with a neutron and becoming a unstable 236 neutron. After this the uranium 236 splits apart and becomes to separate nuclea and in the process neutrons are released, as gamma radiation. This produces a massive amount of energy because the energy that has bound the protons together in the nucleus, ( protons repel each other) is very strong, so the potential energy in that state is massive. And once released...well. BOOM
What is the purpose of nuclear fission and nuclear fusion?
Nuclear fusion is the joining together of two light nuclei to make one heavier one. It is the source of energy of the stars including our sun.
Read more: http://wiki.answers.com/What_is_nuclear_fusion_and_what_is_its_purpose#ixzz1BneLAhLF
Why enormous energy is released during nuclear fission?
Well... It depends on what you mean by "a lot". The binding energy released from a fusion event is actually only about four times that of a fission event, however, the density of the much lighter elements involved in fusion (hydrogen) versus fission (uranium) results in a much more effective total mass to energy ratio, much more than a hundred times that of fission.
I'm not talking about delta-mass to energy - that is constant per e = mc2 - I'm talking about the total fuel mass versus the amount of energy available in the reaction.
How are radioactive decay and nuclear fission alike?
Decay is used in the atomic sense similarly to how you would always use it; gradually falling apart over time. Fission, however, is an instantaneous process, more akin to hammering an ice-pick into a block of ice than to a hill weathering away from wind and rain. The only thing similar about them are that the products existing after both processes finish are in a lower energy state.
How can mass be converted into nuclear fission and fusion reaction?
There is a misunderstanding here. It is a fine, but very important point. Mass can neither be created nor destroyed, and energy can neither be created nor destroyed.
There is a relationship between mass and energy, in the relativistic framework set down by Einstein in his famous mass-energy equivalence equation e = mc2. Do not misunderstand, however - this does not mean that mass can be converted to energy and vice versa - it means that mass has energy, and energy has mass, all depending on relativistic velocity.
In nuclear fission, the nuclear force (residual binding energy) that holds protons and neutrons together in an atom is greater than the nuclear force required to hold the protons and neutrons together in the split atoms that result from the fission process. The differential nuclear force, or mass deficit, is released during fission. It is more correct to say that the mass is carried away with the energy, because the mass is the energy and the energy is the mass, as stated above.
Can large nuclei undergo the process of nuclear fission?
By capture of a neutron, causing the nucleus to be unstable and to split into two parts
Can one nuclear power plant power an entire city?
Depends on the size of the city, but probably yes, in fact why not for a year
What are some problems associated with the use of nuclear fission to supply energy needs?
It is is hard to split a nucleas
What is nuclear fission and fusion?
Nuclear fusion is the joining up of two smaller nuclei into one larger, in our sun it is the fusion of hydrogen which produces helium, and releases energy. Nuclear fission is the splitting of the nucleus of uranium which releases energy, as in a nuclear reactor.
