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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
Describe three advantages nuclear fusion would have over nuclear fission?
1. Unlike fission, during fusion tremendous amount of energy is liberated. Hence fusion of a very small mass generates large amount of energy. 2. Unlike fission the products of fusion reactions are not radio-active. Thus they are harmless and can be replaced easily. 3. Highly penetrating radiations are liberated during fission, which are highly hazardous.
A nuclear fission process in which neutrons produced by fission trigger more fissions?
nuclear chain reaction
Note: there are also chemical chain reactions (e.g. polymerization), of course they involve no neutrons
Uranium-235
If things go according to plan, the neutron encounters a fissionable atomic nucleus and then undergoes what is called neutron capture. That's the next step in the process. The presence of that neutron in the nucleus destabilizes the nucleus (more than it already is as that nucleus is radioactive and unstable anyway). In an extremely short period of time the instability results in nuclear fission. The nucleus splits.
What are the example of nuclear fission?
The only example of nuclear fission in a naturally occurring material is of Uranium 235, which comprises 0.7 percent of natural uranium, the rest being Uranium 238 which is not fissile. To use U235 in a nuclear reactor it is usually enriched to about 4 percent first, though reactors have been designed to use natural uranium. These have to use graphite or heavy water as moderator, as normal water absorbs too many neutrons.
During reactor operation some of the U238 absorbs a neutron and becomes Plutonium 239 which is also fissile, so this contributes to a proportion of the reactor power which increases as the fuel is used and the U235 diminishes.
What is a nuclear weapon in wich enormous energy is released by nuclear fission?
This nuclear weapon is called an atomic bomb or a nuclear bomb
a neutron is absorbed by an atom’s nucleus. (apex)
What are the examples of horizontal articulation of curriculum?
An example of horizontal articulation of curriculum would be all the teachers from across one age grade collaboration together. This collaboration would be used the all programs and activities are coordinated.
Why the alpha particles could not smash the nucleus apart?
The alpha particle is positively charged (as is the nucleus) and is heavy compared with the neutron that is neutral and lighter than the alpha particle.
Another viewpoint:
It depends what experiment the question is about. For example, over a hundred years ago, Rutherford bombarded gold foil with alpha particles and some "bounced off" what we now call the nucleus of the atoms. However, about ten years later he did experiments in which alpha particles did indeed "split" atomic nuclei. So, sometimes alpha particles can certainly smash a nucleus apart.
What emitted particles maintain a nuclear chain reaction?
In most cases neutrons are emitted and capable of maintaining a nuclear chain reaction
Where are the great amounts of energy produced during nuclear fission?
Each element has a distinct binding energy - energy which is required to "glue" the individual constituents of an atom (proton, neutron and electrons) together. During nuclear fission, heavier elements decay into lighter elements, thus changing the binding energy of the individual nuclei formed. This minute change releases energy which, when the large number of decays of atoms per second is considered, produces a high quantity of (thermal) energy which is captured by a nuclear fission reactor.
How nuclear technologies produce enermouse amount of energy?
Nuclear technologies produce enormous amounts of energy through a process called nuclear fission, where the nucleus of an atom is split to release large amounts of heat. This heat is then used to generate steam, which drives turbines connected to generators that produce electricity. The energy released in nuclear reactions is much greater than in chemical reactions, leading to the large amounts of energy produced by nuclear power plants.
How do nuclear fusion differ fundamentally from nuclear fission?
Nuclear fusion doesn't produce energy.
Yes, all natural radiation (in the rocks) is a result of fission (but this fission is not part of a chain reaction like in a fission bomb).
However, it is theoretically possible for natural processes to concentrate radioactive elements (uranium) to the extent where a natural nuclear fission reactor (a chain reaction like in a nuclear power plant) will form. Oklo in in Gabon is the only known location for this to have happened and consists of 16 sites at which self-sustaining nuclear fission reactions took place approximately 1.7 billion years ago.
How does a nuclear reaction take place?
First nuclear reactions always involve the nucleus and except for K capture beta decay never involve any of the electrons around the nucleus.
There are seven different types of ordinary nuclear reactions:
- fission, a massive nucleus splits into two lighter fragment nuclei (about 1/3 & 2/3 the mass of the original nucleus) and several free neutrons, fission can happen spontaneously in some isotopes (e.g. plutonium-240) but is usually triggered by the capture of a neutron, as fission always produces free neutrons it is possible to produce a neutron chain reaction to keep the process going
- fusion, light nuclei join forming a heavier nucleus, this reaction can only happen under conditions of very high temperature and pressure (causing the nuclei to be fully ionized, traveling at high velocity, and pressed tightly together) it is very hard to to get started and keep going (except deep inside stars) Note that fusion is the only one of these seven nuclear reactions that is affected in any way by the temperature or pressure of the environment it happens in
- alpha decay, a nucleus spontaneously ejects a helium nucleus (i.e. alpha particle)
- beta- decay, a neutron in the nucleus spontaneously transforms into a proton and the nucleus ejects an electron and an electron antineutrino
- beta+ decay, a proton in the nucleus spontaneously transforms into a neutron and the nucleus ejects an positron and an electron neutrino
- K capture beta decay, a proton in the nucleus spontaneously transforms into a neutron and the nucleus captures an electron from the innermost (i.e. K) electron shell and ejects an electron neutrino
- gamma decay, a nucleus in a metastable (i.e. excess energy) state spontaneously relaxes its proton and/or neutron shells to a lower energy state and ejects a gamma photon with an energy equal to the energy lost in the nucleus
However if you include other subatomic particles not present in ordinary matter (e.g. muons, antimatter particles, strange particles) a much wider and more confusing variety of nuclear reactions can happen that are beyond the scope of the original question. I will only mention one of these nuclear reactions: muon catalysed cold fusion. This is interesting because it permits the fusion nuclear reaction to happen at ordinary room temperature.
In muon catalyzed cold fusion the electrons around hydrogen nuclei are replaced with muons (particles identical to electrons in every way except that they have 200 times the mass), being much more massive than electrons their orbitals are much smaller. So much smaller that the nuclei can come close enough to each other at ordinary room temperature that the nuclei can fuse! The fusion energy release causes the product nucleus to lose its muons and become ionized. This process is called "muon catalyzed" because these free muons can now replace electrons around fresh hydrogen nuclei, repeating the nuclear reaction over and over without requiring any additional muons. The only problem with muon catalyzed cold fusion is that the muons required to begin this nuclear reaction are very expensive to produce.
What process splits an atom's nucleus to produce normous amounts of heat energy and gamma rays?
This process is called nuclear fission.
Is solar energy nuclear fission or fusion?
The process generating solar energy is one of nuclear fusion.
In a nuclear power plant fission reactions are controlled by inserting what?
In a fission reactor, control is implemented by inserting control rods into the reactor. These are made of a material that absorbs neutrons, and prevents a reaction from taking place.
In a nuclear fission reaction a freely moving neutron?
In a nuclear fission reaction, a freely moving neutron undergoes neutron capture and initiates the nuclear fission of a fuel atom.
Which equation shows why nuclear fission can produce a large amount of energy from very little mass?
E=mc^2
How is the energy produced by nuclear fission used?
- to obtain electrical energy
- to obtain thermal energy
- to obtain bombs
