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Who was the first person to sustain a fissionable chain reaction?
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∙ 14y ago
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What is required for a chain reaction to start?
Critical Mass is that minimum amount of fissionable material needed to maintain a chain reaction
Is it true or false that the only isotopes that can be used as fuel in a nuclear power plant are those in which a chain reaction can occur?
True, only fissionable isotopes that produce enough excess neutrons to sustain a chain reaction can be used directly as fuel.However fertile isotopes that capture neutrons and then transmute to fissionable isotopes can be used indirectly as fuel through a process called breeding.
Atoms that naturally undergo nuclear fissions are called?
These are called fissile or fissionable. Fissile isotopes undergo fission, producing sufficient neutrons of sufficient power that a chain reaction can happen, if there is enough of the isotope to support it. The mass sufficient to support a chain reaction is called critical. Atoms of fissionable isotopes will undergo fission when a sufficiently energetic neutron collides with them, but the neutrons they emit when they divide are either insufficient in number or insufficient in energy to sustain an chain reaction. There is a third type of material that can undergo fission, called fertile, which is isotopes that can be caused to capture neutrons, changing into fissile or fissionable isotopes, so the fission does not happen to atoms of the fertile material directly, but to the atoms of the isotopes they become.
What is the amount of fissionable material that must be present in order for a nuclear reaction to take place called?
The critical mass. With an amount of U-235 or Pu-239, the smallest critical mass will be a sphere. For a nuclear reactor, it will be the minimum number of fuel assemblies loaded to produce a chain reaction.
The smallest amount of a fissionable material that will give a self-sustaining chain reactions is called the?
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.
What is necessary sustain a nuclear chain reaction?
In a chain reaction, neutrons released during the splitting of an initial nucleus trigger a series of nuclear fissions.
What is meant by supercritical andhow dose it relate to making a nuclear bomb?
subcritical - a mass or arrangement of fissionable or fissile material unable to sustain a neutron chain reaction. It can provide a fixed amount of neutron multiplication from a neutron source, but after removal of the neutron source the chain reaction rate drops exponentially.critical - a mass or arrangement of fissionable or fissile material capable of sustaining a constant neutron chain reaction. No increase or decrease. (Nuclear reactors operate at critical)supercritical - a mass or arrangement of fissionable or fissile material capable of not only sustaining a neutron chain reaction, but once initiated the chain reaction rate rises exponentially. (Nuclear fission bombs explode when made supercritical)A nuclear fission bomb must have 2 of these states: subcritical (so that it can't explode until desired) and supercritical (so that it explodes with an effective yield). This requires a rapid "assembly" system using conventional explosives to rearrange the fissile material from subcritical to supercritical in about 1ms. A neutron source starts the chain reaction and the explosion completes in about 1 microsecond.
Why does a chain reaction die out in small pieces of fissionable fuel but not in large pieces?
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.
Describe a characteristic of a fissionable substance that is essential for a chain reaction to sustain itself?
Firstly it must be able to capture neutrons which then have a high probability of causing its nuclei to undergo fission or splitting, and the fissions must produce enough further neutrons so that for every fission that occurs, another one will follow.
How to make nuclear bomb-?
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.
What are the similarities between nuclear reactors and nuclear bombs?
Both have critical mass, and create energy from a fission chain reaction. In nuclear bombs, the chain reaction is uncontained and spreads to all the fissionable material nearly instantaneously.
What is nuclear chain reaction?
A nuclear chain reaction is one in which the disintegration of one nucleus creates a cascade of nucleons which, in their turn, cause the disintegration of other nuclei and thus the process can sustain itself.
