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Can the chain reaction of nuclear fission be stopped or controlled?
Wiki User
∙ 14y ago
The chain reaction can be controlled, and it can be stopped. It is controlled in a nuclear power plant, and it is stopped when the plant shuts down, as it does periodically for refueling.
Wiki User
∙ 14y ago
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What kind of energy is given from a nuclear fission reaction?
The initial release of energy is in the form of kinetic energy of the fission fragments, but they are quickly stopped inside the fuel and the energy appears as heat, which is then passed into the coolant, whether water or gas.
True or false the energy from nuclear fission is released as heat?
Heat is produced by the recoil (kinetic energy) of the fission fragments, when they are stopped in the fuel material
What kind of energy is given off from a nuclear fusion reaction and from a nuclear fission reaction?
the "disappearance" of a small amount of mass. Most of the energy from nuclear fusion of deuterium and tritium, which is the most likely reaction to be harnessed by man, is given off as kinetic energy of the neutrons formed. This is one of the problems involved-how to make use of this energy, even when the plasma can be contained and made to fuse, which has only been achieved for brief bursts so far. The neutrons will have to be stopped in some material surrounding the plasma to produce heat, but what material will stand up to these conditions is not clear. In nuclear fission most of the energy appears first as kinetic energy of the fission fragments, which are then stopped in the fuel resulting in heat being generated which can be removed by the coolant, water or gas. There is also some gamma ray energy released.
Do nuclear isotopes stop decaying when control rods are down?
No, it is not correct; only a nuclear chain reaction can be stopped with control rods.
How can the fission be controlled or stopped in a nuclear reactor?
The nuclear chain reaction is controlled using neutron absorbing control rods containing boron, and in PWR's by also using soluble boron when necessary. Nuclear engineers use a term called reactivity, which just means the surplus of neutrons from one generation to another, and in steady operation this is zero. During the fission reactions fission products are produced, some of these are neutron absorbers like Xenon131, and their concentration changes with power changes, so that adjustments with the control rods are necessary following such changes. On start-up with new fuel for example it takes some hours before equilibrium xenon is reached, and if power has to be reduced the xenon rises again as a delayed action, so enough control to overcome the increased poisoning has to retained, or the reactor will shut itself down. The reactivity with new fuel loaded is higher than at the end of the fuel life, and this is where boric acid added to the reactor water circuit is useful. The reactor power (neutron flux level) is constantly monitored with instruments so that the control room staff know what is happening and can respond. In addition automatic safety circuits are triggered if there is an increase in flux beyond a certain point which the operators don't react to, and this inserts the control rods fully (scram or trip) which shuts the reactor down and holds it down. So there is no chance of a runaway.
What kind of energy is given from a nuclear fission reaction?
The initial release of energy is in the form of kinetic energy of the fission fragments, but they are quickly stopped inside the fuel and the energy appears as heat, which is then passed into the coolant, whether water or gas.
True or false the energy from nuclear fission is released as heat?
Heat is produced by the recoil (kinetic energy) of the fission fragments, when they are stopped in the fuel material
What kind of energy is given off from a nuclear fusion reaction and from a nuclear fission reaction?
the "disappearance" of a small amount of mass. Most of the energy from nuclear fusion of deuterium and tritium, which is the most likely reaction to be harnessed by man, is given off as kinetic energy of the neutrons formed. This is one of the problems involved-how to make use of this energy, even when the plasma can be contained and made to fuse, which has only been achieved for brief bursts so far. The neutrons will have to be stopped in some material surrounding the plasma to produce heat, but what material will stand up to these conditions is not clear. In nuclear fission most of the energy appears first as kinetic energy of the fission fragments, which are then stopped in the fuel resulting in heat being generated which can be removed by the coolant, water or gas. There is also some gamma ray energy released.
Do nuclear isotopes stop decaying when control rods are down?
No, it is not correct; only a nuclear chain reaction can be stopped with control rods.
How can the fission be controlled or stopped in a nuclear reactor?
The nuclear chain reaction is controlled using neutron absorbing control rods containing boron, and in PWR's by also using soluble boron when necessary. Nuclear engineers use a term called reactivity, which just means the surplus of neutrons from one generation to another, and in steady operation this is zero. During the fission reactions fission products are produced, some of these are neutron absorbers like Xenon131, and their concentration changes with power changes, so that adjustments with the control rods are necessary following such changes. On start-up with new fuel for example it takes some hours before equilibrium xenon is reached, and if power has to be reduced the xenon rises again as a delayed action, so enough control to overcome the increased poisoning has to retained, or the reactor will shut itself down. The reactivity with new fuel loaded is higher than at the end of the fuel life, and this is where boric acid added to the reactor water circuit is useful. The reactor power (neutron flux level) is constantly monitored with instruments so that the control room staff know what is happening and can respond. In addition automatic safety circuits are triggered if there is an increase in flux beyond a certain point which the operators don't react to, and this inserts the control rods fully (scram or trip) which shuts the reactor down and holds it down. So there is no chance of a runaway.
When an atom splits (fission) what kind of energy is produced?
The nuclear energy released appears initially as kinetic energy of the fission fragments, but they are quickly stopped in the surrounding material and the energy then turns to heat. There is also some gamma ray energy released.
What is the type of energy transfer taking place during nuclear energy?
Nuclear energy is produced in fission by the destruction of mass (a small proportion of the mass of the U-235 nucleus). The energy appears initially as kinetic energy of the fission fragments, which are quickly stopped inside the fuel rods and the energy is converted to thermal energy (heat)
How do you convert nuclear to thermal energy?
This happens in the fuel rods, the energy released by nuclear fission appears initially as kinetic energy of the fission fragments, which is quickly turned into thermal energy as the fragments slow down and are stopped in the fuel. Thus the fuel rods heat up and transfer thermal energy to the coolant, which in most reactors is water but can be gas or liquid metal.
What is the product of a nuclear reaction?
Fission products, that is lighter elements than the uranium or plutonium fuel, free neutrons, and gamma radiation. The net energy effect is a release of 200 Mev per fission.(Approx 3.2 x 10-11 Joules)
What is done to keep the nuclear reactor under control?
control rods act like brakes to slow the neutron chain reaction rate in normal operation. the SCRAM system acts in emergencies to completely bring the neutron chain reaction to an instant stop. even with the reactor stopped, the cooling system must operate to prevent overheating from the radioactive decay of the built up fission products.
What can happen when a fission chain reaction gets out of control?
A chain reaction has products or byproducts that cause the reaction to continue. One example is a state of nuclear critical mass, in which an atom of u-235 decays to produce fast neutrons (along with other fission fragments), which crash into other u-235 atoms, which release more neutrons. The number of neutrons in the environment increases, and if this is not controlled, then there is a nuclear explosion. That is how an atomic bomb works. Another example is a state of instability in snow on a mountain side. If snow begins to move at the top of the mountain, it pushes the snow below it to give way, this pushes the snow below it to give way in turn, going down the mountainside until the snow runs out or the mountain levels out. This is an avalanche. Another example is a situation where the electric grid is overloaded to the point of instability. A failure in a transformer can cause a power surge that causes another failure, this causes other power surges in other places, resulting in other failures. This produces widespread power outage. Chain reactions continue until some sort of equilibrium is attained, or until the unstable features of the situation have lost their energy. In human terms, the results are often destructive or at least dangerous.
Pros and cons for nuclear fission?
ProsThe fuels that could be used are relatively inexpensive and readily available.The products of a fusion reaction are not radioactive, thus thee are no nuclear waste problems.Fusion is not a chain reaction, therefore it can be stopped at anytime and there is no threat of a meltdown.Fusion would be a virtually inexhaustible energy supply that could eliminate most of the world's dependence on other fuels.fairly expensive to create but virtualy inexpensive energyConsIgnition temperature is extremely high.Any substance at these high temperature are in the plasma state which is very difficult to contain.Large-scale fusion reactions are very expensive.May require more energy to create fusion than one can harvest from a reaction.Nuclear Fusion was not a controlled reaction until now.
