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How can the fission be controlled or stopped in a nuclear reactor?
Wiki User
∙ 14y ago
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.
Wiki User
∙ 15y ago
Wiki User
∙ 14y agoThe fission is controlled in a nuclear reactor using materials that are having high neutron absorption capabilities. Accordingly, rate of nuclear fission is controlled or stopped by controlling the number of neutrons available to produce fissions.
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Can the chain reaction of nuclear fission be stopped or controlled?
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.
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 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.
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.
Can the chain reaction of nuclear fission be stopped or controlled?
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.
What could happen if the water stopped flowing through a nuclear reactor?
overheatingpossibly meltdown
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
How did the Nuclear reactor get damiged?
If you are talking about the Nuclear Reactors in Japan, they were damaged because when they lost power, the water pumps used to cool them stopped, and all of the nuclear material overheated.
Why is the nuclear reactor surrounded by a thick concrete layer?
To stop radiation leaking out. Alpha and Beta types of radiation will be stopped by the concrete
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.
Severe overheating of a nuclear reactor core?
The ultimate would be to cause melting of the fuel. It must be shown (theoretically) that this would be contained in the bottom of the reactor vessel. The fission chain reaction would have stopped but there is after heat from radioactive decay and this must be absorbed by emergency cooling to avoid damage to the vessel. This is an extreme case and might be caused by a severe loss of cooling accident, but is very unlikely in most reactors.
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.
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.
Why did Japan's nuclear plant overheat?
Electrical generators are cooled with hydrogen gas. If the containment of the hydrogen, either the tubes leading from the electrical generators to the cooling water supply fails due to expansion/contraction of the tubes during foundation movement, leaks might occur and the hydrogen, when mixed wit air, becomes explosive. Most hydrogen created in the nuclear fission reaction are kept within the sealed nuclear tubes are are a very minor source of hydrogen for explosive activity.
