How does nuclear energy work?
Nuclear fission is the process where the nucleus (hence ‘nuclear’ energy) of a ‘heavy’, fissionable atom is split. Enormous amounts of energy are released in this process.
This energy, in the form of heat is transferred to steam turbines to generate electricity. So, apart from the source of energy, a nuclear energy plant is in essence no different from any fossil fuel power plant. Both use the energy source to generate heat to drive turbines that generate electricity. Electricity is then fed into a grid for domestic and industrial use.
An atom’s nucleus can only split if it is ‘fissionable’. Only the nuclear isotopes Uranium 235 (U235), Plutonium 239 and Uranium 238 are of this type. Only U235 occurs naturally. The other isotopes are created in the U235’s fission process.
This transformation occurs as in the fission process neutrons bombard the U235 at high speed and penetrate its atoms. Fission happens when a nucleus absorbs a neutron and splits into two nuclei that now have a different composition.
Uranium as it is found contains only about 0.7% of U235 and much of the rest is uranium 238 with which it is much more difficult to achieve fission. It can be achieved with ‘fast breeder reactors’, which can blast neutrons at speeds high enough to penetrate and spit the U238’s nucleus.
Therefore fast breeder reactors are more efficient users of uranium than the common thermal reactors—in fact 60 times more so—and leave far less radioactive waste. They can reuse the current nuclear waste stockpiles. Such reactors can also use thorium, a far more abundant material than uranium but containing mostly U238. There is now only one fast breeder reactor in service but scientists hope that in about 15 years more will come on stream.
How does nuclear energy work and how can a chain reaction be stopped?
When a nuclear chain is uncontrolled it overheats, causes damage to the reactor and radioactivity may spill into the environment. That’s what happened at Chernobyl where there was no separate protective building around the reactor’s housing.
Essentially the chain reaction is slowed, stopped or sped up by addition of rods into the reactor core. These rods absorb neutrons, thereby affecting the nuclear process. These control rods are made of cadmium, hafnium or boron.
To shut a reactor down if this system fails neutron-absorbing fluid can be added. Usually this is water, or heavy water or graphite.
Nuclear fission is the process where the nucleus (hence ‘nuclear’ energy) of a ‘heavy’, fissionable atom is split. Enormous amounts of energy are released in this process.
This energy, in the form of heat is transferred to steam turbines to generate electricity. So, apart from the source of energy, a nuclear energy plant is in essence no different from any fossil fuel power plant. Both use the energy source to generate heat to drive turbines that generate electricity. Electricity is then fed into a grid for domestic and industrial use.
An atom’s nucleus can only split if it is ‘fissionable’. Only the nuclear isotopes Uranium 235 (U235), Plutonium 239 and Uranium 238 are of this type. Only U235 occurs naturally. The other isotopes are created in the U235’s fission process.
This transformation occurs as in the fission process neutrons bombard the U235 at high speed and penetrate its atoms. Fission happens when a nucleus absorbs a neutron and splits into two nuclei that now have a different composition.
Uranium as it is found contains only about 0.7% of U235 and much of the rest is uranium 238 with which it is much more difficult to achieve fission. It can be achieved with ‘fast breeder reactors’, which can blast neutrons at speeds high enough to penetrate and spit the U238’s nucleus.
Therefore fast breeder reactors are more efficient users of uranium than the common thermal reactors—in fact 60 times more so—and leave far less radioactive waste. They can reuse the current nuclear waste stockpiles. Such reactors can also use thorium, a far more abundant material than uranium but containing mostly U238. There is now only one fast breeder reactor in service but scientists hope that in about 15 years more will come on stream.
How does nuclear energy work and how can a chain reaction be stopped?
When a nuclear chain is uncontrolled it overheats, causes damage to the reactor and radioactivity may spill into the environment. That’s what happened at Chernobyl where there was no separate protective building around the reactor’s housing.
Essentially the chain reaction is slowed, stopped or sped up by addition of rods into the reactor core. These rods absorb neutrons, thereby affecting the nuclear process. These control rods are made of cadmium, hafnium or boron.
To shut a reactor down if this system fails neutron-absorbing fluid can be added. Usually this is water, or heavy water or graphite.
Por acaso é um tema sobre o qual gostava de saber mais...mas em inglês acabou por me escapar qualquer coisa por causa dos termos técnicos!! E não sei se o tema da semana justificava este post! :p De qualquer forma:
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