Question by Necsis: Which releases more energy nuclear fusion or fission?
Does one release more then the other, or do they release the same amount?
Also I heard some where we are currently able to harness a small percentage of the energy produced from fission. Can anyone tell me if this is true, and if so that percentage.
Best answer:
Answer by Johnny F
The actual amount depends on what is being “fissed” or “fused.” I believe it is dependent on the element in question.
We actually harness energy from fission all the time. All nuclear power plants use fission for their energy production. When atoms are split the missing mass shows up as energy. This process is a net gain of energy because you get a lot more energy out of the split atoms than it takes to split the atom in the first place.
Currently, we don’t get the same from the fusion process (at least here on Earth). Due to a change in mass for some fused atoms, energy can also show up. Unfortunately, right now it takes more energy for us to fuse atoms together than we get out of it, so it’s not reasonable to construct fusion power plants yet.
Add your own answer in the comments!
One Response
Nuclear energy is literally energy from the nucleus of an atom.
Fission is the splitting of a large atom into two or sometimes, rarely, 3 smaller atoms. Using U-235 as an example, a thermal neutron is absorbed, U-236 is formed which is very unstable and splits into two smaller atoms, the total mass of the resulting atoms is slightly less than the original atom and neutron. This mass is converted to energy per Einstein’s famous theory E=MC squared (about 200 Mev per fission)
Fusion is the joining of 2 small atoms to form a larger atom. This is the reaction which powers the sun. Under the right conditions, Hydrogen atoms may combine to form Helium the resulting Helium atom has less mass than the 2 original Hydrogen atoms. This mass is converted to energy per Einstein’s famous theory E=MC squared (about 17.6 Mev per fusion)
Because fission uses “heavier” fuel, it actually produces less energy out, per unit mass in, than fusion. Unfortunately, at this time, the conditions needed for fusion to occur and be contained require more energy than is produced in the fusion reaction. Nuclear reactions per unit mass in, produce millions of times more energy out than chemical reactions (burning fossil fuels).
All thermal power plants are limited by the laws of thermodynamics, so whatever the heat source, are only between 30%- 40% efficient as far as heat energy produced to electrical power out. Combined cycle plants, which use the “waste” heat can increase this to near 60%