If some radioactive elements radiate for billions of years ...

[Sirona]

To the science aces, here is a question that has long puzzled me. Radioactive elements radiate, some for billions of years. A side effect of nuclear fission is the release of heat that heats water into steam, which then drives turbines in nuclear power plants. So if these elements radiate and generate heat for longer than the presumed end of the Earth, why do we have "nuclear waste" at all? Shouldn't we then have an endless source of energy in these radioactive elements with long half-lives instead?

 

[Polymath257]

The problem is that the elements with long half lives don't produce a lot of energy for any given period of time. And those with short half-lives are gone before much energy can be extracted. Also, there is no control over when the energy is given off: it just is emitted. So, there is no way to adjust for energy demand.

Also, the radioactivity tends to degrade any housing you put it in and to make other things radioactive (depending on what the composition is).

The point is that fission happens fast enough to give a lot of energy and it can be controlled in regard to how fast it gives off energy (by use of control rods).

 

[Twilight Hue]

To the science aces, here is a question that has long puzzled me. Radioactive elements radiate, some for billions of years. A side effect of nuclear fission is the release of heat that heats water into steam, which then drives turbines in nuclear power plants. So if these elements radiate and generate heat for longer than the presumed end of the Earth, why do we have "nuclear waste" at all? Shouldn't we then have an endless source of energy in these radioactive elements with long half-lives instead?

If you could achieve that, you would either win the Nobel peace prize or get wacked by some corporate psychopath for putting him or her out of business.


Seriously though, it would be great to access an endless supply of energy with such potential.

 

[ChristineM]

The problem is that the elements with long half lives don't produce a lot of energy for any given period of time. And those with short half-lives are gone before much energy can be extracted. Also, there is no control over when the energy is given off: it just is emitted. So, there is no way to adjust for energy demand.

Also, the radioactivity tends to degrade any housing you put it in and to make other things radioactive (depending on what the composition is).

The point is that fission happens fast enough to give a lot of energy and it can be controlled in regard to how fast it gives off energy (by use of control rods).

I came here to say something like that but not as eloquently

 

[Heyo]

To the science aces, here is a question that has long puzzled me. Radioactive elements radiate, some for billions of years. A side effect of nuclear fission is the release of heat that heats water into steam, which then drives turbines in nuclear power plants. So if these elements radiate and generate heat for longer than the presumed end of the Earth, why do we have "nuclear waste" at all? Shouldn't we then have an endless source of energy in these radioactive elements with long half-lives instead?

As @Polymath257 already pointed out, if the radioactive substance only gives of little heat (not enough to drive a turbine) and has to be shielded to protect living things and even equipment, than it is no longer economical to use.
There are, however, rare and special applications for the use of simple radioactive decay as a power source. Astronomical probes like the New Horizons spacecraft can make use of the energy as 1. space is cold and any heat is welcome and 2. there are no living things nearby to protect.

 

[sayak83]

To the science aces, here is a question that has long puzzled me. Radioactive elements radiate, some for billions of years. A side effect of nuclear fission is the release of heat that heats water into steam, which then drives turbines in nuclear power plants. So if these elements radiate and generate heat for longer than the presumed end of the Earth, why do we have "nuclear waste" at all? Shouldn't we then have an endless source of energy in these radioactive elements with long half-lives instead?

As other have pointed out, small amounts of heat are not that useful. Small amounts of heat means that the temperature generated are not very high. This makes the efficiency of conversion of the heat to useful things (electricity, mechanical work etc) very low. The second law of thermodynamics is operational here, and being a universal law, there is no work around either.

 

[Aletheia Athanatos]

To the science aces, here is a question that has long puzzled me. Radioactive elements radiate, some for billions of years. A side effect of nuclear fission is the release of heat that heats water into steam, which then drives turbines in nuclear power plants. So if these elements radiate and generate heat for longer than the presumed end of the Earth, why do we have "nuclear waste" at all? Shouldn't we then have an endless source of energy in these radioactive elements with long half-lives instead?

Conservation of energy.

The difference in energy between the before and after states of a particular object is fixed; so if you double the half-life, then you halve the energy output per second.