nuclear energy- renewable or nonrenewble

some websites consider nuclear energy as renewable while others are considering it as nonrenewable..I am confuse, which one is correct
plis help me understanding the fact

What do you mean by renewable?

Renewable energy is sort of like an ad for something that says "SALE." It means nothing.

John

Even solar energy comes form the sun that will, in time, use up all of its fuel, will run out.

I would consider renewable energy to be from sources which are continually there and aren't depleted by use (at least from the human existence point of view) such as wind, solar, tidal action, etc., and non-renewable energy to be from sources that become depleted such as fossil fuels. Nuclear energy can be called either depending upon the time-frame you use. Available nuclear fission fuels are sufficient to last many human lifetimes and available fusion fuels are sufficient to likely last the life of the human race.

jpanhalt said:

What do you mean by renewable?

Renewable energy is sort of like an ad for something that says "SALE." It means nothing.

John

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I agree with John on this one. The trick, if there is a trick to it would be to define renewable energy. Internet definitions are cheap at best. Personally I am an advocate of nuclear energy and that is not to say it is or is not renewable.

Just My Take
Ron

The only source for fissionable elements, whether naturally occurring or forged from something else in a nuclear reactor, and any element heaver than Iron for that matter, is a super nova. Yup, you need to have a star explode at the end of it's fusion life to make any. Similarly, through fusion, you start with Hydrogen and can't go any heaver than, again, Iron and all the Hydrogen in the Universe, including much of the Helium and Lithium, was forged as the big bang cooled enough to permit atoms to exist.

Ever since the star or stars whose nova formed the cloud that the Earth, Sun, and other solar system objects coalesced from went pop, the amount of Uranium 235 has been halved every 700 Million years. ( It's not very radioactive ) In this context, no fuel utilized as a power source is renewable. It may last a while, but if someone is around long enough to use up all that is available, there will be problems finding or making more.

samina said:

some websites consider nuclear energy as renewable while others are considering it as nonrenewable..I am confuse, which one is correct
plis help me understanding the fact

Click to expand...

I remember way back when they used to have "breeder reactors" that supposedly created fuel as a byproduct of the fission process, in effect creating fuel Maybe that's what they are talking about.

https://en.wikipedia.org/wiki/Breeder_reactor

Steaphany said:

The only source for fissionable elements, whether naturally occurring or forged from something else in a nuclear reactor, and any element heaver than Iron for that matter, is a super nova. Yup, you need to have a star explode at the end of it's fusion life to make any. Similarly, through fusion, you start with Hydrogen and can't go any heaver than, again, Iron and all the Hydrogen in the Universe, including much of the Helium and Lithium, was forged as the big bang cooled enough to permit atoms to exist.

Click to expand...

I thought stars converted hydrogen to He4 (an isotope of helium) as the hydrogen "burned"?

**broken link removed**

Correct that all the heavier elements are created in novas.

bountyhunter said:

I thought stars converted hydrogen to He4 (an isotope of helium) as the hydrogen "burned"?

**broken link removed**

Correct that all the heavier elements are created in novas.

Click to expand...

A normal star (like ours "1 solar mass") stops at helium.
http://en.wikipedia.org/wiki/Silicon-burning_process

Ok, two things to consider here.

Firstly is what you consider to be "nuclear" because there are three kinds of nuclear power.

Nuclear Fission which is what most people consider to be nuclear power. This kind of nuclear power can be divided up into the kind of fuel it uses.
This can be Uranium, Plutonium, Thorium or other heavy elements which can also be made to fission, even if they aren't practical for nuclear power.

Nuclear Fusion is also nuclear. The primary source of fuel is Hydrogen or Deuterium (with combinations of other light isotopes).

Nuclear Decay is a third. Radioisotope thermoelectric generators are used for small long term power applications like spacecraft, remote lighthouses, and even pace makers.

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Next we need to consider what is "renewable". Typically it means that your source of fuel can accumulate over time. It is this time period that also determines if the fuel is renewable. Coal is not a fuel we consider to be renewable, but given a long enough time frame, it is.

If we reverse the logic, solar power we consider renewable. It gets its energy from the sun which itself has a finite and non-renewable source of fuel.

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Back to nuclear. We shall just consider a Uranium open fuel cycle. This fuel cycle enriches Uranium to ~3.3% U235 or uses heavy water reactors.
The fuel is assembled and used and the spent fuel assemblies are then removed from the reactor and moved into short term storage and then into long term storage so they can decay to a safe level. This process takes about 1000 years.

If this is the only method used, then with current viable uranium resources and population growth it is not unreasonable to expect there to be enough fuel for the next 200 years. With unproven reserves 300 years is not an unreasonable expectation. Clearly by this logic it is a finite resource and not renewable.

Enter the fast breeder reactor. Natural Uranium is 0.7% U235 and this is the source of conventional nuclear fission. This is enriched to ~3.3% and when a fuel assembly is spent there is about 0.5% remaining. But some of the U238 is also transmutated into Pu239 (via Np239). In normal light water reactors about 2.5% of the U238 is also consumed as fuel and contributes to the power output of the reactor.

A Fast Breeder reactor takes advantage of this and makes more efficient use of fast neutrons to breed more fuel than it consumes. The fuel output is mostly Plutonium Pu239. This is called a closed fuel cycle.
The spent fuel assemblies are sent away for reprocessing. The spent fuel is chemically separated out.
The Uranium U238 and U235 is recovered to be used in new fuel assemblies.
The Plutonium U239 and U241 are also recovered for use as MOX fuel. Pu240 and Pu242 are neutron poisons but they are fertile.
The fission products make up about 4% of the volume and are the true high level nuclear waste. They are isolated, any useful isotopes extracted and the rest is then reduced and enters the waste storage process to decay naturally.

If we consider that we currently make use of only about 1% of Uranium and that is expected to last us about 200-300 years, we can expect a closed nuclear fuel cycle to extend that out to about 2000 years not considering any other factors which may influence use of Uranium as a fuel.

The next thing to consider is Thorium as a source of fuel. With roughly four to five times as much Thorium available as Uranium, we can see that there is a long term source of fuel for nuclear fission. And to a lesser extent, for Radioisotope generation.

If nuclear fusion becomes viable, then the fuel source (water) is one of the most abundant substances we have on earth. As a fuel source it is virtually limitless in a similar way to like solar.

Nuclear Fission should be considered a large non-renewable source of power.
Nuclear Fusion has such a colossal potential (finite) fuel source we consider it limitless or "renewable".