Nuclear power and greenhouse gases

I am a proponent of nuclear power. I want to see electric cars powered by nuclear energy. I want to see every single coal power plant relegated to backup roles only. Let’s forget about nuclear waste, weapons proliferation, the greater possibility of accidents, and other scaremongering.

Nuclear power plants create steam. Lots of it. (As do other types of power plants which use steam pressure to turn turbines.) And water vapour is a greenhouse gas. It is even more effective at trapping heat than carbon dioxide.

I can’t reconcile this issue in my head. Is the amount of CO2 and H2O produced by the worldwide fleet of vehicles (as measured by how much it will increase global temperature) overwhelmingly greater than the amount of greenhouse gas (in the form of water vapour) that will be emitted by the cooling towers of the many nuclear power plants required to accomplish this feat? Has this issue been considered by any studies? Are there ways to negate the release of steam? (I’m picturing giant radiators.) Is it just a non-issue?

And that’s not even mentioning the scarcity of uranium ore, and the cost (monetary and pollutive) of mining it.

Short answer:

Water vapor in the air will readily condense and fall back to the ground as precipitation. So while it would be altering the water cycle, it’s basically just shifted the equilibrium around. Carbon, on the other hand, is not being removed from the atmosphere, so it keeps building up. Eventually the planet will reach some new equilibrium in the carbon cycle, but it’ll probably be on some geological time scale, perhaps between tens of thousands and millions of years.

Well hell, if you are going to ignore those, why not ignore greenhouse gases too? Then nuclear power would be perfect.

Because those aren’t global issues (with the possible exception of major meltdown) and aren’t happening continuously throughout the operation of the plant on a scale that can effect the entire world.

Water vapor is a much more effective greenhouse gas than CO2, but it doesn’t matter (according to our current understanding) because it doesn’t force the temperature up like CO2 does; it just varies according to temperature. Here’s a quick link describing what I’m talking about:

There’s a link at the bottom of the article there to a RealClimate article describing it in more detail.

Another thing to consider is that the operation of a nuclear plant is very similar to that of a coal fired plant. Its a standard steam cycle that has been in use in power plants for years.

Heat source > Turbine > Condenser > Feed pumps > Heat source

For a coal fired plant, the heat source is a coal fired boiler. For nuclear, its the reactor. The cooling process remains the same, so its rather unfair to pick on nuclear about this.

Cooling towers are used because it requires less water overall. Converting water into steam in the cooling process removes a lot more energy(latent heat of vaporization), which reduces the pumping power required for the cooling system, and reduces the water need as a whole.

Another large factor, is thermal pollution. If you were to try to eliminate the release of steam altogether, well… the heat has to go somewhere. The easiest place to do this is the atmosphere. Its very, very large, and will readily cool and condense the water vapor. Your only other option for most plants is to release it back into the water supply the water was initially gathered from, which can have a very detrimental effect on aquatic life in rivers and lakes.

Naval reactors, operating primarily in the ocean(and generally being small anyway) are less of an issue, since the ocean is so vast and the release spread out over such a large area.

Edited to remove a double post.

I concur with Cutter John - and you - that the production of water vapor as a consequence of generating electricity is not specific to nuclear power plants. Those coal-fired plants that you have relegated to a backup role were doing the same, so there’s no net increase per KWH generated.

ISTR that the processing of U ore into feedstock involves a lot of GG emissions, but I don’t remember why. Maybe someone will beat me to it as I research…

Enriching uranium (separating radioactive from non-radioactive isolates) takes lots of power. During WWII, the government set up a huge number of centrifuges at Oak Ridge, TN, not because of Tennessee’s supply of physicists but because of the supply of electrical power from the TVA. I imagine that the gas diffusion process of enriching uranium is similarly power hungry and that is why the Hanford plant was built near the Grand Coulee hydroelectric plant.

The steam doesn’t get released, does it? I was under the impression that steam-turbine driven power operates in a closed loop.

The steam used in the steam cycle is a closed loop. A second loop of water is used to help condense the steam back into water. This second loop is not closed.

See here: