Nuclear Factoids

Aircraft carriers on the Burj Dubai Sometimes it takes a bunch of factoids to get a point across. However, factoids can be misleading since they can hide many of the implications of reality. Here we present some of the astonishing factoids of nuclear power and attempt to discuss them realistically and without (too much) bias.

Also, we are making available our spreadsheet used to calculate these factoids. If you’re interested, check them out and contact us with questions, suggestions, and corrections.
Factoids.ods (open office)
Factoids.xls (MS Excel)


Factoid 1: Energy Density

A kilogram of coal can run a 100W lightbulb for about 4 days while a kilogram of natural uranium can run it for 182 years! If you enrich uranium up to weapons grade, a kilogram can then run the lightbulb for over 24,000 years! Put in better perspective, that kilogram of rock can power the entire USA for 177 seconds (almost 3 minutes!).

Discussion of energy density

Factoid 2: Recycling Nuclear Waste

If we took all the nuclear waste that was sitting around in the USA today from the past 50 years of running reactors and recycled it, we could use it to power the entire USA for about 93 years without mining anything else.

Discussion of recycling waste

Factoid 3: Waste per person

If all power in the USA came from conventional nuclear reactors, each American would be responsible for generating 40 grams of nuclear waste per year. That’s the same as 7 US quarters weigh. If breeder reactors were used, it could be as low as 4 grams. For comparison, each American is currently responsible for about 10,000 kg of carbon emissions directly into the atmosphere from electric plants per year, not to mention particulates and many toxins. Nuclear waste, on the other hand stays out of the biosphere.

Discussion of waste per person

Factoid 4: Amount of Uranium

At current demand, we can run the world fleet of nuclear reactors for about 220 years with expected uranium reserves on Earth.

Discussion of amount of Uranium

Factoid 5: Land use

To replace a regular 1 GW nuclear power plant with 33% efficient solar power in Michigan, you’re going to need 6.2 square miles of space. To do so in Arizona, you need 4.0 square miles.

Discussion of land use

Factoid 6: Scale of energy usage

To store the amount of energy a single typical nuclear power plant generates in one night, you would have to lift 44 fully loaded Nimitz-class aircraft carriers to the top of the Burj Dubai (818 meters) during the day and slowly let them fall on a pulley, spinning generators.

Discussion of scale

Discussions

Factoid 1: Energy Density

There are a couple issues with this statement. Firstly, it is a factoid of scale. You probably can’t actually generate 100W of electricity with a kilogram of wood nor with a kilogram of uranium. You need a big power plant to do these things. But big power plants can power a lot more than 1 light bulb. The idea just to visualize how much energy is contained in each material. Secondly, this factoid assumes 100% efficiency in converting between heat and electricity. Typical power plants usually only get about 33% due to laws of thermodynamics. So you may have to divide the times quoted by about three to get more realistic numbers. However, different types of power plants have different efficiencies, and some conceptual high-temperature nuclear reactors may be able to get up to 50%. So we left out the conversions to give you a better feel of how much energy is inherently stored in materials.

More on enrichment

Factoid 2: Recycling Waste

While technically realistic, this factoid would require much to be done in order to actually happen. Enough nuclear power plants to power the entire USA would need to be built. Only nuclear reactors can run on nuclear waste, not coal plants. The type of reactors needed would be breeder reactors, which do exist, but have not been deployed commercially anywhere in the world on a large scale. We would also need to build reprocessing plants capable of processing all 47,000 tonnes of waste we have lying around. All of this would be very costly and would require a focused national effort. There would still be some nuclear waste after all this recycling as well. Breeders can get rid of most of the actinides, but there are no reactors that can get rid of fission products. These typically remain dangerously radioactive for up to 300 years - significantly shorter than the hundreds of thousands of years of typical nuclear waste. At the end of it all, there would still be about the same mass of nuclear waste, but it would have been used MUCH more efficiently, displaced WAY more carbon/pollutants, and would decay to stability much faster than the original waste.

More on recycling nuclear waste

Factoid 3: Waste per Person

Of course, the 40 grams of stuff are highly toxic. But the beauty is the toxic stuff never spewed into the atmosphere like in fossil plants. We can contain this stuff. This assumes no recycling or anything, just business as usual with all nukes. Again, it would take a lot to replace all the coal plants with nukes. Wind and solar and hydro can help out here! Let’s do it!

More on nuclear waste

Factoid 4: Amount of Uranium

Uranium is not the most plentiful element on the planet. Won’t this just bring us into the same problem we have with oil? The answer is yes, unless we recycle our fuel. Or if we find a way to extract Uranium cheaply from the sea water (not economically feasible yet). If we recycle and breed, the known uranium reserves effectively go up by a factor of at least 8, taking us into the 16,000 year range. If we find a way to get Uranium out of the ocean, we're talking hundreds of thousands of years. Also, nuclear reactors can operate on the element Thorium instead of Uranium, which gives us even more time. So, this is certainly something to worry about if we decide to build a lot of nuclear plants soon, but it just means we have to do things correctly.

Factoid 5: Land Use

Keep in mind 33% efficient solar cells are not commonplace yet. If you used solar-thermal, you might be able to get 33% efficiency cheaply. The solar plant would still require some kind of storage to provide power through the night.

More on solar power

Factoid 6: Scale of energy usage

The point here is that we use unfathomable amounts of energy, and when we talk about storing energy from solar and wind, we need to keep this in mind if we want to be realistic.

More on lifting aircraft carriers