Saturday, January 30, 2010

Post # 12: Your Life In Uranium and Coal

The average American consumes ~ 14000 kWh of electricity per year - among the highest in the world. That's roughly 1,120,000 kWh of electricity in an 80-year lifespan.

Let's examine how much fuel must be consumed in modern nuclear and coal-fired power plants to produce this amount of electricity – "your life in uranium and coal" so to speak...

Nuclear reactors are powered by fission process  ~ 51000 fuel pins (in a typical gigawatt-class nuclear power plant).  Each of these fuel pins is approximately 1/3-inch in diameter and ~ 12 feet in length (there are many variations, but these are reasonable average numbers.)

Based on the current once-through nuclear fuel cycle (which, by the way, extracts < 10% of the energy that is theoretically available in the fuel), the 14000 kWh of electricity each of us "consume" in a year is produced in only 2.6 inches of ONE nuclear fuel rod!  If you "run the numbers", this means that all of the electricity consumed by one American during their 80-yr life is produced by less than two of these small fuel pins !  In more familiar terms, that's about a soda can of nuclear fuel, or a cube of nuclear fuel a bit less than 4 inches on a side.  How's that for an efficient energy source?

Now compare these estimates to the amount of coal required to produce the same amount of energy.  The average energy content of coal is ~ 6150 kW(t)h / metric ton.  If we assume 40% overall thermal efficiency of the coal-fired plant (generous on average), that same American would consume ~ 455 metric tons of coal.  That's equivalent to a solid cube of coal 135-ft on a side.

So picture this... a soda can of nuclear fuel or a cube of coal 135 feet on a side:

That's "your life in uranium and coal"...


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