Physical Insights

An independent scientist’s observations on society, technology, energy, science and the environment. “Modern science has been a voyage into the unknown, with a lesson in humility waiting at every stop. Many passengers would rather have stayed home.” – Carl Sagan

Anti-Nuclear Quote of the Day.

with 2 comments

“It has been estimated that every nuclear reactor daily releases thermal energy – heat – that is in excess of the heat released by the detonation of a 15 kiloton nuclear bomb blast. ” [Sourced here]

Let’s see. One kiloton of TNT equivalent equals 4.184 * 10^12 J. 15 kilotons is equal to 6.276 * 10^13 J.

This is the amount of energy which, when released in a single instant, destroyed Hiroshima. That seems like a lot of energy, doesn’t it?

Let’s try converting 6.276 * 10^13 J of energy to a more relevant unit of energy.

6.276 * 10^13 J = 17.4 gigawatt-hours.

But it’s only 17.4 GWh – on the scale on which we generate electrical energy, it’s tiny! It’s not a lot of energy at all – it’s peanuts!

Let’s say that a power plant has an electrical output of 1 GW, a capacity factor of, say, 90%, and a thermodynamic conversion efficiency of, say 33%.

Such a power plant will generate thermal energy equivalent to a 15 kiloton nuclear weapon – every 6.4 hours.

That’s the power output of the plant. Yes, we know what the typical power output of a large power plant is. Big deal!

It doesn’t matter what it is – a nuclear power plant, a coal-fired plant, a biomass burning plant, or a solar thermal plant – 1.16 GWh of energy is the same as 1 kiloton of TNT energy equivalent, irrespective of where the energy comes from.

Moral of the story? The kiloton of TNT equivalent is a very large unit of explosive energy release. As a unit of energy release in general, there’s nothing especially large about it.

Let’s imagine that you could somehow store up all the electrical power that a typical large city consumes over a single 24 hour period  – say, in some kind of hypothetical, enormous capacitor – and release it in one sudden burst, lasting a tiny fraction of a second. The resulting power output would take the form of an explosion not unlike the detonation of a nuclear weapon, with an explosive yield of tens of kilotons, capable of destroying the city. However, obviously, the normal rate at which energy is generated in our power plants is completely safe and controllable. Everybody knows that!

Here’s another laughably ridiculous statement:

“In addition to horrendous direct impact of this heat on aquatic ecosystems, nuclear power contributes significantly to the thermal energy inside Earth’s atmosphere, making it contraindicated at this time of rapid global warming.”

Geothermal, solar thermal, and fossil-fuel fired power plants are all thermal engines, too, you know. They all discharge waste heat into the environment.

If you want an energy-converting engine that operates with perfect efficiency, perhaps you should consider investing in these guys to solve all your energy problems?

You might not like the laws of thermodynamics – but they are not something that applies exclusively to nuclear power.

2 Responses

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  1. This is sad, the way some people will eat up these statements in a negative way.

    VERY near where I work is a plant that generates more power than that of the entire world (though only for a few ns).

    http://en.wikipedia.org/wiki/Z_machine

    They store it up by burning nearby coal in your monster capacitors, known around here as “Marx generators.” Then poof!

    Reese

    April 5, 2008 at 4:04 am

  2. Sorry, bad English. They burn the coal at the electricity plant, channel the ‘trons into the Marx generators. THEN poof.

    Reese

    April 5, 2008 at 4:05 am


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