Clear Science sources for technical info on nuclear plants

The Clear Science staff thought our readers might want to check out our favorite sources concerning the nuclear plant accidents in Japan. We made use of these writing today’s post.

  1. The Union of Concerned Scientists Tumblr site: All Things Nuclear
  2. The informative posts on BraveNewClimate
  3. And of course Wikipedia, which we believe is the greatest scientific resource ever created in human history
In light of the emergencies at the Fukushima I and II power plants in Japan, we’re going to talk about nuclear power plants for a while. Nuclear power is not super-complicated: there is nuclear fuel, for example either UOX or MOX pellets (uranium oxide or mixed uranium and plutonium oxides in this case), which are packed into zircaloy ceramic rods. The job of the rods is to get hot. This is just like in a fossil fuel power plant, when it’s the coal or oil’s job to get hot.
The fuel rods are surrounded by water, which gets hot, boils, and carries the heat away. In the picture above, the red line is the heat generation profile in the rods: they generate the most heat at their center. Think of the heat as a thing that is generated there, diffuses through the solid rod to the outside, transfers to the cooling water, and exits with the water as it boils and becomes steam.
If there is an interruption in this heat transfer path, then heat will begin to build up. Think of it as a heat traffic jam. If the heat begins to collect in one spot, the temperature there will rise. The zircaloy and nuclear fuel pellets are ceramics and have extremely high melting points. However, if you get a big enough heat traffic jam, they will eventually melt. That’s called a meltdown.

In light of the emergencies at the Fukushima I and II power plants in Japan, we’re going to talk about nuclear power plants for a while. Nuclear power is not super-complicated: there is nuclear fuel, for example either UOX or MOX pellets (uranium oxide or mixed uranium and plutonium oxides in this case), which are packed into zircaloy ceramic rods. The job of the rods is to get hot. This is just like in a fossil fuel power plant, when it’s the coal or oil’s job to get hot.

The fuel rods are surrounded by water, which gets hot, boils, and carries the heat away. In the picture above, the red line is the heat generation profile in the rods: they generate the most heat at their center. Think of the heat as a thing that is generated there, diffuses through the solid rod to the outside, transfers to the cooling water, and exits with the water as it boils and becomes steam.

If there is an interruption in this heat transfer path, then heat will begin to build up. Think of it as a heat traffic jam. If the heat begins to collect in one spot, the temperature there will rise. The zircaloy and nuclear fuel pellets are ceramics and have extremely high melting points. However, if you get a big enough heat traffic jam, they will eventually melt. That’s called a meltdown.

Last week on March 11, 2011 a powerful earthquake occurred with an epicenter 80 miles off the coast of Japan near the city of Sendai, which has a population of about one million people. The Clear Science staff has heard the magnitude of the Sendai earthquake reported from 8.8 - 9.0 on the moment magnitude scale (MMS). The MMS is similar to the Richter scale, a name which is still sometimes used colloquially. (And why not? People know what it means!)
The MMS is a logarithmic scale, meaning that each number higher is actually ten times more powerful in magnitude. That’s why a big truck going by your house might be a 3-4 on the scale, but a huge earthquake that results in massive loss of life will be an 8 or 9. The largest earthquake ever recorded on Earth was the 1960 Valdivia earthquake in Chile, which was a 9.5. If you run through the logarithm math, this is 3.2 times larger than the Sendai earthquake that just happened.
The measurement scale for sound pressure, decibels, is also a logarithmic scale, in which small changes in number signal huge changes in loudness. (Decibels or dB are actually a logarithm multiplied times 20, so every 20 is 10x higher.)

Last week on March 11, 2011 a powerful earthquake occurred with an epicenter 80 miles off the coast of Japan near the city of Sendai, which has a population of about one million people. The Clear Science staff has heard the magnitude of the Sendai earthquake reported from 8.8 - 9.0 on the moment magnitude scale (MMS). The MMS is similar to the Richter scale, a name which is still sometimes used colloquially. (And why not? People know what it means!)

The MMS is a logarithmic scale, meaning that each number higher is actually ten times more powerful in magnitude. That’s why a big truck going by your house might be a 3-4 on the scale, but a huge earthquake that results in massive loss of life will be an 8 or 9. The largest earthquake ever recorded on Earth was the 1960 Valdivia earthquake in Chile, which was a 9.5. If you run through the logarithm math, this is 3.2 times larger than the Sendai earthquake that just happened.

The measurement scale for sound pressure, decibels, is also a logarithmic scale, in which small changes in number signal huge changes in loudness. (Decibels or dB are actually a logarithm multiplied times 20, so every 20 is 10x higher.)