Reply #30: Setting the record straight

[kristopher]

First let me say that I don't think we are to the point where the risks of insufficient energy and the negatives of carbon fuels justify shifting large scale to nuclear. Not yet.

However, I truly dislike people agreeing with based of faulty information.

The fears of a Chernobyl type meltdown are one of the prevailing images that people hold. It is a baseless fear based on lack of knowledge about how the process of fission is initiated and maintained.

The fuel is radioactive, that means it throws off particles that hit other particles and cause them to split hitting other particles and causing them to split - there you have it fission. Most people understand that.

What is not known so well is that the speed that the particles travel at is important. Pay attention here - the faster the particles travel, the less likely they are to hit another particle and cause it to split.

IN ORDER TO INITIATE AND MAINTAIN A FISSION REACTION, SOMETHING MUST BE USED TO SLOW DOWN THE PARTICLES.

This is usually heavy water*, but not always. The reactor at chernobyl used graphite. The human error that caused the meltdown was only possible because they used graphite. If they had used water, they could have emptied the water surrounding the fuel and stopped the reaction; no meltdown.

Don't confuse the three separate uses of water in these nonchernobyl type reactors. One use is to enable the fission reaction. The second use is to transfer heat to some device that powers a turbine.

If the water that is around the fuel is lost, then the reaction naturally and unavoidably shuts down. Of course, it is contaminated and if it is released into the environment, it would be bad, but it is nothing like the threat of a meltdown.

There are many reasons to proceed cautiously with nuclear power, but fear of meltdown shouldn't be one of them.




*heavy water:
A molecule of water contains two atoms of hydrogen and one of oxygen. Most water comprises of hydrogen/oxygen but a small percentage is composed of another hydrogen isotope, deuterium and oxygen. Deuterium differs from hydrogen by having one neutron in the nucleus of each atom. ...
http://www.ch.ic.ac.uk/vchemlib/mol/glossary/