2 results for month: 02/2007


A Few Good Moderators: The Numbers

Yesterday I posted on the issues that surround finding a good moderator. Today I'll walk you through the math that will let you do the calculations yourself. At the end I'll link a spreadsheet that already has the calculations done that you can download and monkey around with if you want.First of all, you want a moderator that's good at moderating. That means that when a neutron hits it, the neutron loses a lot of energy, specifically kinetic energy. Just like in marbles or pool balls, the bigger the moderator nucleus, the less energy the neutron will lose when it hits it.In nuclear engineering, the fancy term for this feature is the average ...

Looking for a few good moderators…

Finding the right salt combination for a fluoride reactor isn't too difficult. If you want a salt that has a relatively low melting temperature, low neutron absorption, and good temperature performance then you use lithium-fluoride/beryllium-fluoride, being careful to use the lithium-7 isotope instead of just the natural stuff.But when looking for a moderator, things are a lot more difficult. It turns out that the inside of the reactor is a pretty tough place for most moderators, and there's really good reasons most of the conventional moderators don't cut it.First of all, why do we want a moderator? Well, the moderator is the "stuff" in the ...