Tag: Scitech

This is sort of a companion piece to Friday’s Popular Culture piece about eight track tapes.  There was quite a response to that piece, and several commentators suggested that we talk about vinyl records tonight.  I have a great respect for my readers, so I am happy to oblige.

On the surface, records seem to be quite simple things indeed.  In practice, few things are further from the truth.  While the concept behind records is fairly simple, the technology is extremely complex to attain high fidelity, defined as sound reproduced with high enough quality as to give the impression that actual performers are playing at the time.  In other words, artifacts of recording and playback should be so small as barely to be noticed.

We hear a lot about carbon these days as a greenhouse gas, sort of giving carbon a bad name.  While I agree that excessive carbon dioxide emissions from the wanton burning of fossil fuels is a  bad thing, it is not the fault of the carbon, but rather the fault of civilization for being unwise in how fossil carbon deposits are used.

As a matter of fact, without some carbon dioxide release, we would all starve because atmospheric carbon dioxide is the sole source of carbon in the food chain, thanks to the photosynthetic ability of green plants.  But this topic has been discussed in many places, sometimes in this regular series.  We shall discuss other properties of carbon and why it is essential to life as we understand life, and perhaps all life yet undiscovered.

The past two weeks we have been looking about current nuclear technology for power production.  Almost all of the plants currently in commercial production are the so called Generation II and Generation III plants, and the most advanced ones are sometimes called Generation III+.  This evening we shall examine nuclear technologies that are not yet used for commercial production.

These designs are called Generation IV plants, and may either be prototypes or merely designs that have not yet even had a prototype built, but appear to be feasible to come on line commercially by 2030 or so, give or take.  There is also a Generation V set of concepts, but they are much further out as far as construction of even a prototype in concerned, and we shall not consider them here.

There was a good bit of feedback from last week’s installment, and I want to point out that I am always glad when people point out flaws in my treatment.  I emphasized a particular sort of reactor, and neglected a couple of other ones.  I intend to set this right tonight.

The concern that seems to be in the forefront at present is the radiation leakage from the stricken plants.  As I write this (20110326), it is still not clear whence it comes, but I suspect that fuel rods are compromised and that nuclear fuel rod material is becoming commingled with the water that is supposed to cool the systems.

I say that because it is unlikely that if the spent fuel rod ponds were the source that the high levels of radioactive materials would have found their way into the turbine rooms, where the subcontractors were exposed to extremely high levels of radiation.

The primary thrust of this piece is to go through some of the fission products in the spent (and in use) fuel rods.  This will give us a basic understanding as to why used nuclear fuel is so much more dangerous than new fuel.

Everyone is familiar with phase transitions even it they are not familiar with the term.  Amongst the most familiar is the melting of ice and the boiling of water to form steam.  Technically, these transitions are called fusion and vaporization, respectively.  There are more and we shall discuss some of them later.

All phase transitions are accompanied by changes in the free energy of the substance undergoing the transition, and this free energy has two components, the enthalpy of the transition and the entropy of the transition.  Unless very careful work is being done, the entropy change is often ignored because it, in many cases, is the lesser contributor.  However, it is never zero (except at absolute zero) and sometimes is the dominant factor.