Monday, October 03, 2005

Power generation...

On the weekend just gone, the WA Liberal Party held their annual meeting to publicise their future directions and show us all the puppet masters in the background of the party.

Matt Birney in his major speech made it clear that the WA Liberals are in favour of uranium mining and nuclear power in WA. Yes, the 'N' word was mentioned. The public has a largely unfavourable view of nuclear power. After Three Mile Island, Chernobyl and a few other minor nuclear accidents worldwide, power generated by the fission of uranium is fairly unpopular.

This may be the speech that will come back to haunt Matt Birney. When the next election rolls around, the Labor crew will use the spectre of nuclear power to scare the voters away.

I think that nuclear power is a very viable power source for WA, we have huge reserves that remain untapped and we have very large areas suitable for the placement of a reactor. Although the initial cost of setting up a reactor can be quite high, the cost per KWh is equal or less than a coal fired power station.

The waste from the power station will be a major issue, but again we have some dead empty space in the middle of a very geologically stable region just ripe for deep drilling for storage of the waste.

I remember hearing that coal fired power stations release more radioactivity than the average nuclear power plant, so I did some looking around and found the following passage (emphasis is mine):
Returning to the wastes from coal-fired electricity production, they arise because coal seams, over eons of time, have accumulated through precipitation a wide variety of minerals. The reactive organic content of coal creates the necessary conditions to trap these elements within the coal seam in recognisable streaks of thucolite, named after the radioactive thorium and uranium they contain.

The annual wastes from a 1,000 MWe coal-fired power station include several hundred tonnes of toxic heavy metals such as arsenic, cadmium, lead, mercury, selenium and vanadium which retain their toxicity permanently, as well as the two radioactive elements in thucolite which have long half lives. The daughter elements they produce when they decay also contribute to the level of radioactivity in the ash.

Radon gas is the daughter element with the greatest mobility and because of its highly active decay products it presents the greatest radiation danger to nearby population. Compared with other naturally occurring sources the radiation levels are not high, but are still over ten times higher than the emissions from a nuclear power station of the same capacity.

It is interesting to note that a coal-fired power station discharges in its wastes more uranium than a nuclear power station consumes for the same amount of energy if fast breeder reactors are used. Here are the facts: Australian coals contain from 0.4 to 5 parts per million uranium, with a mean of 2 parts. The energy released by the nuclear fission of uranium is more than a million times greater than the yield of chemical reactions such as coal-burning. So one tonne of uranium, if fully consumed in a breeder reactor, provides as much energy as more than a million tonnes of coal. That much coal releases more than two tonnes (average) of uranium in its wastes. This may come as a surprise to many readers but is well known in the power industry.

In order to avoid giving a false impression, the more common non-breeding reactors extract only two or three percent of the energy of the uranium fuel, so the ratio drops from several million to a few tens of thousands. This still means that, megawatt for megawatt, the uranium in the wastes from coal-fired power generating stations is considerable and is about as radioactive as unprocessed uranium ore.

Although the emphasised part relates to the comparison between a coal fired power station and a fast breeder reactor, the amount of radioactive waste released from a coal fired power station is immense. Add that radioactive waste to the amount of carbon dioxide released per year by coal into the atmosphere and you have a very dirty power source.

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