Are we running out of uranium ?
People - Investing
Wednesday, 15 July 2009 08:58

Are commodities a good or bad investment ? In the 80-ties I learned at school that commodity prices don't really keep up with inflation. Developing countries were exporting commodities and in return they bought more advanced products from the developed world. Because mankind keeps adding more and more value to raw commodities, prices of end products increased more than the commodity prices. That might have changed for some commodities, in particular for energy related commodities.

In the 90-ties I learned that there is not much uranium on earth. Recently I heard that there might be more uranium than they thought before. So how much uranium do we still have ?

A simple computation takes the known quantity of uranium in ores and divides that by the amount of uranium we use each year. This means that there is about 4-5 million tons of uranium and this should be divided by the 70000 tons uranium we use each year. In that case there is still uranium for about 70 years.

In this simple computation there are two important questions. The first question is how much uranium are we going to use and the second question is how much uranium ore do we really have on earth.

Lets start with the first question. Probably mankind is going to build many new nuclear reactors. Of course they are polluting, but our current oil and coal usage is responsible for huge CO2 emissions, which are causing the global warming up. We will have to use energy without CO2 emissions and this is possible with nuclear energy. For electricity producers fees for CO2 emissions will offset increasing uranium prices. Furthermore as oil gets more expensive demand for electricity will increase. In many countries people are looking forward avoiding high gas prices and taxes by driving an electric car. These people will charge their car overnight, when there is no solar energy available.

The second question is how much uranium do we really have on this planet. Recently I heard the argument that if prices go up then it is economically feasible to use lower grade ores and as a result more uranium can be produced. But there is also another limitation. It takes energy to extract uranium from its ore. And the lower the uranium concentration the more energy it takes to extract it. The limit of 4-5 million tons of uranium is probably based on this. Uranium in seawater ? Yes, but the concentration is several orders of magnitudes lower than the concentration in the lowest grade uranium ore. So again, it will probably take too much energy to extract it.

As the uranium price increases other energy sources will become more competitive, such as solar energy. But even then nuclear energy may still be an option, especially when produced with so called Fast Breeding Reactors. In most electricity plants uranium 235 is used to generate heat and hence electricity. Unfortunately only a very tiny fraction of the available uranium is of type uranium 235. Breeding reactors convert the more common (and cheaper) type uranium 238 into plutonium which can be used to produce electricity. Breeding reactors can also convert thorium into uranium 233, which can also be used to produce electricity. Thorium is available in even bigger quantities than uranium.

Unfortunately breeding reactors have a very bad reputation in terms of safety and economics. So far only few (if any) breeding reactors have been build and used to produce electricity on a large scale (>= 500 MW). At the moment few research is done on breeding reactors. Almost all new reactors built today are of the uranium inefficient non-breeding type and new reactors can be in operation for decades.

Finally a last word about competition from other energy sources. At the moment it looks like only solar energy will be suitable for reliable large scale energy production. Forget about wind energy, tidal energy, etc. I don't think that solar cells on every roof will be good enough. But larger solar plants in deserts can generate enough electricity. Unfortunately that will make the world dependent on a limited number of countries with unstable governments. This is similar to our current dependency on oil with one important difference. With oil we can make inventories but that is not easy to do with electricity. So if we would depend on electricity from deserts then a few countries could literally and instantly switch all lights off. That's unacceptable and therefore there will always be a need for a backup system, such as electricity from nuclear power.