Rossco, please follow this link:

http://www.energypulse.net/centers/article/article_display.cfm?a_id=374

It answers very clearly, your erroneous supposition that U fuel will not extend beyond 50 years. You might also try to think 'Breeder'. Coal ash discards more energy, in the uranium in this waste, than was extracted by burning the coal in the first place. So effectviely nearly all coal ash becomes an ore of uranium - waste recycling - once the breeder is adopted. In addition, extraction of uranium from seawater containing 3 parts per billion of uranium, becomes economic with a breeder cycle.

and Chris,

Consider that 1 kilogram of uranium in an LWR (enriched to 3%)produces about 250,000 kWh of electricity, worth about $25,000+. In a breeder, the same kilogram produces about 3 million kWh, worth about $300,000+. And with breeding, all of the hundreds of thousands of tonnes of depleted uranium, worth more than 100 trillion dollars in extractable energy, are brought back into the nuclear closed cycle. You also might try to read the above article and others by the same author, and others, on this site.

Rossco, the references given by Collywobbles, if you read and understand them, will convince you that there is no problem with the supply of nuclear fuel for the forseeable future.
BTW, referring to an earlier post of yours, I would rather live next door to a nuclear power station than a coal fired one.

Collywobbles
It was Froggie that said uranium would last for 50 years at current consumption rates, not me. My point was how long would it last if we had hundreds of new nuclear power stations come on stream.
I am not too worried actually as it ain't never going to happen!

Frog, Colly et al. Thanks for the valuable links. I would have replied sooner, but having been greedy, the guillotine thing cut me off for my sins.

It is hard to judge if some erudite paper on nuclear energy is tainted by economics, politics or self-interest. My math isn't good enough yet to make a proper distinction. But I press on, trying not to seek the reflection of my own inevitable prejudices.

Perhaps many factors will not be discovered until we actually suck it and see.

On the subject of safety, I dread the thought of decisions being made by "risk mitigating experts", cost-cutters and CEO's looking for fat payouts. Seems to me we need a clean break from "free market" principles.

Cheers

Rossco
I should have perhaps said, to be more accurate, "Current uranium supplies are expected to last 50 years at the current rate of consumption". This does not mean that the world's total uranium resources are expected to last 50 years. This should have been obvious if you had read and understood the references I pointed you to, plus my subsequent comments.
I predict that current anti-nuclear lobbies will be swiftly swept aside if and when energy supplies become a real problem. People are not going to accept energy penury when there is a good and well proven solution available.

The world is running out of energy-economic uranium faster than oil or gas. We shall soon see nuclear stations close for lack of fuel. How so? Primary annual production of 40,000 tonnes from mines provides only 60% of the world's demand for uranium, the other 40% is cobbled together from ex-weapons HEU, re-worked mine tailings, a little mixed oxide (MOX) produced at enormous expense and from inventories.

Three WNA symposiums have signalled the end of the secondary uranium sources in under ten years, so where is the missing 30,000 tonnes coming from to meet the world's demand for 70,000 tonnes?

Not from Canada, where new mines are needed to replace the production from two that have recently closed and two that have passed their "Hubbert" production peaks and will shortly decline. Not from Australia, where even if the price of copper holds up it will still take years to dig an enormous hole in the ground at Olympic Dam before a fraction of the requirement emerges. In desperation to supply their planned reactors the Chinese are seeking permission to prospect and open their own mines in Australia.

To answer previous comments:-

MacDonald's paper compares uranium extraction with other metals, but they are mined for their own sake, not for energy. Once the energy input exceeds that delivered to the network, there is no point to nuclear power and mining low ore grades is non-viable.

Sutherland's EnergyPulse article serves up the same pervading mythology that believes uranium can be extracted from seawater. After 50 years of trying there is still no commercially available breeder and thorium requires a chain of three differing and as yet still experimental reactors.

Nuclear power provides 6% of the world's primary energy, but only 2½% of it as usable electrical energy. The current number of stations would have to be built every year to match the world's annual increase in energy demand. The proponents of nuclear power need to come to terms with reality.

There is no nuclear nirvana!

See http://www.stormsmith.nl and http://www.after-oil.co.uk/nuclear.htm