There is enough accessible Thorium and Uranium to power our civilisation at current levels until the sun kills the earth.
Care to back up that claim with solid data? because many experts would disagree with that assessment on uranium. and thorium reactors are still experimental.
Did you actually read the section of the article you linked to? If you did you would have read this: "If one is willing to pay $300/kg for uranium, there is a vast quantity available in the ocean. It is worth noting that since fuel cost only amounts to a small fraction of nuclear energy total cost per kWh, and raw uranium price also constitutes a small fraction of total fuel costs, such an increase on uranium prices wouldn’t involve a very significant increase in the total cost per kWh produced."
How much uranium is in seawater? 4.6 billion tons, roughly one hundred thousand times current annual consumption.
How much can we afford to pay for uranium without driving up the cost of nuclear power significantly? Well, in a year 2.7*10^12 kwh of nuclear powered electricity are produced, with a value of something like 270 billion dollars (assuming an average price of $0.10 or so). To produce this 50,000 tons of uranium are consumed, or about $5000 worth of electricity per kilogram. Looks like paying $300 per kilogram for uranium is unlikely to seriously inconvenience the nuclear power industry.