The HUGE problem with nuclear power is political - not the lentil knitters, but international politics. As the report points out, uranium reserves are pretty limited if the World decided that fission was the way forward (and it is increasingly looking that way).
Thorium is in some way an even bigger problem than uranium since it needs to be transmuted into U233 before it can be used as a fuel. The Indians, who have some of the largest thorium reserves, have long experience in doing this. BUT U233 is an excellent material for bomb making. It can be used in a uranium cannon bomb (unlike plutonium), a much simpler, cheaper way of becoming a nuclear power as it doesn't need anything like the same level of expertise - the design of Little Boy dropped on Hiroshima didn't need to be tested and the South Africans assembled a number of similar weapons without ever testing their designs.
The way to extend uranium reserves is through reprocessing and recycling U235 for further use and either blending in Pu239 to make MOX or to embark on a real fast breeder program using Pu239 as the fuel and U238 as the breeding blanket. This would mean a huge commitment to reprocessing - an economic disaster in the UK which is the only country to have ever gone wholeheartedly for the process, and something of an environment nightmare as it means finding repositories for spent actinides. Could any government make such a commitment?
BUT the monster in this is the plutonium economy. Such a programme would require hundreds of tonnes of plutonium, all suitable for bomb making, to be shipped around the World on a continuous basis. It would mean providing countries with whom we have awkward, if not hostile, relationships with plutonium. Bearing in mind the fracas we're currently having with Iran over its uranium program does anyone countenance the US or Israel permitting Iran to receive plutonium shipments?
Okay, we could avoid trans-shipments and say that everyone has a reprocessing program of their own. The technology is from the 1940s and is accessible to anyone with a supply of concrete, kerosene and some 1st year degree chemistry. Is the World ready for 200 odd reprocessing programmes all with the potential to divert plutonium into bomb programs?
Or the US and the rest of the Security Council could say that all new nuclear economies must sign up to receive fuel from their enrichment and processing plants and return spent fuel to them. This hasn't worked too well in the past - India's successful civilian and military programs are a direct protest at trying to impose similar rules through the Non Proliferation Treaty, and Iran's current intransigence is in part down to the fact that under the Treaty every country is permitted to have their own civilian nuclear programs - including a complete fuel cycle. The West demanding that Iran must accept fuel from outside is not grounded in law.
So can the readers of this mighty organ see how to get round these problems?