II. Uranium Resources
The USGS map of Uranium Concentrations shows how comprehensive their search was, finding a substantial resource of 5.6Mt. In the 1950s the government issued free Geiger counters to would be explorers. The USA currently imports 95% of its Uranium with most of its mines inactive. Other countries have not been so meticulous but every mining geologist knows what to look for.
The IAEA, OECD, and NEA periodically publish their authoritative Red Book analysis on mineable Uranium [IAEA, 2011]. This lists “Found” mines and reserves, “Reasonably Assured Resources” (RAR) in similar geologies, “Inferred Resources” if we look harder, and “Prognosticated” and “Speculative” resources in unexplored regions. The 40+ Reporting countries also estimate the mining costs per kg of Uranium from their sources. Total production is currently 58,000t/yr. Coal mines now produce ~1Bnt/yr.
Our Chart below shows the world totals for each cost range and Uncertainty level. The “Speculative” resources are the highest. There is a total of only 161,000t U-235 in mined Uranium as indicated by the red caps on each stack. It is not necessary or cost effective to extract all the U-235 from a batch of Uranium. Instead, enrichment is stopped with ~0.2% of U-235 in the tailings, which are set aside and called “Depleted Uranium” (DU). Thus, only ~0.5%, or 115,000 t, is available from the ores for fresh reactor fuel.
The IAEA Red Book completes the tally of possible fuels with some reported resources of 6MT of the non-fissile metal, Thorium. It has a single isotope, Thorium-232 , and like U-238 can breed another fissile Uranium isotope, U-233, which has long disappeared from the planet. A reactor is the only way to make tonnes of U-233. Just the declared resource would be good for 6 million GW-e reactor years, though 60 Mt might be found.
It might appear that there are lots of fissile fuels, but only U-235 lives on in ores. The other fissile isotopes, U-233 and Pu-239, must all be made in reactors. The IAEA has accounted for the only natural resources, Uranium and Thorium.
IAEA 2011 Red Book, latest edition:
McNamara, 2006: Uranium – What is to be done?
1 Why does the US import 95% of its Uranium when it has its own large resources?
2. The NAVAJO Indians oppose Uranium mining on their land. When might this resource be really needed?
3 If 40 countries have their own Uranium does this lead inevitably to widespread growth of nuclear weapons?
4. Is Depleted Uranium a waste product or not?
5 It looks like U235 is only good for 115,000 reactor years but Thorium could be good for 6 million reactor years. Why is this?