Well, yes, the nuclear industry, much like the oil industry has done with petroleum reserves, has pretty much mapped out strategic reserves of uranium ore, as well as thorium.
First of all, 'radioactive material' generally, but specifically certain isotopes of uranium and thorium, whcih exist in nature, and only due to their long half-lives. The principal fissile isotopes are U-233, U-235, and Pu-239. U-233 and Pu-239 must be produced (bred), whereas small quantities of U-235 are found naturally. There are also fertile isotopes, e.g U-238, Th-232, Pu-240 which can become fissile through the absorption of a neutron and subsequent radioactive decay.
In uranium, which fuels most of the world's nuclear power plants, the natural element contains ~0.71% U-235 and ~99.2% U-238, with traces of U-234, and a tiny bit of U-236. The other isotopes pretty much decay away. CANDU reactors are designed to operate with natural U. Light water reactors are designed to operated with U 'enriched' in U-235 - and the current licensing limit in most (or all) countries is 5%, based on the expected and historical burnups (energy produced per unit mass).
There are deposits of uranium ore around the world, e.g. Canada, Australia, Namibia (and other parts of Africa), US and so on. The ores in Australia and Canada are particular rich in uranium compounds compared to others, whereas US ores are generally poor. The lower the uranium content, the more ore that must be mined to obtain a certain amount of uranium.
Now, the fissile resources may be extended by converting fertile isotopes to fissile isotopes, and that is the motivation behind breeding. Th-232 (obtained from thorium ore which is primarily from monazite sand -
http://minerals.usgs.gov/minerals/pubs/commodity/thorium/thorimcs96.pdf ) can be converted to U-233. Pu-239 originates from the neutron capture by U-238, which becomes U-239, which decays by beta emission to Np-239, which decays to Pu-239. LWR reactors actually produce Pu-239, but not at a surplus rate as is the case in a fast breeder reactor. In a reactor, some Pu-239 does not fission, but may become Pu-240, Pu-241 (decays to Am-241) and Pu-242 (decays to Am-242), and some Am decays to Cm. Some of these heavier nuclides are also fissionable, but also have relatively short half-lives.
The industry mines the most economic ores, i.e. those of highest grade or which are easiest to access. As the price of the resource increases, some low grade ores may become economic to extract.
However, like petroleum, uranium and thorium resources are finite. The extent or duration of nuclear energy sources depends on the type of fuel cycle. Without breeding, nuclear resources might last a couple of centuries, but that depends on how much of the total energy is derived from nuclear. Currently the US derives 20-22% of electricity from nuclear (and > 50% from coal), where as France derives 80+% of electricity from nuclear, and actually exports electricity to neighboring countries.
Two major issues regarding nuclear energy are proliferation (disposition of Pu-239, which can be used to make nuclear weapons) and waste (spent fuel and irradiated materials). Both issues are politically sensitive.
Organizations which monitor nuclear energy resources include:
http://www.world-nuclear.org/
http://www.uic.com.au/
http://www.wise-uranium.org/umkt.html
http://www.worldenergy.org/wec-geis/publications/default/tech_papers/17th_congress/3_2_12.asp
http://www.cameco.com/ - The major uranium producer
