And the warhead source is dwindling.

I was eagerly awaiting the release of the Uranium 2009 report (the newest of a bi-annual report on uranium supply prepared jointly by OECD NEA and IAEA). Unfortunately, even the pdf would cost me lots of Euros, there is only a propagandistic press release in the public domain. Still, even in that, one finds disclaimers -- I changed the emphasis to highlight those:

The uranium resources presented in this edition, reflecting the situation as of 1 January 2009, show that total identified resources amounted to 6 306 300 tU, an increase of about 15% compared to 2007, including those reported in the high-cost category (<USD 260/kgU or <USD 100/lbU3O8), reintroduced for the first time since the 1980s. This high-cost category was used in the 2009 edition in response to the generally increased market prices for uranium in recent years, despite the decline since mid-2007, expectations of increasing demand as new nuclear power plants are being planned and built, and increased mining costs. Although total identified resources have increased overall, there has been a significant reduction in lower-cost resources owing to increased mining costs. At 2008 rates of consumption, total identified resources are sufficient for over 100 years of supply.

...current projections of uranium mine production capacities could satisfy projected high-case world uranium requirements until the late 2020s. However, given the challenges and length of time associated with increasing production at existing mines and opening new mines, it is unlikely that all production increases will proceed as planned. As a result, secondary sources of previously mined uranium will continue to be required, complemented to the extent possible by uranium savings achieved by specifying lower tails assays at enrichment facilities and technical developments in fuel cycle technology.

IIRC the 2007 report already claimed an increase in resources based on the inclusion of more lower-grade or less secure resources, shrouding a decrease of better resources.

I find a little more specifics in this NEA pdf, some choice quotes, again with my emphases:

Uranium production in 2008 (the most recent year with full production figures) totalled 43 880 tU, a 6% increase from the 41 244 tU produced in 2007 and an 11% increase from the 39 617 tU produced in 2006. ... Global production increases between 2006 ... and 2008 were driven principally by significant increases in Kazakhstan (76%). More modest increases were recorded in Australia, Brazil, Namibia and the Russian Federation. Reduced production was recorded in a number of countries between 2006 and 2008 (including Canada, Niger and the United States) owing to a combination of lower ore grades and technical difficulties....

At the end of 2008, world uranium production provided two-thirds of world reactor requirements, with the remainder being met by supplies of uranium already mined (so-called secondary sources), including excess government and commercial inventories, the delivery or low enriched uranium (LEU) arising from the down-blending of highly enriched uranium (HEU) derived from the dismantling of nuclear warheads, re-enrichment of depleted uranium tails and spent fuel reprocessing.

...

Although information on secondary sources is incomplete, they are generally expected to decline in importance through the next decade. ...a sustained strong market for uranium will be needed to stimulate the timely development of production capability and to increase the identified resource base should growth in nuclear generating capacity follow currently projected trends. However, because of the long lead times required to identify new resources and to bring them into production (typically in the order of ten years or more), the relatively sparse global network of uranium mine facilities and geopolitical uncertainties in some important producing countries, uranium supply shortfalls could potentially develop.