abundance of uranium in the earth crust; 2,5-3 ppm (mg/kg) abundance of uranium in the sea water: ca. 3 ppb (?g/kg)
Less and less as the Uranium decays into lead and other elements.... More and more as super-novae explode and fuse elements into Uranium...
It is possible because uranium is very expensive.The price of 1 kg of the oxide U3O8 is now approx. 90 US $/kg.
There are approximately 1.19 x 10^28 atoms of U-234 in 1000 kg of natural uranium.
Uranium is expensive in all countries.The price of uranium is approx. 90US $ per kg of oxide U3O8.
Different data in the technical litterature: 0,5-2 μg uranium for each kg of body, per day, for long time (professional) exposure.
1 kg of uranium-235 is equivalent to 24.10ex.6 kWh.
Approx. 125 US $ for 1 kg of unrefined uranium oxide U3O8.
Uranium is the most energetic material available today.
Approx. 70 US $ for 1 kg of nuclear reactor grade uranium doxide (with natural uranium); the enriched uranium is more expensive, depending on enrichment.
Uranium dioxide, nuclear grade, not enriched has a value greater 100 US $/kg.
Approx. 90 000 US $ for 1 000 kg of unrefined uranium octaoxide (U3O8).