Uranium could theoreticaly last forever. The life of each uranium particle is random but over a large mass a half life can be calculated. Uranium-238(most common type of uranium) has a half life of 704 billion years so if you had 12500 tons of uranium after 704 billion years there would be 6250 tons. Every 704 billion years the mass would half until there was only an insignificant amount left.
A lot of unknowns here: how much uranium ore is out there undiscovered? will it be worthwhile mining lower grade ore? How many more reactors will be built in next 50 years? when if ever will fusion become usable?
I believe there is enough ore at reasonable quality left for another 40-50 years, obviously depending on how much gets used. After that lower grade ore will have to be used. At some point it may become economic and technically sound to start building fast breeder reactors, which can use depleted uranium or thorium to breed Pu239 or U234. There will be plenty of depleted U, and thorium is attractive to some countries that have plenty of that.
Personally I doubt usable fusion within this century, but could be wrong!
The half life is different for each isotope of uranium. See the link bellow.
Today the answer is impossible; may be 100 years, may be 200 years.
Uranium 235 half life is: 7,038.108 years.
Depending on the reactor type: 1-2 years.
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Pu-239 has a half-life of 24,110 years.
Each isotope of uranium has its half life. See the link below.
If you think to uranium 235 the half life is 703 800 000 years.
The half-life of 238U is 4.468x109 years.
700 million years
Pu-239 has a half-life of 24,110 years.
Uranium is a radioactive element and conteneously disintegrate into smaller element, that time in which 1g of uranium becomes half g is known as half life period of uranium.
Each isotope of uranium has its half life. See the link below.
If you think to uranium 235 the half life is 703 800 000 years.
The approximate half life of Uranium 238 is 4.5 x 109 years.
The half-life of 238U is 4.468x109 years.
The half life of 238U is 4,468.109 years; this is a very long halflife !
The half-life of uranium-239 is 23.45 minutes.
The half-life of the isotope uranium-238 is 4 468 000 000 years.
700 million years
Uranium has a half life of 5,600 years. After that period, one half of the uranium becomes lead. That is why lead is found in uranium deposits.
Uranium has the longest half-life element