The isotope U-238 has a halflife of 4.5 billion years, roughly the current age of the earth. As the sun is expected to consume the earth in about 6 billion years from now, less than 1.5 halflives will have passed by then. Therefore uranium will remain in the environment as long as earth exists, although at slowly decreasing levels.
Uranium forms almost instantaneously in supernova explosions.
A million billion years
In the reaction238U + n-------239U-------239Np + e--------239Pu + eone atom of uranium become one atom of plutonium.
Uranium is a donor of electrons.
- By melting of metallic uranium. - By sticking sintered uranium dioxide pellets
As long as there are any uranium atoms. Since U-238 has a half-life of over a billion years, that can be a long, long time.
Typically 3% uranium-235, 97% uranium-238.
Depending on the size and type of the bomb and also on the enrichment installation available.
Uranium is not a fossil fuel and cannot be a fossil fuel.
In the reaction238U + n-------239U-------239Np + e--------239Pu + eone atom of uranium become one atom of plutonium.
Uranium is a donor of electrons.
- By melting of metallic uranium. - By sticking sintered uranium dioxide pellets
As long as there are any uranium atoms. Since U-238 has a half-life of over a billion years, that can be a long, long time.
how long does it take to make a crayons
You are orobably thinking of the small cylinders which make up the fuel rods. These are 10mm diameter and about 10mm long, and are packed end to end inside the zircaloy sheath to make a fuel rod. The material is uranium dioxide with the uranium enriched to about 5% U-235.
Billion of years; each isotope has a different half life.
One Half-Life :-)
700 million years
Uranium is not used to make knives !