The processing of natural uranium for Nuclear Reactors:

My favourite subject and least favourite whilst I was in Uni.

Uranium comes in so many isotopes my mind is reeling after reading the wikipedia article. Anyway here is the summation. The most stable found in the ground are 234U which is only .0054% with half life of 245,500 years, 234U which is only .072% with a HL of 7x10 to 8 years, 235U in traces with 2 x 10 to 7 years, and 238U 99% with 4x 10 to 9 years. Only 235U  and bits of others are used in fission for nuclear stuff like making bombs and power plants.

kilogram of uranium-235 can theoretically produce about 80 terajoules of energy (8×10¹³ joules), assuming complete fission; as much energy as 3000 metric tons of coal.

From

First you have the stuff which comes out of the ground called Yellow Cake which is an oxide. then we have to make it more concentrated which happens in a two well cordinated processes.


First purifies the uranium ore concentrate to a very high level, and then converts the uranium ore concentrate into uranium tetrafluoride (UF4).

Second transforms the uranium tetrafluoride into uranium hexafluoride (UF6). This processing gives the uranium concentrate the required purity for the production of nuclear fuel.


The second process is a bit more convoluted than the first the steps taken to turn UF4 to UF6 is below. The reason for the change is due to the volatality of UF4 and the easier to use it as a fuel.


Purification: any impurities are removed from the uranyl nitrate solution in a purification column. On completion of this stage, the uranium satisfies the purity requirements for use in nuclear power plants.




Precipitation and calcination: the "purified" uranyl nitrate solution is then concentrated; Ammonium diuranate is obtained by the injection of gaseous ammonia. This is calcinated in ultra-high temperature furnaces. A solid matter is produced - uranium trioxide (UO3).


Reduction and fluorination: the uranium trioxide is then reduced to uranium dioxide (UO2) by passing through a furnace, and then transformed into uranium tetrafluoride (UF4) upon contact with hydrofluoric acid.
Transportation: the UF4 is packed in a special container and transported

This is used in molten salt reactor (MSR).

But other power plants use a combination of 235U and 238U and bits of others like plutonium. But UF4 has to be enriched to get this. Gosh I is tired like the Donkey in the winnie the pooh.


I am a selfish person. If you cannot find the links in this blog, I have majority of them filed, Email me!claims the wiki article, Now then: