Degree of enrichment

Naturally occurring uranium consists of about 0.7% of the lighter isotope with the mass number 235 ( ²³⁵ U) and 99.3% of the heavier isotope with the mass number 238 ( ²³⁸ U). In order to be able to use uranium as a nuclear fuel in reactors , most reactor types must first be enriched .

The two isotopes are partially separated from each other in an enrichment facility. This creates a product with an increased share of ²³⁵ U compared to the initial value of 0.7% . This value is called the degree of enrichment . In the case of uranium fuel for light water reactors , the degree of enrichment is around 3 to 4%.