: : 189.4 kg ( +43.8 kg since the previous report ) of UF6 enriched up to 20 % U235 ( see Figures 3 and 4 ) 13 . Fuel Enrichment Plant ( FEP ) : FEP is a centrifuge enrichment plant for the production of low enriched uranium ( LEU ) enriched up to 5 % U-235 , which was first brought into operation in 2007 .