Calculation of the cost of enriched uranium products in multi-stream cascades of enrichment process

Abstract

Modern uranium enrichment facilities can simultaneously use several raw materials as feed, including natural uranium, regenerated uranium obtained as a result of SNF reprocessing, or depleted uranium (all in the form of uranium hexafluoride). As the output of the separating cascade, several types of enriched uranium product with different levels of enrichment can be fabricated simultaneously. The paper proposes a methodology, absent in literature, for calculating the cost of each enriched uranium product in multi-stream separating cascades. The proposed methodology uses standard definitions of the isotopic value of feed and product stream and the Peierls-Dirac separation potential. Numerical calculations of the cost of enriched uranium products for three production problems are provided as examples of the methodology effectiveness: 1) involvement of depleted uranium hexafluoride (DUHF) in fabrication of enriched uranium product; 2) simultaneous fabrication of two enriched products; 3) use of depleted uranium to reduce the cost of the product with a higher enrichment level out of two (as applied, e.g., to advanced tolerant fuel). It has been shown that partial additions of DUHF as feed for a multi-product separating cascade make it possible to reduce the cost of a product with a higher level of enrichment; with the current market prices for natural uranium and separative work, there is a range of tails assays in which it is more profitable to enrich DUHF rather than natural uranium.