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Uranium Enrichment Tails Upgrading Calculator - HELP

(last updated 12 Dec 2009)

Contents:


Introduction

This calculator performs calculations of the material balance of the re-enrichment of depleted uranium tails (tails upgrading).
It assumes that the depleted uranium tails generated by Enrichment Plant #1 are fed into Enrichment Plant #2 for re-enrichment. The re-enriched product obtained (for example natural-equivalent uranium) is fed into Enrichment Plant #3 for further enrichment (if required).

The material balance is presented in a flow chart. Upon entry of one value into any of the flow chart's input fields, all other fields are calculated accordingly. So, it is possible to calculate the balance per tonne of feed UF6, as well as per tonne of U in UF6 recovered during re-enrichment, for example.
Note: SWU is the acronym for Separative Work Unit.

The parameters used for the calculation can be set in the Process Parameters table. These parameters show reasonable initial values which can be modified as needed. There are no other hidden parameters used in the calculation.

For background information, see the Tails Upgrading page.

> See also the Nuclear Fuel Material Balance Calculator, the Nuclear Fuel Cost Calculator, and the Nuclear Fuel Population Health Risk Calculator.

 

Process Parameters

Enrichment Plant #1: Product 1 Assay [% U-235]
Weight-percent of the fissile isotope uranium-235 in the uranium contained in the product stream (enriched uranium hexafluoride) of the first enrichment plant. Values for use in pressurized water reactors (PWR) range between 3.6% and 4.1%, and for use in boiling water reactors (BWR) between 3.0% and 3.2%. (Note: Natural uranium contains 0.711 wt-% of uranium-235)

Enrichment Plant #1: Tails 1 Assay [% U-235]
Weight-percent of the isotope uranium-235 in the uranium contained in the waste stream (depleted uranium hexafluoride) of the first enrichment plant. Typical values range between 0.25% and 0.30%. The tails assay can be selected according to economic feasibilty. The Tails 1 Assay is identical to the feed assay of the second enrichment plant.

Enrichment Plant #2 (Re-Enrichment): Product 2 Assay [% U-235]
Weight-percent of the fissile isotope uranium-235 in the uranium contained in the product stream (re-enriched uranium hexafluoride) of the second enrichment plant. In the case of re-enrichment to natural uranium grade, the figure is 0.711. The Product 2 Assay is identical to the feed assay of the third enrichment plant.

Enrichment Plant #2 (Re-Enrichment): Tails 2 Assay [% U-235]
Weight-percent of the isotope uranium-235 in the uranium contained in the waste stream (re-depleted uranium hexafluoride) of the second enrichment plant. The tails assay can be selected according to economic feasibilty; it must be lower than the Tails 1 Assay, however.

Enrichment Plant #3: Product 3 Assay [% U-235]
Weight-percent of the fissile isotope uranium-235 in the uranium contained in the product stream (enriched uranium hexafluoride) of the third enrichment plant. Values for use in pressurized water reactors (PWR) range between 3.6% and 4.1%, and for use in boiling water reactors (BWR) between 3.0% and 3.2%. (Note: Natural uranium contains 0.711 wt-% of uranium-235).
The Product 3 Assay must be higher than the Product 2 Assay, otherwise no further enrichment is assumed.

Enrichment Plant #3: Tails 3 Assay [% U-235]
Weight-percent of the isotope uranium-235 in the uranium contained in the waste stream (depleted uranium hexafluoride) of the third enrichment plant. Typical values range between 0.25% and 0.30%. The tails assay can be selected according to economic feasibilty.

 

Calculation Details

The formulae used by the calculator for the enrichment process can be found under Separative Work Unit (SWU) in the "Enriched uranium" article of Wikipedia.

 

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