Study on Isotope Enrichment of Nitrogen-15 with Cascading Assembly of Thermal Diffusion Columns

A numerical simulation system was developed to analyze isotope separation performance in the thermal diffusion column for nitrogen isotope separation。Hydrodynamic flow in the thermal diffusion column was numerically simulated and mole fractions of nitrogen molecules of mass numbers，28，29and30were computed as function of vertical and radical positions by solving a convective diffusion@equationThe thermal diffusion factor，which is most important value in the analysis，was expressed in a practical form，still keeping consistent relationship with generalized Stefan-Maxwell@equation，applicable to multi-component mixture of nitrogen isotopes.In our study，the effect of inelastic collision of nitrogen molecules was considered to the thermal diffusion factor.The effect of cold wall temperature on separation performance for I D 114个D 1N-I D 115个D 1 N and I D 114个D 1 N个D 22个D 2 separation was evaluated with the numerical simulation system and compared with experimental results with the thermal diffusion column of an effective height of 950毫米，a hot wire of 0.15毫米in radius and a cold wall of 5.0毫米in radius.The solutions numerical analyses gave good reproduction of dependence of separation factors on cut and cold wall temperature.Studied as a design example was cascade composed with an assembly of thermal diffusion columns of an effective height of 10m。The number required for a series of stages of the thermal diffusion column was5so as to achieve the final enrichment of 99.9%of Ii D115 Iee D1N.The total number of the thermal diffusion columns was evaluated#china_person0#，600in a plant which produces I D115西耶D1N to meet the demand for UN fuel of one fast breeder reactor of 1GW electric power in a year。

A numerical simulation system was developed to analyze isotope separation performance in the thermal diffusion column for nitrogen isotope separation. Hydrodynamic flow in the thermal diffusion column was numerically simulated and mole fractions of nitrogen molecules of mass numbers, 28, 29 and 30 were computed as function of vertical and radical positions by solving a convective diffusion equation. The thermal diffusion factor, which is most important value in the analysis, was expressed in a practical form, still keeping consistent relationship with generalized Stefan-Maxwell equation, applicable to multi-component mixture of nitrogen isotopes. In our study, the effect of inelastic collision of nitrogen molecules was considered to the thermal diffusion factor. The effect of cold wall temperature on separation performance for ィイD114ィエD1N-ィイD115ィエD1N and ィイD114ィエD1NィイD22ィエD2 separation was evaluated with the numerical simulation system and compared with experimental results with the thermal diffusion column of an effective height of 950mm, a hot wire of 0.15mm in radius and a cold wall of 5.0mm in radius. The solutions numerical analyses gave good reproduction of dependence of separation factors on cut and cold wall temperature.Studied as a design example was cascade composed with an assembly of thermal diffusion columns of an effective height of 10m. The number required for a series of stages of the thermal diffusion column was 5 so as to achieve the final enrichment of 99.9% of ィイD115ィエD1N. The total number of the thermal diffusion columns was evaluated 89,600 in a plant which produces ィイD115ィエD1N to meet the demand for UN fuel of one fast breeder reactor of 1 GW electric power in a year.