Separation Of Multicomponent Isotope Mixtures Research Articles

Classification of model cascades for separation of multicomponent isotope mixtures

ABSTRACT As far as we know, it is the first attempt to build the classification of the currently existing models of molecular-selective mass transfer in cascades for isotope separation in the stationary mode of their operation. In papers devoted to this subject, such cascades are often called as “model” ones. It is shown that for the case of symmetric separation any of such a “model” cascade can be represented as a special case of a cascade with constant separation factors. There are established interrelationships of the “model” cascades, both with each other and with the symmetrical countercurrent cascades feasible in practice.

Mathematical Modeling of Nonstationary Separation Processes in a Cascade of Gas Centrifuges for Separation of Tungsten Isotopes

We have developed and program-realized a mathematical model of nonstationary separation processes proceeding in cascades of gas centrifuges for separation of multicomponent isotope mixtures. With the help of this model we have calculated the parameters of nonstationary separation processes proceeding in the cascades of gas centrifuges for tungsten isotope separation. It has been shown that the model adequately describes the nonstationary processes in the cascade and is suitable for calculating their parameters during separation of multicomponent isotope mixtures.

Modeling of nonstationary processes during separation of multicomponent isotope mixtures

ABSTRACTThe article presents a mathematical model for calculation of nonstationary hydraulic and separation processes in a gas centrifuge (GC) cascade for separation of multicomponent isotope mixtures. The model has been applied to calculate the parameters of nonstationary processes in a GC cascade for separation of krypton, germanium and tungsten isotopes. As a result, the specifics of the excess holdup distribution along the cascade stages has been identified, and variations of the isotope concentrations in a nonstationary process have been revealed. The data obtained show that the proposed mathematical model is able to adequately describe nonstationary hydraulic processes in GC cascades for separation of multicomponent isotope mixtures.Highlights:Mathematical model of cascade for separation of multicomponent isotope mixture has been developed.The model verification has been done.The isotope transient regularities into cascade during nonstationary processes has been identified.

Mathematical Model of Nonstationary Separation Processes Proceeding in the Cascade of Gas Centrifuges in the Process of Separation of Multicomponent Isotope Mixtures

We have developed and realized on software a mathematical model of the nonstationary separation processes proceeding in the cascades of gas centrifuges in the process of separation of multicomponent isotope mixtures. With the use of this model the parameters of the separation process of germanium isotopes have been calculated. It has been shown that the model adequately describes the nonstationary processes in the cascade and is suitable for calculating their parameters in the process of separation of multicomponent isotope mixtures.

Mathematical model of nonstationary hydraulic processes in gas centrifuge cascade for separation of multicomponent isotope mixtures

This article presents results of development of the mathematical model of nonstationary separation processes occurring in gas centrifuge cascades for separation of multicomponent isotope mixtures. This model was used for the calculation parameters of gas centrifuge cascade for separation of germanium isotopes. Comparison of obtained values with results of other authors revealed that developed mathematical model is adequate to describe nonstationary separation processes in gas centrifuge cascades for separation of multicomponent isotope mixtures.

Mathematical Modeling of Non-Stationary Hydraulic Process Occurring in the Gas Centrifuge Cascade During the Separation of Multicomponent Isotope Mixtures

This article presents results of development of the mathematical model of nonstationary separation processes occurring in gas centrifuge cascades for separation of multicomponent isotope mixtures. This model was used for the calculation parameters of gas centrifuge cascade for separation of germanium isotopes. Comparison of obtained values with results of other authors revealed that developed mathematical model is adequate to describe nonstationary separation processes in gas centrifuge cascades for separation of multicomponent isotope mixtures.

MATHEMATICAL MODEL OF NON-STATIONARY HYDRAULIC PROCESSES IN GAS CENTRIFUGE CASCADE FOR SEPARATION OF MULTICOMPONENT ISOTOPE MIXTURES

It is known that the optimal modes of gas centrifuge (GC) cascades are violated occurring the non-stationary hydraulic processes for a separation of multicomponent isotope mixtures. The perturbation arise and lead to violations of operating specifications and intolerable overloads equipment. The non-stationary hydraulic processes affect the cascade efficiency and the quality of the product. The GC cascades for the separation of multicomponent isotope mixtures have insignificant gas content, and, as a consequence, low inertia. It leads to increased influence of non-stationary processes on the cascade efficiency. In this regard, an important urgent task is the comprehensive investigation and modeling of these processes. We solved this problem by creating mathematical model and software for it. The separation stage of the GC cascade is presented in the form of four dedicated object (a feed manifold, GC, a heavy fraction manifold and a light fraction manifold). The calculation of non-stationary hydraulic amounts to replacing the first order differential equations by difference equations of the implicit Euler scheme [1] and the decision obtained by non-linear algebraic equations. The calculation is iteratively performed; the pressures and flow are determined in all objects at each time step, satisfying the equation of material balance in the cascade. These values must satisfy the balance of substances in the GC cascade. The developed mathematical model was tested for isotope separation of Si, Xe, Ni, W. The deviation of the calculated and actual values was 7.5%. As a result, this mathematical model is universal for calculation of hydraulic parameters of GC cascades for separation of multicomponent isotope mixtures by using different working substances.

Mathematical Modeling of Nonstationary Separation Processes in Gas Centrifuge Cascade for Separation of Multicomponent Isotope Mixtures

Mathematical Modeling of Nonstationary Separation Processes in Gas Centrifuge Cascade for Separation of Multicomponent Isotope Mixtures

Q-cascades for obtaining highly concentrated intermediate components of separated mixtures

A comparative analysis of a Q-cascade with a monotonic flow profile and a Q-cascade with flow expansion in the enrichment part is performed under the condition of equal total flows in both cascades. The given cascade schemes are proposed in order to obtain highly concentrated intermediate (with respect to their mass number) components in the separation of multicomponent isotope mixtures. It is shown that the cascade with expansion provides a higher concentration of the target component in the additional product than the usual cascade with monotonic flow profile. However, the amount of isotope accumulated product per unit feed mixture mass in the Q-cascade with expansion is much lower than in the usual Q-cascade.

Quasi-ideal cascades with an additional flow for separation of multicomponent isotope mixtures

The theory of the R-cascade is generalized to a cascade with an additional external flow, which can be either one more feed flow to the cascade or an additional product flow from the separator at arbitrary degrees of enrichment in the stages of the cascade. Calculations are performed for the enrichment of recycled fuel in the R-cascade to a necessary concentration, provided that the effect of the isotope 236U is compensated and the concentration of the isotope 232U is decreased. It is demonstrated that the theory of the R-cascade with an additional product flow from an intermediate section of the cascade with the maximal component concentration and an intermediate mass number can be used to calculate the optimal conditions in simultaneous separation of several enriched isotopes in the cascade.

TRANSIENT PROCESS IN GAS CENTRIFUGE CASCADES FOR SEPARATION OF MULTICOMPONENT ISOTOPE MIXTURES

The transient process is studied in gas centrifuge cascades for separation of multicomponent isotope mixtures. Two important practical factors, the holdups in connecting pipes among separation stages and material losses, are taken into account in the partial differential-difference equations that describe the concentration distribution of components. The equations are solved at each time step through the q-iteration method. The effects on transient processes are investigated in terms of the total holdup in cascades, the cascade cut, the separation factor, and material losses and may be very significant.

SEPARATION OF MULTICOMPONENT ISOTOPE MIXTURES BY GAS CENTRIFUGE

This article represents an analytical review of the state-of-the-art on separation of multicomponent isotope mixtures in a gas centrifuge. The main physical principles, physical-mathematical models, research techniques and peculiarities of separation of multicomponent isotope mixtures in a gas centrifuge are considered and discussed.

CASCADES FOR SEPARATION OF MULTICOMPONENT ISOTOPE MIXTURES

This article reviews and analyzes the state-of-the art on separation of multicomponent isotope mixtures in cascades. Different methods, which are applied to calculate the cascade configurations and designs as well as those used to describe some transient processes in cascades when separating multicomponent isotope mixtures are discussed and analyzed in detail. The main directions for the further development of isotopes fractionation using cascades are formulated.

Analysis of Gas Centrifuge Cascade for Separation of Multicomponent Isotopes and Optimal Feed Position

Analysis of the concentration distribution in a gas centrifuge cascade for separation of multicomponent isotope mixtures is different from that in a cascade for separation of two-component mixtures. This paper presents the governing equations for a multicomponent isotope separation cascade. Numerically predicted separation factors for the gas centrifuge cascade agree well with the experimental data. A theoretical optimal feed position is derived for a short square cascade for a two-component mixture in a close-separation case. The optimal feed position for a gas centrifuge cascade for separation of multicomponent mixture is discussed.

Some distinctive features of transient processes in the separation of multicomponent isotope mixtures in cascades

The modern theory of unsteady transfer in separation cascades has been developed mainly to describe binary isotope mixtures. As for multicomponent mixtures, only a limited number of semiempirical relations that are applicable to the initial phase of the transient process is available, and their use does not allow a number of experimental facts to be explained. Moreover, of greatest practical interest are the later periods of the transient process, which determine the transient time to the establishment of a steady state. In this paper we present the results of an analytic study of unsteady transfer of multicomponent mixtures for the initial stage of the transient process and also discuss some numerical results obtained for later periods.

Theory of cascades for seperating multi-component isotope mixtures

The article discusses a stationary process for the separation of multi-component isotope mixtures in cascades of arbitrary profile. It includes a theoretical investigation of the extreme cases in which the relative rate of isotope exchange has values of zero and infinity. A solution is obtained for a system of transport equations for a rectangular stepped cascade, and a calculation procedure for such cascades is worked out.