Gas Centrifuge Cascade Research Articles

Optimization of isotopic binary and multi-component separation cascades using a novel nature-inspired horse herd algorithm

ABSTRACT The gas centrifuge process is widely used in the world to separate binary and multi component mixtures of isotopes. The majority of a plant cost is related to the number of centrifuges in a cascade. The cascade should be built so that it uses the fewest possible centrifuges for a given product and waste concentrations. Minimizing the number of centrifuges and the total flow rates, is a key point in designing and optimizing isotope separation cascades. The main purpose of this paper is to present a novel swarm intelligence based algorithm to solve these kinds of problems. This novel algorithm, called the Horse Herd Optimization Algorithm (HOA), is inspired by the behavioral patterns of horses in their habitats. In this work, it is demonstrated that the suggested algorithm can solve complicated multidimensional problems. HOA is tested by some test functions of high-dimensions and the results are compared with the strongest available optimization algorithms. In next, the proposed algorithm is used to optimize gas centrifuge cascades for the separation of binary and multicomponent mixtures of isotopes in several cases. Also, ideal and optimum cascades are compared in different separating regimes of the stages, using this method. Considering the performance of HOA in solving multidimensional problems, this algorithm is proposed for the optimization of long cascades.

Obtaining Highly Concentrated Molybdenum Isotopes According to a Multistage Scheme in a Cascade of Gas Centrifuges

Obtaining Highly Concentrated Molybdenum Isotopes According to a Multistage Scheme in a Cascade of Gas Centrifuges

Calculation of Multistage Schemes for Concentrating Isotopes in a Gas-Centrifuge Cascade with Variable Separation Factors

Calculation of Multistage Schemes for Concentrating Isotopes in a Gas-Centrifuge Cascade with Variable Separation Factors

Preparation of Highly Concentrated Xenon Isotopes by a Multistage Scheme in an Ordinary Cascade of Gas Centrifuges

Preparation of Highly Concentrated Xenon Isotopes by a Multistage Scheme in an Ordinary Cascade of Gas Centrifuges

Concentration of Tellurium Isotopes by a Multistage Scheme in an Ordinary Cascade of Gas Centrifuges

Concentration of Tellurium Isotopes by a Multistage Scheme in an Ordinary Cascade of Gas Centrifuges

Selection of the best 3-section squared-off cascade to enrichment of the 126Xe and 131Xe using particle swarm optimization algorithm

In this study, the effect of arrangements of flexible 3-section squared-off gas centrifuge cascades on middle isotopes of xenon enrichment,126Xe, and 131Xe, to a specific enrichment level (85%) has been investigated. 3-section squared-off cascades can be arranged in three different arrangement types depending on the feed flow that enters in the first, second, or third section. To simulate the 3-section squared-off cascades, the number of equations and unknown parameters must be equalized by considering four unknown parameters as input data in addition to other input parameters. These parameters are returned flow fractions between two sections, cascade cut, and first-stage cut. Two codes named SQ3-PSO and SQ3-SS were developed using Particle Swarm Optimization (PSO) and Salp Swarm algorithms (SSA) to optimize the cascade parameters and were compared together. Maximizing cascade capacity production, recovery factor, and D function were selected as the objective function main items. The comparison of the results showed that the PSO algorithm is somewhat more satisfactory than the SSA. All three cascade arrangement types with 22 stages and 140 centrifuges were optimized for 126Xe and 131X enrichment and their performance was compared. In the end, it was found that the optimal cascade arrangement varies with changing the target isotope. The descending configuration had better 126Xe separation efficiency, 73.64%, than the others, while the ascending counterpart had the highest 131Xe separation efficiency, 77.57%.

Ordinary Gas-Centrifuge Cascades for Purifying Reprocessed Uranium Hexafluoride from 232,234U

Ordinary Gas-Centrifuge Cascades for Purifying Reprocessed Uranium Hexafluoride from 232,234U

Restoration of the Isotopic Composition of Regenerated Uranium in Ordinary and Pentastream Gas-Centrifuge Cascades

Restoration of the Isotopic Composition of Regenerated Uranium in Ordinary and Pentastream Gas-Centrifuge Cascades

Investigation of Cut Control Equations in the Gas Centrifuge Cascades

Stage cut control and simulation are the most important aspects in the optimum binary mixture or multi-component multiobjective cascades. Numerical investigation revealed that by controlling the cut of a separation cascade, defined as the ratio of the product rate to the feed rate, it is always possible to separate a multi-component mixture into two specified groups of components, a light group, and a heavy group, in just one separation run. In this paper, the equations related to the cut control are introduced and it is proposed that for controlling stage cuts, putting one valve in the product section of each stage is enough. By solving the set of non-linear equations related to the machine behavior, valve, and pressure drop in the pipelines and junctions, the valve setting for each stage can be obtained. In the end, some examples of an optimal cascade are studied and valve setting parameters are obtained.

Gas Centrifuge Cascade for Concentrating 235U in Additional Product and Purification of Processed Uranium Hexafluoride from 232,234,236U

Gas Centrifuge Cascade for Concentrating 235U in Additional Product and Purification of Processed Uranium Hexafluoride from 232,234,236U

Implementation of Gray Wolf Optimization algorithm to recycled gas centrifuge cascades

Since the separative power of a single centrifuge is relatively small, to achieve adequate enrichment and throughput, a large number of centrifuges are interconnected to form a cascade. An enrichment plant usually holds thousands of centrifuges. The pattern of connections is determined by the properties of the individual machines, the required quantity, and the concentration of the final product. Because the most separation costs of a cascade are proportional to the number of machines, it is required to determine the optimal operating parameters of the cascade to reduce the number of centrifuge machines. In a problem in which the number of variables is large, the amount of possible arrangement is truly astronomical, and a direct exhaustive search for the best pattern would be prohibitive. In recent years, nature-inspired meta-heuristic optimization algorithms have been developed to treat complicated engineering problems. In this paper, the Gray Wolf Optimization (GWO) algorithm based on the behavior of gray wolves for hunting is implemented to multi-objective optimization of gas centrifuge cascades. In this analysis, the performance of the algorithm is examined for challenging test functions, primarily; and then several real cascades are evaluated and the results are compared with other methods. The GWO is used to minimize the number of machines and optimum operational parameters of cascades for binary mixture separations. It is found from an evolutionary point of view, the performance of the GWO as an efficient method is quite adequate.

Thermally driven countercurrent plasma centrifuge

ABSTRACT Renewed interest in plasma isotope separation stems from the need to produce certain isotopes more inexpensively. These include isotopes of groups I and II, rare earth and some other elements of the periodic table. While gas centrifuge cascades, developed for uranium enrichment, are capable of a wider range of separation applications, they are limited to elements that can form volatile gaseous compounds at room temperature. In the absence of a suitable compound, more expensive separation techniques are used, consuming considerable electrical power for relatively low throughputs. We believe that a new type of plasma centrifuge can be a viable alternative.

Reprocessed Uranium Hexafluoride Purification from 232,234,236U in Pentaflow Gas-Centrifuge Cascades

A computational experiment was performed to purify reprocessed uranium hexafluoride from 232,234,236U in an additional product flow of cascades with a specified number of gas centrifuges in stages. The method used in the calculations takes into account the dependence of the separation coefficients of gas centrifuges on their feed flow and flow division factor. A cascade scheme for purification with simultaneous production of low-enrichment uranium from natural uranium in the main product is investigated. The cascade has to feed flows with regenerated natural-uranium hexafluoride, two product flows, and one waste flow. The cascade parameters that increase the purification efficiency are determined. It is shown that uranium hexafluoride in the products of the cascade satisfies the ASTM C996–15 international specifications established for low-enrichment commercial grading.

Gas-Centrifuge Cascade Systems Optimization via Matrix Description of Step Connections in a General Scheme

A method of optimizing gas-centrifuge cascade systems for separating binary mixtures of isotopes is proposed. This method makes it possible to determine the optimal parameters of a system with an arbitrary scheme for connecting steps and cascades without performing preliminary calculations of each cascade. This method was used to perform calculations of two-cascade systems with different connection schemes and optimization criteria.

Influence of Separating-Cascade Streams on the Duration of a Transient Process

A study has been made of the transient process with the example of obtaining germanium enriched with a 72Ge isotope to 50% in a cascade of gas centrifuges. The influence of the values of outgoing cascade streams on the dynamics of the concentration of isotopes and the duration of the transient process has been shown. Conditions for the change in the values of outgoing cascade streams have been established, with which the minimum duration of the transient process is attained and the efficiency of operation of the cascade rises.

Investigation on the effect of holdup and cascade shape in NFSW cascades

No Feed and Single Withdrawal (NFSW) cascades are of non-conventional gas centrifuge cascades. The present study has been conducted to investigate the effect of holdup of pipes and stages as well as the shape of cascade in separating the multi-component isotopes in NFSW cascades. These cascades are optimized by the Particle Swarm Optimization (PSO) algorithm with an advanced objective function to evaluate the effect of the cascade shape. Moreover, we take into account the holdup term in the equations to study the effect of the holdup of pipes and stages. By investigating the effect of the Holdup of pipes and stages, we found that as the holdup increases, the amount of flow concentration changes. We also compare the optimal tapered structure with the square shape of the NFSW cascade. The results showed that the optimal tapered shape is superior over the square shape in separating the middle component of Xenon.

Change of the External Flows of a Separating Cascade to Shorten the Duration of a Transient Process

A transient process is studied for the example of obtaining in a cascade of gas centrifuges germanium enriched in 72Ge to 50%. The nature of the effect of the cascade flows on the concentration dynamics of the isotopes and duration of the transient process is determined. The conditions under which the accumulation of the desired isotope in the cascade is accelerated and the duration of the transient process is decreased are shown.

Разделение многокомпонентной изотопной смеси в процессе заполнения каскада газовых центрифуг

Разделение многокомпонентной изотопной смеси в процессе заполнения каскада газовых центрифуг

Separation of Nickel Isotopes during the Filling of a Cascade of Gas Centrifuges with Different Numbers of Stages

The results of our study of the filling of a cascade of gas centrifuges with different numbers of stages for separation of nickel isotopes used in nuclear physical research and production of radioactive isotopes are presented. During the filling of the cascade, the natural mixture of nickel isotopes is separated, and the isotopes are concentrated in different cascade stages. The concentrations of nickel isotopes in the stages and flows of light and heavy fractions after the filling of the cascade were shown to depend on the number of stages in the cascade.

Method for Enriching Reprocessed Uranium in a Cascade of Gas Centrifuges with Simultaneous Decrease in the 232,234,236U Content

It is shown that reprocessed uranium can be enriched with simultaneous dilution of 232,234,236U isotopes in a cascade of gas centrifuges that has three feed flows (depleted uranium, low-enriched uranium, reprocessed uranium). Computational experiments are carried out for different 235U content of the lowenriched uranium. It is demonstrated that the chosen combination of diluents can simultaneously reduce the cost of the separation procedure and the consumption of natural uranium, which in turn ensures cost reduction relative to not only the earlier used multiflow cascades but also the standard cascade for enrichment of natural uranium.