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Статті в журналах з теми "POINT REACTOR KINETICS"
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Planchard, J. "On the point-reactor kinetics approximation." Progress in Nuclear Energy 26, no. 3 (January 1991): 207–16. http://dx.doi.org/10.1016/0149-1970(91)90035-n.
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Abramov, B. D., and Yu V. Matveev. "Some Inverse Problems for Reactor Point Kinetics." Transport Theory and Statistical Physics 37, no. 2-4 (December 23, 2008): 327–43. http://dx.doi.org/10.1080/00411450802515973.
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Aboanber, Ahmed E. "Generalized and Stability Rational Functions for Dynamic Systems of Reactor Kinetics." International Journal of Nuclear Energy 2013 (August 13, 2013): 1–12. http://dx.doi.org/10.1155/2013/903904.
Повний текст джерелаАнотація:
The base of reactor kinetics dynamic systems is a set of coupled stiff ordinary differential equations known as the point reactor kinetics equations. These equations which express the time dependence of the neutron density and the decay of the delayed neutron precursors within a reactor are first order nonlinear and essentially describe the change in neutron density within the reactor due to a change in reactivity. Outstanding the particular structure of the point kinetic matrix, a semianalytical inversion is performed and generalized for each elementary step resulting eventually in substantial time saving. Also, the factorization techniques based on using temporarily the complex plane with the analytical inversion is applied. The theory is of general validity and involves no approximations. In addition, the stability of rational function approximations is discussed and applied to the solution of the point kinetics equations of nuclear reactor with different types of reactivity. From the results of various benchmark tests with different types of reactivity insertions, the developed generalized Padé approximation (GPA) method shows high accuracy, high efficiency, and stable character of the solution.
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Zhu, Wenzhang, and Qiang ZHAO. "ICONE19-43375 Solution of Point-Reactor Neutron Kinetics Equation by Gauss Precise Time-Integration Method." Proceedings of the International Conference on Nuclear Engineering (ICONE) 2011.19 (2011): _ICONE1943. http://dx.doi.org/10.1299/jsmeicone.2011.19._icone1943_160.
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Singh, Sudhansu, and Mohapatra Dinakrushna. "Solution of the reactor point kinetics equations by MATLAB computing." Nuclear Technology and Radiation Protection 30, no. 1 (2015): 11–17. http://dx.doi.org/10.2298/ntrp1501011s.
Повний текст джерелаАнотація:
The numerical solution of the point kinetics equations in the presence of Newtonian temperature feedback has been a challenging issue for analyzing the reactor transients. Reactor point kinetics equations are a system of stiff ordinary differential equations which need special numerical treatments. Although a plethora of numerical intricacies have been introduced to solve the point kinetics equations over the years, some of the simple and straightforward methods still work very efficiently with extraordinary accuracy. As an example, it has been shown recently that the fundamental backward Euler finite difference algorithm with its simplicity has proven to be one of the most effective legacy methods. Complementing the back-ward Euler finite difference scheme, the present work demonstrates the application of ordinary differential equation suite available in the MATLAB software package to solve the stiff reactor point kinetics equations with Newtonian temperature feedback effects very effectively by analyzing various classic benchmark cases. Fair accuracy of the results implies the efficient application of MATLAB ordinary differential equation suite for solving the reactor point kinetics equations as an alternate method for future applications.
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Hayes, J. G., and E. J. Allen. "Stochastic point-kinetics equations in nuclear reactor dynamics." Annals of Nuclear Energy 32, no. 6 (April 2005): 572–87. http://dx.doi.org/10.1016/j.anucene.2004.11.009.
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Obaidurrahman, Khalilurrahman, and Om Singh. "A comparative study of kinetics of nuclear reactors." Nuclear Technology and Radiation Protection 24, no. 3 (2009): 167–76. http://dx.doi.org/10.2298/ntrp0903167o.
Повний текст джерелаАнотація:
The paper deals with the study of reactivity initiated transients to investigate major differences in the kinetics behavior of various reactor systems under different operating conditions. The article also states guidelines to determine the safety limits on reactivity insertion rates. Three systems, light water reactors (pressurized water reactors), heavy water reactors (pressurized heavy water reactors), and fast breeder reactors are considered for the sake of analysis. The upper safe limits for reactivity insertion rate in these reactor systems are determined. The analyses of transients are performed by a point kinetics computer code, PKOK. A simple but accurate method for accounting total reactivity feedback in kinetics calculations is suggested and used. Parameters governing the kinetics behavior of the core are studied under different core states. A few guidelines are discussed to project the possible kinetics trends in the next generation reactors.
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Valocchi, G., J. Tommasi, and P. Ravetto. "Reduced order models in reactor kinetics: A comparison between point kinetics and multipoint kinetics." Annals of Nuclear Energy 147 (November 2020): 107702. http://dx.doi.org/10.1016/j.anucene.2020.107702.
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Kale, Vivek, Rakesh Kumar, K. Obaidurrahman, and Avinash Gaikwad. "Linear stability analysis of a nuclear reactor using the lumped model." Nuclear Technology and Radiation Protection 31, no. 3 (2016): 218–27. http://dx.doi.org/10.2298/ntrp1603218k.
Повний текст джерелаАнотація:
The stability analysis of a nuclear reactor is an important aspect in the design and operation of the reactor. A stable neutronic response to perturbations is essential from the safety point of view. In this paper, a general methodology has been developed for the linear stability analysis of nuclear reactors using the lumped reactor model. The reactor kinetics has been modelled using the point kinetics equations and the reactivity feedbacks from fuel, coolant and xenon have been modelled through the appropriate time dependent equations. These governing equations are linearized considering small perturbations in the reactor state around a steady operating point. The characteristic equation of the system is used to establish the stability zone of the reactor considering the reactivity coefficients as parameters. This methodology has been used to identify the stability region of a typical pressurized heavy water reactor. It is shown that the positive reactivity feedback from xenon narrows down the stability region. Further, it is observed that the neutron kinetics parameters (such as the number of delayed neutron precursor groups considered, the neutron generation time, the delayed neutron fractions, etc.) do not have a significant influence on the location of the stability boundary. The stability boundary is largely influenced by the parameters governing the evolution of the fuel and coolant temperature and xenon concentration.
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Nahla, Abdallah A., and Elsayed M. E. Zayed. "Solution of the nonlinear point nuclear reactor kinetics equations." Progress in Nuclear Energy 52, no. 8 (November 2010): 743–46. http://dx.doi.org/10.1016/j.pnucene.2010.06.001.
Повний текст джерелаДисертації з теми "POINT REACTOR KINETICS"
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Parra, S. A. (Santiago Ariel). "Simulating light-water-reactor start-up transients using a point-kinetics model with a precalculated reactivity-table." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/35951.
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Cooling, Christopher. "Development of a point kinetics model with thermal hydraulic feedback of an aqueous homogeneous reactor for medical isotope production." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/24969.
Повний текст джерелаАнотація:
This thesis presents the development of a model of the Medical Isotope Production Reactor (MIPR): a conceptual Aqueous Homogeneous Reactor (AHR). The model is a point kinetics model with zero and one-dimensional thermal hydraulic feedbacks. Three versions of the model of increasing complexity are presented and a number of scenarios are modelled with each version. The results of these simulations shows the stability of the reactor against reactivity insertions caused by the strong negative reactivity feedbacks inherent to AHRs. The first version of the model is modified using intrusive polynomial chaos in order to simulate the effects of uncertainty in key parameters. This allows a novel study into which physical parameters and processes are important at each stage of a transient and in determining steady state conditions. The final version of the model is used to model the CRAC-43 experiment and, after modification to include the delay of radiolytic gas production which accompanies the start up of an AHR, good agreement was found between model and experiment. The development of the equations, correlations and parameters used in the model is approached from the point of view of the governing physics. This approach to model development enables a comprehensive exploration of the physical processes underpinning the behaviour of AHRs. As well as being one of the most complete and fundamentally based models of an AHR presented within the literature, the final model is also extremely versatile and general. Given the appropriate input neutronic and thermal-hydraulic data the model presented in this thesis should be able to simulate a very wide range of AHR behaviour.
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Dal'Maz, Silva Walter. "Mise au point de la carbonitruration gazeuse des alliages 16NiCrMo13 et 23MnCrMo5 : modélisation et procédés." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0158/document.
Повний текст джерелаАнотація:
Le développement de matériaux d'ingénierie combinant ténacité et résistance à l'usure reste encore un défi. Dans le but de contribuer à ce domaine, cette thèse présente une étude de la carbonitruration des aciers 16NiCrMo13 et 23MnCrMo5. L'évolution cinétique des atmosphères à base d'hydrocarbures et d'ammoniac est étudiée numériquement, ainsi que le comportement local à l'équilibre et la cinétique de diffusion pour l'obtention de profils d'enrichissement des alliages traités. Les simulations sont confrontées à des mesures par chromatographie en phase gazeuse des produits de pyrolyse de l'acétylène et de décomposition de l'ammoniac, et aux réponses métallurgiques, par l'évaluation des profils de diffusion, des filiations de dureté et par l'identification des précipités formés par microscopie électronique en transmission. La dureté obtenue après trempe et traitement cryogénique évolue selon la racine carrée de la teneur en interstitiels en solution solide simulée à partir de la composition locale en utilisant des mesures des profils chimiques en carbone et en azote. Après revenu, les zones enrichies en azote montrent une tenue en dureté supérieure à celles obtenues avec la même teneur totale en carbone en solution, ce qui a été attribué après observation par microscopie électronique en transmission à une fine précipitation de nitrures de fer lors de cette dernière étape de traitement. Le bilan de matière des produits de pyrolyse montre que les principales espèces non détectées sont des radicaux fortement carbonés qui peuvent aussi donner lieu à la formation d'hydrocarbures polycycliques de haut poids moléculaire dans les zones froides du réacteur. À la pression atmosphérique et à basse pression l'établissement de conditions d'enrichissement en carbone à concentration constante est possible en utilisant de faibles pressions partielles d'acétylène dilué dans l'azote. La conversion atteinte par la pyrolyse de ce précurseur est pourtant importante à la température de traitement compte tenu du temps de séjour caractéristique du réacteur employé à la pression atmosphérique. La cinétique de décomposition de l'ammoniac étant beaucoup plus lente que celle des hydrocarbures légers, il a été possible de quantifier la vitesse de décomposition de cette espèce par unité de surface métallique exposée pendant la durée d'un traitementThe development of engineering materials combining both toughness and wear resistance is still a challenge. Aiming to contribute to this field of study, this thesis presents a study of the carbonitriding process of alloys 16NiCrMo13 and 23MnCrMo5. Kinetics of hydrocarbon- and ammonia-based atmospheres, as well as local equilibrium and diffusion kinetics for achieving the enrichment profiles, are studied by numerical simulation. These simulations are compared to chromatography measurements of gas phase pyrolysis products of acetylene and ammonia decomposition, and with metallurgical responses, where the comparison is made with evaluated diffusion profiles, hardness measurements and the identification of precipitates by transmission electron microscopy. Hardness after quench and cryogenic treatment depends on the square root of total solid solution interstitial content simulated by using local carbon and nitrogen compositions obtained experimentally. After tempering, the regions enriched in nitrogen show better hardness stability than those with same total carbon interstitial content, what was linked to a fine precipitation of iron nitrides observed by transmission electron microscopy. Mole balance of pyrolysis products show that the main non-detected species are high-carbon radicals, which may also lead to the formation of polycyclic aromatic hydrocarbons of high molecular weight at the reactor outlet. At both atmospheric and reduced pressures, constant concentration enrichment boundary conditions were established by using low partial pressures of acetylene diluted in nitrogen. Pyrolysis of this precursor attains high conversion rates at treatment conditions given the important residence time of the atmospheric pressure reactor. Ammonia decomposition kinetics being much slower than that of low molecular weight hydrocarbons, it was possible to identify the decomposition rate of this species over a metallic sample during a treatment
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Zekri, Mohamed el Mehdi. "Mise au point d'un réacteur photocatalytique pour la dépollution de l'eau." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112168/document.
Повний текст джерелаАнотація:
L’objectif de cette étude est de mettre au point une méthodologie de travail dédiée à la conception d’un réacteur photocatalytique pour la purification des eaux. Notre ambition étant de passer de la photocatalyse comme processus chimique à la photocatalyse comme procédé de dépollution. Pour cela il nous a paru nécessaire de répondre à deux questions, à savoir : - Dans un tel système, quels seront les phénomènes physico-chimiques majeurs mis en jeux ? -Y-a-t’il un moyen de prédire les performances de notre système ?Tout d’abord, nous avons essayé de travailler sur des photocatalyseurs en suspension, donc non immobilisés sur un support. Le but est d’éviter une étape de filtration couteuse et techniquement difficile. Ainsi différents types de dioxyde de titane ont été déposés sur des supports de différentes géométries.Le premier média obtenu était du dioxyde de titane commercial (P25 de Evonik et UV100 de Sachtleben) déposé sur des billes en verre de diamètre 2 et 4 mm, introduit dans un réacteur annulaire siège de la réaction de dégradation photocatalytique et éclairé par une seule source de lumière UV. La photoactivité de ce média a été testée sur du phénol, le polluant primaire modèle choisi dans cette étude. L’hydroquinone et la benzoquinone, deux de ses principaux intermédiaires de dégradation ont également été analysés. L’efficacité du dépôt a ainsi été calculée sur les différentes configurations obtenues. Les résultats ont été satisfaisants sans arriver à avoir un niveau de photoactivité comparable à celui du TiO2 en mode suspension. Nous avons donc cherché à améliorer les performances de notre système réactionnel en travaillant sur un support ayant une autre géométrie. Notre choix s’est porté sur des mousses en alumine épousant parfaitement le vide réactionnel. Le même protocole expérimental a été appliqué à ces dernières. Les résultats de photodégradation ont montrés une durabilité meilleure que celle obtenue sur les billes en verre, mais aussi une photoperformance dépassant celle réalisée sur du dioxyde de titane en mode suspension.Afin de mieux comprendre les différences de photoactivité entre les supports, nous avons tenté de simuler, par la méthode Monte Carlo, la propagation de la lumière à travers les photocatalyseurs, qu’ils soient en mode suspension ou déposés. Les résultats ont montrés que le dioxyde de titane en suspension avait le meilleur taux d’absorption de la lumière comparé au TiO2 fixé sur les supports. Néanmoins l’absorption se fait sur un volume très petit du réacteur et la meilleure répartition de l’énergie lumineuse se trouve dans les mousses en alumine.Les données issues de ces simulations notamment, la LVRPA pour « Local Volumetric Rate of Photon Absorption » nous ont permis d’entamer la dernière étape de notre travail à savoir la construction d’un modèle prédictif des performances photocatalytiques du système réactionnel. Nous avons pour cela introduit un terme qui traduit la probabilité qu’un photon absorbé par le photocatalyseur donne un radical hydroxyle. Les résultats obtenus par notre environnement mathématique ont montrés de bonnes corrélations avec les expériences et ont permis de tirer certaines conclusions quand à l’amélioration de notre système photocatalytiqueThe objective of this work is to develop a methodology dedicated to the design of a photocatalytic reactor for water purification. The principle is to go from photocatalysis as chemical process to photocatalysis as remediation method.Iit necessary for that to respond to two questions: - In such a system, what are the major physico-chemical phenomena? - Is there a way to predict the performance of our system?First of all, we tried to work on suspended photocatalysts to avoid a costly filtration step and technical difficulties. Thus, different types of titanium dioxide were deposited on substrates of different geometries.The first obtained medium was commercial titanium dioxide (P25 from Evonik and UV100 from Sachtleben) deposited on glass beads of 2 and 4 mm, inserted into an annular reactor illuminated by a single UV light source. The photoactivity of this media has been tested on phenol, the primary pollutant model chosen in this study. Hydroquinone and benzoquinone, two of its main degradation intermediates were also analyzed. The deposition efficiency has been estimated on different configurations. The results were satisfactory but did not reach a level comparable to that of photoactivity of TiO2 in suspend mode. Thus, we sought to improve the performance of our reaction system working on a support having a different geometry. Our choice fell on alumina foams perfectly matching the vacuum in the reactor. The same experimental protocol was applied to the foam. The results have shown photodegradation durability better than that obtained on glass beads and also the photoperformance exceeding that of titanium dioxide in suspend mode.To understand better the photoactivity of our media, we simulated by the Monte Carlo method the propagation of the light through the different photocatalysts (suspend mode or deposited). The results showed that the titanium dioxide suspension had the best absorption of light compared to TiO2 fixed on media. Nevertheless, absorption was located on a very small volume of the reactor and a better distribution of the light energy occurs in the alumina foams.The data obtained from these simulations, including the LVRPA "Local Volumetric Rate of Photon Absorption", allowed us to achieve the final step of our work, which is the construction of a predictive model of photocatalytic performance of the reaction system. Thus, we have introduced a term that reflects the probability that a photon absorbed by the photocatalyst gives a hydroxyl radical. The results obtained by our mathematical environment have shown a good correlation with experiments and helped us to draw some conclusions for the improving of our photocatalytic system
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Favorite, Jeffrey Alan. "Variational estimates of point kinetics parameters." Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/16756.
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Schaube, Maximilian [Verfasser], and Joachim [Akademischer Betreuer] Maier. "Impact of point defects on reaction kinetics of systematically doped ceria / Maximilian Schaube ; Betreuer: Joachim Maier." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2020. http://d-nb.info/1210488221/34.
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Silva, Rodney Aparecido Busquim e. "Implications of advanced computational methods for reactivity initiated accidents in nuclear reactors." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/3/3139/tde-20072016-142605/.
Повний текст джерелаАнотація:
Advanced computational tools are applied to simulate a nuclear power plant (NPP) control rod assembly ejection (CRE) accident. The impact of these reactivity-initiated accidents (RIAs) on core reactivity behavior, 3D power distribution and stochastic reactivity estimation are evaluated. The three tools used are: the thermal-hydraulic (TH) RELAP5 (R5) code, the neutronic (NK) PARCS (P3D) code, and the coupled version P3D/R5, with specially developed linkage using the environment code MATLAB. This study considers three different-size cores: NPP1 (2772 MWt); NPP2 (530 MWt); and NPP3 (1061 MWt). The three cores have the same general design and control rod assembly (CRA) positions, and the ejected CRA has similar worth and at the same rod ejection pace. The CRE is assessed under both hot zero power (HZP) and hot full power (HFP) conditions. The analyses indicate that RIA modeling and simulation should be carried out through a systematic coding and configuration approaches, otherwise the results will not capture the true transient behavior of the core under analysis. The simulation of one code depends on the appropriate configuration of parameters generated by the other code and on the correct determination of the TH/NK mapping weight factors for the various mesh regions in each of the models. From the design point of view, the standalone codes predict milder magnitude of power and reactivity increase compared to the coupled P3D/R5 simulation. The magnitudes of reduced peak power and reactivity become larger as the core size shrinks. The HFP simulation shows that the three NPPs have the same transient peak value, but the post-transient steady power is lower for a smaller core. The HZP analysis indicates that the transient peak is lower for the smaller core, but the post-transient power occurs at the same level. The three-dimensional (3D) power distributions are different among the HFP and HZP cases, but do not depend on the size of the core. The results indicate: i) HFP: core power increases in the area surrounding the ejected rod/bank assembly, and this increase becomes lower as the NPPs shrinks however, the power is well-distributed after the transient; and ii) HZP: the area surrounding the CRA stays hotter, but the 3D peak assembly factor becomes lower, during and after the transients, as the NPPs shrinks. These features confirm that the smaller cores yield a safer response to a given inserted reactivity compared to larger cores. A stochastic extended Kalman filter (EKF) algorithm is implemented to estimate the reactivity based on the reactor power profile, after the addition of random noise. The inverse point kinetics (IPK) deterministic method is also implemented and the results of the application of EKF and IPK are compared to the P3D/R5 simulation. The following sophisticated strategies made the EKF algorithm robust and accurate: the system is modeled by a set of continuous time nonlinear stochastic differential equations; the code uses a time step directly based on the power measured and applies that to the model for online discretization and linearization; filter tuning goes automatically up from the first time step; and the state noise covariance matrix is updated online at each time step. It was found that the IPK reactivity has higher noise content compared to the EKF reactivity for all cases. Thus, the EKF presents superior and more accurate results. Furthermore, under a small reactivity insertion, the IPK reactivity varies widely from positive to negative values: this variation is not observed within the EKF. A sensitivity analysis for three distinct standard deviation (SD) noise measurements suggests that EKF is superior to IPK method, independent of the noise load magnitude. As the noise content increases, the error between the IPK and P3D/R5 reactivity also increases. A sensitivity analysis for five distinct carry-over effects of different random noise loads indicates that the random addition of different noise loads to the reactor power does not change the overall performance of both algorithms.Este trabalho aplica métodos computacionais avançados para simular a ejeção de barras de controle (CRE) em uma planta térmica nuclear (NPP). São avaliados o impacto da ocorrência de acidentes iniciados por reatividade (RIAs) na reatividade total, na distribuição da potência em três dimensões (3D) e na determinação da reatividade. As ferramentas utilizadas são: o código termo-hidráulico (TH) RELAP5 (R5), o código neutrônico (NK) PARCS (P3D), a versão acoplada P3D/R5, e o ambiente computacional MATLAB. Este estudo considera três reatores nucleares de diferentes tamanhos: NPP1 (2772 MWT); NPP2 (530 MWt); e NPP3 (1061 MWt). Os três núcleos possuem projeto similar e idêntica posição dos grupos das barras de controle (CRA), além do mesmo valor de reatividade diferencial das CRA ejetadas e idêntica velocidade de ejeção. A ocorrência da CRE é avaliada sob condições de hot zero power (HZP) e de hot full power (HFP). As análises indicam que a modelagem e a simulação de RIAs devem ser realizadas sistematicamente, caso contrário os resultados não irão refletir o comportamento em regime transitório do núcleo. A simulação de um modelo em um código depende da apropriada configuração de parâmetros gerados pelo outro código e da determinação adequada do mapeamento TH/NK para as várias malhas dos modelos. Do ponto de vista de projeto, a utilização de códigos independentes resulta em cálculos de potência e reatividade conservadores em comparação com os resultados utilizando-se P3D/R5. Os picos de potência e de reatividade são menores à medida que o núcleo encolhe. A simulação em condições de HFP resulta em valores de pico de potência similares durante transitório para as três NPPs, mas a potência de pós-transitórios é menor para o menor núcleo. A análise em condições de HZP também indica que o valor máximo durante o transitório é menor para o menor núcleo, mas o pós-transitórios ocorre aos mesmos níveis de potência das demais NPPS. A distribuição de potência em 3D também apresenta resultados distintos para condições de HFP e HZP, mas tais resultados são independentes do tamanho do núcleo: i) HFP: há um aumento da potência do núcleo em torno da CRE, mas tal comportamento diminui para núcleos menores - no entanto, a potência é bem distribuída após o transitório; e ii) HZP: há aumento de potência na área do CRE, mas o pico de potência em 3D é menor durante e depois dos transitórios para núcleos menores. Tais características indicam que os núcleos menores respondem de forma mais segura quando da inserção de reatividade em comparação a reatores de maiores dimensões. O método estocástico de filtragem de Kalman estendido (EKF) foi codificado para estimar a reatividade com base no perfil de potência da NPP, após a adição de ruído aleatório. O método determinístico da cinética pontual inversa (IPK) também foi implementado e os resultados da aplicação dos algoritmos do EKF e IPK foram comparados com os resultados da simulação do P3D/R5. As seguintes estratégias, implementadas neste trabalho, possibilitaram a aplicação robusta e precisa do EKF: o sistema foi modelado por um conjunto de equações diferenciais não-lineares estocásticas de tempo contínuo; o algoritmo obtém o passo de tempo diretamente da potência medida e aplica-o ao modelo para a discretização e linearização online; o ajuste do filtro ocorre automaticamente a partir do primeiro passo de tempo; e a matriz de covariância do ruído no estado é atualizada online. Verificou-se que a reatividade calculada pelo método IPK possui maior nível de ruído quando comparada ao EKF para todos os casos estudados. Portanto, o EKF apresenta resultados superiores e mais precisos. Além disso, sob uma pequena inserção de reatividade, a reatividade calculada pelo método IPK varia consideravelmente de valores positivos para negativos: esta variação não é observada com o EKF. Uma análise de sensibilidade para três desvios padrão (SD) sugere que o algoritmo EKF é superior ao método IPK, independente da magnitude do ruído. Com o aumento da magnitude do ruído, o erro entre as reatividades calculadas pelo IPK e pelo P3D/R5 aumenta. A análise de sensibilidade para cinco ruídos aleatórios indica que a adição de ruído na potência do reator não altera o desempenho global de ambos os algoritmos.
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MANDAVIA, DHAIVAT. "SLIDING MODE OBSERVERS FOR OBSERVING THE DYNAMICS OF NUCLEAR REACTOR SYSTEMS." Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14612.
Повний текст джерелаАнотація:
ABSTRACT
The behaviour of the control system under parameter uncertainties is of utmost importance in
industrial applications. For designing a robust control system, a necessary effort has to be
carried out for achieving desirable control characteristics irrespective of the operating
conditions. With the shortcomings in the design of a conventional controller, a theory with
proper mathematical background is of imminent need for a control designer. The application
of a high speed switching with a suitable switching logic provides attractive feature of
possessing a new property which is not present in the substructures. This fundamental idea
developed into Variable Structure theory. Having derived from variable structure, sliding mode
control is the operational tool of variable structure control. The design of sliding surface is
important for control of the system during sliding mode. The distinguishing feature of sliding
mode is the independence of the system against model dynamics which testifies the robustness
with respect to parametric uncertainties, bounded disturbances and noise.
Numerous applications of sliding mode in controller design is already proposed. The
requirement of all states of the system for effective control was an inherent drawback with
respect to practical system. Estimation of non-measurable states using the input and
information of any measurable state is the fundamental idea of an observer. Luenberger
observer for estimation of states is not robust to handle parametric variations and nonlinearities
present in the system. Hence, the fundamental idea of sliding mode for observer design is used.
This thesis describes the general framework for the design of sliding mode observer with focus
on nuclear reactor system. Point Reactor Kinetics (PRK) model which is derived from the
neutron diffusion equation is the model to be considered. With only nuclear reactor power as a
measurable quantity, the delayed neutron precursor concentration, reactivity, external neutron
source, xenon and iodine concentration is estimated. Out of large number of applications of
sliding mode, fault detection in a nuclear and non-nuclear component with actuator and sensor
faults is carried out. Residual evaluation is carried out using sliding mode observer while
validating the residual signal at different instances where fault occurs.
The inherent drawback of chattering due to formulation of first order sliding mode is minimized
by using smooth functions. This method would forgo the fundamental idea of robustness of
sliding mode. An attempt is made to present the application of higher order sliding mode which
minimizes or sometimes eliminates chattering without compromising the robustness. The state
estimation of a nuclear reactor system using Super Twisting algorithm is in good agreement
with simulated state from PRK model. The independence of states with respect to initial
conditions along with faster convergence time is achieved by the application of uniform second
order sliding mode algorithm validated using the PRK model.
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Wu, Hongjian. "Achieving safe free residual chlorination at point-of-use in emergencies: a modelling approach." Thesis, 2020. http://hdl.handle.net/1828/11737.
Повний текст джерелаАнотація:
While free (breakpoint) chlorination is widely utilized in humanitarian water treatment, a main challenge limiting its effective application is in determining the initial dose to satisfy both health requirements and aesthetic considerations (i.e. taste and odour). International guidelines and studies showed varying recommendations for the initial chlorine dose and many did not consider chlorine decay during water transportation and storage for up to 24 hours. The main objective of this thesis is to develop a tool for humanitarian staff to accurately determine the initial chlorine dose for achieving free chlorine residual (FCR) objectives with the limited instrumentation and information in the field. The first manuscript included in the thesis gathered and evaluated seven basic chlorine decay models’ applicability in humanitarian treatment contexts. All seven models were found able to accurately describe chlorine decay in water representative of humanitarian treatment contexts with more than half of the regression resulted in R2 over 0.95. However, each model had its own limitations, which were discussed. The second manuscript involved conducting extensive chlorine decay tests in water with different characteristics, explored the relationships between the estimated chlorine decay constant and several water parameters including pH, turbidity, ultraviolet absorption at 254 nm wavelength (UVA254), temperature and 30-minute chlorine demand. It was found that the UVA254 of water followed linear and exponential relationships with the decay constant in Feben and Taras’s empirical model and that in the first order model respectively. Arrhenius-type relations were verified between the decay constant and water’s temperature. A model developed to predict FCR decay in water with known 30-minute chlorine demand accurately predicted FCR level in synthetic water (with humic acid being the main constituent) but underpredicted FCR decay in water with additional chlorine consuming matter. Further research on additional chlorine decay mechanisms are needed to expand the applicability of the model.Graduate
2021-04-13
Книги з теми "POINT REACTOR KINETICS"
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Yarman, Tolga. An error criteria for point kinetics and two-mode synthesis techniques. Istanbul: Institute for Nuclear Energy, Technical University of Istanbul, 1999.
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A, Escrivá, U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research, Universidad Politécnica de Valencia. Departamento de Ingenieria Quimica y Nuclear, and IBRDROLA (ID) (Firm), eds. Confrentes NPP (BWR/6) ATWS (MSIVC) analysis with TRAC-BF1: 1D vs. point kinetics and containment response. Washington, DC: Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, 2000.
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3
Sherwood, Dennis, and Paul Dalby. Chemical equilibrium and chemical kinetics. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198782957.003.0014.
Повний текст джерелаАнотація:
Building on the previous chapter, this chapter examines gas phase chemical equilibrium, and the equilibrium constant. This chapter takes a rigorous, yet very clear, ‘first principles’ approach, expressing the total Gibbs free energy of a reaction mixture at any time as the sum of the instantaneous Gibbs free energies of each component, as expressed in terms of the extent-of-reaction. The equilibrium reaction mixture is then defined as the point at which the total system Gibbs free energy is a minimum, from which concepts such as the equilibrium constant emerge. The chapter also explores the temperature dependence of equilibrium, this being one example of Le Chatelier’s principle. Finally, the chapter links thermodynamics to chemical kinetics by showing how the equilibrium constant is the ratio of the forward and backward rate constants. We also introduce the Arrhenius equation, closing with a discussion of the overall effect of temperature on chemical equilibrium.
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Winkler, Adolf. Reaction studies on nanostructured surfaces. Edited by A. V. Narlikar and Y. Y. Fu. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780199533046.013.12.
Повний текст джерелаАнотація:
This article examines the properties of some self-organized nanostructured surfaces with respect to specific model reactions, from a surface-science point of view. It begins with an overview of the most important types of nanostructured surfaces, their preparation and characterization. It then considers the fundamentals of reaction processes, focusing on the kinetics and dynamics of adsorption and desorption. It also describes the experimental techniques used in the context of reaction studies under ultrahigh-vacuum conditions. Finally, it presents some experimental results of model reactions, including hydrogen adsorption and desorption on stepped nickel surfaces, methanol adsorption on self-assembled copper-copper oxide surfaces, and hydrogen desorption and water formation on vanadium-oxide nanostructures on palladium surfaces.
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Banerjee, Diptonil, Amit Kumar Sharma, and Nirmalya Sankar Das. Nano Materials Induced Removal of Textile Dyes from Waste Water. BENTHAM SCIENCE PUBLISHERS, 2022. http://dx.doi.org/10.2174/97898150502951220101.
Повний текст джерелаАнотація:
Nanotechnology has progressed to the point where it can mimic natural systems such as porous membranes or the structure of leaves. Technological advances have resulted in a boom in the use of nanotechnology in different areas of engineering, including water purification systems. This book explores nanomaterials used for removing various textile dyes from water. It compiles 8 chapters that discuss the materials and nano systems used in these processes. This reference is designed to provide answers to common questions for scholars, academicians and technologists about fundamentals of nanoscience and nanomaterial induced removal of textile dyes. College students (physics, chemistry and materials science, engineering) will be able to easily understand the subject matter. Key Features: Covers the basics of nano systems, from synthesis to applications Explains the basics of nanomaterial behavior and characterization Describes the classifications of dyes Explains the interactions nanomaterials with different dyes Explains the reaction mechanisms of photocatalysis and the kinetics behind adsorption two important methods for removing dyes from water Discusses nano systems that are useful for textile dye removal from water. 3 types of nano systems are included: carbon based, oxide based, polymer based or nitride based systems Includes references for further reading Simple presentation for easy and quick understanding of the subject
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Садовников, Василий. Теория гетерогенного катализа. Теория хемосорбции. Publishing House Triumph, 2021. http://dx.doi.org/10.32986/978-5-40-10-01-2001.
Повний текст джерелаАнотація:
This monograph is a continuation of the monograph by V.V. Sadovnikov. Lateral interaction. Moscow 2006. Publishing house "Anta-Eco", 2006. ISBN 5-9730-0017-6. In this work, the foundations of the theory of heterogeneous catalysis and the theory of chemisorption are more easily formulated. The book consists of two parts, closely related to each other. These are the theoretical foundations of heterogeneous catalysis and chemisorption. In the theory of heterogeneous catalysis, an experiment is described in detail, which must be carried out in order to isolate the stages of a catalytic reaction, to find the stoichiometry of each of the stages. This experiment is based on the need to obtain the exact value of the specific surface area of the catalyst, the number of centers at which the reaction proceeds, and the output curves of each of the reaction products. The procedures for obtaining this data are described in detail. Equations are proposed and solved that allow calculating the kinetic parameters of the nonequilibrium stage and the thermodynamic parameters of the equilibrium stage. The description of the quantitative theory of chemisorption is based on the description of the motion of an atom along a crystal face. The axioms on which this mathematics should be based are formulated, the mathematical apparatus of the theory is written and the most detailed instructions on how to use it are presented. The first axiom: an atom, moving along the surface, is present only in places with minima of potential energy. The second axiom: the face of an atom is divided into cells, and the position of the atom on the surface of the face is set by one parameter: the cell number. The third axiom: the atom interacts with the surrounding material bodies only at the points of minimum potential energy. The fourth axiom: the solution of the equations is a map of the arrangement of atoms on the surface. The fifth axiom: quantitative equations are based on the concept of a statistically independent particle. The formation energies of these particles and their concentration are calculated by the developed program. The program based on these axioms allows you to simulate and calculate the interaction energies of atoms on any crystal face. The monograph is intended for students, post-graduate students and researchers studying work and working in petrochemistry and oil refining.
Частини книг з теми "POINT REACTOR KINETICS"
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Oka, Yoshiaki. "Point Reactor Kinetics." In Nuclear Reactor Kinetics and Plant Control, 9–22. Tokyo: Springer Japan, 2012. http://dx.doi.org/10.1007/978-4-431-54195-0_2.
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Zohuri, Bahman. "Reactor Kinetics and Point Kinetics." In Neutronic Analysis For Nuclear Reactor Systems, 407–33. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-42964-9_11.
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Zohuri, Bahman. "Reactor Kinetics and Point Kinetics." In Neutronic Analysis For Nuclear Reactor Systems, 401–26. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-04906-5_11.
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Pyeon, Cheol Ho. "Reactor Kinetics." In Accelerator-Driven System at Kyoto University Critical Assembly, 51–81. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0344-0_3.
Повний текст джерелаАнотація:
AbstractIn static and kinetic experimental analyses, the reactivity effect of introducing a neutron guide has been examined with various materials and adjustments of the beam window. With the objective of improving the KUCA core characteristics, the implementation of the neutron guide is predicted to increase the fast neutrons in directing the fuel region. With regard to the kinetic characteristics, the subcriticality and the prompt neutron decay constant are monitored for several core configurations and detector positions. The KUCA core is equipped to make locally a hard spectrum core region with the combined use of 235U fuel, a polyethylene moderator, and a Pb–Bi reflector for criticality. In this study, the first attempt is made to examine experimentally the characteristics of kinetics parameters in ADS comprised of 235U-fueled and Pb–Bi-zoned core, and spallation neutrons generated by an injection of 100 MeV protons onto the solid Pb–Bi target. Online monitoring of reactivity has been deduced in real time by the inverse kinetic method on the basis of the one-point kinetic equation with measured neutron signals in the core. Here, measurements by the one-point kinetic equation are validated through the subcriticality evaluation with the PNS histogram and the methodology by the inhour equation.
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Masterson, Robert E. "The Point Kinetics Approximation and the Inhour Equation." In Introduction to Nuclear Reactor Physics, 673–718. Boca Raton : Taylor & Francis, a CRC title, part of the Taylor & Francis imprint, a member of the Taylor & Francis Group, the academic division of T&F Informa, plc, [2017]: CRC Press, 2017. http://dx.doi.org/10.1201/9781315118055-16.
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Vyawahare, Vishwesh, and Paluri S. V. Nataraj. "Further Developments Using Fractional-order Point Reactor Kinetics Model." In Fractional-order Modeling of Nuclear Reactor: From Subdiffusive Neutron Transport to Control-oriented Models, 93–123. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7587-2_5.
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Vyawahare, Vishwesh, and Paluri S. V. Nataraj. "Development and Analysis of Fractional-order Point Reactor Kinetics Model." In Fractional-order Modeling of Nuclear Reactor: From Subdiffusive Neutron Transport to Control-oriented Models, 73–91. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7587-2_4.
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Tarantino, F. A., R. P. Jacqmin, and A. F. Henry. "The Validity of the Point Kinetics Model During Reactor Start-Up." In Nuclear Simulation, 170–81. Berlin, Heidelberg: Springer Berlin Heidelberg, 1990. http://dx.doi.org/10.1007/978-3-642-84279-5_13.
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Vyawahare, Vishwesh, and Paluri S. V. Nataraj. "Development and Analysis of Fractional-order Point Reactor Kinetics Models with Reactivity Feedback." In Fractional-order Modeling of Nuclear Reactor: From Subdiffusive Neutron Transport to Control-oriented Models, 125–66. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7587-2_6.
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Saha Ray, Santanu. "Numerical Simulation of Stochastic Point Kinetics Equation in the Dynamical System of Nuclear Reactor." In Nonlinear Differential Equations in Physics, 375–88. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-15-1656-6_9.
Повний текст джерелаТези доповідей конференцій з теми "POINT REACTOR KINETICS"
1
Golovkina, Anna G. "Two-point kinetics model for hybrid cascade subcritical reactor." In 2015 International Conference "Stability and Control Processes" in Memory of V.I. Zubov (SCP). IEEE, 2015. http://dx.doi.org/10.1109/scp.2015.7342080.
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Liu, Dong, Xiuchun Luan, Tao Yu, Weining Zhao, and Lei Liu. "The Controllability of the Point Reactor Neutron Kinetics Equations." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-30494.
Повний текст джерелаАнотація:
In this paper, the conditions to ensure the controllability of the point reactor neutron kinetics equations are studied. In a nuclear reactor, due to the delayed neutron precursor concentration and the internal reactivity, the kinetics equations of the nuclear reactor are nonlinear. To solve the problem of the pole placement, the controllability of the point kinetics equations must be guaranteed. Then, a new method to analysis of the controllability conditions of the point kinetics equations of a reactor is carried out here. The method is based on the controllability matrix directly denoted by relevant symbols, and a formula used for controllability analysis is showed with symbols by calculating the determinant of the matrix. First, with using the linearization technique, the equations are linearized with respect to any possible equilibrium point. Subsequently, an analysis of the controllability of the general linear model that includes only one group delayed neutron precursor is performed, obtaining the interesting result that the controllability of the equations are controllable except when the effective precursor radioactive decay constant and the reciprocal of the fuel-to-coolant heat transfer mean time have the same value, which does not occur in practice. Thus, with the same method, the other analysis obtained the conditions to guarantee the controllability of the point kinetics equations with different groups delayed neutron precursor, which includes two-group, three-group and six-group models. Then, the results are compared with that of the numerical controllability matrix, obtaining the final conclusion that the results of the new analysis method give the closer results to the actual situation and list the restrictions that guarantee the controllability of the point reactor neutron kinetics equations.
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Luan, Xiuchun, Jie Zhou, and Yu Zhai. "Takagi-Sugeno Fuzzy Load-Following Control of Nuclear Reactors Based on Reactor Point Kinetics Equations." In 2014 22nd International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/icone22-30562.
Повний текст джерелаАнотація:
A state differential feedback control system based Takagi-Sugeno (T-S) fuzzy model is designed for load-following operation of nonlinear nuclear reactor whose operating points vary within a wide range. Linear models are first derived from the original nonlinear model on several operating points. Next the fuzzy controller is designed via using the parallel distributed compensation (PDC) scheme with the relative neutron density at the equilibrium point as the premise variable. Last the stability analysis is given by means of linear matrix inequality (LMI) approach, thus the control system is guaranteed to be stable within a large range. The simulation results demonstrate that the control system works well over a wide region of operation.
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Mahfudin, Ikhsan, Igi Ardiyanto, and Adha Imam Cahyadi. "Auto-tuning PID Controller for NuScale Nuclear Reactor using Point Reactor Kinetics Model Simulator." In 2022 9th International Conference on Information Technology, Computer, and Electrical Engineering (ICITACEE). IEEE, 2022. http://dx.doi.org/10.1109/icitacee55701.2022.9923982.
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Vrban, Branislav, Miroslava Dobroňová, Jakub Lüley, Štefan Čerba, Filip Osuský, and Vladimír Nečas. "On the Taylor series solution of the reactor point kinetics equations." In APPLIED PHYSICS OF CONDENSED MATTER (APCOM 2021). AIP Publishing, 2021. http://dx.doi.org/10.1063/5.0066972.
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Wang, Xin, Kathryn D. Huff, Manuele Aufiero, Per F. Peterson, and Massimiliano Fratoni. "Coupled Reactor Kinetics and Heat Transfer Model for Fluoride Salt-Cooled High-Temperature Reactor Transient Analysis." In 2016 24th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/icone24-60728.
Повний текст джерелаАнотація:
Coupled reactor kinetics and heat transfer models have been developed at the University of California, Berkeley (UCB) to study Pebble-Bed, Fluoride-salt-cooled, High-temperature Reactors (PB-FHRs) transient behaviors. This paper discusses a coupled point kinetics model and a two-dimensional diffusion model. The former is based on the point kinetics equations with six groups of delayed neutrons and the lumped capacitance heat transfer equations. To account for the reflector effect on neutron lifetime, additional (fictional) groups of delayed neutrons are added in the point kinetics equations to represent the thermalized neutrons coming back from the reflectors. The latter is based on coupled multi-group neutron diffusion and finite element heat transfer model. Multi-group cross sections and diffusion coefficients are generated using the Monte Carlo code Serpent and defined as input in COMSOL 5.0.
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Vyawahare, Vishwesh, and P. S. V. Nataraj. "Modeling Neutron Dynamics in Nuclear Reactor using Fractional-order Point Reactor Kinetics Model with Adiabatic Temperature Feedback." In 4th International Conference on Simulation and Modeling Methodologies, Technologies and Applications. SCITEPRESS - Science and Technology Publications, 2014. http://dx.doi.org/10.5220/0005038103520360.
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Yamamoto, Takahisa, Koshi Mitachi, and Masatoshi Nishio. "Reactor Controllability of 3-Region-Core Molten Salt Reactor System: A Study on Load Following Capability." In 14th International Conference on Nuclear Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/icone14-89440.
Повний текст джерелаАнотація:
The Molten Salt Reactor (MSR) systems are liquid-fueled reactors that can be used for actinide burning, production of electricity, production of hydrogen, and production of ssile fuels (breeding). Thorium (Th) and uranium-233 (233U) are fertile and ssile of the MSR systems, and dissolved in a high-temperature molten fluoride salt (fuel salt) with a very high boiling temperature (up to 1650K), that is both the reactor nuclear fuel and the coolant. The MSR system is one of the six advanced reactor concepts identified by the Generation IV International Forum (GIF) as a candidate for cooperative development [1]. In the MSR system, fuel salt flows through a fuel duct constructed around a reactor core and fuel channel of a graphite moderator accompanied by fission reaction and heat generation, and flows out to an external-loop system consisted of a heat exchanger and a circulation pump. Due to the motion of fuel salt, delayed neutron precursors that are one of the source of neutron production make to change their position between the ssion reaction and neutron emission events and decay even occur in the external loop system. Hence the reactivity and effective delayed neutron precursor fraction of the MSR system are lower than those of solid fuel reactor systems such as Boiling Water Reactors (BWRs) and Pressurised Water Reactor (PWRs). Since all of the presently operating nuclear power reactors utilize solid fuel, little attention had been paid to the MSR analysis of the reactivity loss and reactor characteristics change caused by the fuel salt circulation. Sides et al. [2] and Shimazu et al. [3] developed MSR analytical models based on the point reactor kinetics model to consider the effect of fuel salt flow. Their models represented a reactor as having six zones for fuel salt and three zones for the graphite moderator. Since their models employed the point reactor kinetics model and the rough temperature approximation, their results were not sufficiently accurate to consider the effect of fuel salt flow.
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Pan, Shibiao. "Research on the Measurement of Deep Subcriticality Based on Pulsed Neutron Source Method." In 2013 21st International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icone21-15883.
Повний текст джерелаАнотація:
During the operating of nuclear reactor, the applicable condition of point reactor neutron kinetics is changed by control rods bulk insertion and reactor lattice deviating from the critical state, The measurement of reactivity, with the increase of subcriticality, shows that the results impact on the kinetic distortion effect, along with prompt neutron flux strongly deteriorated. According to the diffusion theory about prompt neutron and delayed neutron, the theoretical analysis and application of point reactor neutron kinetics have been carried out to quantify the kinetic distortion correction factors in subcritical systems, and these indicate that prompt neutron distributions are strongly affected by kinetic distortion. With the self-developed Pulsed Neutron Source measurement system, subcriticality measurement in different configuration of control rods in the zero power reactor of Nuclear Power Institute of China was carried out. In this paper the reactivity of the deep subcritical system are obtained by experiment of Pulsed Neutron Source method, meanwhile, the bias between experiment results of the areas-ratio method and the characteristic decay constant method are analyzed by comparing the condition of the experiment and the theory model, the main factors inducing the bias are found, which supplies helpful reference for other similar design and experiment.
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Gorton, Jacob P., and Nicholas R. Brown. "Analysis of Reactivity Accidents in Modular HTGRs." In 2020 International Conference on Nuclear Engineering collocated with the ASME 2020 Power Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/icone2020-16731.
Повний текст джерелаАнотація:
Abstract A control rod withdrawal (CRW) is a possible reactivity initiated accident (RIA) in modular high-temperature gas-cooled reactors (mHTGRs). The purpose of this study is to perform a sensitivity analysis of a CRW event in an mHTGR model using the systems code RELAP5-3D with point kinetics feedback to demonstrate the impact of uncertainty in heat transfer and reactor kinetic parameters. The adaptive Sobol decomposition method in the uncertainty quantification code RAVEN is used to perform the sensitivity study and to determine which input parameters have the greatest impact on the figures of merit, which in this case are peak reactor power and maximum fuel temperature. This study addresses a need highlighted by the Nuclear Regulatory Commission (NRC) for transient fuel testing by quantifying the impact of uncertainty in heat transfer and reactor kinetic parameters and by generating potential boundary conditions for transient testing of conventional mHTGR fuel.
Звіти організацій з теми "POINT REACTOR KINETICS"
1
Kontogeorgakos, D. C., and H. M. Connaway. Software Requirements for a Point Kinetics Neutronics Code for Simulating TREAT Reactor Transients. Office of Scientific and Technical Information (OSTI), March 2018. http://dx.doi.org/10.2172/1463242.
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Neher, Daryl E., and II. Research Report Point Reactor Kinetic Analysis. Fort Belvoir, VA: Defense Technical Information Center, December 2002. http://dx.doi.org/10.21236/ada410867.
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Lahav, Ori, Albert Heber, and David Broday. Elimination of emissions of ammonia and hydrogen sulfide from confined animal and feeding operations (CAFO) using an adsorption/liquid-redox process with biological regeneration. United States Department of Agriculture, March 2008. http://dx.doi.org/10.32747/2008.7695589.bard.
Повний текст джерелаАнотація:
The project was originally aimed at investigating and developing new efficient methods for cost effective removal of ammonia (NH₃) and hydrogen sulfide (H₂S) from Concentrated Animal Feeding Operations (CAFO), in particular broiler and laying houses (NH₃) and hog houses (H₂S). In both cases, the principal idea was to design and operate a dedicated air collection system that would be used for the treatment of the gases, and that would work independently from the general ventilation system. The advantages envisaged: (1) if collected at a point close to the source of generation, pollutants would arrive at the treatment system at higher concentrations; (2) the air in the vicinity of the animals would be cleaner, a fact that would promote animal growth rates; and (3) collection efficiency would be improved and adverse environmental impact reduced. For practical reasons, the project was divided in two: one effort concentrated on NH₃₍g₎ removal from chicken houses and another on H₂S₍g₎ removal from hog houses. NH₃₍g₎ removal: a novel approach was developed to reduce ammonia emissions from CAFOs in general, and poultry houses in particular. Air sucked by the dedicated air capturing system from close to the litter was shown to have NH₃₍g₎ concentrations an order of magnitude higher than at the vents of the ventilation system. The NH₃₍g₎ rich waste air was conveyed to an acidic (0<pH<~5) bubble column reactor where NH₃ was converted to NH₄⁺. The reactor operated in batch mode, starting at pH 0 and was switched to a new acidic absorption solution just before NH₃₍g₎ breakthrough occurred, at pH ~5. Experiments with a wide range of NH₃₍g₎ concentrations showed that the absorption efficiency was practically 100% throughout the process as long as the face velocity was below 4 cm/s. The potential advantages of the method include high absorption efficiency, lower NH₃₍g₎ concentrations in the vicinity of the birds, generation of a valuable product and the separation between the ventilation and ammonia treatment systems. A small scale pilot operation conducted for 5 weeks in a broiler house showed the approach to be technically feasible. H₂S₍g₎ removal: The main goal of this part was to develop a specific treatment process for minimizing H₂S₍g₎ emissions from hog houses. The proposed process consists of three units: In the 1ˢᵗ H₂S₍g₎ is absorbed into an acidic (pH<2) ferric iron solution and oxidized by Fe(III) to S⁰ in a bubble column reactor. In parallel, Fe(III) is reduced to Fe(II). In the 2ⁿᵈ unit Fe(II) is bio-oxidized back to Fe(III) by Acidithiobacillus ferrooxidans (AF).In the 3ʳᵈ unit S⁰ is separated from solution in a gravity settler. The work focused on three sub-processes: the kinetics of H₂S absorption into a ferric solution at low pH, the kinetics of Fe²⁺ oxidation by AF and the factors that affect ferric iron precipitation (a main obstacle for a continuous operation of the process) under the operational conditions. H₂S removal efficiency was found higher at a higher Fe(III) concentration and also higher for higher H₂S₍g₎ concentrations and lower flow rates of the treated air. The rate limiting step of the H₂S reactive absorption was found to be the chemical reaction rather than the transition from gas to liquid phase. H₂S₍g₎ removal efficiency of >95% was recorded with Fe(III) concentration of 9 g/L using typical AFO air compositions. The 2ⁿᵈ part of the work focused on kinetics of Fe(II) oxidation by AF. A new lab technique was developed for determining the kinetic equation and kinetic parameters (KS, Kₚ and mₘₐₓ) for the bacteria. The 3ʳᵈ part focused on iron oxide precipitation under the operational conditions. It was found that at lower pH (1.5) jarosite accumulation is slower and that the performance of the AF at this pH was sufficient for successive operation of the proposed process at the H₂S fluxes predicted from AFOs. A laboratory-scale test was carried out at Purdue University on the use of the integrated system for simultaneous hydrogen sulfide removal from a H₂S bubble column filled with ferric sulfate solution and biological regeneration of ferric ions in a packed column immobilized with enriched AFbacteria. Results demonstrated the technical feasibility of the integrated system for H₂S removal and simultaneous biological regeneration of Fe(III) for potential continuous treatment of H₂S released from CAFO. NH₃ and H₂S gradient measurements at egg layer and swine barns were conducted in winter and summer at Purdue. Results showed high potential to concentrate NH₃ and H₂S in hog buildings, and NH₃ in layer houses. H₂S emissions from layer houses were too low for a significant gradient. An NH₃ capturing system was designed and tested in a 100-chicken broiler room. Five bell-type collecting devices were installed over the litter to collect NH₃ emissions. While the air extraction system moved only 10% of the total room ventilation airflow rate, the fraction of total ammonia removed was 18%, because of the higher concentration air taken from near the litter. The system demonstrated the potential to reduce emissions from broiler facilities and to concentrate the NH₃ effluent for use in an emission control system. In summary, the project laid a solid foundation for the implementation of both processes, and also resulted in a significant scientific contribution related to AF kinetic studies and ferrous analytical measurements.