- I enjoy my career as an energy engineer, I like to teach about energy systems and optimization. I love working with y... moreI enjoy my career as an energy engineer, I like to teach about energy systems and optimization. I love working with young people and discover in them their great capacity to learn and to form team. My life goal is to contribute to a sustainable world using clean energy.edit
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An optimization procedure based on the Genetic Algorithms method was developed for the optimization of enrichment and gadolinia distributions in boiling water reactor fuel lattices. The optimization process was linked to the HELIOS code... more
An optimization procedure based on the Genetic Algorithms method was developed for the optimization of enrichment and gadolinia distributions in boiling water reactor fuel lattices. The optimization process was linked to the HELIOS code to evaluate and qualify all the investigated solutions. The goal is to search for the optimal fuel lattice distribution, which has the lowest average enrichment between two defined values, and the minimum local power peaking factor; which satisfies an average gadolinia concentration target and a k-infinite multiplication factor, also target. The weighting factors, used to give the relative importance of the evaluation parameters in the objective function, take two different values depending on the values of the evaluation parameters. This strategy helped the process to rapidly guide the search toward configurations which satisfy all the constraints. The genetic algorithm uses one crossover point, and two offspring. The main contribution of this work is the development of an efficient procedure for BWR fuel lattice design, using a powerful algorithm and an objective function which saves computing time, because it does not require lattice burnup calculations. The results show the good performance of this procedure; fuel distributions were found with low enrichment, low radial power peaking factor and good reactivity performance during the lattice life.
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The reactor studied in this work is the hybrid fusion–fission transmutation system (FFTS), which is a fusion–fission hybrid reactor with a central compact fusion neutron source (CFNS). It is based on the Tokamak concept, and it is... more
The reactor studied in this work is the hybrid fusion–fission transmutation system (FFTS), which is a fusion–fission hybrid reactor with a central compact fusion neutron source (CFNS). It is based on the Tokamak concept, and it is surrounded by a zone made of transuranic elements obtained from reprocessing and recycling of spent fuel of light water reactors. High-energy neutrons, of fourteen MeV, are generated in the CFNS; they are produced by the deuterium-tritium reaction. In this study, the MCNPX Monte Carlo code was used to build up a model of the FFTS for studying the tritium breeding capability of the system. Tritium is produced from neutron capture in lithium, which is located in blankets specifically designed for this purpose. The tritium breeding ratio (TBR) is defined as the average number of tritium atoms bred per tritium atom burnt in the deuterium-tritium reaction. We must have TBR>1, for a self-sustained fusion economy. In the first step of this work, the location of the lithium blankets was defined. Afterwards, different blanket materials were tested: natural lithium, enriched lithium in 6Li, different lithium alloys with neutron multipliers like lead and beryllium [Li4SiO4, LiTiO3, FLiNaBe, FLiBe, Pb-15.8Li (Li-6 at 90 %)]. Finally, a study was carried out to determine the relationship between the width of the blanket and the tritium breeding. Concerning the blanket locations, we defined four: one in the central column of the FFTS, one in the upper and one in the bottom part of the fusion region of the system, and the last one in the external part of the fission region. This means that the first three blankets use high-energy neutrons from the deuterium-tritium reaction, and the fourth blanket uses neutron leaking from the fission reactions. The principal results show that the best option is the blanket with Pb-15.8Li with lithium enriched at 90 % in lithium-6 with TBR = 1.09. It was found that the blanket at the external part of the fission region has the higher tritium breeding capability. Regarding the blanket width, it was observed that most of the tritium breeding is carried out in the first 5 cm of the blanket, and beyond this width breeding is minimal; therefore, for the blanket it is more important to have a high view factor to neutrons (i.e., a big surface exposed to neutrons) than a deep region. Finally, it is important to mention that the FFTS was critical during 1000 days that were simulated with MCNPX.
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Abstract As the continuation of a previous research work, in this paper the utilization of thorium-based metallic fuel is investigated in an ASTRID-like fast reactor core. The main goal of this paper is to compare the neutronic behavior... more
Abstract As the continuation of a previous research work, in this paper the utilization of thorium-based metallic fuel is investigated in an ASTRID-like fast reactor core. The main goal of this paper is to compare the neutronic behavior and the isotopes evolution between the previously studied reference core, based on oxide fuel, and a core loaded with metallic thorium-based fuel for the same ASTRID-like reactor. The reference core, in which the fuel is a material composed of a mixture of U-Pu MOX, was compared with an equivalent core with a U-Pu-Zr metallic alloy fuel (Met-UP) and two alternative thorium-fueled strategies. For the first strategy, a combination of 232Th/233U was introduced in the fertile zone instead of the uranium isotopes, keeping the fissile zone composition unchanged (Met-UPT). For the second strategy, the fertile zone was kept with the same composition as in the first strategy, while a mix of 232Th/233U replaced the fissile fuel zone composition (Met-UT). The calculations were made with the Monte Carlo MCNP6 code and the ENDF/B-VII.0 cross section library. The parameters analyzed were: the neutron multiplication factor for a burnup of one year, the neutron energy spectrum, the Doppler effect, the coolant density reactivity effect, the delayed neutrons fraction and the control rods reactivity worth (shutdown margin). The radial power distribution and the concentration evolution of the main isotopes for each fueling strategy in the core were also analyzed. The main findings of this study were: the effective neutron multiplication factor of the reference core and that of the Met-UPT case is very close, meanwhile, the configuration Met-UT has an important loss of reactivity along the burnup. Regarding the neutron energy spectrum, it becomes harder with a higher thorium fraction in the core. Related to the fissile isotopes, in the reference core 239Pu is produced, meanwhile, 233U is bred in the fertile zone of the configuration with 232Th/233U. The Am and Cm actinides production are lower for the 232Th/233U in the fertile zone compared to the reference configuration and null in the case of the full core with 232Th/233U. Doppler constants have negative values and show similar behavior in all the core configurations. Regarding the coolant density reactivity effect, the metallic fuel configuration with 232Th/233U in the full core shows the better behavior. The power distribution is similar in all the cases, showing a region with the highest power in the outer fuel zone. The metallic fuel configurations have higher power peaks. The full 232Th/233U fuel configuration has the flattest power distribution and the lower effective delayed neutrons fraction. All core configurations show a very good shutdown margin, widely greater than 1000 pcm at the beginning of the cycle. As a result of this study, it can be concluded that the Met-UP configuration can be considered as the best option followed by the Met-UPT configuration.
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In this work a simple method for transuranic fuel lattice design is presented. The method is focused on finding the radial distribution of fuel rods having different transuranic contents to obtain a neutron multiplication factor (k) with... more
In this work a simple method for transuranic fuel lattice design is presented. The method is focused on finding the radial distribution of fuel rods having different transuranic contents to obtain a neutron multiplication factor (k) with a prescribed value and to minimize the rod power peaking factor PPF. The method is based on the factorization of the transuranic content of each fuel rod. The performance of the novel method was demonstrated with a fuel composed of uranium tails and transuranic isotopes coming from the recycling of spent fuel of a typical Boiling Water Reactor (BWR). The results show that the method converges to a minimum PPF and a prescribed k in an efficient and accurate form.
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Page 1. M&C 2001 Salt Lake City, Utah, USA, September 2001. BWR FUEL ASSEMBLY AXIAL DESIGN OPTIMIZATION USING TABU SEARCH C. Martín-del-Campo and JL François Universidad Nacional Autónoma de México ...
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In this paper the radiotoxicity of transuranics from recycled spent fuel is analyzed for three types of boiling water reactor heterogeneous fuel assemblies (Standard MOX, MOX-EU and CORAIL). The results show that in the period from few... more
In this paper the radiotoxicity of transuranics from recycled spent fuel is analyzed for three types of boiling water reactor heterogeneous fuel assemblies (Standard MOX, MOX-EU and CORAIL). The results show that in the period from few hundred years after fuel discharge, until 100,000 years, the radiotoxicity of the first recycling is smaller than radiotoxicity from the direct cycle. At
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In this paper the sensitivity and uncertainty analysis of a SCWR applying a methodology based on Monte Carlo with reduced order models is presented. The numerical code to simulate the SCWR performance of the thermal hydraulics considers a... more
In this paper the sensitivity and uncertainty analysis of a SCWR applying a methodology based on Monte Carlo with reduced order models is presented. The numerical code to simulate the SCWR performance of the thermal hydraulics considers a three-pass core design with multiple heat-up steps. A model using an average channel simulates each pass. The neutronic calculations were performed with HELIOS-2 and the results were used to evaluate the reactivity feedback, caused by changes in the fuel temperature and supercritical water density, which was used to simulate the neutronic process with the point kinetics model. The Monte Carlo’s simulation was applied to establish the operating domain of SCWRs which are not yet in operation, therefore the thermal–hydraulic and nuclear processes rely on numerical modeling with the purpose of developing or confirming the design basis. This methodology has into account an invariability test in order to obtain the representative sample, i.e., invariable results with the simulation size. Additionally, the relative standard deviation is calculated and presented for power, temperature and pressure drop, as well as the regression analysis.
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Résumé/Abstract The development of a basic scatter search (SS) algorithm for the optimization of radial enrichment and gadolinia distributions for boiling water reactor (BWR) fuel lattices is presented in this paper. Scatter search is... more
Résumé/Abstract The development of a basic scatter search (SS) algorithm for the optimization of radial enrichment and gadolinia distributions for boiling water reactor (BWR) fuel lattices is presented in this paper. Scatter search is considered an evolutionary ...
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ABSTRACT Fuel reload pattern optimization is a crucial fuel management activity in nuclear power reactors. Along the years, a lot of work has been done in this area. In particular, several metaheuristic optimization techniques have been... more
ABSTRACT Fuel reload pattern optimization is a crucial fuel management activity in nuclear power reactors. Along the years, a lot of work has been done in this area. In particular, several metaheuristic optimization techniques have been applied with good results for boiling water reactors (BWRs). In this paper, a comparison of different metaheuristics: genetic algorithms, tabu search, recurrent neural networks and several ant colony optimization techniques, were applied, in order to evaluate their performance. The optimization of an equilibrium core of a BWR, loaded with mixed oxide fuel composed of plutonium and minor actinides, was selected to be optimized. Results show that the best average values are obtained with the recurrent neural networks technique, meanwhile the best fuel reload was obtained with tabu search. However, according to the number of objective functions evaluated, the two fastest optimization techniques are tabu search and Ant System.
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Power energy generation in Mexico based on bioenergy is currently insignificant. However, the potential for taking advantage of biomass resources in the country is considerable. This article aims to evaluate the use of biomass waste for... more
Power energy generation in Mexico based on bioenergy is currently insignificant. However, the potential for taking advantage of biomass resources in the country is considerable. This article aims to evaluate the use of biomass waste for the Mexican energy transition in the near future. The methodology starts by identifying sites with biomass waste and establishing the conversion processes needed to produce electricity for each type of biomass. A SWOT analysis was implemented to define the criteria for evaluating all options on the same basis. The opinion of experts in energy systems was collected to assign the priority to each criterion. A fuzzy-logic inference system was formulated to assess the options based on the quality of their attributes. The output obtained from the fuzzy analysis is a sustainability prioritisation of all options. We analysed a case study for the Baja California Sur (BCS) region, and the results show the prioritisation ranking of 24 alternatives regarding t...
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Mexico has positioned itself as a leader among emerging countries for its efforts to mitigate climate change through ambitious climate policies aimed at reducing greenhouse gas (GHG) emissions. However, the Energy Reform bill approved in... more
Mexico has positioned itself as a leader among emerging countries for its efforts to mitigate climate change through ambitious climate policies aimed at reducing greenhouse gas (GHG) emissions. However, the Energy Reform bill approved in 2014 promotes the production of hydrocarbons to develop the economy of this sector, as well as the use of natural gas for electricity generation in order to reduce electricity prices in the short term. In 2016, nearly 80% of Mexico’s total electricity was generated by thermal power plants. While natural gas prices stay low, there might be a limited role for natural gas to act as a fuel bridge in this sector if the government is to pursue deep decarbonisation targets to 2050. There is a risk that over-investing in gas infrastructure may delay a transition to lower carbon sources, potentially leading to less cost-efficient pathways towards decarbonisation. This analysis is based on three decarbonisation scenarios that have been modelled using an energ...
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1 Universidad Nacional Autónoma de México: Av. Universidad S/N, Mexico City, Mexico, pnelson_007@yahoo.com Universidad Autónoma de Nayarit: Área de Ciencias Básicas e Ingenierías, Tepic, Nayarit, Mexico, truizsmx@yahoo.com.mx Boldrick... more
1 Universidad Nacional Autónoma de México: Av. Universidad S/N, Mexico City, Mexico, pnelson_007@yahoo.com Universidad Autónoma de Nayarit: Área de Ciencias Básicas e Ingenierías, Tepic, Nayarit, Mexico, truizsmx@yahoo.com.mx Boldrick Systems, 8502 E Chapman Ave #418,Orange, CA, USA, mb@boldrick.net Universidad Nacional Autónoma de México: Av. Universidad S/N, Mexico City, Mexico, adrianmecast@gmail.com Universidad Nacional Autónoma de México: Av. Universidad S/N, Mexico City, Mexico, cecilia.martin.del.campo@gmail.com
In this paper the implementation of the tabu search (TS) optimization method to a boiling water reactor's (BWR's) fuel assembly (FA) axial design is described. The objective of this implementation is to test the TS method... more
In this paper the implementation of the tabu search (TS) optimization method to a boiling water reactor's (BWR's) fuel assembly (FA) axial design is described. The objective of this implementation is to test the TS method for the search of optimal FA axial designs. This implementation has been linked to the reactor core simulator CM-PRESTO in order to evaluate each
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Countries with emerging economies face a significant challenge when developing strategies to move towards a low emission energy system and keep their economies growing. The power System plays a crucial role in these strategies and by the... more
Countries with emerging economies face a significant challenge when developing strategies to move towards a low emission energy system and keep their economies growing. The power System plays a crucial role in these strategies and by the correct measurement of its sustainability is possible to identify which alternative improves sustainability the most. This article proposes indicators for the evaluation and assessment of the sustainability of Mexican Power System planning scenarios put forward by two government administrations with a study horizon to 2030. The scenarios are characterized by the program of additions and retirements of generating capacity along the period of 2019 to 2030, and eventually, optimal dispatch was obtained to accomplish the hourly demand. Sustainability indicators were developed and calculated to evaluate the energy security, energy equity and environmental sustainability dimensions. Subsequently the indicators were fed to the Position Vector of Minimum Re...
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Abstract In this work the mathematical derivation and numerical analysis of a fractional nuclear reactor point kinetics in time and space (TSFNPK) is presented. The TSFNPK model was derived considering a non-Fickian law for the neutron... more
Abstract In this work the mathematical derivation and numerical analysis of a fractional nuclear reactor point kinetics in time and space (TSFNPK) is presented. The TSFNPK model was derived considering a non-Fickian law for the neutron density current where the differential operators in space and time are of fractional order. The TSFNPK equations presented in this work constitutes a novel model for nuclear reactor kinetics, thus represent an extended model with respect to other fractional models and the classical neutron point kinetics equations. The model considers two diffusion exponents: one for the differential operator dependent in time and another for the dependent operator in space. Both exponents effect is numerically analyzed considering changes of reactivity step type, and temperature feedback reactivity. A first approach of the TSFNPK is presented, without temperature effects, and then a second approach considering temperature feedback effects is analyzed. In a following work, as a demonstration of application, a detailed analysis along with verification will be presented.
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Abstract This paper introduces a PV system model useful for steady-state power flow studies of practical electrical networks. This multi-array PV system model features a comprehensive representation of the three main stages taking part in... more
Abstract This paper introduces a PV system model useful for steady-state power flow studies of practical electrical networks. This multi-array PV system model features a comprehensive representation of the three main stages taking part in solar energy conversion systems: (i) PV arrays for the solar-to-electrical energy conversion, (ii) the DC boost converter useful for establishing the MPPT strategy and for stepping up the output voltage of the PV arrays, and (iii) the DC-to-AC power conversion by the voltage source converter (VSC) used to link the PV system with the AC grid. The derived PV system model is flexible and modular as it permits to consider any desired number of PV arrays with different irradiance conditions each. For validation purposes, a 1.5-MW PV system coupled to a 3-bus AC network was simulated. Its steady-state power flow results were compared against those obtained by a highly-detailed switching-based PV model implemented in Simulink©. It is shown that the proposed model retains sufficient accuracy since the computed relative errors were inferior to 2% between both fundamentally different methods. The IEEE 57-bus test grid is also used to incorporate five PV plants, thus showing the practicality of the introduced modeling approach for distributed PV systems.
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The aim of this work is investigate the stability of fractional neutron point kinetics (FNPK). The method applied in this work considers the stability of FNPK as a linear fractional differential equation by transforming the s − plane to... more
The aim of this work is investigate the stability of fractional neutron point kinetics (FNPK). The method applied in this work considers the stability of FNPK as a linear fractional differential equation by transforming the s − plane to the W − plane. The FNPK equations is an approximation of the dynamics of the reactor that includes three new terms related to fractional derivatives, which are explored in this work with an aim to understand their effect in the system stability. Theoretical study of reactor dynamical systems plays a significant role in understanding the behavior of neutron density, which is important in the analysis of reactor safety. The fractional relaxation time (τα) for values of fractional-order derivative (α) were analyzed, and the minimum absolute phase was obtained in order to establish the stability of the system. The results show that nuclear reactor stability with FNPK is a function of the fractional relaxation time.
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It is a given that fast reactors are sustainable nuclear energy sources, for both utilization of fissile material and minimization of nuclear waste, due to the hard neutron spectrum and the strategies for recycling the nuclear fuel... more
It is a given that fast reactors are sustainable nuclear energy sources, for both utilization of fissile material and minimization of nuclear waste, due to the hard neutron spectrum and the strategies for recycling the nuclear fuel materials. The goal of the gas-cooled fast reactor (GFR) is to convert it into an economic electricity generator, with good sustainability and safety characteristics, but also capable of minimizing nuclear waste via transmutation of minor actinides. This work presents a contribution to the neutronic analysis of the GFR as a transmutation facility of minor actinides. In this study, the fuel assembly is a hexagonal lattice of fuel pins. The materials used are mixes of uranium and plutonium carbide or oxide as fuel in pins, silicon carbide as cladding, and helium gas as coolant. The Monte Carlo code SERPENT was used to perform the criticality calculations during the fuel depletion. Two different fuel mixes of uranium, plutonium and minor actinides in the pins of the assembly were compared during a burnup of 1200 days of irradiation (equivalent to 50 GWd/t). The evolution of the atomic densities and the mass inventory, that of consumption versus production, and that of different fissile, minor actinides, fission products and transuranic nuclides in the fuel, as well as the k-effective multiplication factor during the irradiation time, were tracked. The results confirmed that the radiotoxicity of the nuclear waste of LWRs can be reduced using GFRs. One of the fuel mixes studied came from nuclear fuel discharged of a typical PWR with a burnup of 48 GWd/t and five years of cooling post-discharge. This mix was compared with another resulting from a second recycling. Results for several nuclides are presented and an assessment in terms of advantages for breeding and/or transmutation capabilities of each mix is discussed in the paper.
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ABSTRACT A comparative assessment of alternative expansion plans for the Mexican electricity generation system was made by applying the Position Vector of Minimum Regret Analysis as a decision tool. The expansion plans were ranked... more
ABSTRACT A comparative assessment of alternative expansion plans for the Mexican electricity generation system was made by applying the Position Vector of Minimum Regret Analysis as a decision tool. The expansion plans were ranked according to seven decision criteria which consider: internal cost, risk, diversity, external cost, foreign capital fraction, carbon-free fraction, and severe accidents. Electricity expansions were optimized by using the WASP-IV model; internal costs and externalities over a long-term planning horizon were simultaneously minimized when the external cost was added into the variable component of the operation and maintenance cost. Special attention was paid to studying the convenience of including nuclear power in the electricity expansion. The new decision analysis tool ranked the plans in terms of the minimum global regret, and results showed that the plans which added nuclear power plants were in general relatively more attractive than the plans that did not.
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ABSTRACT In this paper the transmutation of light water reactors (LWR) spent fuel is analyzed. The system used for this study is the fusion-fission transmutation system (FFTS). It uses a high energy neutron source produced with... more
ABSTRACT In this paper the transmutation of light water reactors (LWR) spent fuel is analyzed. The system used for this study is the fusion-fission transmutation system (FFTS). It uses a high energy neutron source produced with deuterium-tritium fusion reactions, located in the center of the system, which is surrounded by a fission region composed of nuclear fuel where the fissions take place. In this study, the fuel of the fission region is obtained from the recycling of LWR spent fuel. The MCNPX Monte Carlo code was used to setup a model of the FFTS. Two fuel types were analyzed for the fissile region: the mixed oxide fuel (MOX), and the inert matrix fuel (IMF). Results show that in the case of the MOX fuel, an important Pu-239 breeding is achieved, which can be interesting from the point of view of maximal uranium utilization. On the contrary, in the case of the IMF fuel, high consumption of Pu-239 and Pu-241 is observed, which can be interesting from the point of view of non-proliferation issues. A combination of MOX and IMF fuels was also studied, which shows that the equilibrium of actinides production and consumption can be achieved. These results demonstrate the versatility of the fusion-fission hybrid systems for the transmutation of LWR spent fuel.
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In this paper the production and destruction, as well as the radiotoxicity of plutonium and minor actinides (MA) obtained from the multi-recycling of boiling water reactors (BWR) fuel are analyzed. A BWR MOX fuel assembly, with uranium... more
In this paper the production and destruction, as well as the radiotoxicity of plutonium and minor actinides (MA) obtained from the multi-recycling of boiling water reactors (BWR) fuel are analyzed. A BWR MOX fuel assembly, with uranium (from enrichment tails), plutonium and minor actinides is designed and studied using the HELIOS code. The actinides mass and the radiotoxicity of the