Juan José Ortiz-Servin

National Institute of Nuclear Research, Mexico | ININ · Sistemas Nucleares

A configuration for the integral problem of in-core fuel management consists of a fuel lattice and a fuel assembly designs, as well as a fuel reload and a control rod pattern design, so that the different criteria for the proper operation of a BWR reactor are met. Such a configuration or solution is not unique. There is an universe of potential can...

In this paper a new methodology to speed up the fuel lattice design optimization in a BWR is explored. In previous works, fuel lattice optimization was made using LPPF (Local Power Peaking Factor) at the beginning of the fuel lattice life. However, undesirable LPPF vs. fuel lattice exposure behaviors were observed. Due to this, LPPF vs. fuel lattic...

A new approach for optimizing the enrichment and gadolinia distribution in a typical BWR fuel lattice is presented. It takes advantage of potentialities of two different methodologies: the Ant-Colony-System (ACS) meta-heuristic technique and S15 a method based on knowledge. The S15 method was programmed in such a way that can reduce the objective f...

In this paper the estimation of 3D BWR nuclear reactor parameters starting from 2D data is presented. The 3D parameters are obtained through a steady state simulation of the nuclear reactor's operation, namely; thermal limits and cold shutdown margin. Data mining techniques were applied to build decision trees in order to estimate those 3D reactor...

In this paper, a dynamic assessment of optimal BWR Fuel Reload Patterns (FRP) is presented. Using two meta-heuristics techniques: Tabu Search (TS) and Artificial Neural Networks (ANN), the FRPs were designed. In order to perform the stability analysis, a point in the operation map, which is under the instability region defined in technical specific...

In this work, a statistical analysis in the neutronic fuel lattice design process is shown. It presents a study where different ways to choose rods with uranium and uranium-gadolinia are considered, and their allocation into the fuel lattice was analyzed. The analysis was carried out studying three different frequency distributions for fuel materia...

A Heuristic-Knowledge Method was developed to determine the enrichment and gadolinia distribution in a fuel lattice of boiling water reactors. The method was called S15 and is based on the experience obtained for the fuel lattice design for this kind of nuclear reactors. It also takes advantage of the symmetry aspects found in a typical BWR fuel la...

In this paper a data mining analysis for BWR nuclear fuel lattice performance is shown. In a typical three-dimensional simulation of the reactor operation simulator gives the core performance for a fuel lattice configuration measured by thermal limits, shutdown margin and produced energy. Based on these results we can determine the number of fulfil...

In this paper, a Modified Bi-parametric Method for optimization of fuel reload patterns of the Laguna Verde Nuclear Power Plant BWR reactors is presented. This method is a modification of Bi-parametric Method developed by D.P. Burte and Vaidya. The BWR reactors of LVNPP operate under a reactivity control system that is not compatible with the origi...

The global fuel management problem in BWRs (Boiling Water Reactors) can be understood as a very complex optimization problem, where the variables represent design decisions and the quality assessment of each solution is done through a complex and computational expensive simulation. This last aspect is the major impediment to perform an extensive ex...

In the present study a comparison of the performance of five heuristic techniques for optimization of combinatorial problems is shown. The techniques are: Ant Colony System, Artificial Neural Networks, Genetic Algorithms, Greedy Search and a hybrid of Path Relinking and Scatter Search. They were applied to obtain an "optimal" enrichment and gadolin...

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: gene...

Huitzoctli system was developed to design Control Rod Patterns for Boiling Water Reactors (BWR). The main idea is to obtain a Control Rod Pattern under the following considerations: (a) the critical reactor core state is satisfied, (b) the axial power distribution must be adjusted to a target axial power distribution proposal, and (c) the maximum F...

In nuclear fuel management activities for BWRs, four combinatorial optimization problems are solved: fuel lattice design, axial fuel bundle design, fuel reload design and control rod patterns design. Traditionally, these problems have been solved in separated ways due to their complexity and the required computational resources. In the specialized...

This paper presents a new approach to deal with the boiling water reactor radial fuel lattice design. The goal is to optimize the distribution of both, the fissionable material, and the reactivity control poison material inside the fuel lattice at the beginning of its life. An ant-colony-based system was used to search for either: the optimum locat...

In this paper a new system, called ohtli-PR, is presented. This system was developed for fuel lattice design optimization in Boiling Water Reactors (BWR) using the Path Relinking and Scatter Search techniques. As input data, the system uses an initial uranium enrichment and gadolinia percentage. At the beginning of the optimization process, the sys...

This paper presents some results of the implementation of several optimization algorithms based on ant colonies, applied to the fuel reload design in a Boiling Water Reactor. The system called Azcaxalli is constructed with the following algorithms: Ant Colony System, Ant System, Best–Worst Ant System and MAX–MIN Ant System. Azcaxalli starts with a...

Radial and axial optimization of the fuel assembly in a boiling water reactor are usually solved as independent problems, despite they are highly related. In this work we propose GreeNN, a hybrid system composed by a simple greedy search technique and a neural network that allows approaching the solution of both problems in a coupled way. Firstly,...

RENO-CC, a system to optimize nuclear fuel lattices for boiling water reactors using a multi-state recurrent neural network, is shown. This kind of neural network is formed by only one layer of neurons. Each neuron is associated with a pin of the fuel lattice array. RENO-CC was tested through the fuel lattice design of 10 x 10 arrays with two water...

This paper presents the training of an artificial neural network (ANN) to accurately predict, in very short time, a physical parameter used in nuclear fuel reactor optimization: the local power peaking factor (LPPF) in a typical boiling water reactor (BWR) fuel lattice. The ANN training patterns are distribution of fissile and burnable poison mater...

This paper deals with one of the steps of the nuclear fuel design: the radial fuel lattice design. It can be seen as a combinatorial optimization problem for determining the optimal 2D fuel rods enrichment and gadolinia distribution. In order to solve this optimization problem, the ant colony system technique is proposed. The main idea of the ant c...

A new system to obtain Control Rod Patterns designs for Boiling Water Reactors was developed. Among the main requirements to obtain a good Control Rod Pattern are the critical reactor core state, the axial power distribution must be adjusted to a target axial power distribution, and the thermal limits Minimal Critical Power Ratio (MCPR) and Linear...

A new system to optimize both control rod pattern and fuel-loading design in boiling water reactors is shown. The system is named OCOTH, and it is based on heuristic techniques such as genetic algorithms, neural networks, and ant colonies. Each heuristic technique is used to design a part of the optimization process. So, the neural network finds an...

This paper presents the QuinalliBT system, a new approach to solve fuel loading and control rod patterns optimization problem in a coupled way. This system involves three different optimization stages; in the first one, a seed fuel loading using the Haling principle is designed. In the second stage, the corresponding control rod pattern for the pre...

Resumen En este trabajo se presenta una comparación de tres técnicas de optimización aplicadas al diseño de la recarga de combustible en reactores de agua en ebullición. En concreto, se aplicaron las técnicas al diseño de una recarga de un ciclo de equilibrio de 18 meses de la Central Nucleoeléctrica de Laguna Verde. Las técnicas empleadas fueron A...

Resumen En este trabajo se presenta un nuevo sistema de optimización axial de combustible basado en una red neuronal recurrente multiestado llamado RENODC. Se describen con detalle las características principales de este tipo de red neuronal (arquitectura, función de energía y actualización de estados neuronales) y como se adaptó al diseño de ensam...

We show a new system named AZCATL-CRP to design full power control rod patterns in BWRs. Azcatl-CRP uses an ant colony system and a reactor core simulator for this purpose. Transition and equilibrium cycles of Laguna Verde Nuclear Power Plant (LVNPP) reactor core in Mexico were used to test Azcatl-CRP. LVNPP has 109 control rods grouped in four seq...

A methodology for 10x10 fuel lattice design for BWR's was developed. A linear equation based on a matrix of coefficients (change ratio of relative power due to U-235 enrichment changes) was proposed for estimating pin by pin relative powers of a fuel lattice. Based on above description the fast calculation program PreDiCeldas was developed which al...

We show a new system to optimize fuel lattices in BWRs named RENO-CC. The system employs a multi state recurrent neural network (MSRNN) for optimizing a fuel lattice pin-by-pin U235 enrichment distribution. Local Power Peaking Factor (LPPF) and k-infinite (k ∞) are involved in the MSRNN energy function. Both parameters are calculated by the 2D HELI...

An optimization system to get control rod patterns (CRP) has been generated. This system is based on the tabu search technique (TS) and the control cell core heuristic rules. The system uses the 3-D simulator code CM-PRESTO and it has as objective function to get a specific axial power profile while satisfying the operational and safety thermal lim...

In this paper we show the system RENOPBC to optimize control rod patterns in Boling Water Reactors using a Multi State Recurrent Neural Network. Control Rod Pattern design is based on the fulfillment of operational thermal limits, the fitness of adjustment of an axial power distribution to a target axial power distribution and keeping the reactor c...

One of the most important questions related to both safety and economic aspects in a nuclear power reactor operation, is without any doubt its reactivity control. During normal operation of a boiling water reactor, the reactivity control of its core is strongly determined by control rods patterns efficiency. In this paper, GACRP system is proposed...

A Multi-State Recurrent Neural Network is used to optimize Loading Patterns (LP) in BWRs. We have proposed an energy function that depends on fuel assembly positions and their nuclear cross sections to carry out optimisation. Multi-State Recurrent Neural Networks creates LPs that satisfy the Radial Power Peaking Factor and maximize the effective mu...

A genetic algorithm is used to optimize the nuclear fuel reload for a boiling water reactor, and an order coding is proposed for the chromosomes and appropriate crossover and mutation operators. The fitness function was designed so that the genetic algorithm creates fuel reloads that, on one hand, satisfy the constrictions for the radial power peak...

Nowadays there is a trend of increasing the cycle length of commercial operation in nuclear reactors. This demands to control a greater quantity of reactivity excess in this type of cycles. In this work, a comparative study of the use of various absorbent materials in the control rods of a BWR is presented. The behavior of the different absorbent m...

The problem of optimizing refueling in a nuclear boiling water reactor is difficult since it concerns combinatorial optimization and it is NP-Complete. In order to solve this problem, many techniques have been applied, ranging from expert systems to genetic algorithms. In most of these procedures, nuclear reactor simulators are used, which require...

Resumen La Comisión Federal de Electricidad anunció recientemente el comienzo de los trabajos relacionados con el aumento de la potencia a 120% de la nominal original en los reactores de agua en ebullición (BWR) de la Central Laguna Verde (CLV). En el Instituto Nacional de Investigaciones Nucleares (ININ) se realizan estudios del impacto sobre el d...

A new system, named Ohtli-PR, for the optimization of fuel lattice design in Boiling Water Reactors (BWR), using the heuristic technique called Path Relinking was developed. The system starts with an initial proposal of uranium enrichment and gadolinia concentration. With this information, the system generates a seed fuel lattice, which is used to...