Desenvolvimento e avaliação de procedimentos de operação computadorizados para salas de controle avançadas de plantas industriais

O Laboratório de Interfaces Homem-Sistema (LABIHS) é formado por um conjunto de equipamentos e programas de computadores que simulam os processos de uma usina nuclear com 930 MWe de potência, formando um simulador compacto de uma planta nuclear PWR (Pressurized Water Reactor) e constituindo uma sala de controle avançada com várias interfaces gráficas representando os vários sistemas que compõem o reator nuclear. Uma das linhas de pesquisa do LABIHS é o desenvolvimento e avaliação de sistemas de procedimentos computadorizados para salas de controle avançadas de plantas industriais. Este relatório tem como principal objetivo apresentar de maneira sucinta o estado da arte dos sistemas de procedimentos computadorizados, enfatizando a descrição de quatro sistemas implementados. O relatório também apresenta uma descrição dos principais componentes de hardware e software do LABIHS, com ênfase para as ferramentas de desenvolvimento e avaliação de procedimentos computadorizados

Modelos de validação de sinal utilizando técnicas de inteligência artificial aplicados a um reator nuclear

This work develops two models of signal validation in which the analytical redundancy of the monitored signals from an industrial plant is made by neural networks. In one model the analytical redundancy is made by only one neural network while in the other it is done by several neural networks, each one working in a specific part of the entire operation region of the plant. Four cluster techniques were tested to separate the entire region of operation in several specific regions. An additional information of systems' reliability is supplied by a fuzzy inference system. The models were implemented in C language and tested with signals acquired from Angra I nuclear power plant, from its start to 100% of power.Este trabalho desenvolve dois modelos de validação de sinal que utilizam fedes neuronais para realizar a redundância analítica de sinais monitorados em uma instalação industrial. Um dos modelos utiliza uma única rede neuronal para efetuar a redundância analítica dos sinais e o outro modelo utiliza várias redes neuronais para efetuar esta redundância, cada uma trabalhando em uma região de operação específica da instalação. Para efetuar a divisão de todos os pontos de operação da instalação em várias regiões específicas foram estudados quatro métodos de separação em classes. Adicionalmente os modelos fornecem uma indicação da confiança das suas respostas através de conceitos baseados em lógica nebulosa. Os modelos foram implementados em linguagem C e foram ensaiados com sinais monitorados do reator nuclear Angra I, durante uma de suas partidas até atingir 100% de potência

Modeling and control of a nuclear power plant using AI techiniques

In pressurized water reactor (PWR) nuclear power plants (NPPs) pressure control in the primary loops is fundamental for keeping the reactor in a safety condition and improve the generation process efficiency. The main component responsible for this task is the pressurizer. The pressurizer pressure control system (PPCS) utilizes heaters and spray valves to maintain the pressure within an operating band during steady state conditions, and limits the pressure changes during transient conditions. Relief and safety valves provide overpressure protection for the reactor coolant system (RCS) to ensure system integrity. Various protective reactor trips are generated if the system parameters exceed safe bounds. Historically, a proportional-integral-derivative (PID) controller is used in PWRs to keep the pressure in the set point, during those operation conditions. The purpose of this study is to develop fuzzy controllers for the PWR pressurizer modeled by an artificial neural network (ANN) and compare their performance with conventional ones. Data from a 2785 MWth Westinghouse 3-loop PWR simulator was used to test both the conventional and the fuzzy controllers. The simulation results show that the fuzzy controllers have better performance compared with conventional ones

Modular remote radiation monitor

The Modular Remote Radiation Monitor (MRRM) is a novel radiation monitor suitable for monitoring environmental exposure to ionizing radiation. It is a portable compact-size low-power microprocessor-based electronic device which provides its monitoring data to other electronic systems, physically distant from it, by means of an electronic communication channel, which can be wired or wireless according to the requirements of each application. Besides its low-power highly-integrated circuit design, the Modular Remote Radiation Monitor is presented in a modular architecture, which promotes full compliance to the technical requirements of different applications while minimizing cost, size and power consumption. Its communication capability also supports the implementation of a network of multiple radiation monitors connected to a supervisory system, capable of remotely controlling each monitor independently as well as visualizing the radiation levels from all monitors. A prototype of the MRRM, functionally equivalent to the MRA-7027 radiation monitor, was implemented and connected to a wired MODBUS network of MRA-7027 monitors, responsible for monitoring ionizing radiation inside Argonauta reactor room at Instituto de Engenharia Nuclear. Based on the highly positive experimental results obtained, further design is currently underway in order to produce a consumer version of the MRRM

Requisitos básicos para implementação de um sistema de procedimentos computadorizados no Laboratório de Interfaces Homem-Sistema - LABIHS

O Laboratório de Interfaces Homem-Sistema (LABIHS) é formado por um conjunto de equipamentos e programas de computadores que simulam os processos de uma usina nuclear com 930 MWe de potência, formando um simulador compacto de uma planta nuclear PWR (Pressurized Water Reactor) e constituindo uma sala de controle avançada com várias interfaces gráficas representando os vários sistemas que compõem o reator nuclear. Uma das linhas de pesquisa do LABIHS é o desenvolvimento e avaliação de sistemas de procedimentos computadorizados (PBCs) para salas de controle avançadas de plantas industriais. Este relatório tem como principal objetivo descrever os requisitos básicos para implementação do Cliente PBC a ser implementado para a planta nuclear do simulador do LABIHS bem como descrever o estágio atual de implementação deste sistema no laboratório

Design and evaluation of new overview screens for the labihs simulator

The development and evaluation of Human-System Interfaces (HSIs) for control rooms is a research area at the Human-System Interface Laboratory (LABIHS). The main objective of this laboratory is to develop and evaluate projects of HSIs for industrial plants using different methodology construction. The evaluation of the interfaces is carried out in the LABIHS simulator at the Nuclear Engineering Institute (IEN). Previous evaluation of the overview screen of the nuclear power plant (NPP) simulator of the LABIHS showed the necessity of additional information to reduce the operator workload. To overcome this issue, a set of three 52-inch LCD TV was acquired to replace the projector in the task of showing the overview screen to the simulator operators. A new set of screens was developed to gather information in the three LCD screens. The approach used on the development of the new screens was based on human factors guidelines and recommendations. The objective of this work is present the design of these new overview screens and to evaluate their contribution to reduce the operators mental workload in this new scenario

Integration of computerized operation support systems on a nuclear power plant environment

Automation of certain tasks in a Nuclear Power Plant (NPP) control room is expected to result in reduced operators’ mental workload, which may induce other benefits such as enhanced situation awareness and improved system performance. The final goal should be higher level of operational safety. Thus, recent works are increasingly assessing automation. The LABIHS compact NPP simulator, though, still operates under strictly manual printed hard-copy procedures, despite of the fact that the simulator incorporates several advancements in design of digitalized Human–System Interfaces (HSIs). This work presents the development, implementation and integration of selected components to achieve increased level of computerized/automated operation of the LABIHS compact NPP simulator. Specifically, we discuss three components: (i) Automatic Plant Mode Detection, (ii) Automatic Alarm Filtering, and (iii) Computerized Procedures. Each one of these components has to be carefully designed/integrated so that one can avoid the undesired effects of some known implementations of automated systems on NPP, such as the reduction in the operator's system awareness, an increase in monitoring workload, and the degradation in manual skills, which could lead to automation-induced system failures

Implementação e avaliação de um sistema de procedimentos computadorizados no Laboratório de Interfaces Homem-Sistema - LABIHS

O Laboratório de Interfaces Homem-Sistema (LABIHS) é formado por um conjunto de equipamentos e programas de computadores que simulam os processos de uma usina nuclear com 930 MWe de potência, formando um simulador compacto de uma planta nuclear PWR (Pressurized Water Reactor) e constituindo uma sala de controle avançada com várias interfaces gráficas representando os vários sistemas que compõem o reator nuclear. Uma das linhas de pesquisa do LABIHS é o desenvolvimento e avaliação de sistemas de procedimentos computadorizados (PBCs) para salas de controle avançadas de plantas industriais. Este relatório tem como principal objetivo implementar um sistema de procedimentos computadorizados no LABIHS. Atualmente, para operar o simulador da planta nuclear PWR do LABIHS, os operadores utilizam procedimentos de operação baseados em papel (PBPs). Antes de iniciar a construção de um sistema PBC próprio para o simulador do LABIHS, optou-se por implementar e avaliar um sistema de PBCs no simulador do LABIHS, bem como verificar o impacto sobre a equipe de operação do simulador com a mudança de PBPs para PBCs. Para tal foi utilizado como referência o sistema ImPRO pois, por facilidade,este sistema está disponibilizado para download na Internet

Chemical control of adult sourgrass in coffee crops, through various associations

Weed management in coffee plants is carried out largely through the adoption of chemical control, with the use of herbicides. In this context, one of the species that most affects the development of coffee plants, and due to its difficulty in control, is sourgrass. Above all, most sourgrass biotypes are not efficiently controlled with the herbicide glyphosate, which is the most used in coffee growing. Thus, the search for strategies that can minimize the damage caused by this weed, appears with increasing demand, due to the great damage to coffee plants. Therefore, the objective of this study was to evaluate the chemical control of adult sourgrass in coffee plants, through several associations. Treatment control efficiency was visually evaluated, where a scale ranging from 0 to 100 was used, with 0 corresponding to the absence of symptoms and 100 corresponding to the total control of weed plants by the action of herbicides, respectively. This evaluation method was used at 7, 14, 21, 28, 35 and 42 days after application. The data obtained were subjected to analysis of variance using the SISVAR statistical software. The association of the herbicides Fluazifop-p-butyl and Clethodim, implies greater efficiency in controlling sourgrass over time. The association of the herbicide ammonium glufosinate with systemic herbicides implies a reduction in the control capacity of sourgrass plants over time.Weed management in coffee plants is carried out largely through the adoption of chemical control, with the use of herbicides. In this context, one of the species that most affects the development of coffee plants, and due to its difficulty in control, is sourgrass. Above all, most sourgrass biotypes are not efficiently controlled with the herbicide glyphosate, which is the most used in coffee growing. Thus, the search for strategies that can minimize the damage caused by this weed, appears with increasing demand, due to the great damage to coffee plants. Therefore, the objective of this study was to evaluate the chemical control of adult sourgrass in coffee plants, through several associations. Treatment control efficiency was visually evaluated, where a scale ranging from 0 to 100 was used, with 0 corresponding to the absence of symptoms and 100 corresponding to the total control of weed plants by the action of herbicides, respectively. This evaluation method was used at 7, 14, 21, 28, 35 and 42 days after application. The mixture of the herbicides Fluazifop-p-butyl and Clethodim is more efficient in controlling sourgrass over time. The association of the herbicide ammonium glufosinate with systemic herbicides implies a reduction in the control capacity of sourgrass plants over time

HSI for monitoring the critical safety functions status tree of a NPP

Critical safety function (CSF) is the most significant design concept for prioritize operator actions based on the potential threat to the three barriers (fuel cladding, primary coolant system boundary, and containment) and allows the operator to respond to these threats prior to event diagnosis. CSF has a hierarchical information structure that organizes the system variables affecting the plant safety in terms of goal-means relations. It is important that the operator should be aware of various success paths associated with each CSF in order to respond to unanticipated system failures quickly. When an emergency occurs in NPPs, the operator should monitor CSFs periodically and identify possible success paths as necessary, and try to stabilize or safely shut down the plant using emergency operating procedure (EOP) that includes steps to check the CSFs. This implies that safety function status check may become a cognitively burdensome task that needs to be supported by proper information display. The advanced human-system interface (HSI) in nuclear power plants provides an information environment that supports the operators’ burdensome cognitive tasks. This paper describes a CSFs interface design for supporting the operator’s tasks to monitor and identify the associated success path for Westinghouse 3-loops NPP