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Different types of faults could occur in a nuclear power plant, and there was no direct correspondence between a specific fault and its symptoms. So, a hybrid intelligence approach is proposed for the fault diagnosis at a nuclear power plant. Depending up the symptoms observed and the progress of fault diagnosis process, different fault diagnosis technologies, such as artificial neural network, data fusion and signed directed graph, could be combined as appropriate to detect and identify different faults at local or global level in nuclear power plants. The effectiveness of hybrid intelligence approach in improving the fault diagnosis efficiency in nuclear power plants was verified through simulation experiments. [ABSTRACT FROM AUTHOR]

In order to solve SDG online fault diagnosis and inference, matrix diagnosis and inference methods are proposed for fault detection and diagnosis (FDD). Firstly, “rules matrix” based on SDG model is used for FDD. Secondly, “status matrix” is proposed to achieve SDG online inference. According to different diagnosis results, “status matrix” is applied for the depth-first search and the breadth-first search respectively to find the propagation paths of each fault. Finally, the SDG model of the secondary-loop system in pressurized water reactor (PWR) is built to verify the effectiveness of the proposed method. The simulation experiment results indicate that the “status matrix” used for online inference can be used to find the fault propagation paths and to explain the causes for fault. Therefore, it can be concluded that the proposed method is one of the fault diagnosis for nuclear power plants (NPPs), which can be used to facilitate the development of fault diagnostic system. [ABSTRACT FROM AUTHOR]

A dynamic model was developed using two back-propagation neural networks of the same structure, one for online training and the other for prediction, and proposed for continuous dynamic prediction of the time series of NPP operating parameters. The proposed prediction model was validated by predicting such time series of NPP operating parameters as coolant void fraction, water level in SG and pressurizer. Validation results indicated the proposed model could be used to achieve a stable prediction effect with high prediction accuracy for the prediction of fluctuating data. [ABSTRACT FROM AUTHOR]

A minimum dose method based on staff walking road network model was proposed for the walking-path planning in nuclear facilities. A virtual–reality simulation program was developed using C# programming language and Direct X engine. The simulation program was used in simulations dealing with virtual nuclear facilities. Simulation results indicated that the walking-path planning method was effective in providing safety for people walking in nuclear facilities. [ABSTRACT FROM AUTHOR]

Abstract: During the design, maintenance and decommissioning of nuclear facilities, nuclear radiation protection is an important part. In recent years, researchers have explored a lot of radiation protection approach, and some radiation protection approach have been applied in practice, such as visualization technique of radiation environment, path-planning method, robotics and etc., in these techniques the path-planning in radiation environment technology has become an important radiation protection measure. In this paper, we addressed a staff walking path-planning approach in radiation environment based on particle swarm algorithm and introduced some key technologies of path-planning in radiation environment. To obtain the optimal walking route to verify the operation of the proposed method, we carried out the simulation experiment in which dose and distance were as decision factors. The experiment results represented the probability and the effectiveness of path-planning in radiation environment based on particle swarm algorithm. [Copyright &y& Elsevier]

Workers’ behavior during the dynamic process of nuclear decommissioning is a complex phenomenon. In a nuclear environment, some workers may spontaneously and inadvertently engage in unsafe behavior which has high risks of serious injury and accident. In this paper, we determined and classified some of the unsafe behavior of workers in the nuclear decommissioning process. The evaluation factor system and the AHP model were established. The safety of behavior of virtual human, a trainee controlled in digital simulation, was quantified by fuzzy evaluation method. A primary virtual training method to reduce the chance of unsafe behavior was proposed and a safety training simulation software was developed. The feasibility of the proposed methods was tested through a hypothetical case. [ABSTRACT FROM AUTHOR]

In this paper, virtual simulation was taken as an auxiliary tool for radiation protection, dose assessment. So radiation protection using virtual reality was taken as a research subject. A simple voxel modeling for virtual human was proposed. Based on the voxel model, dose assessment and visualization methods for virtual human in radiation environment were proposed. The parallel technology contributed to dose assessment in real-time. Based on dose assessment and visualization methods, a radiation protection method using virtual simulation was developed for the preparation of working in radiation environment. These validation tests demonstrate these methods make it possible to plan for the exposure dose to workers in radiation environment using virtual simulation. [ABSTRACT FROM AUTHOR]

This paper proposes a sampling-based method (SBM) for planning minimum dose path navigation for workers in nuclear facilities. To simulate and avoid obstacles, they were approximated by a combination of basic geometries and detected with the aid of virtual reality. To obtain an optimized walking path with minimum dose without considering the pre-designed road networks, a sampling-based method that utilizes the rapidly exploring random tree star (RRT*) algorithm, applicable in both continuous and discrete radiation fields, was proposed and implemented. The performance of this method was evaluated by simulating walk paths and estimating their radiation dose rates in a hypothetical nuclear facility, and the simulation results were compared with those derived from Dijsktra's algorithm under various radioactive environments. [ABSTRACT FROM AUTHOR]

Unstructured and multi-objective task arrangement in radiation field is a complicating problem decision-makers are most concerned about. Proper task arrangement is helpful to improve efficiency of engineering and reduce hazard. The goal of this work is to discuss some criteria of task, build task hierarchy structure model, and then propose a task analytic method in radiation field based on analytic hierarchy process (AHP). The proposed method is useful for selection of schemes to reduce hazard and increase efficiency of task. In addition, we use this proposed method solve a hypothetical case, which is utilized to explain how the method works and to prove the method effective. [ABSTRACT FROM AUTHOR]

Based on minimum dose path-searching method, walking path-planning method for multiple radiation areas was designed to solve minimum dose path problem in single area and find minimum dose path in the whole space in this paper. Path-planning simulation platform was built using C# programming language and DirectX engine. The simulation platform was used in simulations dealing with virtual nuclear facilities. Simulation results indicated that the walking-path planning method is effective in providing safety for people walking in nuclear facilities. [ABSTRACT FROM AUTHOR]

Walking path-planning technology can be taken as a radiation protection measure to reduce radiation exposure to workers in radiation environment, and to guarantee work order and efficiency. Considering the nuclear facilities scene can be dynamic and changeable, we designed a dynamic minimum dose walking path-searching method based on the static minimum dose walking path-planning method earlier, and built path-planning simulation platform for nuclear radiation environment with virtual reality technology to plan walking path and virtual simulation. [ABSTRACT FROM AUTHOR]