Analysis of the anticipated transient without scram (ATWS) initiated by emergency power mode through the full scope simulator

The integrity of the reactor coolant system is severely challenged as a result of an Emergency Power Mode – ATWS event. The purpose of this paper is to simulate the Anticipated Transient without Scram (ATWS) using the full scope simulator of Angra 2 Nuclear Power Plant with the Emergency Power Case as a precursor event. The results are discussed and will be used to examine the integrity of the reactor coolant system. In addition, the results were compared with the data presented in Final Safety Analysis Report (FSAR – Angra 2) in order to guarantee the validation of the methodology and from there analyze other precursor events of ATWS which presented only plausibility studies in FSAR – Angra 2. In this way, the aim is to provide and develop the knowledge and skill necessaries for control room operating personnel to ensure safe and reliable plant operation and stimulate information in the nuclear area through the academic training of new engineers. In the presented paper the most severe scenario is analyzed in which the Reactor Coolant System reaches its highest level of coolant pressure. This scenario is initiated by the turbine trip jointly with the loss of electric power systems (Emergency Power Mode). In addition, the failure of the reactor shutdown system occurs, i.e., control rods fail to drop into the reactor core. The reactor power is safely reduced through the inherent reactivity feedback of the moderator and fuel, together with an automatic boron injection. Several operational variables were analyzed and their profiles over time are shown in order to provide data and benchmarking references. At the end of the event, it was noted that Reactor shutdown is assured, as is the maintenance of subcriticality. Residual heat removal is ensured.

Evaluation of Working Conditions as a Factor of Well-Being of Workers in an Electronic Industry in Mexicali

The objective of this research was developed to evaluate the working conditions of workers in an electronic industry located in the city of Mexicali, analyzing a process in a work table where welding operations of electronic components are made and certain factors are presented that generated discomfort to the operating personnel of this manufacturing area. The workers frequently visited the company doctor and health institutions in Mexicali due to symptoms of discomfort and pain in the head, neck, back, spine, arms, hands, and shoulders in addition to discomfort in the eyes due to not having a position due to poor structure (work table and chair) and low light intensity, which caused fatigue and stress and discomfort with eyestrain. In addition, certain employees in the production areas presented symptoms of respiratory diseases caused by an environment contaminated by pollutants, essentially derived from sulfur (sulfides), as well as variations in temperature and relative humidity in the four seasons of the year.

Gradual Technology Development for Ethnic Groups

This chapter presents the application of the concept of gradual technology to improve and increase the productivity of a workshop for the manufacture of handcrafted furniture owned by a cooperative formed by members of the Guarijía ethnic group, located in San Bernardo, Alamos, Sonora. The production process of the rustic furniture called “stool” was systematized and equipment was designed taking into account basic ergonomic aspects. Production sub-processes of the workshop and equipment were improved, including machinery design, purchase of basic technology, adaptation of electric current, water, and air conditioning systems. The basic inputs for manufacturing the furniture, such as wood and cowhide, were studied to determine whether the production of the stool affected the environment. The operating personnel in charge of the cooperative were trained in the use of the equipment and in the visualization of the improved processes.

Management of nuclear materials containing natural uranium and thorium salts

This paper highlights an experimental model proposed for the management of nuclear materials containing natural uranium and thorium salts, based on technical and legislative methods. The investigated nuclear materials originate from laboratory chemicals with expired validity, having as manufacturers companies specialized in the manufacture of laboratory substances such as: Merck, Chemapol, Sigma Aldrich, Bucharest Reagent. The experimental program refers to several issues of great importance in the waste and environmental management, such as: a) the processing of radioactive substances containing nuclear materials and radioactive waste represented by solid objects contaminated with radionuclides from the radioactive series of U-238 and Th-232; b) gamma dose rate measurement during handling and processing of open sources of ionized radiation; c) measurement of suspicious contamination of the operating personnel which handles the equipment, including the materials used in the processing of open sources of ionizing radiation; and d) the inventory of nuclear materials according to the chemical formula, the mass of chemical substance, the mass of the nuclear element in each container and type of packaging. For the good development of processing these open sources of ionizing radiation containing nuclear materials, the ALARA principle (As Low As Reasonably Achievable) was applied, which is fundamental to the principles of radiation protection. All the measurements for determining the gamma dose rate and suspicious contamination were performed with the aid of a CoMo 170 radiometric device produced by Nuvia Instruments Gmbh Germany, equipped with a 170x100 mm2 PL detector with zinc sulfide calibrated with the aid of C-14, Co-60, Cs-137, U-238 and Am-241 radioactive isotopes and an external probe containing a scintillating crystal with sodium iodide enriched with thallium calibrated with Cs-137.

Determination of Electromagnetic Influence of 25 kV AC Electric Traction Network on 10 kV High-Voltage Overhead Line

Electrified railways include a system of cable and overhead lines. An analysis of the operation of alternating current (AC) electrified railways sections shows that the value of the induced voltage caused by the operation of the traction network can significantly exceed the permissible level on adjacent disconnected high-voltage overhead lines. As a consequence, this leads to serious injuries to operating personnel, including deaths, failure of electrical equipment. From this point of view, 1x25 kV 50 Hz AC railway system networks are considered the most dangerous. The electromagnetic influence of the traction network of a double-track section of an AC railway on an adjacent 10 kV high-voltage overhead line for power supply of automatic block signalling is investigated in the offered paper. Emergency cases of traction network operation are considered: short-circuit situation and forced state. The calculations of short-circuit currents in the influencing inter-substation zone, as well as estimation of the induced voltage on the wires of the 10 kV disconnected high-voltage overhead line for various schemes of grounding, have been performed. The investigations were carried out on models built using the ATP-EMTP program.

HVDC Interference on MGL Pipelines

Mahanagar Gas is a City Gas Distribution Company engaged in the distribution of Natural Gas in and around Mumbai City. MGL has around 415 km of commissioned steel pipeline network which is being protected by ICCP. These pipelines are coated with three layer polyethylene coatings. Rectifying the external interferences on pipeline network is a major challenge for pipeline operating personnel in order to maintain safety and integrity of their pipeline. This technical paper is based on study of one of such external interference which posed a threat to MGL’s steel pipeline network. High Voltage Direct Current (HVDC) is a system for transmission of electricity over long distances. This system uses Direct Current (DC) for bulk transmission of electricity in contrast with the more common Alternating Current (AC) systems. HVDC is considered to be more effective to increase power grid delivery capabilities. A part of MGL’s pipeline network is currently facing interference due to a HVDC power substation on the outskirts of Mumbai. This substation is being operated by State Government and is affecting around 145 kms of MGL’s steel pipeline network during its monopolar operation for transmission of electricity. This interference is creating multiple anodic and cathodic areas on pipeline network with the help of a high magnitude current entering and exiting from pipeline at multiple locations which are difficult to predict and rectify. This technical paper will elaborate the concept of HVDC interference on steel pipelines. It will give a brief overview on the methodology adopted for identifying, monitoring and analyzing this interference phenomenon and will comment on the results of this analysis. It will throw light on a variety of technical challenges faced in dealing with this interference while operating a city gas distribution network in particular. And finally, it will discuss about possible remedial measures available and their effectiveness to curb this interference.

Development and validation of the interactive unit start-up procedure as a software tool in the implementation of the operator information support system at the NVNPP

This article is focused on the current issue of developing an operator information support system (OISS) for the Novovoronezh NPP II project. One of the main reasons to raise this topic is the MCR operator’s overload with data due to the greatly increased information flows related to the VVER-1200 Process I&C compared to the serially produced VVER-1000 power units. The other important reason, in the authors’ opinion, is the increased volume of existing procedures in hard copy due to the strengthened requirements for their registration and attempts to describe all possible failures and deviations in the programs and plant evolution sheet, which complicates the work on them. In the era of ubiquitous digitalization, the paper procedures can only distract the attention of the operator, who is overloaded with information even without that. The obvious solution is to create a system providing automatic collection and analysis of information. In addition, the functionality of the operator information support system allows the use of operating experience, thus minimizing the impact of the human factor. The lack of knowledge or experience could be especially challenging with procedures being applied infrequently, for example, for starting up and shutting down the unit. The authors consider the development and functionality of interactive procedures and applicable requirements for them. Particular attention is paid to the ergonomics of the workplace and the convenience of operating personnel working with an interactive procedure. Since the transition from the paper version of the programs can cause problems with reading the procedures and, ultimately, lead to the failure of the unit start-up time, the personnel of the operating station were directly involved in the development of the interactive programs. Based on the review results, conclusions were made about the correctness of the approaches in developing the interactive procedures and validated solutions to be disseminated for all routine operations.

Kinematic Viscosity Prediction Guide: Reviewing and Evaluating Empirical Models for Diesel Fractions, and Biodiesel-Diesel Blends according to the Temperature and Feedstock

Experimental analysis of viscosity can be a straightforward and inexpensive analysis for few samples. However, in industrial processes that have high demands of properties measurements, the determination of viscosity and other properties involves time-consuming with sampling, analysis and availability of results. Also in refineries, the sampling routines for experimental determination of the viscosity of streams are not enough to represent variations that occur in the process, such as the shift of an oil tank in distillation units. In addition, besides requiring cost of operating personnel and laboratory analyst, all of these steps can take up to one shift until the result is available. Therefore, as an alternative, the use of predictive methods of kinematic viscosity are essential. Empirical methods have been used in simulations and design calculations of streams and mixture at industries regarding kinematic viscosity (KV) of petroleum fractions and fuels at different temperatures. However, there are uncertainties about the most accurate method to use at specific condition (temperature, feedstock, volume fraction) which might affect the KV prediction of fuels with unknown composition. Therefore, we assembled and evaluated several methods to predict KV of different diesel systems. In addition, new methods for predicting KV of diesel fractions at several temperatures were also developed for improving the estimation accuracy. As a result, we developed a guide with suggestions of the most accurate models to be applied for diesel fraction from assays, diesel fractions S500 from blend system at several temperatures, and biodiesel-diesel blends at different temperatures, volume fractions and feedstock.

On damage rate of overhead power transmission lines in power supply systems

The purpose of the article is to analyze the damage rate of overhead power transmission lines (OPL) in medium-voltage electrical distribution networks of the Irkutsk region. The established International Indices that determine the level of reliability of the functioning of electric networks are considered, and information on the compliance of the condition of electric networks in Russia with these indices is analyzed. Analytical information on the damage rate of elements of these networks and their causes in Europe, America, and Russia is presented. The emphasis is placed on the fact that the most common damage is characteristic of overhead power lines, especially 6–10 kV lines. As an object of research, two branches of the Irkutsk electric grid company (IEC) were taken, one of which provides electricity to rural consumers, the other — mainly to consumers residing in the territory of the city Irkutsk. The characteristics of these electric networks, their territorial location and basic technical data are presented. To conduct analytical monitoring of the level of reliability of overhead power transmission lines, logs of disconnection of the Eastern and Southern electric networks of the IEC over a long-term period were used. On the basis of this information, tables of failures and their consequences in the studied electrical networks were compiled for monthly average data over the period under examination for various causes of damage. To plot time diagrams of the parameters under examination, computer programs were compiled in the Matlab system, the use of which made it possible to obtain visualization of changes in failures for various reasons for the electrical networks under consideration. The information on the time of power supply interruptions in these networks, as well as the amount of electricity underutilized by consumers during these interruptions and its cost are analyzed. It is shown that in the electric networks under consideration, most of the power failures are related to the territorial dispersion of these networks, and the low level of equipment controls and insufficient qualification of operating personnel, as evidenced by the significant number of failures for unknown reasons. Besides, a significant part of the failures is due to damage to the overhead line wires, switching equipment and the effect of wind load. Recommendations for improving the condition of power transmission lines and a number of measures aimed at improving the level of reliability of power supply are presented.