Nuclear Installations Research Articles

INNOVATIVE APPROACH TO ASSESSMENT OF INSULATION DURABILITY OF ASYNCHRONOUS ELECTRIC MOTORS

A new method has been developed to assess the insulation durability of the VAZ 215/109-6АМО5 asynchronous electric motor, which is used to drive the circulating pumps of the VVER-1000 reactor. The application of this calculation method significantly simplifies and speeds up the process of designing and analyzing insulation systems, as well as electric motors in general. This can contribute to increasing their reliability and efficiency in operational conditions, which is especially important for ensuring the safe operation of nuclear installations. The article describes in detail all stages of experimental research, including the manufacture of test samples, their testing and comparative analysis of the obtained data. This consistent approach allows not only to check the compliance of the samples with the specified characteristics, but also to evaluate their effectiveness in real operating conditions. In addition, the results of the comparative analysis can serve as a basis for further research aimed at improving manufacturing technologies and increasing the reliability of materials. An important aspect is also the study of the influence of various factors on the test results, which can help in the formation of recommendations for the practical application of the obtained data in industry. The study was conducted with the aim of developing an innovative method for calculating the service life, which will contribute to the acceleration of the process of designing the insulation systems of the stator windings of the VAZ 215/109-6АМО5 electric motor. This technique also lays the foundations for the further development of insulation systems in electric motors in general. The results of the conducted research can become an important step in creating reliable and durable insulation systems for the main circulation pumps of nuclear power plants (NPP). This, in turn, will contribute to ensuring the safety of their operation in the conditions typical for work at nuclear power plants, where the reliability and stability of systems are critically important for preventing emergency situations. Improvements in insulation systems and technologies can reduce the risks associated with overheating and electrical breakdown, which is particularly relevant in the context of modern requirements for the insulation of installations in general.

Nuclear plants in Ukraine: international legal provision of nuclear safety in conditions of war

The article is devoted to the study of international legal provision of nuclear safety in the conditions of war in Ukraine using the example of nuclear power plants. Attention is drawn to the fact that by launching a full-scale invasion of the territory of our country, Russia threatened the entire world with a nuclear war. Her actions showed imperfections and gaps in the international legal framework for the protection of nuclear installations, which did not provide for their protection in cases of terrorist attacks, sabotage and armed conflicts. The article highlights the general chronology of events that took place at the Chernobyl and Zaporizhia NPPs after the start of the full-scale invasion. The dangerous actions of the aggressor country and their possible consequences are outlined. It was found that in the conditions of an armed conflict, nuclear power plants, according to international humanitarian law, are subject to special legal protection, which provides for their protected status and the prohibition of any attacks on them. Key international legal documents on nuclear safety were systematized and researched, determined their role and significance for legal regulation in the field of nuclear safety. These documents mostly focus on issues of internal technical security of nuclear facilities, while their provisions on the general provision of nuclear security do not cover effective mechanisms of international regulation and responsibility, especially in the context of armed conflicts, hostilities or occupation. The reaction of the international community to the crisis events related to nuclear power plants in Ukraine, as well as the key international legal acts adopted to strengthen nuclear security in the context of armed conflict, were also investigated. In particular, the IAEA resolution “Implications of the situation in Ukraine regarding safety, security and guarantees” was analyzed, which emphasizes the importance of observing nuclear safety standards and establishes the principles of protecting nuclear infrastructure in wartime. Special attention is paid to the concept of “Seven indispensable pillars of nuclear safety”, which was proposed by the IAEA to ensure the security of nuclear facilities and prevent incidents that could cause catastrophic consequences. The study emphasizes that the international mechanisms for regulating nuclear safety in conflict conditions remain limited, which necessitates the further strengthening of international legal standards and the development of more effective tools to prevent risks associated with nuclear infrastructure in the war zone. The situation at Ukrainian nuclear power plants demonstrated significant gaps in the international system of ensuring nuclear safety, in particular, the lack of proper international legal regulation for the protection of nuclear facilities in the zone of military conflicts. The result of the study was the conclusion that the experience of Ukraine should give impetus to the rethinking and improvement of the international legal framework for ensuring nuclear safety, in particular, by developing new effective mechanisms for the protection of nuclear installations, responsibility for violation of rules, as well as effective influence on violators.

Development of a Self-Assessment Tool for Safety Culture in Nuclear Installations

A study has been conducted to develop a self-assessment tool for safety culture that BAPETEN can use for nuclear installations in Indonesia. Safety culture is one of the safety and licensing requirements in nuclear energy laws and regulations. BAPETEN is also entrusted to conduct assessments and foster safety culture. BAPETEN has carried out these activities at BATAN nuclear installations from 2005 to 2012. As a follow-up, BATAN has taken various measures to evaluate and develop a safety culture at all its nuclear installations. In 2021, all Non-Ministerial Government Institutions in the research sector, including BATAN, were merged into one under the management of BRIN. This organizational change certainly has the potential to affect safety and safety culture performance. In practice, the results of inspections in the last two years have shown a tendency for an increase in the number of findings. BAPETEN has yet to have a documented, comprehensive method for assessing safety culture performance. Thus, this study aims to develop a documented and comprehensive method for assessing safety culture performance at nuclear installations. This study applies descriptive, qualitative, and analytical techniques, using primary and secondary data, and is conducted in several stages: literature study, presentation and discussion of information transfer and documentation from past practices, comparative study with a high-risk industry, safety culture assessment workshops, and review and validation. In conclusion, this study has produced safety culture assessment tools through a questionnaire survey, document analysis field observation, interviews, and focus groups. The four tools, which refer to the IAEA safety culture systematics with five characteristics, complement each other and can be expected to be comprehensive but realistic enough to be implemented. The study also recommends that an immediate assessment should be carried out using these four tools on the existing nuclear installations. At the end of the assessment, the assessment team should evaluate the implementation and effectiveness of the four tools for improvement. Keywords: safety culture, independent assessment, nuclear installation

Hand Extremity Dose Monitoring Hp(0.07) Using in Radiation Workers with Procedure18F in Nuclear Medicine

The high number of activities in procedures in nuclear medicine installations, such as in the process of handling open radioactive sources, results in radiation workers being exposed to greater levels of radiation compared to radiation workers in other installations on their skin organs. Therefore, radiation protection is necessary to monitor the amount of radiation exposure received by the extremities of radiation workers. Regulation of the Head of BAPETEN No. 17 of 2012 Article 33 explains that the dose limit for radiation workers must not exceed the equivalent dose for the hands, feet, or skin of 500 mSv per year. Monitoring of the extremity dose Hp(0.07) received by radiation workers in nuclear medicine with radiopharmaceuticals labeled 18F-FDG and 18F-PSMA was carried out using a Hasto Dosimeter made by NuklindoLab with TLD CaSo4:Dy material, which has been calibrated at the SSDL Malaysian Nuclear Agency by ISO 12794. The study was conducted at one of the hospitals in Indonesia. Measurements were made of radiopharmacists and nurses during 5 weeks of monitoring; the measured dose results, namely for radiopharmacists in the range of 15 - 77 μSv/GBq and nurses ranging from 0.8 - 2.85 μSv/GBq per week. The dose received by radiopharmacists is much higher than that of nurses because radiopharmacists carry out more related activities, such as preparing and delivering radiopharmaceuticals. The estimated dose value of radiopharmaceuticals can exceed the dose limit, while nurses are less than the dose limit over a period of 1 year. The magnitude of this value indicates the need for special attention regarding safety and radiation protection for radiation workers in nuclear medicine installations, so efforts need to be made to increase shielding or increase the number of personnel, especially radiopharmacists, in the nuclear medicine installation. Keywords: nuclear medicine, extreme dose Hp (0.07), Radiopharmaceuticals 18F-FDG, 18F-PSMA, TLD CaSo4: Dy, Hasto Dosimeter.

Comparison of calibration results for α, β surface contamination monitors.

Surface contamination monitors are used intensively in many facilities, like in the nuclear medicine departments for clearance measurements and decontamination and in decommissioning of nuclear installations. For a reliable use, all surface contamination monitors should have a valid calibration with traceability to the international standards. A comparison exercise for calibrations in terms of efficiency in 2π steradian for surface contamination monitors was organized between five dosimetry calibration laboratories, members of EURAMET (The European Association of National Metrology Institutes). Four β-beta radionuclide sources, Sr-90, Cl-36, Cs-137, Co-60, and one α-alpha source, Am-241, were used for calibrations during this exercise. Two transfer surface contamination monitors, one Canberra SABG 100 and one Berthold LB 124 with 100cm2 and 343cm2 effective area, respectively, were used. The monitors were circulated between the partners and were periodically returned to the pilot laboratory for stability checks. The efficiencies in 2π steradian measured by the participants do not fully agree for all sources and both detectors despite the fact that all laboratories used similar types of surface contamination sources and had proper traceability to primary standards for surface emission rate measurements. As no evident difference in measurements of surface emission rates is expected between the primary standard laboratories that calibrated the sources, it is very probable that the observed differences are mainly due to the calibration procedures used by each laboratory and that the measurement uncertainties of efficiency in 2π steradian are underestimated. This report presents the results of this pilot comparison for calibration of surface contamination monitors and stresses the need to organize similar generalized exercises. This report also identifies some gaps in procedures for calibration of surface contamination monitors.

Evaluation of the Seismicity Index for Nigerian Nuclear Installations

Seismic Hazard Assessment (SHA) is a quantitative measure of assessing the seismic hazard or risk involved for a given site. The parameter computed for such an assessment is needed for building engineers or national decision makers especially when it concerns nuclear installations. Even though the International Atomic Energy Agency (IAEA) currently makes it mandatory to provide such an index before undertaking any form of development or construction of a nuclear installation, this computation has not been done for Nigeria. Data over long period of time is usually necessary for a quantitative seismic hazard assessment, but because such information is scarce in Nigeria a fractal approach is therefore used in this research. A SHA index called the b-value is evaluated by determining the fractal dimension of the network of locations of recorded past tremor events within Nigeria. In this work a b-value of 0.43 which quantitatively measures the seismic hazard or risk of a given region is computed for Nigeria. Aeromagnetic data was used in producing analytic signal maps that accurately mapped faults that could have been responsible for causing the earth tremors, and the coordinates of these faults or lineament were used in calculating the fractal dimension of the system of faults. The fractal dimension of 0.8568 was obtained by determining the slope of line of best-fit of the plot of the log of the average number of tremor locations <N(R)> within radius R of each location against log of radius R, which was in turn used to determine the b-value. A b-value of 0.43 obtained indicates that Nigeria is in a less seismically active region and this can be used in the IAEA safety guidelines for nuclear installations.

Optimal Configuration of Physical Process Parameterization Scheme Combination for Simulating Meteorological Variables in Weather Research and Forecasting Model: Based on Orthogonal Experimental Design and Comprehensive Evaluation Method

The weather research and forecasting (WRF) model is frequently used to investigate the meteorological field around nuclear installations. The configuration of physical process parameterization schemes in the WRF model has a significant impact on the accuracy of the simulation results. Consequently, carrying out a pre-experiment to quickly obtain the optimal combination of parameterization schemes is essential before conducting meteorological parameter research. To obtain the optimal combination of physical process parameterization schemes from the planetary boundary layer (PBL), land surface (LSF), microphysical (MP), long-wave (LW), and short-wave (SW) radiation processes of the WRF model for simulating the near-surface meteorological variables near a nuclear power plant in Sanshan Town, Fuqing City, Fujian Province, China on 4 June 2019 were observed. Orthogonal experimental design (OED), a comprehensive evaluation method based on the CRiteria Import Through Intercriteria Correlation (CRITIC) weight analysis, and comprehensive balance method were employed for the first time to conduct the research. The sensitivity of meteorological variables to physical processes was first discussed. The findings revealed that the PBL scheme configuration had a profound impact on simulating wind fields. Furthermore, the LSF scheme configuration had a significant influence on simulating near-surface temperature and relative humidity, which was much greater than that of other physical processes. In addition, the choice of the radiation scheme had a significant impact on how the temperature was distributed close to the ground and how the wind field was simulated. Furthermore, the configuration of the MP scheme was found to exert a certain influence on the simulation of relative humidity; however, it demonstrated a weak influence on other meteorological variables. Secondly, The MYNN3 scheme for PBL process, the NoahMP scheme for LSF process, the WSM5 scheme for MP process, the RRTMG scheme for LW process, and the Dudhia scheme for SW process are found to be the comprehensive optimal physical process parameterization scheme combination for simulating meteorological variables in the research area selected in this study. As evident from the findings, the use of the OED method to obtain the combinations of the optimal physical process parameterization scheme could successfully reproduce the wind field, temperature, and relative humidity in the current study. Thus, this method appears to be highly reliable and effective for use in the WRF models to explore the optimal combinations of the physical process parameterization scheme, which could provide theoretical support to quickly analyzing accurate meteorological field data for longer periods and contribute to deeply investigating the migration and diffusion behavior of airborne pollutants in the atmosphere.

Digitalization, Management, and Synthesis of Thermal-Hydraulic Legacy Data Using the Dynamical System Scaling

A unique attribute of the nuclear industry is the extent by which designers, developers, operators, and regulators pay attention to demonstrating the safety case. Nuclear installation resiliency or safety takes overriding priority over function and performance. The preparation of the safety case heavily relies on extensive experimental campaigns that challenge the target design under a spectrum of postulated accident scenarios. For safety reasons, these experiments, typically conducted in subscale test apparatuses intended to reproduce the postulated accident scenarios and event sequences realistically, but subject to proven similarity criteria, are often referred to as scaling analyses. Since the dawn of the nuclear industry, significant resources have been committed to the construction and operation of such test facilities, and a massive amount of data has been generated. Such test data have been and are still used to validate the fundamental assumptions of nuclear power plant phenomena. As we move into the digital world, capturing this multiple decades worth of information in a transparent, easily accessible, and usable manner for the public and industry stakeholders is of paramount importance. Over the last few years, FPoliSolutions has been actively developing an enterprise digital data ontology platform (OGMA) intended to do just that. The goal is to help designers use experimental data to assess their safety case evaluation models. The platform or application programming interface (API) was designed to ontologically organize the experimental data, as well guide the user in the complex analytics associated with the interpretation and use of such test results. The OGMA API supports the user in accessing a library of sophisticated mathematical procedures for performing scaling analyses. For this purpose, the dynamical system scaling (DSS) procedure invented by Dr. Jose’ Reyes was formulated as one of the services in the digital platform. These methods have been demonstrated to provide an excelled mathematical apparatus to identify similarity criteria or quantify distortions between measured data and the target prototypical conditions. Moreover, DSS can provide a level of synthesis across separate effect tests and integral effect tests that has the promise of yielding efficiency in the evaluation code assessment activities, as setting up evaluation models that support the safety case of current and future nuclear power plants is often a daunting and expensive task.

Gamma radiation shielding and interaction properties of MoO3-Doped cadmium zinc lithium-borate glasses

This study, theoretically examined the impact of MoO3 addition on gamma radiation shielding properties of cadmium zinc lithium-borate (BCZLMx) glasses to find the optimal quantity of molybdenum oxide (MoO3) needed for a stable glass matrix with excellent gamma shielding capabilities. Gamma radiation transmission parameters that include Mass attenuation coefficient, Mass energy absorption coefficient, Equivalent atomic number, Effective electron density, Dose rate, Exposure buildup factors and Energy absorption buildup factor were evaluated using FLUKA and XCOM computer programs. Results showed that 60B2O3-20CdO-10ZnO-8Li2O-2MoO3 (BCZLM5) was the most stable and efficient glass sample for X-rays and gamma radiation shielding across all photon energy ranges. Hence, BCZLM5 should be deployed for X-rays and gamma radiation shielding to provide maximum protection and exceptional safety for workers in hospital X-ray rooms and nuclear installations against ionizing radiation.

Assessment of background dose rate on non-human biota in a Mediterranean terrestrial ecosystem.

The assessment of radiological impact to the environment is usually carried out by the dose rate estimation to hypothetical entities named Reference Animals and Plants (RAPs). There are many codes to carry out this assessment, which requires the definition of a scenario and using site-specific transfer parameters when possible. Transfer parameters present a geographical bias, as they are mostly derived from temperate and arctic climate datasets, but there is a scarcity of data for Mediterranean climates. In this study, a terrestrial Mediterranean scenario was defined using the distribution of activity concentrations of anthropogenic (90Sr, 137Cs) and naturally occurring radionuclides (40K, 210Pb, 210Po, 226,228Ra, 235,238U, 232Th) in Cáceres province (Spain). Site-specific transfer factors, CRwo-media, defined as the ratio between the concentration in the whole organism and the medium (soil in this case) were considered. Dose rate assessments for terrestrial RAPs were carried out using Tier 3 in ERICA Tool, ranging 0.23-3.73µGy/h which is below the screening level of 10µGy/h. Therefore, no harmful effects are expected to occur. Internal dose rate predominates over external one because the main contributors are naturally occurring radionuclides (in most cases 40K, 226,228Ra, 210Pb, 210Po), which are mostly α-emitting radionuclides. These results can be used for the evaluation of other radiological and nuclear installations in Mediterranean climates, as they set the background dose rate.

Research on the radioactive safety of industrial steam supplied by PWR nuclear power plant

The heating source of the nuclear power steam supply installation is PWR secondary steam, but the secondary steam is potentially radioactive, and the radioactive material may migrate to the industrial steam, which goes through the leakage of the heat exchanger. Compared with the conventional industrial steam, the steam supplied by the nuclear power has potential radioactivity. Nuclear power is first introduced to produce the industrial steam, in order to analyze the specific activity and radiation effects of the industrial steam on the staffs at the user side, an analytical model of industrial steam radioactivity is developed based on the technological process of industrial steam under operating conditions, and then the exposure pathways of the staff at the user side from the industrial steam is analyzed. The specific activity of the industrial steam and the exposure dose of the staff is evaluated. According to the evaluation results, it can be seen that the dose to staff caused by the industrial steam is far smaller than the radiation impact on the public caused by the nuclear power plant, and can meet the requirements of relevant regulations and standards. Therefore from the radiation safety point of view, the industrial steam supplied by the nuclear power steam supply installation is safe and acceptable for industrial use.

Evaluation of the unavailability of the primary circuit of Triga SSR reactor, importance factors and risk criteria for its components

Abstract Probabilistic Safety Assessment is a tool for improving a nuclear installation and its safety in all its function phases. PSA provides a methodical way of identifying sequences resulting from a wide range of initiating events concerning an accident, and includes systematic and realistic determination of accident frequencies and their consequences. This paper analyzes the unavailability of the TRIGA SSR reactor primary circuit, obtaining the system unavailability value, identifying main contributors to system failure, and calculating risk importance factors. Two cases were considered: one without considering Common Cause Failure (CCF) in the developed fault tree, and the second considering CCF on pumps and heat exchangers lines. The aim was to assess their influence on the primary system’s unavailability. Two importance factors, Fussell–Vesely and Risk Achievement Worth, were employed to identify components with a strong impact on the risk (probability of system failure). These factors aid in enhancing maintenance activities and testing. The analysis utilized the EDFT code, part of the PSAMAN code package developed in SCN-Pitesti.

The impact of national policies on Europe-wide power system transition towards net-zero 2050

This research aims to investigate the potential impact of national policies on the attainment of Europe's goal of achieving net-zero greenhouse gas emissions by 2050. Specifically, it analyses the effects of policies on the power sector, by evaluating capacity expansion portfolios, import reliance, and costs by 2050. A linear programming model, the IESA-EUPS, is utilized to optimize the expansion and operation of the power system, considering 28 nodes and hourly temporal resolution. The study includes five scenarios from 2020 to 2050, with varying levels of biomass and nuclear penetration based on existing member state policies. Results show that by 2050, changes mainly occur in the interplay between firm capacities and cross-border transmission levels. Limiting biomass can significantly increase nuclear energy generation, while enforcing all policies leads to a 40 % rise in cross-border transmission by 2050, due to imbalances between countries. Some member states, such as Spain and Finland, are less affected, whereas others are heavily reliant on firm nuclear capacities. Western European countries with strict biomass and nuclear restrictions may see a boost in nuclear installations in countries allowing it. Member states without both nuclear and biomass may rely more on variable renewables, resulting in surplus electricity and increased LCOE.

The protection of nuclear installations in time of armed conflict – Old rules, new challenges

AbstractIn 2022, for the first time in some while, the public around the world was confronted with an armed conflict between states, which directly involved a nuclear facility, specifically a nuclear power plant in operation. Unfortunately, the situation following Russia's armed attack on Ukraine on 24 February 2022 and the acts of war around the Zaporizhzhya nuclear power plant once again draw attention to the need to protect nuclear facilities during armed conflicts. Therefore, this paper reviews the relevant rules of public international law and scrutinizes the norms that have been established through international legislation and soft law mechanisms to protect and guarantee the nuclear safety and security of nuclear installations.

How Does Nuclear Energy Affect Environmental Pollution? Evidence from the United States

Research Originality: Nuclear power plant installation activities, which have gained momentum since the 1970s, have made the use of nuclear energy widespread, and especially the US ranks first in the world in the nuclear energy use. This article contributes to the existing literature on environmental economics by incorporating environmental technologies and globalization into the investigation of the impact of nuclear energy on environmental pollution. Research Objectives: The aim of this study is to analyze the effects of nuclear energy consumption, environmental technologies and globalization on environmental pollution in the US.Research Methods: The paper use ARDL approach with the data of 1970-2018 period. Empirical Results: According to the findings, nuclear energy consumption negatively affects environmental quality in the US both in the short and long run. On the contrary, while environment-related technologies contribute positively to environmental quality with a reducing effect on carbon footprint in the long run. Also, globalization has an insignificant effect on environment in both short and long run.Implications: It is thought that environmental quality will improve as a result of supporting environmental technologies and exchanging nuclear energy with renewable energy sources in the US.JEL Classification: Q43, C32How to Cite:Atay Polat, M., Savranlar, B., Arslan, F. (2024). How Does Nuclear Energy Affect Environmental Pollution? Evidence from US. Etikonomi, 23(2), 511 – 526. https://doi.org/10.15408/etk.v23i2.37692.

Uncertainty propagation from crustal geologies to rock-site ground motion with a Fourier Neural Operator

Seismic hazard analyses in the area of a nuclear installation must account for a large number of uncertainties, including limited geological knowledge. Combining the accuracy of physics-based simulations with the expressivity of deep neural networks can help to quantify the influence of crustal geological uncertainties on surface ground motion. This work uses a Factorised Fourier Neural Operator (F-FNO) to learn the relationship between 3D crustal heterogeneous geologies and time-dependent wavefields at the Earth’s surface up to a 5 Hz maximal frequency. The F-FNO is pretrained on a generic database and then, fine-tuned with only 250 samples targeted to the Le Teil region (South-Eastern France). The F-FNO correctly predicts the wave arrival times and the main wavefronts. As quantified by Goodness-Of-Fit (GOF) criteria, 83% of predictions have excellent phase GOF and 75% have very good envelope GOF. The Peak Ground Velocity and Pseudo-Spectral Acceleration are also accurate, especially for geologies with low-to-moderate heterogeneities. Thanks to the F-FNO speed, ground motion distributions can be easily computed and provide safety margins compared to 1D simulations. These results show that the F-FNO is an efficient surrogate model to quantify the range of ground motion a nuclear installation could face in the presence of geological uncertainties.

Trends and Perspectives on Nuclear Waste Management: Recovering, Recycling, and Reusing

This paper focuses on the highly radioactive, long-lasting nuclear waste produced by the currently operating fission reactors and on the sensitive issue of spent fuel reprocessing. Also included is a short description of the fission process and a detailed analysis of the more hazardous radioisotopes produced either by secondary reactions occurring in the nuclear installations or by decay of the fission fragments. The review provides an overview of the strategies presently adopted to minimize the harmfulness of the nuclear waste to be disposed, with a focus on the development and implementation of methodologies for the spent fuel treatments. The partitioning-conditioning and partitioning-transmutation options are analyzed as possible solutions to decrease the presence of long-lived highly radioactive isotopes. Also discussed are the chemical/physical approaches proposed for the recycling of the spent fuel and for the reusing of some technologically relevant isotopes in industrial and pharmaceutical areas. A brief indication is given of the opportunities offered by innovative types of reactors and/or of new fuel cycles to solve the issues presently associated with radioactive waste.

Design of a Facility for Simultaneous Irradiation with Two Ion Beams based on the HIPR Accelerator for Simulations Neutron Influence

Ion accelerator facility is a powerful tool to simulate neutron irradiation effects in reactor materials. Defects in the crystal lattice arise and the accumulation of transmutation products (helium and hydrogen) occurs in the structure of the material under the action of neutrons in the structural materials of nuclear installations. At Kurchatov Complex for Theoretical and Experimental Physics the heavy ion accelerator HIPr (heavy ion prototype) is used to simulate radiation damage in steels and alloys using a 5.6 MeV Fe2+ ion beam. The second beam line is designed at the HIPr facility to simultaneously implant helium (or hydrogen) into the region of defects. The second beam line provides a beam of helium ions with energy up to 300 keV. The report presents a description of second beam line design and a status of construction the second beam line.

Non-Destructive Inspection of Additively Manufactured Classified Components in a Nuclear Installation

Non-Destructive Inspection of Additively Manufactured Classified Components in a Nuclear Installation

Stabilized voltage source inverter for sensitive loads in nuclear installations

The present paper proposes a novel design of a stabilized single-phase voltage-source inverter with pure sinusoidal output voltage for photovoltaic systems employed for feeding sensitive loads in nuclear installations. Such types of loads require a voltage source with quite stabilized magnitude and frequency and pure sinusoidal shape that is free from higher-order harmonics. The inverter is based on an H-bridge four insulated gate bipolar transistors (IGBTs) with gate drivers and optocoupler isolators. A control system based on a fast DSP unit and a microcontroller is designed for cancelation of the higher-order harmonics to produce a pure sinusoidal output with almost zero total harmonic distortion (THD). The sinusoidal purity, frequency and magnitude stabilization are achieved through pulse width modulation (PWM) controlled by a fast-response feedback system that measures the time wave form of the output voltage applied to the load and then calculates the THD, frequency and amplitude. The sinusoidal shaping is performed with aid of a sinusoidal shaping filter (SSF) to fasten the operation of higher-order harmonic cancellation. The frequency measurement is achieved through a frequency counter whereas the amplitude measurement is carried out through a differential amplifier that amplifies the difference between the output voltage of the inverter (while being applied to the load) and reference voltage that determines the desired amplitude. A prototype of the entire system of the proposed voltage-source inverter is fabricated for experimental evaluation of its performance. It is shown through simulation and experimental work that the proposed control system of the inverter output voltage is able to stabilize both the amplitude and frequency of the voltage applied to the load irrespective of the load impedance. Also, it is shown that the THD of the output voltage is -57dB\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$-57 \ ext{ dB}$$\\end{document} (0.00025%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$0.00025 \\%$$\\end{document}), which is almost zero. Moreover, the switching losses are considerably reduced and can be negligible owing to the use of the appropriate IGBTs. The efficiency of the proposed inverter is obtained by simulation taking into account all types of losses. Also, the dependence of the inverter efficiency on the load current is investigated. The average efficiency of the proposed voltage-source inverter is shown to be higher than 97%\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$97\\%$$\\end{document}.