Institute For Nuclear Research Research Articles

Development of a fully implicit ODE-solver for containment analysis code

The thermal–hydraulic dynamics in containment are governed by a system of stiff ordinary differential equations (ODEs). A fully implicit discretization scheme is adopted to discretize these ODEs in order to mitigate the effects of stiffness. In comparison with explicit or semi-implicit discretization schemes that are subject to Courant limits on time steps, the fully implicit discretization scheme is more suitable for a containment analysis code that focuses on predicting both short-term and long-term thermal–hydraulic parameters after an accident. This study introduces a general-purpose ODE solver for the containment analysis code. The outline of the solver is as follows: The fully implicit discrete equations lead to a large set of nonlinear equations that need to be solved using Newton’s iterative method. The partial derivative components in the Jacobi matrix are calculated by the perturbation method using finite difference approximation, which avoids the complicated derivation of partial derivatives. The scaling modification technique is incorporated into this ODE solver to deal with significant differences in unknown variable magnitudes, and the line search method is introduced to address the difficulty of obtaining an accurate root estimate with Newton’s method when the initial guess is far from the actual root. This proposed ODE solver was applied to two typical stiff ODE problems to test its stiffness-suppressed ability and to demonstrate that this proposed solver can perform calculations with a very large time step. Then, the CASSIA code, a containment analysis code developed by China Nuclear Power Technology Research Institute Co., Ltd (CNPRI), equipped with this ODE solver, was applied to the CSNI (Committee on the Safety of Nuclear Installations) benchmark problem and the Carolinas Virginia Tube Reactor (CVTR) test 3 problem to preliminarily demonstrate that the proposed ODE solver can perform containment thermal–hydraulic analysis correctly. This study could provide references for the development of a home-made containment analysis code.

Automated thickness measurement system for nuclear fuel plates: A metrological study

Thickness measurements of nuclear fuel plates manufactured at the Nuclear Fuel Center of the Nuclear and Energy Research Institute (IPEN-CNEN/SP) are currently performed using manual external U-shaped frame micrometers with non-rotating spindles and beveled measurement anvils. Results are then manually recorded on dedicated forms. To improve the efficiency and the metrological reliability of the process, a novel thickness measurement system for nuclear fuel plates was developed. This work presents a comprehensive metrological study of the newly designed measurement system, achieved through the construction of a new apparatus with automated mechanisms for synchronized movement, data capture, transcription, and processing. The study results demonstrate the metrological adequacy of the developed system and underscore the importance of the design and structural quality of the measurement equipment. Consequently, the metrological reliability of the results in the dimensional control of nuclear fuel plates is confirmed.

Multimodal immersive digital twin platform for cyber–physical robot fleets in nuclear environments

AbstractThe nuclear energy sector can benefit from mobile robots for remote inspection and handling, reducing human exposure to radiation. Advances in cyber–physical systems have improved robotic platforms in this sector through digital twin (DT) technology. DTs enhance situational awareness for robot operators, crucial for safety in the nuclear energy sector, and their value is anticipated to increase with the growing complexity of cyber–physical systems. The primary motivation of this work is to rapidly develop and evaluate a robot fleet interface that accounts for these benefits in the context of nuclear environments. Here, we introduce a multimodal immersive DT platform for cyber–physical robot fleets based on the ROS‐Unity 3D framework. The system design enables fleet monitoring and management by integrating building information models, mission parameters, robot sensor data, and multimodal user interaction through traditional and virtual reality interfaces. A modified heuristic evaluation approach, which accounts for the positive and negative aspects of the interface, was introduced to accelerate the iterative design process of our DT platform. Robot operators from leading nuclear research institutions (Sellafield Ltd. and the Japan Atomic Energy Agency) performed a simulated robot inspection mission while providing valuable insights into the design elements of the cyber–physical system. The three usability themes that emerged and inspired our design recommendations for future developers include increasing the interface's flexibility, considering each robot's individuality, and adapting the platform to expand sensor visualization capabilities.

Investigations of Chemical Element Distributions in Soil, North Macedonia—A Review

This review article considers the following aspects: naturally distributed chemical elements and their enrichments, and the increased occurrence of PTEs due to anthropogenic and urban activities, as well as due to the geochemical uniqueness of certain geochemical landscapes, depending on the lithological environment. The review article is the result of many years of successful cooperation between the Geological Survey of Slovenia and the Faculty of Natural Sciences in Skopje, Ss. Cyril and Methodius University in Skopje, as well as several other institutions from North Macedonia, Russia and Romania but, also, through the voluntary and enthusiastic work of Prof. Trajče Stafilov’s PhD and Master’s students. To create the Geochemical Atlas, the territory of North Macedonia was covered with 995 sampling locations, but 16 separate areas with soil contamination were additionally sampled. The total sum of all collected soil samples was 3983 from 2449 different sampling sites in the period from 2006 to 2017. The analyses were performed at the Institute of Chemistry, Faculty of Natural Sciences in Skopje, at the Ss. Cyril and Methodius University in Skopje, North Macedonia, at the Research Institute for Analytical Instrumentation (ICIA), Cluj-Napoca, Romania, at the Joint Institute for Nuclear Research in Dubna, Moscow Region, Russia, and at Acme Labs in Vancouver, Canada. The sum of all analysed soil samples in all four mentioned laboratories was 7991 from 2006 to 2017. Using advanced mathematical methods such as multivariate statistical methods (HCA, FA, PCA) and artificial neural networks–multilayer perceptron (ANN-MP), predictions were made about the concentrations of potentially toxic elements (PTEs) and their distribution in real space. In less than two decades (2007–2023) of fruitful collaboration, a large number of scientific works have been published: 188 scientific publications, 8 geochemical atlases and 23 chapters in monographs.

Using Factor Analysis To Find Source Atmospheric Pollution By Moss Technique

The aim of this investigation was to apply the moss biomonitoring technique using Barbula Indica moss and factor analysis to evaluate the possible sources of atmospheric pollution in the Thua Thien Hue province. The Barbula Indica moss samples were collected at sixteen sites in the areas of Thua Thien Hue province, the central Vietnam. The concentrations of thirty elements in the collected Barbula Indica moss samples were determined by neutron activation analyses at the reactor IBR-2 at the Joint Institute for Nuclear Research (JINR) in Dubna, Russian Federation. Factor analysis has been applied to the obtained concentrations to reveal the possible pollution sources. Rotated factor loadings suggested three factors, that could explained more than 84% of variability. Additionally, factor scores were calculated, that confirmed the presence of pollution sources in the corresponding sites.

Обеспечение безопасного контроля радиационно-защитных свойств спецодежды пожарных

The radiation-protective clothes production to equip firefighters guarding nuclear power plants has been established in Russia. Special protective clothes were designed at the Institute for Nuclear Research of the Russian Academy of Sciences under the supervision of Boris Benetsky (1933–2015). According to the state standard GOST R 53264—2019, the radiation-protective properties of special protective clothes are tested with gamma and beta rays in accordance with the methodology developed at the Institute for Nuclear Research of the Russian Academy of Sciences, which ensures the radiation safety of the test. It is required to check the decontamination coefficient; however, this testing method is still hazardous due to the use of open-type radiation-hazardous substances. To ensure the safety of the test, the simulation method has been proposed based on the substitution of the hazardous substance with a safe dust-like pollutant, whereas the decontamination is to be assessed by the adhesion index. The adhesive tape method to assess the contamination of the surface is used. Two casts are taken from two sections of the tested surface before and after the treatment with a detergent. The images of the casts are converted into digital form via a scanner and then computer-processed by the specially designed GLASS application. The contamination of the casts depends on the amount of dust stuck. Upon the determination of the average contamination of each cast, data is obtained to calculate the adhesion index. The result of the test of the same material by simulation method differs from the standard method by 20 %.

Delivery of High-Intensity Proton Beam for the Study of Flash-Effect in Radiotherapy

Flash-therapy is a rapidly developing field of radiology that has the potential to revolutionize future cancer treatment techniques. The method involves delivery the therapeutic radiation dose to the tumor volume at an ultra-high dose rate in the beam, several orders of magnitude higher than that usually used in conventional radiotherapy. In this mode of irradiation, the degree of damage to normal tissues surrounding the tumor and falling under the influence of radiation decreases, at the same time, the effect on cancer cells remains at the same level, which preserves the prospect of local control of the tumor with a lower frequency of side effects.
 The paper presents the results on the delivery of a high-intensity proton beam with an energy of 660 MeV from the Phasotron of the Joint Institute for Nuclear Research, Dubna, designed for radiobiological studies under flash therapy irradiation of cell cultures and small laboratory animals (mice, rats). In addition, the main design features and parameters of the created detectors for measuring the characteristics of this beam are presented.

An examination on the porosity of Er[formula omitted] doped Ca[formula omitted] crystal using the Rutherford back-scattering method

This work investigates the porosity of ErF3 doped CaF2 crystals using the Rutherford back-scattering (RBS) method. Two ErF3:CaF2 samples of 2.0 and 5.5% doping ratios were prepared using the Bridgman method. The RBS spectra of these samples at two incident angle configurations of the projectile alpha, i.e., 0 and 30 degree, were collected using the Rutherford back-scattering spectrometer at the Joint Institute for Nuclear Research in Dubna, Russia. The measured spectra were analyzed with sample models of porous materials using the SIMNRA program. It turns out that the porous volume ratio and diameter are probably in the intervals of 18 to 22% and 2.4×1018 to 3.0×1018 atoms per cm2, respectively. However, the RBS method exhibits significant uncertainty, impeding our ability to establish a correlation between porosity characteristics and doping ratios.

Interaction of photons with silver and indium nuclei at energies up to 20 MeV* *The authors express their gratitude to the team of the LINAC-200 electron accelerator and the management of the Joint Institute for Nuclear Research for their support in conducting the experiments.

The yields of photonuclear reactions in the 107Ag, 113In, and 115In nuclei were measured. Monte Carlo simulations were performed using the Geant4 code, and the results were compared with the experimental values. The isomeric ratios of the yields in the reactions 107Ag(γ, n)106m,g Ag and 113In(γ, n)112m,g In were determined, and the cross sections for the reactions 107Ag(γ, n)106g Ag and 107Ag(γ, 2n)105Ag at an energy of 20 MeV were calculated based on the experimental data.

II International Scientific School-Conference “Atom. Science. Technology”

June 6-9, 2023, Almaty, Republic of Kazakhstan School Organizers • Council of young scientists of RSE on REM "Institute of Nuclear Physics" of the Ministry of Energy of the Republic of Kazakhstan • Institute of Nuclear Physics of the Academy of Sciences of the Republic of Uzbekistan • International intergovernmental organization Joint Institute for Nuclear Research “Atom. Science. Technology.” is a scientific conference with the participation of leading Kazakhstani and foreign scientists on its subject, within which leading scientists conduct a scientific school for young scientists and specialists in order to familiarize them with the latest results of scientific research on the subject of the conference, discuss the progress and results of research by young scientists . The conference provides for the presentation in the form of reports of the results of research works of young scientists, students, undergraduates and doctoral students, contains plenary review and specialized reports of leading scientists in the field of theory, practice and innovation management on the subject of the conference, is multi-sectional for a wider coverage of participants. The conference is dedicated to the Day of Science in Kazakhstan.Like ANT-2021, ANT-2023 is held online. In 2024, our conference will be held in a hybrid format, that is, it will be possible to participate both online and come in person. This will provide an opportunity for participants to get to know each other better, establish contacts, etc. At the same time, from 2024 the conference will be held only in English.List of Organising Committee, School topics, Registration of participants, Rules of speech, s, Important dates, Contact addresses of the secretariat of the School are available in this pdf.

Optimization of IEA-R1 reactor core parameters using the particle swarm algorithm

This work aims on the development of a FORTRAN 90 code to solve the Loading Pattern Optimization Problem (LPOP) in the IEA-R1 research reactor at the Nuclear and Energy Research Institute (IPEN/CNEN-SP) in São Paulo, Brazil. The code integrates the Particle Swarm Optimization (PSO) method, with the current reactor calculation methodology. The objective function seeks to maximize the effective multiplication factor (keff), minimize the peak power factor (PPF), and achieve the most uniform neutron flux distribution possible. A comparison with the parameters of the reactor’s current configuration, and the code successfully finds solutions meeting the standard problem requirements. The new configuration enhances peak power (6.93%) and variance (9.62%), slightly increases neutron flux (0.48%), and marginally reduces in keff (0.45%). Additionally, it lowers the maximum fuel cladding temperature (0.7%), contributing to reactor safety.

Contamination characteristics in runoff fractions from a nuclear facility in São Paulo, Brazil.

The stormwater runoff may act as a nonpoint pollutant source and contributes to aquatic ecosystem quality decay in urban environments. The aim of this work was to evaluate the runoff characteristics on the transport of total solids and total metals, as well as pH and conductivity responses during the rainfall evolution. During 2017 and 2018, 12 rain events were monitored in 4 sampling stations at a car parking lot located at Nuclear and Energy Research Institute (IPEN/CNEN) in São Paulo/Brazil. A 4-chamber integrated collector allowed the sequential/temporal runoff evolution assessment. The runoff composition, in decreasing order of quantities, was Ca > K > Mg > Si > Al > Fe > Na > Zn > Mn > Sr > Ti > Mo > V > Cu > B > Pb > Ni > Ce > Sb > Cr > La > U > Th > Cd. The amount of total solids, Al, and Fe exceeded the Brazilian water quality standards. Principal component analysis (PCA) identified the elemental clusters linked to the facility activity, soil, and traffic/atmospheric-related deposition. The results show that the runoff characteristics could be differentiated by pollutant source. Factors such as seasonal variation, rain event intensity, air mass from oceanic or continental origin, spatial distribution inside the monitoring area, and the intensity of the first flush must be considered in order to disentangle the elemental clusters and pollution source contributions. In winter, continental air masses were associated with higher concentrations of heavy metals in the surface runoff. Spatial changes with no seasonal variation were observed for U, Th, La, and Ce.

Construction and measurement of the prototype side-coupled standing-wave tube for electron Linac

Due to Iran's growing need for accelerators in various applications, NSTRI (Nuclear Science and Technology Research Institute) has defined a 6 MeV e-Linac (electron linear accelerator) project for medical and inspection applications. This electron accelerator has a side-coupled standing wave tube that operates in π/2 mode at the frequency of 2998.5 MHz. This paper presents a summary of the construction and cold test stage of the prototype tube for this accelerator. The prototype tube was constructed from aluminum and clamped with bolts.In the cold test stage, low-power RF measurements werecarried out using a side-coupled cavity tuning method and a bead-pull measurement technique. Using a network analyzer, magnetic and electric probes, and a mechanical structure constructed for this tube made the RF tuning possible. After tuning, the resonant frequency, unloaded quality factor, and effective shunt impedance of the aluminum tube were achieved at 2998.57 MHz, 7970, and 83.25 MΩ/m respectively.

Experimental Study of the Compressibility of a Helium Plasma at a Pressure up to 20 TPa

A nonideal helium plasma has been compressed to a density of ρ ≈ 14 g/cm3 at a pressure of \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$P \\approx 20{\\kern 1pt} $$\\end{document} TPa (200 Mbar) in a spherical two-cascade device. The design of the device has been presented and the thermodynamic parameters of the helium plasma reached in it have been estimated. Data on the dynamics of the external and internal cascades in the device used to choose the calculation method have been obtained in a preliminary experiment with a hemispherical prototype. The experiment has been performed on the X-ray complex at the Russian Federal Nuclear Center All-Russian Research Institute of Experimental Physics, which includes BIM 234.3000 betatrons with a boundary energy of 60 MeV used in the multipulse bremsstrahlung generation regime with a multichannel optoelectronic system of recording X-ray images. A high-current linear accelerator LIU-R-T and an image detector assembly consisting of photochromic ADC screens have been used in addition to betatrons to detect the compressed shell cavity.

Pneumatic Transport System REGATA-2 for Automation of Activation Analysis at the IREN Facility, FLNP JINR

The IREN facility at the Frank Laboratory of Neutron Physics (FLNP) of the Joint Institute for Nuclear Research (JINR) is used for experiments to determine elemental composition of various samples by neutron activation analysis (NAA). A pneumatic transport system (PTS) REGATA-2 was implemented to automate the delivery of containers with samples to the irradiation position and back. The article describes the characteristics of the PTS, its adaptation for operation at the IREN facility, and also plans for subsequent modernization and future prospects. After the assembling of the system, the optimal parameters were chosen for irradiating the typical samples, and a calibration was created for a high-purity germanium detector, which let to consider the volume nature of the samples. Samples of archaeological ceramics from Kazakhstan were studied using the PTS. The features of the IREN facility let to use not only a neutron, but also a gamma-producing target. The first experiments on the qualitative determination of elements by gamma-activation analysis (GAA) were carried out, and the prospects for using the facility for these purposes were confirmed. The creation of the PTS let to automate the process of irradiation samples and increase the efficiency of research in NAA and GAA, especially for short-lived isotopes. It also reduces the negative impact of radiation on the human body.

A test experiment on determining the cluster structure of highly excited states of 6Li

The paper presents the results of test measurements to determine the possibilities of studying the cluster structure of highly excited states of the 6Li nucleus in the 6Li(𝑛, 3He 𝑛) 3H reaction on the RADEX neutron channel of the Institute for Nuclear Research of the Russian Academy of Sciences. In the experiment, scattered neutrons were detected in coincidence with the decay products of highly excited states (helium-3). The first experimental data on the excitation energy of the 6Li nucleus have been obtained.

Test experiment to determine the time distribution of the background between MMF accelerator pulses on the RADEX channel

The authors offer works using the MMF INR RAS neutron channel to study the cluster structures in light nuclei, in particular, 𝛼-4n-𝛼 and 8Be-4n in the highly excited state 12Be*. This needs the registration of charged particles from the 12Be* 𝛽-decay during its formation in the 𝑛+13C reaction in the intervals between cascade neutron pulses. The paper presents the first results of an experiment on measuring the spectra and time distributions of gamma-quanta and neutrons using a proton beam of 50 Hz and a duration of 0.3 𝜇s.

SUMMER：A small modular lead-bismuth-cooled fast reactor for mobile energy supply

The pursuit of small modular reactors (SMRs) has become a trend in this century due to their potential to expand the use of clean and reliable nuclear energy to a broader range of customers and applications. One promising candidate is the lead-based fast reactor. A mobile energy supply unit based on a lead-bismuth-cooled, pool-type, small modular fast reactor named SUstainable Modular Mobile Enhanced Reactor (SUMMER) is being developed by the University of Science and Technology of China (USTC) and China Nuclear Power Technology Research Institute. SUMMER is intended to provide stable energy supply in the field or remote regions, which are potential application scenarios for SMRs. Key features of SUMMER include a long lifetime of over a decade, mobility (transportable by truck or train), and inherent safety. In this paper, the reactor design is completed under the constraints of fulfilling these features, such as the limitation of size and lifetime. Neutronic and thermal-hydraulic analyses are implemented, as well as safety analyses of the reactor under several typical accidents. The results show that the design meets all these criteria and that the reactor has an adequate safety margin under both steady-state and transient conditions.

Investigation of Elemental Deposition in Lamdong Province (Vietnam) by the Moss Biomonitoring Method and Neutron Activation Analysis

The results of an investigation of heavy metal air pollution in Lamdong province (Vietnam) using the moss biomonitoring method are presented in this paper. Barbula Indica moss samples were collected at 30 different locations in Dalat and Baoloc, two major cities of Lamdong province. The concentrations of 10 heavy metal and metalloid elements, Sc, V, Cr, Mn, Fe, Co, Zn, As, Hf, and Ta in the collected moss samples, were determined by the neutron activation analysis method using the nuclear reactor at the Nuclear Research Institute in Dalat. The results show that the air in Lamdong province may be polluted by Mn and is moderately polluted by Sc, V, Cr, Fe, Co, Zn, As, Hf and Ta. The main sources of heavy metal pollution in the Lamdong atmosphere may be soil dust, traffic emissions, industry, bauxite mining and refining, chemical fertilizers and pesticides, and combustion of coal and oil. By comparing heavy element concentrations in the moss from Lamdong with that of Hanoi, Thainguyen, and several European countries, it is found that heavy metal air pollution in Lamdong is much lower than in Hanoi and Thainguyen and much higher than in the European countries.

NICA heavy-ion collider at JINR (Dubna). Status of accelerator complex and first physics at NICA.

The NICA facility is under active realization at the Joint Institute for Nuclear Research (JINR, Dubna). Its main goal includes experimental studies of hot and dense baryon rich matter forming in heavy ion collisions to search for possible manifestations of phase transitions and critical phenomena, as well as investigation of nucleon spin structure with polarized proton and deuteron beams. The NICA general design, construction status, and prospects for physics program are presented.