Research Center Kurchatov Institute Research Articles

Measurement of the Cross Section for the Neutron-Induced Fission of 237Np Nuclei in the Energy Range of 0.3–500 MeV

The cross section for the neutron-induced fission of 237Np nuclei in the neutron energy range of 0.3–500 MeV has been measured using the time-of-flight spectrometer of the GNEIS neutron complex at the Petersburg Nuclear Physics Institute, National Research Center Kurchatov Institute. The 237Np(n, f) fission cross section has been measured with respect to the 235U(n, f) fission cross section and fission fragments have been detected by low-pressure position-sensitive multiwire proportional counters. The data obtained have been compared to the previous experimental results and to estimates from various evaluated data libraries.

SPEECH BY THE VICE PRESIDENT OF THE RAS RAS ACADEMICIAN V.Ya. PANCHENKO

On May 22, 2023, meetings of the Division of Mathematical Sciences of the Russian Academy of Sciences and the Division of Physical Sciences of the Russian Academy of Sciences took place, as well as a ceremonial meeting of the RAS Division of Nanotechnologies and Information Technologies (ONIT RAS), dedicated to the 40th anniversary of the ONIT, at which President of the Russian Academy of Sciences G.Ya. Krasnikov and President of the National Research Center Kurchatov Institute M.V. Koval’chuk delivered congratulations.

Measurement of the Cross Section for the Neutron-Induced Fission of 238U Nuclei in the Energy Range of 0.3–500 MeV

The cross section for the neutron-induced fission of 238U nuclei has been measured using the time-of-flight spectrometer of the GNEIS neutron complex at the Petersburg Nuclear Physics Institute, National Research Center Kurchatov Institute, in the neutron energy range of 0.3–500 MeV. Fission fragments have been detected by low-pressure position-sensitive multiwire proportional counters. The cross section for 238U(n, f) fission has been measured with respect to the cross section for 235U(n, f) fission, which is an accepted international standard. Data on the energy dependence of the anisotropy of the angular distribution of fragments of neutron-induced 238U nuclei are also presented. The data obtained have been compared to previous experiments carried out using both similar and significantly different methods.

Обследование содержимого ячеек хранилища высоко- и среднеактивных отходов реактора МР

The article presents the results of a survey carried out at a storage facility for intermediate- and high-level waste established during the operation of MP and RFT research reactors at the site of the Russian Research Center Kurchatov Institute. Relevant survey methods were selected based on the personnel safety requirements for measurements, permissible individual and collective annual exposure of personnel and the population, standards for contaminated environmental objects. All RW containers held in the storage cells were certified and handled properly to ship them from the site of the RRC Kurchatov Institute. The decommissioning designs for this storage facility will be developed based on the data obtained.

Reevaluating reactor antineutrino spectra with new measurements of the ratio between U235 and Pu239 β spectra

We report a reanalysis of the reactor antineutrino energy spectra based on the new relative measurements of the ratio $R=\!^{e}S_5/^{e}S_9$ between cumulative $\beta$ spectra from $^{235}$U and $^{239}$Pu, performed at a research reactor in National Research Centre Kurchatov Institute (KI). A discrepancy with the $\beta$ spectra measured at Institut Laue-Langevin (ILL) was observed, indicating a steady excess of the ILL ratio by the factor of $1.054\pm0.002$. We find a value of the ratio between inverse beta decay cross section per fission for $^{235}$U and $^{239}$Pu: $(^5\sigma_f/^9\sigma_f)_{KI} = 1.45 \pm 0.03$, and then we reevaluate the converted antineutrino spectra for $^{235}$U and $^{238}$U. We conclude that the new predictions are consistent with the results of Daya Bay and STEREO experiments.

Development and Construction of Track and Identification Systems for Experiments Aimed at Studying Extreme Properties of Nuclear Matter in Nucleus–Nucleus Collisions

Investigation of properties of nuclear matter at extremely high temperature and/or extremely high baryon densities under laboratory conditions is one of the fundamental lines of research in high-energy physics. Throughout the past decades, such investigations have been performed in collisions of ultrarelativistic heavy ions in several experiments at modern accelerator complexes, including the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL, USA) and the Large Hadron Collider (LHC) at CERN (Switzerland). In the near future, it is also planned to launch investigations of this kind at the FAIR (Facility for Antiproton and Ion Research at Gesellschaft fur Schwerionenforschung (GSI), Darmstadt, Germany) and NICA (Nuclotron-based Ion Collider fAcility at Joint Institute for Nuclear Research (JINR), Dubna, Russia) accelerators. In order to implement such investigations, it is necessary to create sophisticated detector systems that are able to record events featuring high-multiplicity product particles and to measure reliably their properties. The present article gives a brief survey of all detector systems that have already been created and are being developed at Laboratory of Relativistic Nuclear Physics at Petersburg Nuclear Physics Institute (National Research Center Kurchatov Institute) for the PHENIX (BNL, USA), ALICE (CERN, Switzerland), and CBM (GSI, Germany) experiments aimed at studying nuclear matter under extreme conditions.

Соочистка рекомбинантных модифицированных глюкагоноподобного и глюкозозависимого инсулинотропного пептидов для создания двухкомпонентного препарата для лечения сахарного диабета типа 2 и ожирения

In addition to the previously developed recombinant modified human glucagon-like peptide 1 (rmglp1, Glypin), a recombinant modified human glucose-dependent insulinotropic peptide (RMGIP) has been obtained. A new universal reverse-phase HPLC technique has been proposed allowing quantitative analysis of rmGlp1 and rmGip separately and as part of a two-component preparation. The data show that the design of recombinant human rmGip according to the Glypine formula makes it possible to produce one-component and two-component preparations containing various rmGip and rmGlp1 protein ratios ranging from 1:0 to 20:1, using cell biomass samples mixed in predetermined proportions. Studies of human rmGip activity in a mouse model revealed reduced specific activity and signs of weak antagonistic effects. In this regard, there is a need for further study of human rmGip activity in a mouse model, including the use of alternative mouse or rat rmGip. type 2 diabetes mellitus; two-component drug, glucose-dependent insulinotropic peptide, glucagon-like peptide-1 The work was supported by the Internal Grant from National Research Center Kurchatov Institute.

Межштаммовая гибридизация дрожжей Kluyveromyces lactis для создания штаммов, активно сбраживающих лактозу

A molecular genetic study of Kluyveromyces lactis yeasts isolated from various dairy products in the countries of the former Soviet Union and other regions of the world has been carried out. Based on physiological tests, four strains were selected that carry different LAC loci and are characterized by good fermentation intensity: VKM Y-1339 (LAC3), VKM Y-1333 (LAC3), NRRL Y-1118 (LAC1), and NRRL Y-1140 (LAC2). Eleven hybrids of the selected strains with different rates of lactose fermentation were obtained. No correlation was found between the intensity of lactose fermentation and the amino acid sequences of the LAC12 lactose permease gene of the LAC1, LAC2, and LAC3 loci. Apparently, a specific combination of genotypes of crossed strains has a more significant effect on the fermentation activity. The results obtained showed that inter-strain hybridization of K. lactis dairy yeast is an effective method for creating new strains with high fermentation capacity. Hybrids H2-3 (NRRL Y-1118 × VKM Y-1333) and H3-3 (NRRL Y-1140 × VKM Y-1333) with the highest ability to ferment lactose are of interest for further molecular genetic research and breeding programs. Key words: Kluyveromyces lactis, β-galactosidase, lactose permease, LAC4, LAC12, LAC1 locus, LAC2 locus, LAC3 locus, inter-strain hybridization, lactose fermentation, heterosis Acknowledgment - The authors are grateful to the Genomic Center of the Kurchatov Institute SRC---GosNIIgentika for sequencing the nucleotide sequences of the LAC12 genes for lactose permease on the Applied Biosystems 3730 automated analyzer. Funding - This work was supported by an internal grant from the National Research Center Kurchatov Institute (order of the National Research Center Kurchatov Institute No. 1779).

Experimental Thermonuclear Installation Tokamak T-15MD

At present, the T-15MD tokamak is being built and its supporting technological systems are being modernized at the National Research Center Kurchatov Institute in the framework of the federal target-oriented program “New Generation Nuclear Power Technologies in 2010–2015 and in Prospect to 2020.” The T-15MD magnet system is to ensure producing and confinement of hot plasma in the divertor configuration. The T-5MD plasma parameters are as follows: major radius R0 = 1.48 m, minor radius a = 0.67 m, elongation k95 = 1.7–1.9, triangularity δ95 = 0.3–0.4, plasma current Ip = 2 MA, and toroidal magnetic field at the plasma axis BTO = 2 T. The tokamak will be equipped with an auxiliary plasma heating and current drive system (Paux = 15–20 MW), which will enable achieving a high plasma temperature (Ti ~ Te of 5–9 keV) and a plasma density (ne ≈ 1020 m–3) during a discharge with a pulse duration of up to 30 s. The magnet system includes a toroidal winding and a poloidal magnet system. The poloidal magnet system may generate the one- or two-null divertor magnetic configuration. The power supply system provides the necessary current scenarios in the magnet system windings. The T-15MD magnet together with the vacuum vessel was pre-assembled at the NPO GKMP Ltd. plant in Bryansk. All elements of the magnet system and the vacuum vessel are delivered to the National Research Center Kurchatov Institute in Moscow, where the T-15MD tokamak will be assembled. The technological systems are to be reconstructed by the end of 2019. The physical start-up of the T-15MD is scheduled for December 2020.

A Biomimicking Method for Fabrication of Polymer Nanocomposites and Study of Their Physicochemical Properties

NpCdS nanocrystals are prepared by a microbial synthesis technique at the NRC “Kurchatov Institute”—GOSNIIGENETIKA. The stabilizing layer of nanocrystals consists of proteins, and the composition of the protein layer depends on the strain used in nanoparticle (NP) biosynthesis. The morphology and size, hydrodynamic diameter, zeta-potential, and luminescence properties of the biogenic NPs are investigated using electron microscopy, dynamic light scattering, and spectrofluorimetry, and the NPs are identified as quantum dots. The effects that temperature, pressure, and solvents have on the stability and luminescence intensity of biogenic NPs are studied in collaboration with the National Research Center Kurchatov Institute—IREA. For the aqueous NpCdS suspension, the dependence of luminescence intensity on the NP concentration range is established. The feasibility of incorporation and identification of NpCdS in an epoxy resin, polyimide, and polyvinyl alcohol is evaluated. Polymer nanocomposites find use in optoelectronics, biomedicine, and agriculture.

Study of a Sample of Frankincense from Vetchany Gorod of Ancient Vladimir

The paper presents the results of research performed at the National Research Center Kurchatov Institute on a sample of frankincense found in 1993 during excavations in the eastern part of the historic core of the city of Vladimir known as Vetchany Gorod (Decayed Town), currently part of the collection of the Federal State Budgetary Institution of Culture State Vladimir-Suzdal Historical, Architectural, and Art Museum-Reserve. Identification of bioactive substances of frankincense in the museum sample by European Pharmacopoeia methods did not detect the presence of boswellic acids and their derivatives, which are characteristic of frankincense. A gas chromatography-mass spectrometry (GC/MS) examination of the fragment of museum frankincense detected compounds present in modern frankincense, amyrenones and amyrins, and thermal decomposition products but not the primary biomarkers—boswellic acids and their derivatives. GC/MS analysis of a sample of modern frankincense after thermal treatment that simulated the process of censing as done in church services showed the absence of boswellic acids and their derivatives. The remains left after the thermal treatment were found to contain more stable chemical compounds of frankincense as well as products of its thermal decomposition. A hexane extract of the residue of the studied sample was found to contain odd carbon numbered n-alkanes, which are biomarkers of beeswax. Based on the results of the study, it was concluded that the studied museum sample is a mixture of beeswax and incense remains left in a censer after a church service.

The Impact of Cesium Vapor Bulk Condensation on the Transport of Aerosols in the Reactor Plant’s Primary Circuit during a Severe Accident at a Nuclear Power Plant with VVER

The article presents the results from numerical modeling of aerosol particles' deposition process during their transportation in the horizontal section of the reactor plant’s primary circuit model for the conditions typical for a severe accident at an NPP equipped with VVER reactors. The effect that the bulk condensation of cesium vapors has on the growth and deposition of aerosols during their transportation is analyzed. The influence of the initial size and concentration of aerosol particles on their growth rate and subsequent deposition is considered. Homogeneous condensation occurring in the absence of heterogeneous condensation nuclei (solid aerosol particles) and also heterogeneous condensation under the conditions in which nuclei of the new phase do not emerge according to the homogeneous mechanism are considered as the limit cases. Data on the average size of the produced droplets and aerosol particles along the channel axis in the condensation zone with the varied value of aerosol particles mass fraction in the flow have been obtained, which corresponded to different ratios of the condensate mass fraction in the form of droplets and liquid layer on the surface of solid aerosol particles. It has been established that the general deposition rate decreases if the flow contains droplets generated as a result of homogeneous bulk condensation and having a size smaller than the size of grown aerosol particles. The article describes the analysis scheme of the modeled section whose geometrical shape was specified based on the horizontal section of the experimental installation in the FALCON-ISP1 series of experiments on the deposition and transport of radionuclide aerosols. The cesium vapor homogeneous-heterogeneous condensation process is modeled by numerically solving—using the method of moments—the kinetic equation for the droplet size distribution function with involvement of the authors’ COND-KINET-1 computer program. The transport and deposition of aerosol particles in the primary circuit channel were modeled using the MAVR-TA computer code developed at the National Research Center Kurchatov Institute.

Drift Chambers Made of Mylar Tubes with Diameter of 15 mm and Length of up to 2.5 m

The design and the procedures for assembling and testing drift tubes 15 mm in diameter made of 125-µm-thick Mylar film with a double-sided aluminum coating are presented. The technology of assembling three-layer chambers made of such tubes with a length of up to 2.5 m intended for use in experiments at the accelerator facility at the Institute for High Energy Physics of the National Research Center Kurchatov Institute—IHEP is described. Some results obtained during detection of cosmic muon tracks in the chambers are presented.

A Neutron Testing Facility to Study the Radiation Hardness of the Electronic Components at the SC-1000 Synchrocyclotron of National Research Center Kurchatov Institute—Petersburg Nuclear Physics Institute

The article presents a description of the ISNP/GNEIS testing facility with a neutron spectrum that reproduces the spectrum of atmospheric neutron radiation. The facility was developed at the Petersburg Nuclear Physics Institute (PNPI) of the National Research Center Kurchatov Institute in collaboration with the Institute of Space Device Engineering, a branch of JSC (Joint Stock Company) United Rocket and Space Corporation. The spallation neutron source of the facility is based on the 1-GeV SC-1000 proton synchrocyclotron at the PNPI. The internal neutron-production lead target produces 10-ns pulses of neutrons with a repetition rate of 45–50 Hz and an average neutron intensity of 3 × 1014 n/s (in the 4σ solid angle). In the irradiation area located at a distance of 36 m from the neutron source, a high-quality collimated neutron beam with a broad energy spectrum of 1–1000 MeV and a neutron flux of 4 × 105 n/(cm2 s) allows conducting accelerated single-event soft error testing of electronic components. In the course of the irradiation, the neutron energy spectrum and intensity and the spatial profile of the beam are controlled using a fission ionization chamber (beam monitor) and a position-sensitive multiwire proportional counter (beam profile meter). The data acquisition system of the ISNP/GNEIS facility utilizes 250 MS/s 12 bit CAEN waveform digitizers for the processing of signals from the monitor and profile meter by the neutron time-of-flight technique. In the report, parameters of the ISNP/GNEIS testing facility are discussed in comparison with analogous world-class facilities, as well as requirements and recommendations of the standards used in this field.

High-performance version of the RPB code based on graphic processors for determination of the plasma boundary in tokamaks

The operation of modern tokamaks is impossible without an effective system for controlling the plasma boundary during the discharge. In this paper, we consider a method for determining the plasma boundary on the basis of integral equations. A high-speed parallel code using GPUs was developed for this purpose. Different methods of parallelization of the algorithm have been considered. The possibility of processing the magnetic measurements in real time during experiments is shown. The effect of the technical parameters of GPUs (the number of cores, the data bus width, the amount of internal memory) on the performance is also shown. The simulation results for the T-15MD tokamak, currently under construction at National Research Center Kurchatov Institute, are presented.

Biotechnological Method of Obtaining Nanoparticles of Silver, Cadmium, and Zinc Sulfides. Physico-chemical Characteristics. Creation of Polymeric Nanocomposites

A simple and environmentally safe method for obtaining stable nanoparticles of metal sulfides nanoparticles—NpAg2S, NpCdS, and NpZnS—was developed using different strains of microorganisms in an aqueous solution of metal salts and sulfur sources at the National Research Center Kurchatov Institute—GosNIIgenetika. The concentration of nanoparticles is 1‒4 mg/mL in aqueous suspensions. Using the methods of electron microscopy, spectrofluorimetry, and dynamic light scattering, the main characteristics of biogenic nanoparticles were determined: shape, size distribution, crystal structure, effective diameter, luminescent spectrum, and zeta potential. According to their characteristics, these nanoparticles are referred to quantum dots. It is established that the stability of nanoparticles in aqueous suspensions is due to protein molecules adsorbed on the surface of nanoparticles, which are supplied by cells of microorganisms. Effective immobilization of biogenic nanoparticles on the surface of various polymer supports was carried out. Biogenic nanoparticles along with nanoparticles obtained by physico-chemical methods can be used as fluorophores for imaging of biological processes, also as photocatalysts, solar cells, and for new nanocomposite materials.

Radiation-Induced Phase Formation in Steels of VVER Reactor Pressure Vessels Containing ~0.3–1.3 wt % Nickel

The radiation-induced structural elements in the materials of water-moderated water-cooled reactor pressure vessels have been studied by TEM and atomic probe tomography at the National Research Center Kurchatov Institute. The effect of Ni concentration in the range from 0.34 to 1.28 wt % on the formation of phases under fast neutron irradiation has been analyzed. The volume density of radiation-induced phases has been shown to depend on the Ni concentration in steel; the phase sizes and compositions remain almost the same. The volume density of these precipitations affects the radiation hardening, one of the radiation embrittlement mechanisms. The quantitative parameters of radiation-induced phases have been shown to control the service life growth, the enhancement of the thermal stability, and the melting technology of reactor vessel steels bearing nickel in the 0.3–0.7 wt % range.

Experimental Studies of the Efficiency of Heat-and-Mass Transfer Intensifier Spacer-Grids

Several variants of intensifier grids which have a positive influence on the equalization of the coolant parameters over a section of an assembly as well as on the enhancement of critical heat-emission are proposed for intensifying heat-and mass-transfer in connection with the increase in the power of operating power-generating units with VVER. A large volume of experimental studies of the efficiency of different types of intensifier grids has been conducted at the National Research Center Kurchatov Institute. Among the intensifier grids studied is the developed universal intensifier spacer-grid. The investigations were performed on 37-pin models of VVER-1000 fuel assemblies. The influence of the grid spacing on the critical heat flux was studied. The dependence of the hydraulic resistance of a grid on the size of the deflector was studied. The experimental studies can be used to develop intensifier grids with new designs and to verify computational models and codes.

Additive Technologies for Design of Structural Materials on the Basis of the Nanocenter of the National Research Center Kurchatov Institute—CRISM Prometey

At present, additive technologies which employ metal-powder compositions of various alloys as building materials are in demand. These technologies in some cases represent the only tool during the construction and recovery of bulk products of almost any shape and degree of complexity. In this work, the structure and mechanical properties of the specimens fabricated via selective laser melting from the powders of 12Kh18N10T and 03Kh16N15M3 stainless austenite steels are evaluated.

Cинтез и испытания 1 m-=SUP=-3-=/SUP=- жидкого сцинтиллятора на основе линейного алкилбензола

AbstractThe stability of a liquid organic scintillator based on linear alkylbenzene in a volume of 1 m^3 was measured. The measurements were performed using an iDREAM reactor antineutrino detector at the National Research Center Kurchatov Institute. No systemic degradation of the scintillator light yield within an observation time of 225 days was observed. These long-term stability measurements of a large-volume liquid organic scintillator based on linear alkylbenzene are the first in Russia.