Laws of the oxidation of carbon isotopes in plasma processes under magnetic field

From law of quantum mechanics it follows that spin precession phase of unpaired electron in external magnetic field cannot be determined. It uncertainty necessary take into account in different physical and chemical processes. The expression of the rate constant of a chemical reaction based on the number of discrete spin states was obtained. The equations of chemical kinetics of plasma oxidation of carbon isotopes in the magnetic field were given

Automation of the Monitoring System for Surface Contamination with α-Active Radionuclides

The paper presents research on radiation control at nuclear enterprises working with [alpha]-active radionuclides. The focus of the research is on the registration of 239Pu radionuclides on hands surface. The experimental results show the possibility to create a turnstile for automatic monitoring the presence of α-active radionuclides on hands. Such a device can be used with a minimum helium consumption of 66 liters per hour in a measuring chamber with an open bottom of 5.4 liters

Registration of a Laser Beam Scattered from an Aerosol Located in the Probe Beam Aperture

An experimental setup has been developed that allows recording the flux of probing radiation scattered from dispersed particles in the 0° direction. To suppress the beam passing through the swarm of dispersed particles a reference beam was used. The reference beam was formed from the probe beam and aligned in the registration plane with the beam passing through the swarm of particles. The Michelson interferometer was tested in an experimental setup to determine the sizes of dust particles of heterogeneous systems. It was shown that by placing a heterogeneous system in one of the arms of the interferometer, it was possible to register the scattered radiation at the angle 0°. This facilitates calculation of the sizes of particles with the same accuracy over the entire size range. To verify the method the iron powder particles sized 50-63 [mu]m were used

Nanoparticle Formation in a Mixture of Fe, C, O[2] in Low-temperature Plasma in a Magnetic Field

The paper presents the results of researching a magnetic field influence on the formation of dispersed particles from the mixture of Fe+C+N[2]+Ar+O[2] at the temperature of more than 4000K. To optimize the composition of the plasmaforming gas, thermodynamic modeling was performed. The research establishes that an external magnetic field has a significant effect on the formation of a dispersed phase in the mixture of carbon and iron vapor. For example, in a powder obtained without a magnetic field, X-ray diffraction shows up to 95% C. In a powder obtained in the magnetic field of 15 mT, C (up to 50%), Fe[3]O[4] (up to 45%), Fe[2]O[3] (up to 15%), and FeO (less than 5%) are recorded. The observed results are explained by the coagulation of nanoparticles in the magnetic field

Formation of the gas flow in the plasma-chemical reactor

The relevance of the discussed issue is caused by the need to optimize the geometry of the plasma-chemical reactor to increase the isotope effects. The main aim of the study is the search for the optimal geometry of plasma-chemical reactor, which provides high-localization of the plasma flow in the axial region for increasing isotope effects by reducing the back diffusion effect, leading to equalization of isotope concentration. The methods used in the study: calculation and optimization of the gas flow within the plasma-chemical reactor by the unsteady Navier? Stokes equations and Fourier by the method of finite-difference components using ANSYS Fluent. The results. The authors explained the mechanism of isotopic concentration change in the products of plasma-chemical reactions due to the spin separation of carbon isotopes in a nonequilibrium low-temperature plasma in a magnetic field. An analysis of the processes occurring inside the plasma-chemical reactor of constant width was carried out. It is expected that the reduction of isotope effects is associated with the oxidation of the dispersed phase, which is located on the reactor walls. A method and apparatus for limiting the contact area of the high-temperature plasma flow with the walls of the chamber was proposed. Calculation of gas flows inside the plasma-chemical reactor of the selected geometry was carried out. It is shown that for the contraction of high temperature gas flow in the central region and isolating it from the walls of the plasma reactor can be used thin diaphragm of temperature-resistant material. It was also shown that the wall temperature of the plasma-chemical reactor in the region between the diaphragms does not exceed the evaporation temperature of the dispersed phase in some plasma gas flow. The highest possible isotope effect which occurs in the processes of plasma in a magnetic field is largely retained

Particularities of Cu and Zn nanoparticles formation in a magnetic field

We studied experimentally the condensation of Zn and Cu vapors from a high-temperature gas in an external weak constant magnetic field. We observed at all applied conditions, a chaotic time shift of the maximum of the size distribution function of dispersed particles. Simultaneously, a decrease in the width of the size distribution function of dispersed Zn particles from 40 nm (0 mT) to 10 nm (44 mT or 76 mT) was observed. The sizes of Zn particles were determined by laser probing. The sizes of dispersed Cu particles, determined by analyzing a substrate sample, were in the range of 10-400 nm without a magnetic field, and the range 30-320 nm in a magnetic field of 30 mT. The authors explain the observed results by arranging the dynamics of the spin pair of unpaired electrons of an atom from the gas phase and of an atom on the surface of a condensed particle in a magnetic field. Therefore, in a magnetic field, when an atom collides with a dispersed particle or condensation nucleus, the probability of creation of a singlet pair of spins of unpaired electrons is higher than that without a field

Automation of the monitoring system for surface contamination with [alpha]-active radionuclides

The paper presents research on radiation control at nuclear enterprises working with [alpha]-active radionuclides. The focus of the research is on the registration of 239Pu radionuclides on hands surface. The experimental results show the possibility to create a turnstile for automatic monitoring the presence of [alpha]-active radionuclides on hands. Such a device can be used with a minimum helium consumption of 66 liters per hour in a measuring chamber with an open bottom of 5.4 liters

Formation of the gas flow in the plasma-chemical reactor

Актуальность работы обусловлена необходимостью оптимизации геометрии плазмохимического реактора для увеличения изотопных эффектов. Цель работы: поиск оптимальной геометрии плазмохимического реактора, обеспечивающего локализацию высокотемпературной части плазменного потока в осевой области для увеличения изотопных эффектов за счет снижения эффекта обратной диффузии, приводящей к выравниванию изотопной концентрации. Методы исследования: расчеты и оптимизация газовых потоков внутри плазмохимического реактора путем решения нестационарных уравнений Навье-Стокса и Фурье методом конечно-разностных элементов при помощи пакета ANSYS Fluent. Результаты. Объяснен механизм изменения изотопной концентрации в продуктах плазмохимических реакций за счет спиновой сепарации изотопов углерода в низкотемпературной неравновесной плазме, помещенной в магнитное поле. Проведен анализ процессов, происходящих внутри плазмохимического реактора постоянный ширины. Предположено, что уменьшение изотопных эффектов связано с окислением дисперсной фазы, находящейся на стенках реактора. Предложены способ и устройство для ограничения площади контакта высокотемпературного плазменного потока со стенками камеры. Проведен расчёт газовых потоков внутри плазмохимического реактора выбранной геометрии. Показано, что для контрагирования высокотемпературного газового потока в центральной области и изолирования его от стенок плазменного реактора можно использовать тонкие диафрагмы из жаростойкого материала. Также было доказано, что при некоторых расходах плазмообразующего газа температура стенок плазмохимического реактора в области между диафрагмами не превышает температуру испарения дисперсной фазы. При этом в значительной мере сохраняется максимально возможный изотопный эффект, возникающий в плазменных процессах в магнитном поле.The relevance of the discussed issue is caused by the need to optimize the geometry of the plasma-chemical reactor to increase the isotope effects. The main aim of the study is the search for the optimal geometry of plasma-chemical reactor, which provides high-localization of the plasma flow in the axial region for increasing isotope effects by reducing the back diffusion effect, leading to equalization of isotope concentration. The methods used in the study: calculation and optimization of the gas flow within the plasma-chemical reactor by the unsteady Navier? Stokes equations and Fourier by the method of finite-difference components using ANSYS Fluent. The results. The authors explained the mechanism of isotopic concentration change in the products of plasma-chemical reactions due to the spin separation of carbon isotopes in a nonequilibrium low-temperature plasma in a magnetic field. An analysis of the processes occurring inside the plasma-chemical reactor of constant width was carried out. It is expected that the reduction of isotope effects is associated with the oxidation of the dispersed phase, which is located on the reactor walls. A method and apparatus for limiting the contact area of the high-temperature plasma flow with the walls of the chamber was proposed. Calculation of gas flows inside the plasma-chemical reactor of the selected geometry was carried out. It is shown that for the contraction of high temperature gas flow in the central region and isolating it from the walls of the plasma reactor can be used thin diaphragm of temperature-resistant material. It was also shown that the wall temperature of the plasma-chemical reactor in the region between the diaphragms does not exceed the evaporation temperature of the dispersed phase in some plasma gas flow. The highest possible isotope effect which occurs in the processes of plasma in a magnetic field is largely retained

Possibility of using clay-based barrier materials for localizing the consequences of radiations accidents (for example, the Fukushima Daiichi NPP)

Актуальность работы обусловлена необходимостью выбора эффективных подходов и новых инновационных барьерных материалов, обладающих противофильтрационными и противомиграционными свойствами, для локализации последствий аварий на радиационно опасных объектов. Цель: обзор возможности использование отечественных технологий по локализации радионуклидов внутри пунктов размещения радиоактивных отходов и ядерных материалов (кориума) для решения проблемы миграции радионуклидов на АЭС "Фукусима-Дайити". Методы: математическое моделирование процесса миграции радионуклидов из разрушенных энергоблоков атомной электростанции "Фукусима-Дайити" (АЭС "Фукусима-Дайити") через глиносодержащие барьеры безопасности. Результаты. Рассмотрена возможность использования барьерных материалов для локализации последствий радиационных аварий. На основе положительного отечественного опыта предложено использование барьеров безопасности на основе глинистых композиций и гелеобразующих растворов для предотвращения подземной миграции радионуклидов из разрушенных энергоблоков в окружающую среду. В качестве примера такой ситуации выбрана произошедшая 11 марта 2011 г. авария на АЭС "Фукусима-1", которая в настоящее время является объектом для отработки технологий и подходов ликвидации аварий. В работе описаны основные источники радиоактивного загрязнения, образованные в результате аварии на АЭС "Фукусима-Дайити" и распространяющиеся грунтовыми водами, дождевыми потоками и охлаждающей водой, которую закачивают в поврежденные активные зоны. Выявлены недостатки использующейся системы барьеров безопасности, основанной на заморозке грунтов. На основе положительного отечественного опыта предложено использование глиносодержащих барьеров безопасности для предотвращения миграции радионуклидов из разрушенных энергоблоков в океан. Для этих целей рассмотрены такие природные материалы, как вермикулит, перлит, цеолит, шунгит, и определены их сорбционные характеристики. Представлены результаты математического моделирования процесса миграции наиболее мобильных радионуклидов (Pu, Cs, Sr, U) через барьерные материалы из глины. Показана возможность использования барьера безопасности на основе смеси глин. При этом ширина такого барьера не превышает 3,7 м (определяется скоростью миграции урана). Общий объем глиносодержащего барьерного материала, необходимого для предотвращения миграции радионуклидов, составляет ~145900 м3 . Для замедления миграции трития предложен противофильтрационный барьер на основе гелеобразующего раствора. В качестве геля возможно использование специальных растворов, содержащих продукты разложения геологических пород ийолитуртитовой группы. В результате разложения в растворе образуются щелочноземельные, переходные и щелочные элементы, ионы Al и H4SiO4. Предлагается использовать указанный гель путем его инжекции вокруг энергоблоков АЭС "Фукусима-Дайити". Это позволит полимеризировать ортокремневую кислоту, что приведет к адсорбции катионов Ca, Mg, Fe и гидратированного алюминия.The relevance of the research topic is caused by the need to develop new innovative barrier materials with anti-filtration and anti-migratory properties to localize the consequences of the disaster at the Fukushima Daiichi NPP. The main aim of the study is the review of the possibility of using domestic technologies for localization of radionuclides inside the points of placement of radioactive waste and nuclear materials (corium) to solve the problem of migration of radionuclides at the Fukushima-Daiichi NPP. Methods: mathematical modeling of radionuclides migration from the active zone of the destroyed power units of the Fukushima Daiichi NPP through clay-containing safety barriers. The results. The paper presents the results of consideration of possibility of using barrier materials for localizing the consequences of radiations accidents. Using the safety clay-based barriers and gelling solutions to prevent the underground migration of radionuclides from destroyed power units to environment was suggested according to positive domestic experience. Accident on nuclear power plant Fukushima-1, occurred on 11 March 2011, was chosen as an example of such a situation. Currently this object is the area for working out the technology and approaches to eliminate the radiation accidents. It was shown that the inflow of radioactive contamination into the ocean is caused by groundwater, rainwater and cooling water, which is daily pumped into the damaged core. Disadvantages of the system used by the safety barrier based on ground frosts were described. On the basis of positive domestic experience, the use of clay-containing safety barriers was proposed to prevent migration of radionuclides from destroyed power units to the ocean. Clay-content materials based on vermiculite, perlite, zeolite, schungite and their sorption characteristics were determined for these purposes. The results of modeling the migration of the most active radionuclides (Pu, Cs, Sr, U) through the described barrier materials were presented. The possibility of using the safety barrier based on a mixture of clays was shown. The width of such a barrier does not exceed 3,7 m (determined by the rate of migration of uranium). The total volume of clay-based material barrier required to prevent migration of radionuclides is ~145900 m3