Advanced Materials Research Vol. 1084

Abstract: The measurements of X-ray polarization’s bremsstrahlung in the back scattering geometry (PBBS) generated during the interaction of 7 MeV electrons with polycrystalline foils of copper and niobium were performed. The analysis has shown a good agreement of the spectral width and position of the peaks with the theoretical calculations. The obtained results confirm the availability to develop a new method based on the PBBS peaks measurements for diagnostics of materials with a polycrystalline atomic structure.

Abstract: This work considers the existing approaches and devices for the composition analysis of multiphase medium are considered. A new technique for analyzing three-phase mediums based on the wave dispersive analysis of radiation is proposed. The fluxes of a multiphase fluid, composite materials, etc. can act as the mediums. Preliminary estimates show that the sensitivity is about 0.25% of the oil content in water and 1% of the content of gas.

Abstract: A resonant microwave pulse compressor with a waveguide H-tee-based interference switch has been studied for its capability to produce output pulses with adjustable power, energy, waveform, and carrier frequency. Output radiation characteristics are controlled by the variation of transition attenuation of the unit of microwave energy extraction. Results of theoretical estimations of the parameters tuning range and experimental investigations of the S-band compressor are presented. The possibility of forming combined pulses comprising a microsecond prepulse and nanosecond main pulse of comparable energies has been demonstrated. It has been shown that such pulses can be applied for finding criteria levels of impact on electronics of a personal computer.

Abstract: The compressor contains the oversized cylindrical cavity with two interference output units each in the figure of a circular waveguide H-tee. The H-tees are coupled by a waveguide section and the energy is extracted synchronously through two output ports. The synchronism is provided through using a single microwave switch mutual for both H-tees. Simulation and experimental study of the X-band microwave compressor were carried out. The simulation made it possible to optimize the configuration of the oversized storage cavity and the output element. The amplification factor was 14 dB when the energy was extracted though one output unit at the output pulsewidth of 6...7 ns. Amplification factor and the output power were increased by 2dB and the pulsewidth was decreased down to 3...3.5 ns when the energy was extracted synchronously through two output units.

Abstract: Evaluations for possible using of superconducting materials in high power microwave generators based on the method of the resonant microwave compression were made. As an example the relationship between the power amplification factor and frequency was determined for superconducting rectangular cavities. Capabilities of superconducting cavities as energy accumulators were analyzed. Microwave power value required for feeding superconducting accumulator is estimated. Experimental results of storing and extracting the energy in superconducting cavities are presented.

Abstract: The explanation of the effects which were found earlier in numerical simulation of parameters of open thorium-plutonium nuclear fuel cycle has been offered. Scientific and technical solutions allow considering the possibility of including thorium-232 in the fuel of nuclear reactors, which are based on existing design solutions, and beginning to design of new generation materials: a new generation of fuel rods and fuel assemblies, where the isotope uranium-238 will be completely replaced with thorium-232.

Abstract: The article considers the dynamics of the changes in the intensity and shape of the angular distributions of the backward transition radiation and quasi-monochromatic radiation emitted by the periodic structure of a multilayer mirror in a vacuum ultraviolet region for electrons with the energy of 5.7 MeV, depending on the orientation of the target. It has been shown that the dynamics of the changes in the intensity and shape of the angular distributions of the backward transition radiation and those of the periodic structure radiation observed after directing the radiation through an absorption edge filter display opposite tendencies. These opposite tendencies may be used as an indicator in the experiments aimed at detecting the effect of the periodic structure radiation in the ultraviolet region of the analog of parametric X-ray in crystals.

Abstract: This work considers conceptual approaches to handling fuel irradiated in thermal reactors in technical “dry storage” systems. The experiments carried out in the work allow for improving the ecological, nuclear and radiation safety systems of storage and transportation of irradiated nuclear fuel for new generation reactors.

Abstract: This paper presents the results of a numerical calculation of beryllium poisoning of an IRT-T reactor and its effect on the excess reactivity and neutron flux density in the beam ports. Also, the prediction of ⁶Li and ³He poison concentrations in the beryllium reflectors of the IRT-T reactor is presented. The results are based on MCU Monte Carlo calculations. The part of reactor history was taken into account to predict reliable values of parasitic isotope concentrations. The impact of shut-down time and operating time on the excess reactivity is shown. The results presented in this paper could be used to perform the safety analysis of an IRT-T reactor.

Abstract: This work assesses real graphite lifespan distribution of pressurized-tube reactors (RBMK) with graphite moderator. The changes in heat exchange and heat transfer conditions were taken into consideration, which changes are induced by the thermal properties’ degradation and the changes in the form of structural elements. Besides, some features associated with the differences in the neutron flux spectrum and differences in characteristics of gamma radiation field in the fuel and in the channels of control and protection system (CPS) were all taken into account.