Nuclear Analysis最新文献

This article examines the impact of temperature on the steel collimator cap and the primary beam shutter. These components will be used to implement the Prompt Gamma Activation Analysis (PGAA) technique in the Moroccan TRIGA Mark-II research reactor. The steel collimator plug is essential for forming the neutron beam, while the main role of the shutter is to stop the beam when the channel is inactive. This study analyzes the effect of temperature on the collimator and shutter system, particularly focusing on the variation in maximum temperature over a month of operation with 8-h cycles per day, the behavior of temperature over 24 h, the total heat flux as a function of the length of the experimental device, the temperature distribution in mild steel (E235) and 304L stainless steel materials, and the total displacement and strain gradient as a function of temperature. All calculations were performed using COMSOL Multiphysics simulation software, based on the finite element method.

This study investigates the critical significance of anode material selection in defining the energy spectrum and properties of X-ray photons in medical physics applications. Using the GATE platform and Monte Carlo simulations, a direct relationship between anode material atomic number and photon fluence is demonstrated. As the atomic number increases from Z = 29 (Copper) to Z = 74 (Tungsten), photon fluence rises by 62 %, indicating a substantial impact on X-ray production. Furthermore, the X-ray spectrum is affected by this material-driven changes, revealing a noticeable shift towards higher energy values: the mean energy of the continuous spectrum rises from 46.97 keV for Copper to 49.0 keV for Tungsten. The thermal properties of the material affect the temperature increase at the focal point. Rhodium and Molybdenum have a higher temperature rise than Copper (Cu) and Tungsten (W), because Cu and W have a greater thermal diffusion compared to other materials. These findings underscore the significance of anode material choice in optimizing X-ray systems which may enhance diagnostic accuracy and efficiency in diverse applications.

This study delves into the thermal dynamics induced by an electron beam sourced from the CIRCE III accelerator, focusing on a lead target previously employed at the National Centre for Nuclear Science and Technology (CNSTN) in Tunisia for neutron and photon production. Leveraging FLUKA software, we simulate the intricate interplay between electrons and the target surface, analyzing variations in deposited energy across different target thicknesses. Beyond elucidating the electron-target interaction, our investigation extends to predicting crucial parameters such as the maximum operational threshold and surface temperature distribution of the target. To achieve this, a computational model harnessing the finite volume method is employed, offering insights into the thermal response dynamics and paving the way for optimized operational protocols and target design refinements. Through this comprehensive analysis, we aim to advance the understanding of thermal phenomena in electron-target interactions, thereby bolstering the efficiency and safety of particle accelerator operations in diverse scientific applications.

The purpose of this study is to provide a new deterministic model for the SLOWPOKE-2 nuclear research reactor at École Polytechnique de Montréal (EPM) with LEU (Low Enriched Uranium) core. Using the latest release of the code system DRAGON5 and DONJON5 and the cross-section data library ENDFB.VII rel.1 evaluation, the developed model is applied to simulate the neutronic behavior of the SLOWPOKE-2 research reactor. We studied the separate temperature effects of the main components of the core (i.e., fuel, coolant/moderator, beryllium reflector, and water reflector). The contribution of different physical phenomena to the RTC was assessed. The temperature reactivity feedback calculated using the deterministic approach based on the DRAGON5 and DONJON5 code system using the ENDF/B-VII.1 evaluated nuclear data library produced in the WIMD-D4 format is in good agreement. Therefore, this work proves the capability of DRAGON5 and DONJON5 codes, normally used for power reactors, to reliably simulate a low-power research reactor.

Morocco's exploration of nuclear energy aligns with both climate goals and national energy ambitions, offering a promising low-carbon alternative to conventional fossil fuels. Despite the nation's significant strides in renewable energy, nuclear power remains understudied, revealing a critical literature gap. This research underscores the global imperative to transition to net-zero emissions and the pivotal role nuclear energy plays in addressing climate change. Within the context of Morocco's 2030 plan, which prioritizes renewable energy, nuclear energy stands as an underexplored aspect, lacking comprehensive research. To bridge this gap, the study employs a PESTLE analysis to examine the political, economic, societal, technological, legal, and environmental factors influencing Morocco's nuclear energy landscape. The integration of insights from various sources, including press releases, reports, and scientific publications, ensures a holistic and well-informed perspective on Morocco's nuclear industry. The paper concludes by providing an overview of nuclear energy use on different scales, accompanied by a detailed discussion of the PESTLE analysis outcomes. This approach seeks to contribute valuable insights for informed decision-making and strategic planning in the realm of nuclear energy development.

With the aim of removing ⁹⁹Mo from radioactive wastewater, a metal-organic framework Zr-MOF and its functionalized derivatives (Zr-MOF-SO₄ and Zr-MOF-C₂O₄) were prepared as adsorbents, and characterized by SEM, XPS and FI-IR. The results showed the –SO₄ and –C₂O₄ groups were successfully loaded onto the surface of the original Zr-MOF; the obtained Zr-MOF-SO₄ and Zr-MOF-C₂O₄ presented different morphologies as small pellets. Both exhibit high adsorption efficiency and fast adsorption rates due to their abundant –SO₄ and –C₂O₄ surface groups, that provide many adsorption sites for Mo(VI). The maximum adsorption capacities for Mo(VI) of Zr-MOF-SO₄ and Zr-MOF-C₂O₄ are 192.5 mg g⁻¹ and 432.3 mg g⁻¹, respectively, which is an improvement over other similar adsorbents. In addition, thermodynamic studies indicate a spontaneous exothermic mechanism for the adsorption process. These results demonstrate that anchoring of the functionalized groups is a good way to improve Mo(VI) adsorption capacity of MOF materials.

Traditionally, the determination of isotope ratios is analyzed by mass spectrometry (MS) method, which is usually destructive to sample (i.e., sample dissolution). Furthermore, the ⁵⁸Fe abundance (0.282%) is generally rather low relative to other Fe isotopes, therefore, ⁵⁸Fe/⁵⁴Fe results is not reported in the routine measurement for MS methods. Given the importance of investigating a possible genetic relationship between the stable isotope composition of the Moon and the Earth, here, we firstly report the isotope ratios of ⁵⁸Fe/⁵⁴Fe in the Chang’E-5 (CE-5) scooped bulk lunar sample. In this work, the ⁵⁸Fe/⁵⁴Fe ratios were analyzed by instrumental neutron activation analysis (INAA) which is essentially distinguished and a potentially complementary advantage for MS in the determination of stable isotope ratios. These data obtained for the CE-5 lunar sample were also compared with those of terrestrial sample GBW07105.

Low dose rate gamma irradiation blackening effect of organotin catalyzed silicone adhesive is presented. When the total dose accumulated to 350 kGy at low dose rate (0.03 Gy/s), there is a significant blackening of the color changing from transparent to black by the increasing of dose, which is simultaneously deepened by the decreasing of dose rate. That is, low dose rate and accumulated dose both affect the final color of silicone adhesive. The structure changes of silicone adhesive before and after blackening are characterized by UV–vis, FTIR, and SPME-GC-MS, and the mechanism of blackening is deduced to be related to the content of SnO.

Providing sufficient energy in emergency situations in nuclear power plants is of great importance due to their crucial role in improving power plant safety and eliminating disasters.

Solar power is capable of providing a secure energy source which could be used for emergency power loads. The main goal of this study is application of solar energy for providing emergency loads of the Tehran research reactor. A 100 kW solar power plant connected to the grid and 400 kWh battery pack which is capable of providing 50 kw loads for 8 h is designed. As the first priority, the plant charges the battery pack and discharges excess energy to the power grid. Therefore, the proposed scheme, in addition to increasing safety, also has economic benefits. Design procedure of the power plant was carried out using PVsyst which is international well known software for designing solar power plants and results were investigated. Economic evaluation of the project is carried out using RETSCREEN software and different schemes are evaluated. Due to the critical nature of the power loads and their sensitivity, application of this scheme for providing emergency energy loads of the Tehran research reactor is suggested. Considering the expansion of nuclear safety and the protection of the environment and humanity, we request the respected editors and reviewers of the journal to have positive opinions about the publication of the article.

In order to describe the behavior of finite fission chains in a fission system initiated by a δ neutron source, we present the conception of the finite fission chains group (FFCG). The group is the collectivity of the fission chains initiated by plenty of neutrons at the same time. Based on the result of the solving generating function, we deduced the lifetime distribution formula of FFCG based on the point kinetics model. Finally, the formula is validated by the experiment with a single pulse neutron source in CFBR-Ⅱ.