Hasil untuk "Nuclear engineering. Atomic power"

Ángel García-Durán, Antonio Baltazar-Raigosa, José Juan Ortega-Sígala et al.

The use of ionizing radiation sources spans a wide range of applications; however, it inherently entails significant risks. Consequently, gamma-ray spectroscopy has become an essential tool for radionuclide identification, with high-purity germanium (HPGe) detectors representing one of the most suitable options due to their superior energy resolution. Nevertheless, their implementation in educational, training, and laboratory settings faces several limitations, including high cost, the requirement for cryogenic cooling, and the strict regulations governing the handling of radioactive sources. This work presents the development of a high-purity germanium detector simulator embedded in an FPGA. The system was designed not only to reproduce the nuclear pulses that compose the spectra of various radionuclide sources, but also to control the number of simulated pulses as a function of the type of source employed (Cs-137, Co-60, Ba-133, Eu-152, Na-22) and its distance from the detector. In addition, in the absence of a placed source, the simulator generates pulses corresponding to background radiation. The results demonstrated a strong similarity between the simulated and experimental spectra. Furthermore, three calibration procedures, based on energy, time, and distance, yielded correlation coefficients close to unity. The FPGA-based simulator thus constitutes a viable and cost-effective alternative for teaching gamma-ray spectroscopy, effectively overcoming the limitations of purely computational simulations. Its implementation enables the reproduction of calibration exercises, spectrum analysis, and demonstrations of fundamental physical phenomena without the need for real radioactive sources, thereby contributing to training in nuclear instrumentation and the development of accessible educational resources.

Daniil Zhukov

What roles do nuclear weapons play in the national security of Russia in the context of Northeast Asian security dynamics, and how should the regional risks associated with Russia’s nuclear weapons policy be managed? This paper argues that the growing prominence of Russia’s Far Eastern nuclear assets creates additional risks in the tangled ball of relationship threads connecting the key players in Northeast Asia. The Russian Far East houses a significant share of Russia’s strategic and non-strategic nuclear assets, and the region’s importance is set to grow as the role of nuclear weapons in Russia’s foreign and security policy expands following its war against Ukraine. As a direct consequence of the war and the growing animosity toward the United States, Russia seeks greater alignment with China and North Korea and perceives rising threats from the US allies in the region, Japan and South Korea. Meanwhile, regional tensions combine with impending proliferation of long-range strike capabilities to exacerbate risks of conflict and nuclear escalation. The solution to reducing these risks lies through multilateral arms control and risk reduction arrangements, and this paper assesses Moscow’s preferences for such negotiations if the Russian leadership joins them.

Tomi Suomi, Petri Ihantola, Tommi Mikkonen et al.

Agile software development relies on self-organized teams, underlining the importance of individual responsibility. How developers take responsibility and build ownership are influenced by external factors such as architecture and development methods. This paper examines the existing literature on ownership in software engineering and in psychology, and argues that a more comprehensive view of ownership in software engineering has a great potential in improving software team's work. Initial positions on the issue are offered for discussion and to lay foundations for further research.

Bao-An Li

Nuclear symmetry energy $E_{\mathrm{sym}}(ρ)$ encoding the cost to make nuclear matter more neutron rich has been the most uncertain component of the EOS of dense neutron-rich nucleonic matter. It affects significantly the radii, tidal deformations, cooling rates and frequencies of various oscillation modes of isolated neutron stars as well as the strain amplitude and frequencies of gravitational waves from their mergers, besides its many effects on structures of nuclei as well as the dynamics and observables of their collisions. Siemens (1970s) observed that $E_{\mathrm{sym}}(ρ)$ scales as $(ρ/ρ_0)^{2/3}$ near the saturation density $ρ_0$ of nuclear matter, since both the kinetic part and the potential contribution (quadratic in momentum) exhibit this dependence. The scaling holds if: (1) the nucleon isoscalar potential is quadratic in momentum, and (2) the isovector interaction is weakly density dependent. After examining many empirical evidences and understanding theoretical findings in the literature we conclude that: (1) Siemens' $ρ^{2/3}$ scaling is robust and serves as a valuable benchmark for both nuclear theories and experiments up to $2ρ_0$ but breaks down at higher densities, (2) Experimental and theoretical findings about $E_{\mathrm{sym}}(ρ)$ up to $2ρ_0$ are broadly consistent, but uncertainties remain large for its curvature $K_{\mathrm{sym}}$ and higher-order parameters, (3) Above $2ρ_0$, uncertainties grow due to poorly constrained spin-isospin dependent tensor and three-body forces as well as the resulting nucleon short-range correlations. Looking forward, combining multimessengers from both observations of neutron stars and terrestrial heavy-ion reaction experiments is the most promising path to finally constraining precisely the high-density $E_{\mathrm{sym}}(ρ)$ and the EOS of supradense neutron-rich matter.

Filipe R. Cogo, Gustavo A. Oliva, Ahmed E. Hassan

The rapid advancement of AI-assisted software engineering has brought transformative potential to the field of software engineering, but existing tools and paradigms remain limited by cognitive overload, inefficient tool integration, and the narrow capabilities of AI copilots. In response, we propose Compiler.next, a novel search-based compiler designed to enable the seamless evolution of AI-native software systems as part of the emerging Software Engineering 3.0 era. Unlike traditional static compilers, Compiler.next takes human-written intents and automatically generates working software by searching for an optimal solution. This process involves dynamic optimization of cognitive architectures and their constituents (e.g., prompts, foundation model configurations, and system parameters) while finding the optimal trade-off between several objectives, such as accuracy, cost, and latency. This paper outlines the architecture of Compiler.next and positions it as a cornerstone in democratizing software development by lowering the technical barrier for non-experts, enabling scalable, adaptable, and reliable AI-powered software. We present a roadmap to address the core challenges in intent compilation, including developing quality programming constructs, effective search heuristics, reproducibility, and interoperability between compilers. Our vision lays the groundwork for fully automated, search-driven software development, fostering faster innovation and more efficient AI-driven systems.

Yong-ming YANG, Ning GE

14C, a radionuclide, which is widely used in all works of life, such as medical research and determination of PM2.5, has been realized autonomous production in China. It relied on imports, which was expensive and unstable supply in the past time. At present, Qinshan Nuclear Power has started 14C production to completely solve the problem of the serious shortage of 14C independent supply in China. Aluminum nitride powder is the main raw material for the preparation of 14C, whose elemental aluminum directly affects the safety and quality of 14C isotopic targets in nuclear reactors. Aluminum nitride is very stable in an inert high temperature environment. But a lot of elemental aluminum will react with water producing hydrogen in a high temperature environment which can result in the expansion of component rods or it will react with cladding tubes producing hydrogen embrittling effect, and these can affect the quality of 14C isotopic target. According to the characteristic of aluminum nitride insoluble in acid, this study researched different dissolution effect of elemental aluminum in aluminum nitride nano-powder by nitric acid, hydrochloric acid and sulfuric acid. It was found that the above mentioned acid can only dissolve a small amount of aluminum nitride powder, and there was a small amount of aluminum nitride powder suspending in solution, which would seriously interfere the determination of elemental aluminum. At present, microwave digestion, laser ablation, X-ray fluorescence and other methods are used to dissolve or determinate aluminum nitride, but they are not suitable for the determination of elemental aluminum. The determination of elemental aluminum is generally used in pharmaceutical, soil, tea and other samples, but most of the aluminum in the above samples exists as an impurity element, or aluminum is combined with organic matter, which is easy to separate from elemental aluminum. However, it is difficult to achieve complete separation of elemental aluminum(unbound elemental aluminum) and the aluminum nitride matrix in the aluminum nitride powder. This study used replacement reaction to selectively dissolve elemental aluminum. Then the suspended aluminum nitride powder was separated by filter membrane filter. By this method, it could solve the determination interference to elemental aluminum. This study established the determination of elemental aluminum in aluminum nitride nanoparticles by inductively coupled plasma mass spectrometer(ICP-MS), which has the advantages of low determination limit, high accuracy, fast determination speed and small matrix effect. This method’s linear range is 10-100 μg/g and the relative standard deviation is 3.8%(n=6). Using high purity alumina powder to verify the established determination method, the dissolution efficiency can reach 96%-98%.

Taehyun Hwang, Jae-Hwan Kim, Yutaka Sugimoto et al.

This purpose of study is to establish the material database of neutron multiplier for the JA DEMO design. In the previous study, we reported the effects of sintering conditions as temperature and pressure on hardness and sintered density mainly in the sintering temperature from 1050 °C to 1200 °C. In this study, the microstructure observation and compressive tests were carried out. As results of microstructure observations, the pores were almost disappeared, and the grain size increased with increase in sintering temperature. Compression tests were carried out from room temperature (R.T.) to 1000 °C with the samples sintered at 1200 °C. The compressive strength at R.T. was approximately 1.69 GPa. With the increase in testing temperature, there was a tendency for the strength to decrease from 800 °C to 1000 °C. In addition, the load-compressibility indicated that the yield point appears at 850 °C.

Xicheng Wang, Dmitry Grishchenko, Pavel Kudinov

Advanced Pressurized Water Reactors (APWRs) and Boiling Water Reactors (BWRs) employ a suppression pool as a heat sink to prevent containment overpressure. Steam can be discharged into the pool through multi-hole spargers or blowdown pipes in both normal and accident conditions. Direct Contact Condensation (DCC) creates sources of momentum and heat. The competition between these two sources determines the development of thermal stratification or mixing of the pool. Thermal stratification is of safety concern as it reduces the cooling capability compared to a completely mixed pool condition. In this work we develop a scaling approach to prediction of the thermal stratification in a water pool induced by steam injection through spargers. Experimental data obtained from large-scale pool tests conducted in the PPOOLEX and PANDA facilities, as well as simulation results obtained using validated codes are used to develop the scaling. Two injection orientations, namely radial injection through multi-hole Sparger Head (SH) and vertical injection through Load Reduction Ring (LRR), are considered. We show that the erosion rate of the cold layer can be estimated using the Richardson number. In this work, scaling laws are proposed to estimate both the (i) transient erosion velocity and (ii) the stable position of the thermocline. These scaling laws are then implemented into a 1D model to simulate the thermal behavior of the pool during steam injection through the sparger.

Wen Guo, Xiaohu Hou

The action characteristics of power system relay protection devices can well analyze whether the relevant actions are correct. An analysis method of relay protection action characteristics in power system based on fault recording data is designed. After analyzing the relay device structure and protection action characteristics and requirements, the power system relay protection action record data recorded by the fault recorder; The second order RC low-pass filter is used to preprocess the recorded data; The filtered data is input into the analysis model of relay protection action characteristics based on SVM algorithm. The SVM algorithm classifies whether the relay protection action characteristics recorded by the filtered fault recording data meet the expectations, and completes the analysis of power system relay protection action characteristics. The experimental results show that this method can effectively analyze the operation characteristics of power system relay protection, and can accurately check whether the relay protection device can operate correctly.

M. Spieker, S. Almaraz-Calderon

Since its foundation in the 1960s, the John D. Fox Superconducting Linear Accelerator Laboratory at Florida State University (FSU) pursued research at the forefront of nuclear science. In this contribution, we present recent highlights from nuclear structure and reaction studies conducted at the John D. Fox Superconducting Linear Accelerator Laboratory, also featuring the general experimental capabilities at the laboratory for particle-$γ$ coincidence experiments. Specifically, we focus on light-ion induced reactions measured with the Super-Enge Split-Pole Spectrograph (SE-SPS) and the CATRiNA neutron detectors, respectively. Some results obtained with the CeBrA demonstrator for particle-$γ$ coincidence experiments at the SE-SPS are presented. A highlight from the first experimental campaigns with the combined CLARION2-TRINITY setup, showing that weak reaction channels can be selected, is discussed as well.

Nikita V. Kovalev, Alexander M. Prokoshin, Alexander S. Kudinov et al.

The VVER-1000 thermal neutron reactor can operate on mixed uranium-plutonium fuel with a content of reactor-grade plutonium up to 5% with a 100% loaded core. In this case, plutonium burns up to 56% of odd isotopes. The energy potential of such plutonium is very low, and its further use in thermal reactors is impractical. However, such plutonium can be used in fast neutron reactors. The paper presents the results of investigating the possibility for such isotopic plutonium composition to be used in the BN-1200 thermal neutron reactor and its value be increased for the plutonium recycle in the reactor. For this purpose, a precision model of the BN-1200 reactor has been developed using the Serpent Monte Carlo code. The model has been verified against the reference values of the nuclear fuel burnup and breeding ratios. The study has shown that such plutonium can be used in the BN-1200 reactor MOX fuel. Maintaining the operating cycle length requires the plutonium fraction in the MOX fuel to be increased up to 2%. In the BN-1200 reactor, the isotopic composition has been found to improve for the further recycle of plutonium in the thermal reactor, i.e. odd plutonium isotopes increase. The fewer odd plutonium isotopes at the beginning of the BN-1200 operating cycle, the greater their increase. It can be seen as the result of the calculation that plutonium from VVER-1000 spent mixed fuel must be loaded into the BN-1200 reactor at least twice to increase the fraction of odd isotopes to the level of reactor-grade plutonium.

S.A. Hagag, A.E. Kayed, T.K. El-maghraby

Polyphenolic compounds are a natural compounds found in some plants such as fruits, vegetables, coffee, tea, nuts, chocolate, and spices. Curcumin, quercetin, and hesperidin belonging to the polyphenols are characterized by their ability to act as anti-cancer, anti-inflammatory, antimicrobial, and anti-oxidants. On the other hand, nanoparticles may significantly increase the bioavailability of natural products against cancer. Hepatocellular carcinoma (HCC) has a high incidence of cancer diseases, and a high level of mortality. The current study aims to study the possibility of inhibiting the viability of HepG2 cancer cells by using some nano-polyphenolic compounds combined with (or without) small doses of gamma rays. HepG2 cell lines were treated with different doses of nano-curcumin, nano-quercetin, and nano-hesperidin together with2 doses γ-radiations., 2and 5Gy. The viability of the cell line was examined by MTT assay.Real-timetime PCR was used to evaluate the expression of p53, Bax, and Bcl-2 genes. The nano-polyphenolic compounds decreased cell viability in all groups when compared with the control group. Furthermore, nano-compounds increased the expression of p53, and Bax genes, but in Bcl-2 gene expression decreased.The data obtained from the current study revealed that the use of curcumin, hesperidin and quercetin in appropriate doses in their nanoform with gamma rays has an effective effect in killing cancer cells.

QIN Zhi, FAN Fang-li, TIAN Wei et al.

Spent nuclear fuel reprocessing is the key step of the nuclear fuel cycle. It also restricts the sustainable development of nuclear power. With the help of external neutron source in an accelerator driven advanced nuclear energy system(ADANES), spent nuclear fuel reprocessing only needs to remove some volatile fission products and neutron poisons, such as rare elements. Moreover, it is not necessary to separate the long-lived minor actinides Np, Am and Cm finely. These minor actinides can be refabricated as new nuclear fuels together with uranium dioxide for burn, transmutation, breeding, and power production in the accelerator driven advanced nuclear energy system. Based on this, our group proposed a technical route for spent nuclear fuel reprocessing and regeneration of accelerator driven advanced nuclear energy system, including high-temperature oxidation pulverization and volatilization, selective dissolution separation, and fuel regeneration. The recent research of our group is summarized, which has a great significance for implementation of accelerator driven advanced nuclear energy system.

Nigar Demircan Çakar, Seyfettin Erdoğan, Ayfer Gedikli et al.

Global climate change brings environmental quality sensitivity, especially in developed countries. Developed countries use non-renewable energy sources intensively both in their own countries and in other countries, they make productions that cause an enormous rate of increase in CO2 emissions and unsustainable environmental costs. This has increased the interest in environmentally friendly alternative energy sources. The aim of this study is to investigate the impact of nuclear energy consumption and technological innovation on environmental quality in G7 countries using annual data over the period 1970–2015. The Panel Threshold Regression Model was used for the analysis. Empirical findings have indicated that the relationship between nuclear energy consumption and carbon emissions differs according to innovation for nuclear power plants. It was also concluded that nuclear energy consumption reduces carbon emissions more after a certain level of innovation. This result shows that the increase in innovative technologies for nuclear power plants not only increases energy efficiency but also contributes positively to environmental quality.

Y. Shinoda, N. Yamano

Yoshihiko SHINODA and Naoki YAMANO Department of Nuclear Power and Energy Safety Engineering, Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui-shi, Fukui 910-8507, Japan Research Institute of Nuclear Engineering, University of Fukui, 1-2-4 Kanawa-cho, Tsuruga-shi, Fukui 914-0055, Japan Japan Atomic Energy Agency, Tsuruga Head Office, 65-20 Kizaki, Tsuruga-shi, Fukui 914-8585, Japan (Received July 17, 2014; accepted in revised form November 27, 2014; published online March 11, 2015)

Gao-Feng Wei, Xin Huang, Qi-Jun Zhi et al.

Within a transport model, we study effects of the momentum dependence of nuclear symmetry potential on pion observables in central Sn + Sn collisions at 270 MeV/nucleon. To this end, a quantity $U_{sym}^{\infty}(ρ_{0})$, i.e., the value of nuclear symmetry potential at the saturation density $ρ_{0}$ and infinitely large nucleon momentum, is used to characterise the momentum dependence of nuclear symmetry potential. It is shown that with a certain $L$ (i.e., slope of nuclear symmetry energy at $ρ_{0}$) the characteristic parameter $U_{sym}^{\infty}(ρ_{0})$ of symmetry potential affects significantly the production of $π^{-}$ and $π^{+}$ as well as their pion ratios. Moreover, through comparing the charged pion yields, pion ratios as well the spectral pion ratios of theoretical simulations for the reactions $^{108}$Sn + $^{112}$Sn and $^{132}$Sn + $^{124}$Sn with the corresponding data in S$π$RIT experiments, we find that our results favor a constraint on $U_{sym}^{\infty}(ρ_{0})$, i.e., $-160^{+18}_{-9}$~MeV, and the $L$ is also suggested within a range, i.e., $62.7<L<93.1$~MeV. In addition, it is shown that the pion observable of $^{197}$Au + $^{197}$Au collisions at 400~MeV/nucleon also supports the extracted value for $U_{sym}^{\infty}(ρ_{0})$.

Mohamed A. Alzamly, Moustafa Aziz, Alya A. Badawi et al.

We used MCNP6 computer code to model HTR-10 core reactor. We used two types of fuel; UO2 and (Th+Pu)O2 mixture. We determined the critical height at which the reactor approached criticality in both two cases. The neutronic and burnup parameters were investigated. The results indicated that the core fueled with mixed (Th+Pu)O2, achieved about 24% higher fuel cycle length than the UO2 case. It also enhanced safeguard security by burning Pu isotopes. The results were compared with previously published papers and good agreements were found. Keywords: Pebble-bed, HTR-10, Burnup, Thorium based fuel

Morteza Khosravi Mirzaee, A. Zolfaghari, A. Minuchehr

In this part, an implicit time dependent solution is presented for the Boltzmann transport equation discretized by the analytic coarse mesh finite difference method (ACMFD) over the spatial domain as well as the simplified P3 (SP3) for the angular variable. In the first part of this work we proposed a SP3-ACMFD approach to solve the static eigenvalue equations which provide the initial conditions for temp dependent equations. Having solved the 3D multi-group SP3-ACMFD static equations, an implicit approach is resorted to ensure stability of time steps. An exponential behavior is assumed in transverse integrated equations to establish a relationship between flux moments and currents. Also, analytic integration is benefited for the time-dependent solution of precursor concentration equations. Finally, a multi-channel one-phase thermal hydraulic model is coupled to the proposed methodology. Transient equations are then solved at each step using the GMRES technique. To show the sufficiency of proposed transient SP3-ACMFD approximation for a full core analysis, a comparison is made using transport peers as the reference. To further demonstrate superiority, results are compared with a 3D multi-group transient diffusion solver developed as a byproduct of this work. Outcomes confirm that the idea can be considered as an economic interim approach which is superior to the diffusion approximation, and comparable with transport in results. Keywords: Multi-dimensional multi-group neutron transport, Reactor core analysis, Simplified P3 (SP3) equations, ACMFD method, Static and transient analysis, PARCS code, Thermal feedbacks

Pol Bernard Gossiaux

I review the current status and some prospects of theoretical studies on open heavy flavor physics in nuclear collisions at RHIC and LHC energies.

Mohamed Kareem Abdel Rahman AlAshery

Climate change has been identified as one of the greatest challenges facing nations, governments, businesses and citizens of the globe. The threats of climate change demand an increase in the share of renewable energy from the total of energy generation. Meanwhile, there are tremendous efforts to decrease the reliance on fossil fuel energies which opens the venue for increasing the usage of alternative resources such as nuclear energy. Many countries (e.g. Egypt) are planning to meet increasing electricity demands by increasing both renewable (especially wind energy) and nuclear energies contributions in electricity generation. In the planning phase of siting both new Wind Farms (WFs) and Nuclear Power Plants (NPPs), many benefits and challenges exist. An important aspect taken into consideration during the NPP siting is the existence of ultimate heat sink which is sea water in most cases. That is why most NPPs are sited on sea coasts. On the other hand, during WF siting, the main influential aspect is the existence of good wind resources. Many coastal areas around the world fulfill this requirement for WF siting. Coupling both NPPs and WFs in one site or nearby has many benefits and obstacles as well. In this thesis, based on international experience and literature reviews, the benefits and obstacles of this coupling/adjacency are studied and evaluated. Various case studies are carried out to verify the coupling/adjacency concept.