Reaction Engineering Research Articles

Monte Carlo Simulations of the Interaction of 55Mn with 14.7-MeV Protons Produced by D+3He Fusion Reaction

The global energy crisis and climate change pose significant challenges for the future of humankind. To address these issues, clean energy sources are being promoted, with nuclear energy being an effective solution. The development of fission reactors and the promising advancements in fusion reactor technology provide potential solutions. However, challenges related to security and costs remain. This study focuses on the interaction between 55Mn and protons at 14.7 MeV using Monte Carlo simulations. Various Monte Carlo codes, including TALYS-1.96, GEANT4 (for GEometry ANd Tracking), PHITS-3.31 (for Particle and Heavy Ion Transport Code System), SRIM-2013 (for Stopping and Range of Ions in Matter), and ATIMA v1 41 (for ATomic Interaction with MAtter), were employed to investigate different interaction mechanisms. The research aims to understand the impact of these interactions on reactor performance, particularly in the context of the fusion facility. Manganese-containing steels play a crucial role in enhancing efficiency, durability, and safety in fusion reactors. The findings contribute to ongoing research and development activities in the field of nuclear energy.

From Chooz to the Ling’ao NPP: The Technology Transfer of Pressurized Water Reactor Technology from France to China

From Chooz to the Ling’ao NPP: The Technology Transfer of Pressurized Water Reactor Technology from France to China

Protocell Flow Reactors for Enzyme and Whole-Cell Mediated Biocatalysis.

The design and construction of continuous flow biochemical reactors comprising immobilized biocatalysts have generated great interest in the efficient synthesis of value-added chemicals. Living cells use compartmentalization and reaction-diffusion processes for spatiotemporal regulation of biocatalytic reactions, and implementing these strategies into continuous flow reactors can offer new opportunities in reactor design and application. Herein, the fabrication of protocell-based continuous flow reactors for enzyme and whole-cell mediated biocatalysis is demonstrated. Semipermeable membranized coacervate vesicles are employed as model protocells that spontaneously sequester enzymes or accumulate living bacteria to produce embodied microreactors capable of single- or multiple-step catalytic reactions. By packing millions of the enzyme/bacteria-containing coacervate vesicles in a glass column, a facile, cost-effective, and modular methodology capable of performing oxidoreductase, peroxidase and lipolytic reactions, enzyme-mediated L-DOPA synthesis, and whole-cell glycolysis under continuous flow conditions, is demonstrated. It is shown that the protocell-nested enzymes and bacterial cells exhibit enhanced activities and stability under deleterious operating conditions compared with their non-encapsulated counterparts. These results provide a step toward the engineering of continuous flow reactors based on cell-like microscale agents and offer opportunities in the development of green and sustainable industrial bioprocessing.

Integrating challenge-based learning and design thinking in a course of reaction engines for aerospace

This study presents an approach to aerospace engineering education based on the integration of challenge-based learning (CBL) and design thinking in a course on reaction engines. The paper describes how this approach addresses the evolving demands of the aerospace sector, particularly the need for sustainable propulsion systems. It provides a sistematic analysis, starting with a literature review that establishes some foundational understanding of CBL and design thinking while highlighting their importance in fostering problem-solving and critical thinking skills among engineering students. The main body of the paper explores the practical application of these methodologies in an aerospace course. It details a series of sessions designed to provide students with basic understanding of sustainable ideas in reaction engines. These sessions encourage students to engage in critical thinking and collaborative problem-solving, aligning with real-world environmental concerns in aerospace propulsion. In addition, we present the students` feedback concerning the classroom sessions based on a semi-structured interview technique to assess the effectiveness of the teaching approach. The feedback, analyzed from these interviews, indicates a positive reception of CBL and design thinking. Students appreciated the interactive nature of the sessions and the emphasis on real-world problem-solving. However, challenges such as balancing theoretical and practical aspects, pacing, and providing clear guidelines were noted for future improvement. The study emphasizes the need for ongoing adaptation and iteration of teaching methodologies, informed by regular student feedback, to ensure their effectiveness in preparing students for future challenges in the aerospace sector.

Radiation shielding properties of composites of TiZrNbHfTa refractory high entropy alloy reinforced with TiZrNbHfTaOx high-entropy oxide

Radiation shielding materials play a critical role in advancing the next generation of nuclear reactors. Among these, high-entropy materials with refractory properties emerge as a new category for radiation shielding applications. This study introduces TiZrNbHfTa-TiZrNbHfTaOx composites tailored for such purposes. Initially, a TiZrNbHfTa refractory high-entropy alloy (RHEA) is synthesized via mechanical alloying, followed by the oxidation of the alloy to obtain its refractory high-entropy oxide (RHEO), TiZrNbHfTaOx. Composites are then prepared by blending 5%, 10%, and 20% weight fractions of RHEO with RHEA using mechanical alloying. Comparative analysis of shielding properties reveals a decrease in mass attenuation coefficient and effective atomic number with increasing RHEO content. While RHEA exhibits superior shielding performance against gamma photons and neutrons, the composite containing 20% RHEO emerges as the optimal shield against alpha and proton irradiations. The equivalent neutron dose rate and removal cross-section values are obtained 49.8% and 0.142 for the composite with 20% RHEO, respectively. These findings, supported by computational simulations in this study, contribute valuable insights for the advancement of novel shielding materials crucial for future nuclear reactor technologies.

Survey Analysis of Potential Nuclear Safety Research of Thailand for International Research Collaborative Reinforcement in the 2020s

Abstract To achieve the long-term challenge of nuclear energy public acceptance in Thailand, nuclear safety research needed to be properly determined in both domestic and international directions, especially in the 2020s which was a period passing the Fukushima disaster over 10 years. Thailand Institute of Nuclear Technology (TINT) has studied nuclear safety research after the Fukushima accident to answer technical and social issues of nuclear power. An update of nuclear safety research from domestic experts and international surveys was needed in order to identify potential collaborative research to serve the goal of public acceptance reinforcement. The objective of this study was to survey, assess and rank the importance and knowledge level of nuclear safety research in Thailand among domestic experts in various fields. The survey was extended to collect the opinion of international participants of the ASEAN Network on Nuclear Power Safety Research (ASEAN NPSR) to analyze the similarity of the nuclear research interest for reinforcing the future collaborative project. As a result, the importance and knowledge level showed diverse important research topics with the priority of research scopes on human factor novel reactor technologies, and risk assessment. According to the ASEAN NPSR survey, the nuclear safety research of severe accidents, risk assessment, and novel reactor technologies were listed as potential collaborative projects. Also, the domestic and ASEAN NPSR survey results helped support the new collaborative research extension session in the annual ASEAN NPSR meeting to together discuss the potential nuclear safety research between members for the 2020s.

Feasibility of Converting NuScale SMRs from UO2 to Mixed (Pu,Th)O2 and (U,Th)O2 Cores: A Parametric Study of the Seed-Blanket Fuel Assembly

The article proposes to implement the concept of seed-blanket in SMRs (Small Modular Reactors), providing a comparative analysis of NuScale in terms of the seed-blanket. This comparison reveals variations in its performance and operational characteristics, such as thermal conductivity and temperature management. The integration of uranium and thorium fuel cycles in SMRs, particularly with the inclusion of plutonium in some designs, is seen as a key advancement for sustainable nuclear technology. Thus, the research compares various fuel element configurations, including those combining (U,Th)O2 and (Pu,Th)O2, and the specific design of the NuScale element. These designs highlight the diversity and robustness of fuel elements, offering customized solutions for different reactor needs, thereby improving the safety and effectiveness of nuclear reactors. The results obtained show high conversion rates and sustainable reduction with the self-shielding effect, providing a comprehensive analysis of advances in nuclear reactor technology, focusing on the role of innovative fuel elements in improving operational efficiency, safety, and sustainability in the nuclear energy sector.

Photothermal CO2 Catalysis toward the Synthesis of Solar Fuel: From Material and Reactor Engineering to Techno-Economic Analysis.

Carbon dioxide (CO2), a member of greenhouse gases, contributes significantly to maintaining a tolerable environment for all living species. However, with the development of modern society and the utilization of fossil fuels, the concentration of atmospheric CO2 has increased to 400ppm, resulting in a serious greenhouse effect. Thus, converting CO2 into valuable chemicals is highly desired, especially with renewable solar energy, which shows great potential with the manner of photothermal catalysis. In this review, recent advancements in photothermal CO2 conversion are discussed, including the design of catalysts, analysis of mechanisms, engineering of reactors, and the corresponding techno-economic analysis. A guideline for future investigation and the anthropogenic carbon cycle are provided.

Shock tube and comprehensive kinetic modeling study of ammonia/diethyl ether (DEE) mixtures

Ammonia (NH3) is a promising alternative clean fuel due to its carbon-free and high hydrogen content, along with the well-established infrastructure for storage and distribution. To overcome the issue of the low reactivity of NH3, a feasible strategy is co-burning ammonia with highly reactive fuels. Diethyl ether (DEE) is considered a promising alternative and biomass-oxygenated clean diesel substitute. Therefore, the NH3/DEE blend is also a promising carbon neutral alternative fuel. In this work, we measured the ignition delay times (IDTs) of NH3/DEE mixtures with DEE fractions (XDEE) of 0.05, 0.10, 0.30, and 1.00 at equivalence ratios of 0.5, 1.0, and 2.0, pressures of 1.75 and 10 bar, and temperature ranges from 1102 K to 1673 K in a shock tube. The DEE-NH3 model was proposed in this work, which included the DEE sub-model, NH3 sub-model, and some new cross-reactions between N-containing species and C-containing species. The DEE sub-model from Shrestha et al. (Fuel Communications, 2022) was modified in this work, NH3 sub-model was from our previous work (Reaction Chemistry & Engineering, 2023). The DEE-NH3 model was extensively validated by the IDTs, laminar flame speeds (LFSs), and species profiles (SPs) of NH3/DEE mixtures as well as pure DEE and NH3. The comparison of the prediction performance between the DEE-NH3 model and the Shrestha model was conducted for the ignition, flame propagation, and NH3 consumption. The effects of the cross-reactions on the NH3/DEE ignition and combustion were studied in detail.

A revisit from CVD kinetics to CVD reactor: Investigating uniform growth mechanism of polysilicon in a reduction furnace

The uniform growth of polysilicon rods is essential for CVD process in the reduction furnace. Considering the complex interaction of CVD reaction and transport phenomena, the reaction engineering analysis of CVD reaction has been investigated and the requirements for the design and operation of CVD reactor are proposed concerning temperature and species concentrations. Based on the numerical simulation of CVD process in a reduction furnace with 12 pairs of rods, the non-uniform deposition is mainly attributed to the mismatching between the TCS transportation and consumption. Moreover, two measures have been attempted. One is to enhance axial mixing by increasing inlet velocity and the other is to reduce TCS consumption by reducing inlet TCS mole fraction and heat flux at the rod surface. Both measures have been confirmed beneficial for the uniform growth of the polysilicon rods.

The role of the NPT in preventing further proliferation of nuclear weapons

The entire atmosphere created by the Treaty on the Non-Proliferation of Nuclear Weapons and its presence in the world played one of the responsible roles, since after the US bombing of Hiroshima and Nagasaki, nuclear weapons were never used in a military situation (unless, of course, you take into account that the nuclear powers conducted more than 2,000 nuclear explosions at their test sites).
 It can be said that this is the result of a broad consensus reached by the international community on the prevention of the proliferation of nuclear weapons and other types of weapons of mass destruction, as well as the result of the actual operation of the Treaty on the Non-Proliferation of Nuclear Weapons during its more than 50 years of existence. Currently, no bilateral or multilateral meeting on international security issues, including at the highest level, is held without a mention of nuclear non-proliferation, and it is often at the top of the agenda.
 The Treaty on the Non-Proliferation of Nuclear Weapons is an international legal and ethical norm that has entered the minds of millions of people. Many countries have developed and adopted national legislation establishing export control rules for materials used in the production of weapons of mass destruction, as well as other laws (customs, etc.) to help ensure the non-proliferation of weapons of mass destruction. Extensive training of young experts in basic knowledge to support the international non-proliferation regime of nuclear weapons is ongoing.
 In the field of technology, scientists and experts in reactor engineering are working in many countries to build nuclear power plants that will not produce materials used to create weapons of mass destruction. Many scientists are working to prevent the construction of reactors that threaten the proliferation of technologies and nuclear materials capable of producing nuclear weapons and other weapons of mass destruction.
 The conclusion of the Treaty on the Non-Proliferation of Nuclear Weapons and the establishment of an international non-proliferation regime contributed to a fundamental change in the world’s attitude to nuclear weapons. From the first impression in the eyes of the world public that nuclear weapons are a «genius» discovery, the latter is increasingly perceived as a mortal danger that threatens human existence, and this idea penetrates deeper and deeper into the consciousness of millions of people.

Comparing mass transfer and reaction rate kinetics in starch hydrolysis during food digestion

AbstractThis study demonstrates evidence that the mass transfer process of an enzyme (a biocatalyst) is the rate‐limiting step in the starch hydrolysis reaction during food digestion. The significance of this work has been to compare the reaction rate of starch hydrolysis by salivary enzymes with the mass transfer rate of rate‐limiting enzymes. This research has applied mass transfer and reaction engineering theory in a quantitative study of starch hydrolysis, and a dimensionless group, the Damköhler number (Da), has been calculated based on glucose measurements from a beaker and stirrer system. The values of the Da number in this study (0.3–19) indicate that both the time constant for mass transfer and the time constant for reaction are significant parameters. Scanning electron microscopy images emphasize that compression (simulated mastication) helps to break the plant cell wall of starch. Mass‐transfer resistance needs to be considered during food digestion studies. The Da numbers are significantly affected by both compression forces (internal mass‐transfer coefficients) and stirrer speeds (external mass‐transfer coefficients) in this beaker and stirrer system.

Design and analysis of redundant electro-hydraulic-driven manipulator for tokamak vacuum vessel

Remote handling (RH), as one of the key technologies for fusion reactors in the future, has been the focus of research by researchers. This paper presents the design and analysis of a redundant manipulator with 10° of freedom (DOF) intended for use in vacuum vessel of the Tokamak. With a span of 3.15 m and a payload of 10 kg, the manipulator is powered by a combination of hydraulics and motors. The manipulator is mainly composed of the macro-operating arm, the micro-operating arm, and an end-effector, each serving its specific functions. This paper introduces and discusses the roles and capabilities of these components in the manipulation process. The finite element analysis (FEA) of the manipulator's structure reveals that the maximum stress of the structure is significantly lower than the permissible stress of the material Aluminium alloy 2A14. By utilizing the modified Denavit-Hartenberg (DH) method, the kinematic model was created, the forward kinematic matrix was established, and the workspace was analysed accordingly. The inverse kinematics solution was elaborated by the combination of geometric and numerical solutions. Given velocity and acceleration of the joints and the mass of the links, the force and torque of each joint were computed by the inward iterations method based on the Newton-Euler equation, and the rationality of the results was verified by ADAMS simulation. The results indicate that the manipulator, with sufficient strength and appropriate kinematic and dynamic properties, can fulfill the design objective and functional requirements.

Evaluating nuclear power's suitability for climate change mitigation: technical risks, economic implications and incompatibility with renewable energy systems

This paper presents a comprehensive analysis of the suitability of nuclear power as an option to combat the escalating climate emergency. Summarizing and evaluating key arguments, we elucidate why nuclear power is unsuitable for addressing climate change. The primary argument centers around the unresolved technical and human risks of accidents and proliferation, which are unlikely to be effectively mitigated in the future. Furthermore, we highlight the significant cost disparities between nuclear power and other non-fossil energy sources, such as solar photovoltaics and wind power, considering levelized costs of electricity. We also address the incompatibility of nuclear power with renewable energy systems, emphasizing the need for flexibility in the face of variable solar and wind resources. Alternative reactor technologies will not be available in time to make a major contribution. Nuclear power also poses challenges in power plant operation amid climate change and war. Ultimately, we argue that other motivations should be explored to explain the continued interest in nuclear power in some countries, as energy supply arguments alone are insufficient to justify new investments.

HHDH-Catalyzed Synthesis of Enantioenriched Fluorinated β-Hydroxy Nitrile─Process Advances through a Reaction Engineering Approach

HHDH-Catalyzed Synthesis of Enantioenriched Fluorinated β-Hydroxy Nitrile─Process Advances through a Reaction Engineering Approach

Gamma noise to non-invasively monitor nuclear research reactors

Autonomous nuclear reactor monitoring is a key aspect of the International Atomic Energy Agency’s strategy to ensure nonproliferation treaty compliance. From the rise of small modular reactor technology, decentralized nuclear reactor fleets may strain the capacities of such monitoring and requires new approaches. We demonstrate the superior capabilities of a gamma detection system to monitor the criticality of a zero power nuclear reactor from beyond typical vessel boundaries, offering a powerful alternative to neutron-based systems by providing direct information on fission chain propagation. Using the case example of the research reactor CROCUS, we demonstrate how two bismuth germanate scintillators placed outside the reactor vessel can precisely observe reactor criticality using so called noise methods and provide core status information in seconds. Our results indicate a wide range of applications due to the newly gained geometric flexibility that could find use in fields beyond nuclear safety.

Diphenyl Carbonate: Recent Progress on Its Catalytic Synthesis by Transesterification

Diphenyl carbonate is one of the raw materials used for the synthesis of polycarbonate, and its green and clean production is of great importance to the non-phosgene process for polycarbonate. The production of diphenyl carbonate by transesterification is its representative process route and is considered to be one of the typical examples of a green and sustainable process for chemicals. Since the discovery of the transesterification catalyst for diphenyl carbonate in the 1970s, researchers have been committed to improving its catalytic activity and selectivity and, correspondingly, the reaction engineering process. However, thermodynamic limitations, low activity, low selectivity, and limited stability have been bottlenecks that the transesterification catalyst has not been able to completely overcome, and the improvement of the catalyst is still ongoing. Therefore, this review takes the transesterification reaction of dimethyl carbonate and phenol as a model reaction and, based on a review of the progress in catalyst research on catalytic reaction processes, tries to clarify the structure–activity relationship between catalytic active sites and catalytic performance in homogeneous and heterogeneous catalytic processes and provides an overview of the progress in catalyst synthesis and modification.

Application of Pure and Modified Polyvinylidene Fluoride Materials for Wastewater Treatment Using UASB Reactor Technologies: A Review

Wastewater treatment is now required because of the problems caused by water constraints. Wastewater is anaerobically digested to produce biogas, which can be used as a source of energy for things like lighting and heating. The upflow anaerobic sludge blanket (UASB) reactor has been recognized as an important wastewater treatment technology among anaerobic treatment methods. Although their treated effluent typically does not meet most discharge criteria, UASB reactors are generally stated to have a chemical oxygen demand (COD) reduction ranging from 60 to 90% for most types of wastewater. In comparison to traditional anaerobic procedures, anaerobic municipal wastewater treatment using membranes can produce higher effluent quality in terms of COD, suspended solids (SSs) and pathogen counts, as well as a steady treatment performance to fulfill strict discharge regulations. The objective of this review was to perform a literature review on parameters to consider when selecting a membrane to include in a UASB reactor. Membranes that are available in the market were compared in terms of both physical and chemical properties. Polyvinylidene fluoride (PVDF) membranes were found be superior to the others, and their modification also reduced the fouling propensity. When comparing modified PVDF (PVDF/PVDF-g-PEGMA) to pristine PVDF (116 L·m−2 h−1), a higher pure water flux (5170 L·m−2 h−1) was noted. The main drawback of such modifications could significantly increase the final membrane production costs. Research is still lacking when it comes to research on comparing the membranes and PVDF and UASB reactor technology interaction, including effects of its modification as discussed (stability, longevity of improved flux, etc.

Analyze the Impact of Nuclear Energy on Many Aspects of Life Cycles—Review

AbstractEnergy has long been seen as an important factor in meeting needs of people, in order to sustain and support the economic growth and livelihood. To understand the various technological processes in the nuclear power life cycle, it is first necessary to know the types of fuels used today. There are two types of gasoline in use today, “open” and “partially closed,” respectively, referred to as “single cycle” (OTC) and “double cycle” (TTC). A distinction must be made between “partial” closed fuel cycles, as they apply to current critical (thermal neutron spectrum) reactor technology, which is limited to two passes, and “full” closed cycles, which allow for greater circulation of spent oil but must be used. Fast reactors (FR) are included in the reactor fleet. Many recoveries of FR—already proven but not yet widely used in industry—will lead to reduced demand for uranium mining. In this section, references to “closed” fuel cycles include “partially” closed cycles, i.e., TTCs. What type, if any, is the correct content or information in question? Analysis of the world's energy consumption in recent years shows that the world's energy consumption has increased by 50% in less than a decade.

Conceptual Project for Diagnostics of Erosion of the First Wall and Divertor of the Tokamak with Reactor Technologies TRT

Conceptual Project for Diagnostics of Erosion of the First Wall and Divertor of the Tokamak with Reactor Technologies TRT