bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Transient Model of Sodium Heat Pipe With Phase Change Temperature Difference
Authors: Zhong Ruicheng , Ma Yugao , Zhao Qingzhu , Deng Jian , Liu Yu , Ding Shuhua 
Published: November 2022

Abstract
The heat pipe is the essential component in the heat pipe cooled reactor, it conducts heat through the phase change of the working medium and the circulating flow of gas and liquid. One end of the heat pipe is inserted into the reactor as the evaporation section, while the other end serves as the condensation section connecting to the thermoelectric conversion system. Its heat transfer capacity and temperature distribution under a steady state affect the safety, core temperature and energy conversion efficiency of the heat pipe cooled reactor system. Predicting the heat transfer process and steady-state temperature distribution of the heat pipe is helpful to learn about the heat transfer mechanism inside the heat pipe and key factors affecting its performance. It is also helpful to predict the operating characteristics of the heat pipe cooled reactor system and improve the performance of the heat pipe. The heat pipe is generally considered to be a heat transfer element with good isothermal properties. Past studies, however, proved the significant quantity of its phase-change thermal resistance, resulting in a temperature difference at the gas-liquid interface of the heat pipe that affects the evaporation and condensation. Studies on the relationship between the temperature difference, the working temperature, and heat transfer power of the heat pipe are conductive to building a heat pipe model, to predict the temperature distribution of the heat pipe in a steady state in a much more accurate manner. This paper offered a heat pipe model that applies the temperature difference of the phase change interface to calculate the evaporation and condensation. Meanwhile, a 1-meter-long sodium heat pipe was adopted to carry out steady-state heat transfer experiments. Measured and computed the temperature difference of the phase change interface of the heat pipe under varying power and temperature and conducted the relational equation as the input of the heat pipe model. The model predicted the steady-state temperature distribution of the sodium heat pipe and the transient when the power changes after the steam reach the continuous flow stage and compared the calculated outcomes with the experimental values. The transient error was less than 20K, and the steady-state error was less than 12K. The results show that the temperature difference at the phase change interface has a great influence on the steady-state temperature distribution of the heat pipe, which changes with the operating temperature. However, the physical and geometric factors affecting the temperature difference need to be further studied, to reduce the temperature difference as much as possible and improve the energy conversion efficiency of the heat pipe reactor system in the future.
Effect of Oxidizing All-Volatile Treatment on Alumina-Forming Austenitic Oxidation Behavior in Supercritical Water
Authors: Yang Gao , Sun Dayun , Cong Shuo , Zhang Lefu , Guo Xianglong 
Published: November 2022

Abstract
The corrosion behavior of a novel alumina-forming austenitic stainless (14Cr-24Ni-2.5Al) after 1000 hours of exposure to supercritical water (SCW) with deaerated and AVT(O) water chemistry.
X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy was used to investigate the microstructure evolution of oxide layers and to explain the likely mechanism.
Although the corrosion weight gain in deaerated supercritical water was lower than in AVT(O), the weight gain curves of AFAs in deaerated SCW followed near-linear rate equations, whereas the kinetic weight gain curves in AVT(O) followed the near-parabolic rate equations.
The oxide film of AFAs could be separated into two distinct layers in both water chemistry environments, an exterior Fe-rich later and an inner Cr-Al internal oxidation layer, and neither formed a visible continuous alumina film, which was attributed to the lower Cr concentration.
The development of amorphous Fe2O3 oxide filling the magnetite spinel interstices may explain the reduced porosity of the outer iron oxide in the AVT(O) environment compared to the deaerated environment.
The reasons for the differences in corrosion behavior between the two chemical feedwater conditions were discussed and explained.
These findings revealed that while AVT(O) was not effective in short corrosion resistance, it can help with long-term corrosion resistance.
Research Progress of Neutron Shielding Materials
Authors: Chang Bing , Li Saisai , Li Minghui , Chen Ruoyu 
Published: November 2022

Abstract
Neutron shielding materials are widely used in aviation, medical treatment, nuclear reactor and other fields. Neutrons is difficult to shield because of their high energy. With the development of neutron shielding materials, different kinds of shielding materials have been developed. Compared with other kinds of materials, composite material is an ideal candidate for neutron shielding material because of their outstanding physical and chemical properties. Therefore, a lot of researchers continue exploring and preparing novel composite neutron shielding materials to meet the complex working conditions. This paper summarized the research status of different neutron shielding materials in recent years, mainly including inorganic non-metallic based neutron shielding materials, polymer based neutron shielding materials, metal based neutron shielding materials, beside for composite shielding materials. Moreover, the existing problems in the research of shielding materials and the possible future development direction are put forward.
Phase-Field Fracture Simulation of Dual-Cooled Annular Fuel Pellet
Authors: Li Wei 
Published: November 2022

Abstract
The dual-cooled annular nuclear fuel is an advanced design that is expected to greatly lower fuel temperature even under high linear power density, as compared to traditional cylindrical fuel pin. Although fuel temperature can be much lower, the annular pellet also receives much higher neutron fluence, which may induce severe cracking during normal operation. This work deals with quasi-static cracking of dual-cooled annular UO2 pellet under neutron radiation. The analysis is based on the phase-field fracture model coupled with an oxygen diffusion model, heat conduction model and mechanical equilibrium model. The considered thermo-mechanical properties and irradiation behaviors of the nuclear fuel are both temperature and irradiation dependent. Especially, the acceleration of fuel creep due to oxygen redistribution is included. The fracture is represented by a scalar phase-field variable governed by a cohesive phase-field fracture method. These models are numerically implemented in the multi-physics coupling simulation framework MOOSE. For the first time, the diffusion-thermo-mechanical coupled fracture model is applied to the dual-cooled annular UO2 fuel pellet cracking during reactor startup, power ramp and reactor shutdown. Preliminarily, UO2 irradiation creep is found to play an important role on the fuel pellet fragmentation. The developed capability supports interpretation of experimental data and can guide material design of advanced ceramic nuclear fuel.
Numerical Analysis of Simple Heat Equation to Predict the Opening Time of the Freeze Plug in Molten Salt Reactors
Authors: Ilham Muhammad , Okawa Tomio 
Published: November 2022

Abstract
Freeze plug is an important safety system that can be used in Molten Salt Reactors (MSRs). Capable of removing the decay heat of the fuel in the core by draining the liquid fuel in the core to the safety tank located underneath the core by gravity, with no use of a mechanical valve or operator and electrical supply. The better understanding of designing the freeze plug system, the more efficient the MSRs safety system will be. The opening time of the freeze plug is one of the major importance in ensuring the passive safety of the MSRs. In this study, systematic numerical simulations are carried out to understand the solidification and melting processes of salt in MSRs freeze plugs. The simulation results from a previous study showed that the steady-state form of the frozen salt in the solidification process has a big impact on the opening time of the plug in the melting process. Based on these results, a simple method to estimate the opening time using the thermal conduction theory was developed. It was found that the opening time of the simulation results has a good agreement with the opening time from the analytical equation. Thus, it was demonstrated that this method is useful to estimate the performance of well-designed freeze plugs.
Solution of Unsteady Flow Equations for Nanoscale Heat and Mass Transfer, Advanced Fluidics, Bioengineering, and High Energy Blast Wave Propagations
Authors: Sinha Ramlala P. 
Published: November 2022

Abstract
A new innovative stable time-dependent compressible flow solution over the order of nanoseconds is provided here for wide-ranging critically important challenging applications. Specifically, a solution of the highly complex unsteady high speed oscillating compressible flow field inside a cylindrical tube, closed at one end with a piston oscillating at very high resonant frequency at the other end, has been obtained numerically, assuming one dimensional, viscous, and heat conducting flow, by solving the appropriate fluid dynamic and energy equations. An iterative implicit finite difference scheme is employed to obtain the solution. The scheme permits arbitrary boundary conditions at the piston and the end wall and allows assumptions for tansport properties. In successfully predicting the time dependent results/data, an innovative simple but stable solution of unsteady fluid dynamic and energy equations is provided here for wide ranging research, design, development, analysis, and industrial applications in solving a variety of complex fluid flow heat transfer problems. The method is directly applicable to pulsed or pulsating flow and wave motion thermal energy transport, fluid-structure interaction heat transfer enhancement, nanoscale heat and mass transfer, diverse range of advanced fluidics, biofluidics / bioengineering, and fluidic pyrotechnic initiation devices. It can further be easily extended to cover muzzle blasts and high energy nuclear explosion blast wave propagations in one dimensional and/or radial spherical coordinates with or without including energy generation / addition terms.
Research on In-Core Reactivity Control Method and Neutron Characteristic Analysis of a Space Gas-Cooled Reactor
Authors: Chen Zhiqi , Cai Jiejin , Li Xuezhong 
Published: November 2022

Abstract
Compared with the conventional power system, the space nuclear reactor power system can provide a more stable and longer-life electricity supply, which can better meet the requirements of deep space exploration. For space gas-cooled reactors, the impact of the submerged accidents after a launch abort situation must be considered. In such an accident, the core void is filled with seawater and wet sand, the neutron spectrum in the reactor is thermalized, and the reactivity increases significantly and probably making the reactor supercritical. In this paper, the research focuses on a novel control system named the control ring. Two different neutron-absorption materials are doped in the control ring, and the reactivity control effect of the control ring in submerged accidents is analyzed with different enrichments of fuel. Also, the burnup and neutron spectrum of these two materials are also studied. The result shows that the performance of the reactivity control effect of gadolinium in the submerged accidents is equal to boron-10, and the control effect of the control drums will slightly increase when gadolinium is doped in the control ring. In addition, the reactivity penalty of gadolinium is smaller than boron-10. These results can provide a reference for the design of space gas-cooled nuclear reactors.
Effect of Contact Stress on Fretting Corrosion Behavior of Alloy 690 Tube Exposed to Simulated Secondary Water
Authors: Zhuang Wenhua , Han Zhongli , Guo Xianglong , Zhang Lefu 
Published: November 2022

Abstract
Flow-induced vibration is unavoidable in the steam generator, so the wear of heat transfer tubes can’t be ignored. It is essential to evaluate the fretting wear damage of the heat exchanger tube. In this paper, the high frequency fretting wear tests of Alloy 690 tubes/405 stainless steel plate were carried out in the dynamic water loop experimental device, simulated the secondary water (285°C, 10.5 MPa). Changing the contact stress is realized by applying a range of normal forces. As the contact stress increased, the wear volume increased, and the material removal increased the contact area and wear depth. The wear coefficients of Alloy 690 tubes were found to be intensely dependent on the contact stress. The damage mechanisms of Alloy 690 tube were mainly delamination and abrasive wear, and accompanied by material oxidation in the fretting process. The oxide type of wear debris mainly consisted of (Ni, Fe) (Fe, Cr)2O4 and Fe3O4. The profile shape of wear scar was dependent on the action of the wear particles. When the contact stress is minor, the debris was easy to escape from the interface, and the typical profile shapes were U-shaped. As the contact stress increased, the elastic deformation of the contact material increased, followed by adhesion and delamination in the contact area.
Application of Stiffness Confinement Method on Pin Resolved Variational Nodal Method and Its Implementation to C5G7-TD Benchmark Problem
Authors: Xiao Wei , Zhang Tengfei , Liu Xiaojing , He Donghao , Pan Qingquan 
Published: November 2022

Abstract
This paper presents an implementation of the stiffness confinement method in the framework of the variational nodal method (VNM) to solve time-dependent pin resolved neutron transport equations. With frequency-transform, the time-dependent neutron transport equation is decoupled from the precursor equation and transformed into a transient eigenvalue problem (TEVP) which can be solved with the in-house VNM code VITAS-FE. The verification tests were performed using the C5G7-TD benchmark problems. The result agrees well with solutions of the MPACT. The study indicates that the VNM and SCM can be applied to solve the high-fidelity pin-resolved transient problem accurately.
The Study on Microwave Process for Spent Resin
Authors: Chao Gao , Meilan Jia , Hongxiang An 
Published: November 2022

Abstract
The moisture content of spent resin from NPPs is generally 50% ∼ 60%, which concentrates radionuclides such as 60Co, 90Sr and 137Cs. It belongs to wet solid waste, accounting for about 1/4 of the total solid waste of NPPs. Pent resin is a dispersive material, which must be stabilized and packaged to meet the requirements of waste transportation and final disposal; However, the characteristics of radioactive organic waste also cause the radiolysis of spent resin and the production of H2, CH4, NH3 and other gases; The spent resin contains more sulfur and nitrogen, and the incineration products and degradation products have strong corrosive to the equipment and storage containers. Therefore, how to treat the spent resin safely and effectively is a difficult problem.Microwave process for spent resin using microwave penetration ability and body heat characteristics, remove the water and organic components from spent resin, so as to achieve the inorganic for organic waste. Compared with the original resin, the ashing product capacity and weight reduction ratio greatly. The spent resin dried by microwave does not contain free water, the volume is 1/3 of the resin volume before drying, and the mass is half of the resin mass before drying; After Microwave ashing, the ashing product of the spent resin does not contain organic components, and the ashing product is only 1/20 of the mass of the dried resin and 1/3 of the volume of the dried resin, that is, for the spent resin with a moisture content of about 50%, after microwave drying and ashing process, not only the organic components in the spent resin are removed, but also the volume and quality are greatly reduced. Most of the treated radionuclides exist in the ashing products, 60Co in the ashing products is 1011 Bq/kg and 137Cs is 108 Bq/kg. The technology processing are used to get the product, which can be convenient for subsequent processing. On the study, the technological parameters of microwave drum drying and microwave ashing of spent resin are determined.
Analysis of Trace Components in Neon by Gas Chromatography
Authors: Yang Li-ling , Zhan Qin 
Published: November 2022

Abstract
In order to complete the test of trace concentrations in neon carrier gas of solid tritium breeder system for fusion reactor, it is very necessary to establish a high precision analytical system and develop a method of Gas Chromatography (GC). The GC system was composed of three detectors and five separated columns and other auxiliary systems, meanwhile it has established analysis methods of testing trace He, H2 and impurity components in Ne carrier gas. The results showed that the Relative Standard Deviation (RSD) values of the concentration and peak area of each component were less than 5.0%, and the linear correlation coefficients (R2) were greater than 0.99 with the GC analysis system, which could be used to testing trace concentrations in neon with good repeatability. It could support the requirement of tritium efficiency in the Tritium Analysis and Measurement system (TAMS), besides, it could provide technology data and support for the radiation tritium system.
A Modified Two-Zone Model for Predicting Heat Release Rate of Pool Fire in a Confined Space
Authors: Peng Lan , Huang Xianjia , Wang Jinkai , Zhu He , Yang Ping , Xing Chaoliang , Zhao Chunyang 
Published: November 2022

Abstract
The heat release rate of the fire source is one of the most important parameters for the fire hazards analysis in nuclear power plants. For a fire in a confined compartment, the oxygen concentration has a critical effect on the fire heat release rate under oxygen-deficient situation. In the present work, a modified two-zone fire model was developed to predict the pool fire heat release rate in the oxygen-deficient situation. A simple model estimating the effect of the oxygen concentration on the fire heat release rate was incorporated into two-zone model, CFAST. Furthermore, the conservation of fuel mass was also taken into consideration. Experimental results from three fire experiments of pool fire under the oxygen-deficient situation in the literature available were used to validate the reliability of the modified two-zone model. The oxygen concentration in the compartment was decreased and became oxygen-deficient condition due to the mechanical ventilation. Compared with the original CFAST model, the accuracy of predicting pool fire under oxygen-deficient situation was increased considerably by the modified model, especially for the pool fire at steady under oxygen-deficient situation. In comparison with the experimental data, the cosine similarities of the three heat release rate curves were all over 0.95 and the max relative error of the burning time was 41.9%, which is significantly lower than that of the original two-zone model prediction.
Discussion on Setting Value and Grounding Mode of Grounding Protection for the Construction of a Nuclear Power Plant Power Loop Network
Authors: Yuhan Wang , Zhijian Wang 
Published: November 2022

Abstract
Based on the case of a single-phase ground fault protection failure in the power supply ring network of a certain project, through the calculation of capacitance current and the protection setting calculation, the reason for the failure of the protection is analyzed in depth, and further suggestions for protection settings are put forward. Finally, based on the above analysis and combined with the actual situation of the project, an in-depth discussion on the grounding method of the construction power ring network was carried out, and the direction of optimization and improvement was pointed out.
Discussion on Selection of Codes and Standards on Nuclear Power Plant Safety
Authors: Yuxiu Chen , Yuhong Wang , Haiying Luo , Jinkai Wang , Qing Shi , Zengpei Zhu , Bei Wu 
Published: November 2022

Abstract
Requirements of evaluating and determining applicability, adequacy and sufficiency of codes and standards applied in nuclear power plant design are required by IAEA, NNSA etc. without detailed guidance or suggestion yet. Purpose of the article is going to discuss and provide a methodology for selecting codes and standards methodology to evaluate their applicability, adequacy and sufficiency, purpose is tying to react those requirements. The methodology is explored based on GDA (Generic Design Assessment) practice, 5 steps are included: breakdown of design activities, collection and identification, evaluating applicability and adequacy, evaluating sufficiency, evaluating consistency. Process and detailed evaluation method are discussed. Selection process could supplement the gap of selecting applicable codes and standards, providing a mentality for engineers to focus on and continually raising other better process or methods for ensuring applicable codes and standards can be selected at the beginning of the nuclear power plant design and implementing nuclear security culture more deeply on selection of codes and standards.
Simulation Analysis of Main and Auxiliary Switching and Motor Starting in Nuclear Power Plants
Authors: Xingzhen Zhang , Hui Sun 
Published: November 2022

Abstract
The main and auxiliary switching process involves the large-capacity asynchronous motor used in various systems (such as water pumps, fans, etc.) that are accompanied by strong electrical and mechanical shocks during the restarting or reinput process, especially the influence of the motor group restarting shock. The process includes the dynamic behavior of the electromagnetic and mechanical transient change process. In Order to quantitatively analyze the dynamic behavior of induction motor starting, the general steady-state analysis method can no longer be accurately solved, it is necessary to consider the dynamic load model of the transient process, and select ETAP software to realize the model establishment and transient process simulation calculation. For high-power motor load starting, the motor may fail to start due to low starting torque or other running motors connected to the power grid. Therefore, this paper selects typical high-power motors as the research object as the largest single load, and considers the harsh power supply conditions, and the transient conditions of the above-mentioned plant power switch motor group start, To verify whether the motor starting or restart will cause itself and other motors to stall, or whether it causes the EDG diesel generator to start. Whether the power system of nuclear power plant can resume stable operation after the above transient process has become an important index for evaluating the power system design of nuclear power plant. In this paper, the simulation study of the switching between the main power supply and the auxiliary power supply of the nuclear power plant, and the starting process of the high-power motor is established, the power system model of the power grid is analyzed at high voltage and low voltage, and the transformer is automatically loaded. The on-load voltage regulation, the plant power switching process and the high-power motor starting simulation calculation, effectively reduce the cost of the experiment, Has great economic benefits, it has positive significance for fault analysis.