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Study on the base isolation design and parameter optimization analysis of friction pendulum bearings for reactor building in swimming pool-type low-temperature heating reactor 泳池式低温加热堆堆座舱摩擦摆轴承基座隔震设计及参数优化分析研究
IF 2.1 3区 工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2026-04-01 Epub Date: 2026-01-30 DOI: 10.1016/j.nucengdes.2025.114739
Yingying Gan , Xiaoying Sun , Pengxiang Dong , Ziqiao Liu
The swimming pool-type low-temperature heating reactor (SPLTHR) is a single-unit small heating reactor that can serve as an alternative to fossil energy. The peak ground acceleration (PGA) for the safe shut- down earthquake (SSE) at the proposed site is up to 0.5 g in horizontal direction. To ensure seismic safety and improve economic efficiency of the reactor, the Friction Pendulum (FP) bearing is employed for the base isolation design of the reactor building. Firstly, a three-dimensional finite element model (FEM) of the reactor building is established. The layout scheme of the base isolation layer is designed. Subsequently, a parameter optimization analysis about the equivalent radius of curvature and dynamic friction coefficient of the FP bearing is conducted to achieve the optimal isolation performance for the reactor building. Finally, the acceleration response spectrum (ARS) in three directions were compared between the base-isolated system and non- isolated system at the same place. The acceleration reduction rate was defined to quantified the isolation performance. The study results indicate that the base isolation layer using 28 FP bearings with load capacity in axial direction of 15,000 kN and 8 viscous damper can meet the design requirement. The dynamic friction coefficient of the FP bearing has a more significant influence on the isolation performance than the equivalent radius of curvature. In general, a larger equivalent radius of curvature and a smaller dynamic friction coefficient result in better isolation performance. The ARS in horizontal direction of the superstructure in the non-isolated system completely envelops that of the base-isolated system. The seismic response of the base-isolated system shows a substantial reduction in the dominant frequency and a significant decrease in the ARS of the superstructure in horizontal direction. The maximum reduction rates for zero-period acceleration (ZPA) and peak acceleration can reach up to 75.0 % and 85.4 %, respectively, demonstrating excellent isolation performance. Compared to the ARS in vertical direction of the non-isolated system, the base-isolated system has a lower dominant frequency, a leftward shift in peak acceleration response (with lower peak frequency), and an insignificant increase in peak values. It is recommended to focus on the seismic response of key equipment which is sensitive to the vertical frequency ranges of the base-isolated system, and to implement appropriate local vertical isolation measures if necessary.
游泳池式低温加热反应堆(SPLTHR)是一种可替代化石能源的单机组小型加热反应堆。安全停堆地震(SSE)的峰值地加速度(PGA)在水平方向上可达0.5 g。为保证反应堆的抗震安全,提高反应堆的经济效益,采用摩擦摆轴承对反应堆建筑进行基础隔震设计。首先,建立了反应堆建筑的三维有限元模型。设计了基本隔离层的布置方案。随后,对FP轴承的等效曲率半径和动摩擦系数进行了参数优化分析,以实现反应堆建筑的最佳隔震性能。最后,比较了基隔震系统与非隔震系统在同一地点三个方向上的加速度响应谱。通过定义加速度降低率来量化隔震性能。研究结果表明,采用28个轴向承载能力为15,000 kN的FP轴承和8个粘性阻尼器的基础隔震层可以满足设计要求。FP轴承的动摩擦系数比等效曲率半径对隔震性能的影响更显著。一般情况下,等效曲率半径越大,动力摩擦系数越小,隔震性能越好。非隔震体系上部结构水平方向的ARS完全包住了基础隔震体系的ARS。基础隔震体系的地震响应表明,上层结构在水平方向上的主频率显著降低,ARS显著降低。零周期加速度(ZPA)和峰值加速度的最大降低率分别可达75.0%和85.4%,具有良好的隔离性能。与非隔离系统垂直方向的加速度响应相比,基础隔离系统的主导频率更低,峰值加速度响应向左移动(峰值频率更低),峰值加速度响应的增加不显著。建议重点关注对基础隔震系统垂直频率范围敏感的关键设备的地震响应,必要时在局部实施适当的垂直隔震措施。
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引用次数: 0
Modelling of MSRE graphite temperature in porous-medium multi-physics simulations 多孔介质多物理场模拟中MSRE石墨温度的建模
IF 2.1 3区 工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2026-04-01 Epub Date: 2026-01-26 DOI: 10.1016/j.nucengdes.2026.114757
S. Amirkhosravi , A. Scolaro , F. van Niekerk , M.H. du Toit , A. Pautz
MSRs stand out as prominent candidates among advanced reactor designs, addressing the global demand for safer and more sustainable nuclear energy. Accurate multi-physics modelling is essential for the advancement of MSR technology, particularly for understanding the thermos-hydraulic behaviour of graphite under irradiation. This study focuses on developing and implementing a high-fidelity methodology within the GeN-Foam code to model graphite temperature distribution within porous-medium multi-physics simulations, using the MSRE as a benchmark. The approach combines thermal-hydraulic and neutronic modelling by using Serpent-generated cross-section data as inputs for the Gen-Foam neutronic solver. Validation against MSRE measurements performed at ORNL benchmark data confirms the framework's reliability. The axial temperature distribution yields a Mean Absolute Percentage Error (MAPE) of 1.09%, while the radial distribution shows a MAPE of 0.62%. The average graphite temperature of 935.6 K is consistent with the ORNL reference value of 936.4 K under steady-state conditions.
msr在先进反应堆设计中脱颖而出,满足了全球对更安全、更可持续核能的需求。精确的多物理场建模对于MSR技术的进步至关重要,特别是对于理解辐照下石墨的热-水力行为。本研究的重点是在GeN-Foam代码中开发和实现高保真度方法,以MSRE为基准,在多孔介质多物理场模拟中模拟石墨温度分布。该方法结合了热工和中子建模,使用蛇形生成的横截面数据作为Gen-Foam中子求解器的输入。在ORNL基准数据上进行的MSRE测量验证证实了该框架的可靠性。轴向温度分布的平均绝对百分比误差(MAPE)为1.09%,径向温度分布的平均绝对百分比误差为0.62%。稳态条件下石墨平均温度为935.6 K,与ORNL参考值96.4 K一致。
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引用次数: 0
Design of nuclear fuel loading patterns for a PWR with Wasserstein generative adversarial networks 基于Wasserstein生成对抗网络的压水堆核燃料装载模式设计
IF 2.1 3区 工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2026-04-01 Epub Date: 2026-01-18 DOI: 10.1016/j.nucengdes.2026.114765
Anderson Alvarenga de Moura Meneses , Lenilson Moreira Araujo
The Loading Pattern (LP) design is part of the nuclear fuel management of a Nuclear Power Plant (NPP). The design of an LP includes the permutation of fuel assemblies, as well as calculations performed with reactor physics codes, aiming to producing energy with the satisfaction of constraints such as those related to safety. From a computational perspective, it is an NP-hard combinatorial problem solved with success by optimization metaheuristics. With the breakthrough of generative Artificial Intelligence (AI), the immediate question is whether LPs can be designed within such paradigm. In the present article, a methodology is proposed for training and applying Wasserstein Generative Adversarial Networks (WGANs) for automatic generation of LPs of a Pressurized Water Reactor. With the application of the methodology to the benchmark IAEA-2D, WGANs generated LPs satisfying the safety constraints and objectives proposed. Thus, WGANs can learn implicit probability distributions of nucler fuel and automatically design high-quality LPs.
装载模式(LP)设计是核电站核燃料管理的一部分。LP的设计包括燃料组件的排列,以及用反应堆物理代码进行的计算,目的是在满足安全等限制的情况下产生能量。从计算的角度来看,它是一个NP-hard组合问题,并通过优化元启发式成功解决。随着生成式人工智能(AI)的突破,迫在眉睫的问题是lp是否可以在这种范式下设计。在本文中,提出了一种方法来训练和应用Wasserstein生成对抗网络(WGANs)来自动生成压水反应堆的lp。将该方法应用于基准IAEA-2D, wgan生成的lp满足所提出的安全约束和目标。因此,wgan可以学习核燃料的隐式概率分布,并自动设计高质量的lp。
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引用次数: 0
Optimizing iPWR SMR core design: a power peaking factor analysis of annular fuel rods using MCNP5 iPWR SMR堆芯设计优化:基于MCNP5的环形燃料棒功率峰值因子分析
IF 2.1 3区 工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2026-04-01 Epub Date: 2026-01-20 DOI: 10.1016/j.nucengdes.2026.114768
Fatima Ghandour , Salah Hamieh , Ziad Francis
This study investigates the neutronic performance of dual cooled annular fuel rods in the CAREM 25 integral Pressurized Water Reactor (iPWR), a small modular reactor (SMR), using MCNP5 Monte Carlo simulations. The motivation is to reduce power peaking factors (PPFs) and enhance thermal-hydraulic safety margins by adopting an annular fuel geometry with internal and external cooling. Three annular fuel configurations with 100%, 95%, and 93% fuel loading were analyzed and compared to the conventional solid fuel design. Geometric transformations were performed analytically—introducing, for the first time, closed-form equations for the inner and outer radii of annular fuel rods—to maintain the fuel-to-coolant volume ratio while limiting fuel mass reduction to ≤10%. The results show that the total PPF decreased by up to 27.45% in the 95% fuel loading case, dropping from 2.404 (solid design) to 1.744. Additionally, the effective multiplication factor (Keff) was reduced from 1.12445 to 1.09512, enhancing reactor controllability. The 95% loading configuration emerged as the optimal design, balancing neutronic performance and safety. These findings demonstrate that annular fuel can significantly flatten the power distribution and improve the safety profile of iPWR SMRs without compromising core performance.
本研究利用MCNP5蒙特卡罗模拟研究了小型模块化反应堆CAREM 25整合式压水堆(iPWR)中双冷环形燃料棒的中子性能。其动机是通过采用带有内部和外部冷却的环形燃料结构来降低功率峰值因子(ppf),并提高热液安全余量。研究人员分析了100%、95%和93%三种环形燃料配置,并与传统固体燃料设计进行了比较。为了保持燃料与冷却剂的体积比,同时将燃料质量降低到≤10%,对环形燃料棒进行了几何变换,首次引入了环形燃料棒内外半径的封闭方程。结果表明,在95%载油工况下,总PPF从2.404(固体设计)下降到1.744,降幅达27.45%;有效倍增因子(Keff)由1.12445降至1.09512,增强了反应器的可控性。95%载荷配置是平衡中子性能和安全性的最优设计。这些研究结果表明,在不影响堆芯性能的情况下,环形燃料可以显著地平稳化功率分布,提高iPWR小堆的安全性。
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引用次数: 0
Computational modeling of graphite degradation in molten salt reactors: Role of infiltration 熔盐反应器中石墨降解的计算模型:渗透的作用
IF 2.1 3区 工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2026-04-01 Epub Date: 2026-01-29 DOI: 10.1016/j.nucengdes.2026.114796
Veerappan Prithivirajan , Benjamin Spencer , Joseph Bass , Somayajulu L.N. Dhulipala , Daniel Schwen , Mustafa K. Jaradat
Molten salt reactors (MSRs) often employ graphite as a moderator and reflector. An important challenge for deploying graphite in these reactors is that, due to limited experimental data, our understanding of graphite’s structural integrity in molten salt environments remains incomplete. This study addresses heat generation from fuel-bearing salt that has infiltrated open pores in the graphite, driven primarily by pressure differentials. This is one of multiple identified physical and chemical mechanisms through which molten salt could potentially degrade graphite. Thermally driven stresses are quantified using the Molten-Salt Reactor Experiment (MSRE) graphite moderator elements as a case study. Finite element simulations predict stress distributions at varying infiltration levels, indicating that thermal stresses increase with higher infiltration. Rare-event simulations using the parallel subset simulation framework identify the combinations and corresponding ranges of input parameters that lead to stresses above a specified threshold. In particular, combinations involving high infiltration amounts, high power density, and low thermal conductivity tend to induce the highest stresses. Under the inputs and assumptions considered in this work, the magnitudes of the thermally driven stresses are quite low, with a very low likelihood of causing failure due to exceeding the graphite’s tensile strength. Additionally, rare-event simulations were performed for two more scenarios: a scaled-up moderator geometry and a localized hotspot in the original geometry. Both cases resulted in increased susceptibility to failure, though not to a detrimental extent. Furthermore, the combined effects of irradiation and infiltration-induced thermal stresses were evaluated. The results showed that thermal stresses from infiltration were negligible compared to those caused by irradiation. The findings of such a study are inherently component-specific, but the methodology presented here could be used for similar assessments of salt-infiltration effects in other graphite components.
熔盐反应堆(MSRs)通常使用石墨作为慢化剂和反射器。在这些反应堆中部署石墨的一个重要挑战是,由于实验数据有限,我们对熔盐环境中石墨结构完整性的了解仍然不完整。该研究主要解决了由压差驱动的含燃料盐渗透石墨孔隙产生的热量问题。这是多种已确定的物理和化学机制之一,通过熔盐可以潜在地降解石墨。以熔融盐堆实验(MSRE)中石墨慢化剂元素为例,对热驱动应力进行了量化。有限元模拟预测了不同入渗水平下的应力分布,表明热应力随入渗水平的增加而增加。使用并行子集仿真框架的罕见事件仿真识别导致应力超过指定阈值的输入参数的组合和相应范围。特别是,涉及高入渗量、高功率密度和低导热系数的组合往往会产生最高的应力。在这项工作中考虑的输入和假设下,热驱动应力的大小非常低,由于超过石墨的抗拉强度而导致失效的可能性非常低。此外,还对另外两种场景进行了罕见事件模拟:放大的慢化剂几何形状和原始几何形状中的局部热点。这两种情况都增加了对失败的易感性,尽管没有达到有害的程度。此外,还对辐照和渗透引起的热应力的联合效应进行了评价。结果表明,与辐照引起的热应力相比,渗透引起的热应力可以忽略不计。这样的研究结果本质上是组分特异性的,但这里提出的方法可以用于其他石墨组分盐渗透效应的类似评估。
{"title":"Computational modeling of graphite degradation in molten salt reactors: Role of infiltration","authors":"Veerappan Prithivirajan ,&nbsp;Benjamin Spencer ,&nbsp;Joseph Bass ,&nbsp;Somayajulu L.N. Dhulipala ,&nbsp;Daniel Schwen ,&nbsp;Mustafa K. Jaradat","doi":"10.1016/j.nucengdes.2026.114796","DOIUrl":"10.1016/j.nucengdes.2026.114796","url":null,"abstract":"<div><div>Molten salt reactors (MSRs) often employ graphite as a moderator and reflector. An important challenge for deploying graphite in these reactors is that, due to limited experimental data, our understanding of graphite’s structural integrity in molten salt environments remains incomplete. This study addresses heat generation from fuel-bearing salt that has infiltrated open pores in the graphite, driven primarily by pressure differentials. This is one of multiple identified physical and chemical mechanisms through which molten salt could potentially degrade graphite. Thermally driven stresses are quantified using the Molten-Salt Reactor Experiment (MSRE) graphite moderator elements as a case study. Finite element simulations predict stress distributions at varying infiltration levels, indicating that thermal stresses increase with higher infiltration. Rare-event simulations using the parallel subset simulation framework identify the combinations and corresponding ranges of input parameters that lead to stresses above a specified threshold. In particular, combinations involving high infiltration amounts, high power density, and low thermal conductivity tend to induce the highest stresses. Under the inputs and assumptions considered in this work, the magnitudes of the thermally driven stresses are quite low, with a very low likelihood of causing failure due to exceeding the graphite’s tensile strength. Additionally, rare-event simulations were performed for two more scenarios: a scaled-up moderator geometry and a localized hotspot in the original geometry. Both cases resulted in increased susceptibility to failure, though not to a detrimental extent. Furthermore, the combined effects of irradiation and infiltration-induced thermal stresses were evaluated. The results showed that thermal stresses from infiltration were negligible compared to those caused by irradiation. The findings of such a study are inherently component-specific, but the methodology presented here could be used for similar assessments of salt-infiltration effects in other graphite components.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"450 ","pages":"Article 114796"},"PeriodicalIF":2.1,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146057606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Clarifying the trends of hydraulic resistance parameters for supercritical pressure fluids with the aid of CFD 利用CFD阐明了超临界流体阻力参数的变化趋势
IF 2.1 3区 工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2026-04-01 Epub Date: 2026-02-13 DOI: 10.1016/j.nucengdes.2026.114828
Md Radwan Ahmed , Sara Kassem , Andrea Pucciarelli , Walter Ambrosini
The paper addresses the observed trends of friction factor and shear stress at the wall as a function of operating conditions in supercritical pressure fluids. Previous literature suggests that the friction factor correlations applicable at supercritical pressures, at which fluids show considerable changes in properties while crossing the pseudocritical threshold, should be mostly the same as those for fluids with relatively constant properties in the liquid-like and gas-like regions, though corrections should be instead applied for conditions in between the two extremes. Basing on a previous work performed in past years at the University of Pisa to address this issue and after a review of selected information proposed in the field, some experimental conditions are here addressed with the aid of a CFD code, aiming to consider the behaviour predicted by the available models and to discuss the possible agreement of this information with experimental evidence. In particular, a circular pipe with supercritical carbon dioxide and a 2 × 2 rod-bundle mock-up with supercritical water are considered; in the latter case, the capability of CFD to provide local data of the shear stress at the heated and the unheated walls of the bundle helps in suggesting with sufficient clarity the different influence that bulk and wall temperatures have on friction parameters. The obtained results support the use of the classical correction factors proposed in previous literature to correct isothermal friction factor correlations with density and/or viscosity ratios to account for an observed decrease across the pseudocritical region. This information supports a meaningful explanation of some of the available experimental data that, at the moment, cannot be so detailed as to highlight such local effects, thus proposing a rationale to explain the role of the different parameters influencing hydraulic resistance at supercritical pressure.
本文讨论了在超临界压力流体中观察到的摩擦系数和壁面剪应力随工况变化的趋势。以前的文献表明,在超临界压力下,流体在越过伪临界阈值时表现出相当大的性质变化,适用于超临界压力下的摩擦系数相关性应该与在类液和类气区域中具有相对恒定性质的流体的摩擦系数相关性大致相同,尽管应该对介于两个极端之间的条件进行修正。基于过去几年在比萨大学为解决这一问题所做的工作,在对该领域提出的选定信息进行审查之后,本文借助CFD代码解决了一些实验条件,旨在考虑可用模型预测的行为,并讨论这些信息与实验证据的可能一致性。特别考虑了含超临界二氧化碳的圆管和含超临界水的2 × 2棒束模型;在后一种情况下,CFD能够提供管束加热壁面和未加热壁面的局部剪切应力数据,这有助于充分清楚地表明体积温度和壁面温度对摩擦参数的不同影响。所获得的结果支持使用经典校正因子在以前的文献中提出的,以校正等温摩擦因子与密度和/或粘度比的相关性,以解释在伪临界区域观察到的减少。这一信息支持了对一些现有实验数据的有意义的解释,这些数据目前还不能如此详细地突出这种局部影响,从而提出了解释不同参数在超临界压力下影响水力阻力的作用的基本原理。
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引用次数: 0
A preferable siliconized graphite with high graphite content in thrust bearings of shaft-sealed main coolant pump 一种较理想的石墨含量高的硅化石墨用于轴封主冷却液泵止推轴承
IF 2.1 3区 工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2026-04-01 Epub Date: 2026-02-12 DOI: 10.1016/j.nucengdes.2026.114831
S.H. Liu , T.H. Liang , B.J. Zhang , J.Q. An , L. Cai , M.K. Lei
A challenge of achieving high load capacity and low wear loss for siliconized graphite counterparts of the thrust bearings in shaft-sealed nuclear main pump of pressurized water reactor power plant is urgent due to the mixed lubrication under high contact pressure × sliding velocity (pv) factor above 65.0 MPa·m/s in high-temperature and high-pressure water. Wear and lubrication of siliconized graphite 42C-44SiC-14Si (vol%) with elevated graphite content were investigated using self-mated pairs in the high-temperature and high-pressure tribometer on a pin-on-disc configuration. Contact pressure p of 0.87 and 2.08 MPa with sliding velocity v from 0.5 to 33.1 m/s supply the pv factors of 0.4–68.8 MPa·m/s in 50 °C and 1.5 MPa water. A tribology-induced oxidation mechanism on SiC of siliconized graphite is proposed under the mixed lubrication. The selective oxidation of SiC characterizes the supersaturation of oxygen, fragmentation of SiC, and amorphization of silicon oxide. Oxidized SiC peaks alternating with valleys of non-oxidized graphite and Si phases facilitate the regular and corrugated-like texture on mated surfaces that promotes hydrodynamic effect. The lower wear depth of 0.12 μm and coefficient of friction (COF) of 0.015 are achieved under 68.8 MPa·m/s. Siliconized graphite 42C-44SiC-14Si with high graphite content provides the solid lubricant under boundary lubrication, and the uniform pressure distribution of water film under mixed lubrication. Therefore, the siliconized graphite as a promising material enables a long service life of thrust bearings in demanding nuclear applications, withstanding high load under operating conditions and offering superior resistance to more startup-shutdown cycles under specific conditions.
压水堆电站核主泵轴封推力轴承硅化石墨轴承在高温高压水中高接触压力×大于65.0 MPa·m/s的滑动速度(pv)系数下的混合润滑,迫切需要实现高承载能力和低磨损。采用针盘式高温高压摩擦计,研究了高石墨含量硅化石墨42C-44SiC-14Si (vol%)的磨损和润滑性能。接触压力p为0.87和2.08 MPa,滑动速度v为0.5 ~ 33.1 m/s,在50℃、1.5 MPa水中,pv因子为0.4 ~ 68.8 MPa·m/s。提出了混合润滑条件下硅化石墨对碳化硅的摩擦学氧化机理。SiC的选择性氧化表现为氧的过饱和、SiC的破碎和氧化硅的非晶化。氧化后的碳化硅峰与非氧化石墨和硅相的谷交替形成规则的波纹状织构,促进了流体力学效应。在68.8 MPa·m/s下,磨损深度为0.12 μm,摩擦系数为0.015。高石墨含量的硅化石墨42C-44SiC-14Si在边界润滑下提供固体润滑剂,在混合润滑下提供均匀的水膜压力分布。因此,硅化石墨作为一种有前途的材料,使推力轴承在苛刻的核应用中具有较长的使用寿命,在运行条件下承受高负载,并在特定条件下提供更强的启动-关闭周期阻力。
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引用次数: 0
Modeling considerations for passive safety systems in Korean SMRs using system analysis codes 使用系统分析代码对韩国smr被动安全系统建模的考虑
IF 2.1 3区 工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2026-04-01 Epub Date: 2026-01-16 DOI: 10.1016/j.nucengdes.2025.114747
Seong-Su Jeon, Jungjin Bang, Sang Gyun Nam, Jehee Lee, Youngjae Park, Soon-Joon Hong
Numerous Small Modular Reactors (SMRs) are being developed worldwide, and they are equipped with various types of Passive Safety Systems (PSSs). In the Republic of Korea, SMART100 and i-SMR are representative SMRs. SMART100 includes the Passive Safety Injection System (PSIS), the Passive Residual Heat Removal System (PRHRS), and Containment Pressure and Radioactivity Suppression System (CPRSS) while i-SMR is equipped with the Passive Emergency Core Cooling System (PECCS), the Passive Containment Cooling System (PCCS), and the Passive Auxiliary Feedwater System (PAFS). These systems operate based on natural forces such as gravity and buoyancy, performing safety functions without external power or operator action. However, because their operation relies on relatively weak and time-varying driving forces, reliable modeling using system analysis codes is important. In particular, improper simulation of key thermal-hydraulic phenomena such as pressure drop, condensation, boiling, and natural circulation can lead to predictions that deviate considerably from actual performance. To address these concerns, this study reviews the modeling and simulation of PSIS, PAFS, and PCCS in Korean SMRs using various system analysis codes. Based on the authors' extensive experience, detailed modeling considerations are derived to improve the representation of key physical phenomena. Furthermore, the study discusses the importance of robustness evaluation under degraded conditions using the Best Estimate with Performance Issues (BEPI) framework. The insights provided herein are expected to support the credible and technically robust application of system analysis codes to the design and safety assessment of passive safety systems.
世界范围内正在开发大量的小型模块化反应堆(smr),它们配备了各种类型的被动安全系统(pss)。在韩国,SMART100和i-SMR是代表性的smr。SMART100包括被动安全喷射系统(PSIS)、被动余热排出系统(PRHRS)和安全壳压力和放射性抑制系统(CPRSS),而i-SMR则配备了被动应急堆芯冷却系统(PECCS)、被动安全壳冷却系统(PCCS)和被动辅助给水系统(PAFS)。这些系统基于重力和浮力等自然力运行,在没有外部电源或操作人员操作的情况下执行安全功能。然而,由于它们的运行依赖于相对较弱且时变的驱动力,因此使用系统分析代码进行可靠的建模非常重要。特别是,对关键的热水力现象(如压降、冷凝、沸腾和自然循环)的不正确模拟可能导致预测与实际性能偏差很大。为了解决这些问题,本研究回顾了韩国smr中使用各种系统分析代码的PSIS, PAFS和PCCS的建模和仿真。根据作者的丰富经验,详细的建模考虑是派生的,以改善关键物理现象的表示。此外,该研究还讨论了使用性能问题的最佳估计(BEPI)框架在退化条件下鲁棒性评估的重要性。本文提供的见解有望支持系统分析代码在被动安全系统的设计和安全评估中的可靠和技术稳健的应用。
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引用次数: 0
The impact of Rudi J. J. Stamm'ler on the development of the nuclear industry in Argentina 鲁迪·j·j·斯塔姆勒对阿根廷核工业发展的影响
IF 2.1 3区 工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2026-04-01 Epub Date: 2026-02-09 DOI: 10.1016/j.nucengdes.2026.114817
Eduardo Villarino , Aldo Ferri
This paper examines the technical and methodological contributions of Rudi J. J. Stamm'ler that shaped the historical development of nuclear technology and reactor physics capabilities in Argentina. Through successive missions supported by the International Atomic Energy Agency (IAEA), Rudi Stamm'ler played a decisive role in the training of highly qualified human resources at the Balseiro Institute and in the establishment of national computational capabilities in reactor physics and design. His influence extended to the development of essential calculation tools, the consolidation of independent nuclear design methodologies in Argentina, and the professional growth of engineers who later contributed to major national and international nuclear initiatives. The long-term impact of this work is reflected in the continued use of the computational methods he promoted and in an enduring technical and academic legacy within Argentina's nuclear engineering community.
本文考察了Rudi J. J. Stamm'ler在技术和方法上的贡献,这些贡献塑造了阿根廷核技术和反应堆物理能力的历史发展。通过国际原子能机构(原子能机构)支助的连续任务,鲁迪·斯塔姆勒在训练巴尔塞罗研究所的高素质人力资源和建立反应堆物理和设计方面的国家计算能力方面发挥了决定性作用。他的影响力扩展到基本计算工具的开发,阿根廷独立核设计方法的巩固,以及后来为重大国家和国际核倡议做出贡献的工程师的专业成长。这项工作的长期影响反映在他所倡导的计算方法的持续使用以及阿根廷核工程界持久的技术和学术遗产中。
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引用次数: 0
Experimental investigation of gas-phase migration behaviors in a 1 × 2 rod bundle under two-phase equilibrium and non-equilibrium flow 两相平衡和非平衡流动下1 × 2棒束气相迁移行为的实验研究
IF 2.1 3区 工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY Pub Date : 2026-04-01 Epub Date: 2026-01-31 DOI: 10.1016/j.nucengdes.2026.114806
Hao Xie, Wenhai Qu, Jinbiao Xiong
Void fraction gradient was assumed as the mechanism of void drift between subchannels. However, classical void drift models based on this assumption predict poor results under bubbly flow and cap-bubbly flow against experimental data. In this work, void fraction and bubble diameter in an enlarged 1 × 2 rod bundle was experimentally investigated by wire mesh sensors (WMS) system under equilibrium and non-equilibrium gas flow rates. The total 168 cases cover bubbly flow, cap-bubbly flow and churn flow defined with bubble shape and volume-base probability density function (VPDF). In general, small bubbles gather near channel walls, while large bubbles concentrate in sub-channel centers. For bubbly flow and cap-bubbly flow, it is difficult for bubbles passing through gap between subchannels. Thus, classical void drift models deviate from experimental results in bubbly flow and cap-bubbly flow. However, when bubble diameter is larger than 0.75 time of pitch of rod bundle, void drift improves obviously because bubbles are large enough to disturb the corresponding subchannel. Under bubbly flow and cap-bubbly flow, large bubbles coalesce in each subchannel. With gas superficial velocity increasing, void fraction and bubble diameter of large bubbles increase, while VPDF of small bubbles decreases. With liquid superficial velocity increasing, void fraction and bubble diameter of large bubbles decrease, while VPDF of small bubbles increases. For churn flow, strong void fraction migration between sub-channels is mainly caused by large bubbles with diameter larger than pitch of 32 mm. Thus, equilibrium distribution of void fraction can be fully developed within distance of 1830 mm under equilibrium and non-equilibrium inlet conditions. This is the reason that classical void drift models predict well against experimental data in churn flow. Large bubbles break down in churn flow. With gas superficial velocity increasing, void fraction and bubble diameter of large bubbles increase, while VPDF of small bubbles decreases. With liquid superficial velocity increasing, void fraction and bubble diameter of large bubbles decrease, while VPDF of small bubbles increases. This work helps to under mechanism of gas migration between sub-channels.
假设孔隙分数梯度是孔隙在子通道间漂移的机制。然而,基于这一假设的经典空洞漂移模型在气泡流和帽泡流条件下对实验数据的预测结果较差。本文采用金属丝网传感器(WMS)系统,实验研究了平衡和非平衡气体流速下,放大1 × 2杆束中的空隙率和气泡直径。共168种情况,包括气泡流、帽状气泡流和以气泡形状和体积基概率密度函数(VPDF)定义的搅拌流。一般情况下,小气泡聚集在通道壁附近,而大气泡集中在次通道中心。对于气泡流和帽状气泡流,气泡很难通过子通道之间的间隙。因此,在气泡流和帽状气泡流中,经典的空洞漂移模型与实验结果存在偏差。而当气泡直径大于杆束节距的0.75倍时,由于气泡大到足以干扰相应的子通道,空隙漂移明显改善。在气泡流和帽状气泡流作用下,各子通道内大气泡聚集。随着气体表面速度的增加,大气泡的孔隙率和气泡直径增大,小气泡的VPDF减小。随着液体表面流速的增大,大气泡的孔隙率和气泡直径减小,而小气泡的VPDF增大。对于搅拌流,子通道之间的强空隙率迁移主要是由直径大于32 mm的大气泡引起的。因此,在平衡和非平衡进口条件下,在1830 mm范围内可以充分发展空隙率的平衡分布。这就是为什么经典的空洞漂移模型能很好地预测搅拌流的实验数据。大气泡在搅拌流中破裂。随着气体表面速度的增加,大气泡的孔隙率和气泡直径增大,小气泡的VPDF减小。随着液体表面流速的增大,大气泡的孔隙率和气泡直径减小,而小气泡的VPDF增大。这一工作有助于研究子通道间天然气运移机理。
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Nuclear Engineering and Design
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