{"title":"A cavitation performance prediction method for pumps PART4—Sensitivity and accuracy validation for axial-flow reactor coolant pump","authors":"Xu Yuan, Long Yun","doi":"10.1016/j.nucengdes.2025.114224","DOIUrl":"10.1016/j.nucengdes.2025.114224","url":null,"abstract":"<div><div>To address the challenges of predicting cavitation performance in axial-flow reactor coolant pumps (RCPs), a new method was proposed in the study titled “A Cavitation Performance Prediction Method for Pumps PART3 Feasible for Axial-Flow Reactor Coolant Pump” [1]. The feasibility of this method was validated through experimental studies on axial pumps. Building upon this work, the current research proposes a single-phase cavitation performance prediction method based on the pressure isosurface area ratio. By integrating numerical simulations and experimental validation, the study explores how the pressure isosurface correlates with the critical net positive suction head (NPSH) across different flow conditions. A model was developed to represent the ratio of the pressure isosurface area to the blade area, offering insights into the mechanisms of cavitation onset and progression. The findings emphasize the sensitivity of this area ratio to variations in flow rate. During validation, predictions for different area ratios (Rs = 9.67 %, Rs = 10.52 % and Rs = 11.76 %) and compared with experimental data. The results demonstrate that when Rs = 10.52 %, the cavitation performance prediction aligns closely with the experimental results, exhibiting high accuracy. This method significantly reduces the iterative optimization steps required during the pump design process, thereby improving design efficiency. Additionally, a detailed analysis of the trends in pressure isosurface area variation under different flow conditions further validates the reliability and applicability of this method across multiple operating conditions.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"442 ","pages":"Article 114224"},"PeriodicalIF":1.9,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144255114","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}
Koji Nishida, Hirokaki Takanami, Seitaro Sakurai, Michio Murase
{"title":"Evaluation of core degradation and relocation before and after water injection in the LOFT experiment LP-FP-2","authors":"Koji Nishida, Hirokaki Takanami, Seitaro Sakurai, Michio Murase","doi":"10.1016/j.nucengdes.2025.114208","DOIUrl":"10.1016/j.nucengdes.2025.114208","url":null,"abstract":"<div><div>We used MAAP5 to examine the fuel cladding temperature, hydrogen generation amount and flow area distribution of the LOFT Experiment LP-FP-2. We confirmed that the computed cladding temperature and hydrogen generation amount became close to their measured values when the heat transfer degradation and cladding oxide film spalling that occurred immediately after the water injection were considered. Furthermore, the computed flow area distribution in the height direction approached the measured value if the time for fuel bundle collapse was estimated with the Larson-Miller parameter without the minimum time limit in MAAP5.</div><div>After confirming the applicability of MAAP5 to the LOFT Experiment LP-FP-2, we clarified the hydrogen flow rate and the fuel material relocation before and after the water injection. We found that UO<sub>2</sub> relocated from the upper to the middle heated region after the water injection. On the other hand, the U-Zr-O mixture relocated to the lower heated region before the water injection and its mass increased after the water injection. Furthermore, we also found that the Ag-In-Cd of the control rods relocated to the lower heated region adjacent to the lower unheated region before the water injection.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"442 ","pages":"Article 114208"},"PeriodicalIF":1.9,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144255205","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}
Daiquan Du, Ting Zhang, Wenbin Zhuo, Guangjin Wang
{"title":"Experimental investigation of thermal–hydraulic parameters on the performance of a once-through steam generator (OTSG)","authors":"Daiquan Du, Ting Zhang, Wenbin Zhuo, Guangjin Wang","doi":"10.1016/j.nucengdes.2025.114202","DOIUrl":"10.1016/j.nucengdes.2025.114202","url":null,"abstract":"<div><div>The Once-Through Steam Generator (OTSG) is a critical component in multi-purpose modular small reactor power systems. In this study, a dual-loop experimental system was established to investigate the thermal–hydraulic characteristics of OTSGs, with a focus on analyzing the effects of key parameters—primary-side average temperature, load, steam pressure, and feedwater temperature—on the steady-state thermal–hydraulic behavior. Experimental results reveal that deviations in thermal parameters significantly influence the outlet steam temperature (superheat), heat transfer power, and secondary-side pressure drop. Among these parameters, the primary-side average temperature exhibits the most pronounced impact on the outlet steam temperature, followed by steam pressure, load, and feedwater temperature. Specifically, the superheat decreases as the primary-side average temperature decreases, with a more significant reduction observed near the saturation temperature. At low loads (20%–60% of full power, FP), the superheat decreases linearly with steam pressure, whereas at high loads (60%–120% FP), the rate of decrease in steam superheat intensifies with increasing steam pressure. The superheat initially increases slowly with load, reaches a maximum, and then decreases rapidly. The maximum superheat decreases with increasing steam pressure, and the load required to achieve the maximum superheat point decreases accordingly at higher pressures. Additionally, as the feedwater temperature increases, the superheat decreases, albeit at a relatively modest rate. These findings enhance the understanding of OTSG thermal–hydraulic behavior and provide valuable insights for optimizing their design and operational performance.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"442 ","pages":"Article 114202"},"PeriodicalIF":1.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144241439","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}
Zongkun Li , Yiming Yan , Guangming Fan , Jiyun Zhao , Xiaobo Zeng , Changqi Yan
{"title":"Experimental study on natural circulation flow fluctuation characteristics in tube bundle channels under marine conditions","authors":"Zongkun Li , Yiming Yan , Guangming Fan , Jiyun Zhao , Xiaobo Zeng , Changqi Yan","doi":"10.1016/j.nucengdes.2025.114212","DOIUrl":"10.1016/j.nucengdes.2025.114212","url":null,"abstract":"<div><div>Natural circulation steam generators are of most importance for floating nuclear power plants and nuclear propulsion systems. Marine U-tube steam generators have the characteristics of natural circulation with free liquid surface, and lateral non-uniform heating, coupled with ocean motion, making the flow behavior extremely complex. Therefore, the paper built an experimental platform for natural circulation flow in tube bundle channels with the ability of non-uniform heating under marine conditions, conducting a series of experiments to study the effects of inclination, rolling motion, non-uniform heating, and the above-coupled action on flow fluctuation behavior of natural circulation. The experimental results indicate that rolling motion can cause periodic fluctuations in the natural circulation flow rate, but there are two peaks of the flow rate during one rolling period, which is caused by the periodic aggregation and discharge of bubbles. The increase in heat flux can increase the number of bubbles, making them more susceptible to rolling motion, and it can also increase the steam flow rate, resulting in a more stable flow. The fluctuation of the flow rate increases with the increase of rolling amplitude and frequency, and it is more sensitive to variations in rolling amplitude. The introduction of non-uniform heating results in a significant difference in the two peaks of flow rate during one rolling cycle, thereby exacerbating the degree of flow fluctuations under rolling motion.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"442 ","pages":"Article 114212"},"PeriodicalIF":1.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144241438","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}
{"title":"Review of experimental models and findings on gas entrainment by vortex in hot plenum of sodium fast reactors","authors":"D. Guenadou","doi":"10.1016/j.nucengdes.2025.114211","DOIUrl":"10.1016/j.nucengdes.2025.114211","url":null,"abstract":"<div><div>The presence of gas above the free surface in the hot plenum can have significant safety implications for Sodium Fast Reactors, as gas pockets within the core can affect neutron behavior and potentially lead to variations in core reactivity. One of the primary mechanisms for gas entrainment into the core is associated with vortices formed at the free surface. In response to this observation, extensive studies have been conducted to assess the risk of vortex-induced gas entrainment. Given the complexity and high cost of conducting experiments with sodium, most studies have employed water as a simulant fluid using a similarity approach. These studies generally fall into two categories: one involving basic geometries to identify the key phenomena driving vortex formation, and the other involving scaled models of actual reactor designs aimed at safety assessment and validation of numerical tools. This article provides an overview of past models used to study gas entrainment and highlights the main findings achieved through these studies.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"442 ","pages":"Article 114211"},"PeriodicalIF":1.9,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144241440","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}
{"title":"Time-dependent neutron transport calculation with a parallel discontinuous finite element SN code SNIPER","authors":"Boran Kong, Tao Dai, Ni Dai","doi":"10.1016/j.nucengdes.2025.114214","DOIUrl":"10.1016/j.nucengdes.2025.114214","url":null,"abstract":"<div><div>Discontinuous finite element method (DFEM) based discrete ordinates (S<sub>N</sub>) is an important numerical method for solving time-dependent transport equation due to its geometry adaptivity and high accuracy. The parallel strategies of DFEM S<sub>N</sub> can be divided into Gauss-Seidel and block Jacobi. In this article, the parallel performance of several Gauss-Seidel parallel strategies and the block Jacobi strategy are compared and analyzed. The thresholds of fixed source scaling factor method (FSSFM) are analyzed through 2D C5G7-TD benchmarks. Also, a 2D time-dependent Fourier analysis is performed. Fourier analysis results show that the convergence behavior of time-dependent S<sub>N</sub> calculation is insensitive to the S<sub>N</sub> quadrature order. With the increase of the number of inner iterations, the spectral radius decreases. With the increase of fission-time term ratio <em>w</em> and scattering ratio <em>c</em>, the spectral radius increases. From the numerical results of the C5G7-TD benchmarks with a parallel S<sub>N</sub> code SNIPER, it can be concluded that the online-judged strategy achieves the highest parallel efficiency among several Gauss-Seidel parallel strategies. Block Jacobi parallel strategy saves about 30 % total time than the Gauss-Seidel strategy. Also, for transient calculation, FSSFM with reasonable thresholds decreases the number of outer iterations by an order of magnitude.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"442 ","pages":"Article 114214"},"PeriodicalIF":1.9,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144241437","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}
{"title":"The modified GOMS model based on CREAM in nuclear power plants of complex scenarios","authors":"Shengyuan Yan, Xiaodan Zhang, Xin Liu","doi":"10.1016/j.nucengdes.2025.114209","DOIUrl":"10.1016/j.nucengdes.2025.114209","url":null,"abstract":"<div><div>This paper proposes a modified GOMS (Goals, Operators, Methods, and Selection Rules) model based on CREAM (cognitive reliability and error analysis method) to decompose the tasks in complex scenarios, and calculate the mental workload of operators in nuclear power plants. The modified GOMS model has two parts, one is the task analysis based on the basic GOMS and CREAM, and the other is the complex scenarios analysis based on Bayesian networks. The modified GOMS method decomposes the tasks using hierarchical task analysis (HTA), and gets the operators combining the cognitive activities from CREAM and the values from the Multiple Resources. The complex scenarios analysis uses the COCOM (contextual control model) from CREAM to analyze complex scenarios, and it considers the 2-Tuple linguistic to evaluate the CPCs when the operators execute the tasks. The approach gets the prior probabilities of complex scenarios and uses Bayesian networks to obtain the control modes impact factor (CMIF). It calculates the mental workload by the modified approach in complex scenarios. A case study uses the modified GOMS model to decompose the hot shutdown, and calculate the mental workload in nuclear power plants. It compares the HTA and the modified GOMS model with the results of NASA-TLX. It verifies the modified GOMS model’s corrective and effective.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"442 ","pages":"Article 114209"},"PeriodicalIF":1.9,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144241436","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}
Jie Cheng, Yibo Zhang, Di Wu, Xiaobo Zeng, Xu Han, Jianjun Wang
{"title":"Experimental study on thermal stratification characteristics of C-shaped heat exchanger under stationary and rolling conditions","authors":"Jie Cheng, Yibo Zhang, Di Wu, Xiaobo Zeng, Xu Han, Jianjun Wang","doi":"10.1016/j.nucengdes.2025.114213","DOIUrl":"10.1016/j.nucengdes.2025.114213","url":null,"abstract":"<div><div>This study investigates the thermal stratification characteristics and operating performance of a C-shaped heat exchanger in the secondary passive residual heat removal system (PRHRS) under stationary and rolling conditions, relevant to Offshore Floating Nuclear Power Plants (OFNPs). A scaled-down experimental facility was designed to simulate the PRHRS, incorporating a swaying platform to replicate marine rolling motions. Experiments were conducted under varying rolling amplitudes (15°, 24°) and periods (8 s, 14 s), with heating powers of 34 kW and 31 kW, to analyze the effects of dynamic conditions on heat removal capacity, system stability, and thermal stratification. Key findings reveal that rolling motion enhances heat removal during the initial operational phase by promoting fluid mixing and natural circulation. However, under quasi-steady states, rolling conditions induced periodic oscillations in system pressure, mass flow rate, and heat removal power, synchronized with the imposed rolling period. Thermal stratification was weakened under rolling motion due to enhanced fluid mixing, though the duration of stratification persistence increased. Notably, larger rolling amplitudes reduced the heat exchanger outlet temperature, while longer periods lowered system pressure. These results provide critical insights into optimizing PRHRS design for OFNPs operating in dynamic marine environments.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"442 ","pages":"Article 114213"},"PeriodicalIF":1.9,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144241435","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}
Md. Nobir Hosen, H. Rainad Khan Rohan, Afroza Shelley
{"title":"Optimization of loading quantity of minor actinides for elimination of boric acid and burnable absorbers from PWRs","authors":"Md. Nobir Hosen, H. Rainad Khan Rohan, Afroza Shelley","doi":"10.1016/j.nucengdes.2025.114198","DOIUrl":"10.1016/j.nucengdes.2025.114198","url":null,"abstract":"<div><div>The use of burnable absorbers for reactivity control in PWRs comes with added costs, potential residual reactivity and power peaking effects, and demands careful consideration of depletion time and reactivity feedback. Again, boric acid in the coolant further complicates reactor operation by requiring water chemistry adjustments and presenting issues such as corrosion, tritium production (from boron) and a less negative moderator temperature coefficient (MTC). This study investigates the feasibility of using minor actinides (MAs) to eliminate both burnable absorbers and boric acid from PWRs, thereby improving safety and reducing long-term radiotoxicity. Six different models were analyzed – three featuring integral burnable absorbers (IBAs) with MA-based fuels, and three without IBAs. The reference was a VVER-1000 fuel assembly with 1000 ppm boric acid in the coolant. MAs were introduced either as inner or outer coatings on the fuel or as homogeneous mixtures within the fuel matrix. Simulations using OpenMC over a 600 EFPD burnup period showed that all studied cases could suppress excess reactivity equivalently to conventional poisons, though with varying MA requirements. MA addition also led to significant transmutation and improved MTC, albeit with some degradation in fuel cycle performance. Homogeneously loaded cases (3A and 3B) proved to be the most effective in controlling reactivity, achieving higher transmutation rates (TRs), improved reactivity feedback, and reduced penalties in cycle length and discharge burnup. Notably, Case 3B fully compensated for both gadolinia and boric acid, achieved the highest TR of 25.82 %/y for all MAs combined, and exhibited the most negative MTC.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"442 ","pages":"Article 114198"},"PeriodicalIF":1.9,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144229523","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}
Andika Putra Dwijayanto , Fitria Miftasani , Nina Widiawati
{"title":"Evaluating the benefit of thorium in a two-zone thermal molten salt reactor using open fuel cycle","authors":"Andika Putra Dwijayanto , Fitria Miftasani , Nina Widiawati","doi":"10.1016/j.nucengdes.2025.114216","DOIUrl":"10.1016/j.nucengdes.2025.114216","url":null,"abstract":"<div><div>Thorium is a promising alternative fuel to uranium. Unlike uranium, thorium can attain breeding condition in thermal neutron spectrum. This benefit can be achieved especially by using molten salt reactor (MSR), especially with its online reprocessing capability. In an open fuel cycle, however, this benefit is less clear. This study evaluates the utilisation of thorium in an MSR using open fuel cycle using OpenMC code and ENDF/B-VII.1 library. The evaluated model was based on two-zone, single fluid MSR commonly used in thermal breeder MSR. Four fuel scenarios were simulated, namely LEU-U8, LEU-Th, RGPu-U8, and RGPu-Th, based on different configurations of fissile and fertile materials. Among the analysed parameters are reactor effective full power days (EFPD), conversion ratio (CR), fuel utilisation efficiency, and minor actinide (MA) production. The LEU-U8 configuration exhibits high initial reactivity but a large reactivity swing, which shortens its EFPD. In contrast, LEU-Th demonstrates slower reactivity depletion due to the efficient conversion of <sup>232</sup>Th to <sup>233</sup>U. RGPu-based fuels, particularly RGPu-U8, have shorter cycles due to the large neutron absorption by <sup>240</sup>Pu. LEU-Th and RGPu-Th attain the highest CR, indicating more efficient use of fertile fuel than their uranium counterparts. Using thorium generates lower MA waste, although the difference is small in RGPu-based fuel. Therefore, in a two-zone MSR using open fuel cycle, thorium exhibits some advantages over uranium both using LEU or RGPu as the fissile driver.</div></div>","PeriodicalId":19170,"journal":{"name":"Nuclear Engineering and Design","volume":"442 ","pages":"Article 114216"},"PeriodicalIF":1.9,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144230355","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}