Progress in Nuclear Energy最新文献

{"title":"Uncertainty aware unsupervised fault diagnosis of PWR nuclear power plant using KNN and SHAP method","authors":"Fazle Haseeb ,&nbsp;Minjun Peng ,&nbsp;Furqan Arshad ,&nbsp;Wasiq Ali","doi":"10.1016/j.pnucene.2025.106191","DOIUrl":"10.1016/j.pnucene.2025.106191","url":null,"abstract":"<div><div>Machine learning based fault diagnosis methods in nuclear power plants (NPPs) often exhibit lack of labeled fault data in sufficient quantity, thus posing a significant challenge for the supervised fault diagnosis. This paper presents a novel, uncertainty-aware, and unsupervised fault diagnosis framework for pressurized water reactor (PWR) type NPP. For this purpose, it integrates the k-nearest neighbors (KNN) method with shapley additive explanations (SHAP) analysis, not only to enhance the model interpretability but also to ensure its reliability. The KNN model, trained on steady-state operational data, firstly detects anomalies, while SHAP analysis subsequently performs the fault classification in an unsupervised manner. For the purpose of fault classification, feature contributions are computed for each detected anomaly, thus providing an interpretable features pattern. This pattern information is further analyzed and transformed into an entropy-based metric, which is calculated from the normalized SHAP values. This metric enables a transparent classification between the sensor and process faults. Regarding the sensor faults, this methodology further provides the identification of the faulty sensor through the analysis of the highest contributing feature. In this way, explainable artificial intelligence (XAI) has been utilized not only for model interpretation but has also played its role in the fault diagnosis process. Additionally, a bootstrap resampling approach has been incorporated for the estimation of model uncertainty, thus providing the confidence measures that support safer and risk-informed decisions. Performance of the proposed methodology has been evaluated against various sensor and process faults, not only through clean data but also against noisy data. An inter-comparison among various anomaly detection methodologies within the proposed framework has also been presented. The testing results demonstrate that the proposed method achieves 99.56% ± 0.051% (mean ± standard deviation) classification accuracy across 100 bootstrap iterations, and also shows resilience under noisy conditions. This fully unsupervised, interpretable, and uncertainty-informed framework thus offers a significant advancement for reliable fault diagnosis in safety-critical nuclear power plant operations.</div></div>","PeriodicalId":20617,"journal":{"name":"Progress in Nuclear Energy","volume":"193 ","pages":"Article 106191"},"PeriodicalIF":3.2,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789077","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":"Enhanced safety and emergency decision-making in NPPs: Multi-step parameter prediction for complex accident scenarios","authors":"Siwei Li ,&nbsp;Yichun Wu ,&nbsp;Jiayan Fang ,&nbsp;Wei Wang ,&nbsp;Jiale Ling","doi":"10.1016/j.pnucene.2025.106185","DOIUrl":"10.1016/j.pnucene.2025.106185","url":null,"abstract":"<div><div>Early fault detection and timely initiation of appropriate control or maintenance actions can significantly mitigate operational risks in nuclear power plants (NPPs) and enhance the reliability of operator decision-making during emergencies. Therefore, developing an efficient, multi-step Prognostics and Health Management (PHM) model is essential for the prediction of system health status to support accident mitigation and recovery efforts in NPP operations. In this paper, we propose a novel predictive approach that integrates a bidirectional long short-term memory (BiLSTM) neural network within a multiple input multiple output (MIMO) framework guided by an Expert Fuzzy Evaluation Method (EFEM). The model is trained and validated on simulation data from a CPR1000 pressurized water reactor under various accident scenarios, and it demonstrates a remarkable capability to accurately forecast key NPP parameters up to 128 steps into the future (with a 10-s interval per step, totaling 1280 s, thereby satisfying the temporal advance requirement for fault prognostics in NPPs, and provides valuable decision-support information for operators to control and recover from accidents. The proposed method also serves as an effective reference for other PHM applications such as anomaly detection and remaining useful life estimation.</div></div>","PeriodicalId":20617,"journal":{"name":"Progress in Nuclear Energy","volume":"193 ","pages":"Article 106185"},"PeriodicalIF":3.2,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145739066","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":"Nondestructive burnup evaluation and gamma spectroscopy analysis of spent fuel elements in the ITU TRIGA Mark II research reactor","authors":"A. Kaya ,&nbsp;O. Erbay ,&nbsp;Z. Boduroglu ,&nbsp;I.A. Reyhancan ,&nbsp;M.S. Kiziltas ,&nbsp;T. Akyurek","doi":"10.1016/j.pnucene.2025.106186","DOIUrl":"10.1016/j.pnucene.2025.106186","url":null,"abstract":"<div><div>This study presents a comprehensive burnup analysis of all fuel elements in the ITU TRIGA Mark II research reactor core using non-destructive assay (NDA) techniques based on gamma spectroscopy. Two distinct fuel inspection systems were employed to measure the gamma activity, with ¹³⁷Cs used as the primary burnup indicator due to its strong correlation with fuel depletion. The results show a clear burnup pattern, with higher values in the inner core rings that gradually decreases toward the outer rings. This asymmetric burnup distribution underscores the need for reactor core reconfiguration, for which an optimized layout is proposed. Additionally, gamma spectroscopic analysis of fuel element F30 was conducted at cooling times of 10, 130, and 755 days. The results also suggest that ¹⁴⁰La is a promising candidate for future burnup studies, which will be pursued in subsequent research.</div></div>","PeriodicalId":20617,"journal":{"name":"Progress in Nuclear Energy","volume":"192 ","pages":"Article 106186"},"PeriodicalIF":3.2,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145736226","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":"Multi-physics simulation of the MSFR reactor for an explorative thermo-mechanical analysis of its confinement","authors":"S. Deanesi ,&nbsp;D. Pizzocri ,&nbsp;F. Valsecchi ,&nbsp;A. Cammi ,&nbsp;S. Lorenzi","doi":"10.1016/j.pnucene.2025.106189","DOIUrl":"10.1016/j.pnucene.2025.106189","url":null,"abstract":"<div><div>The Molten Salt Fast Reactor (MSFR) is the representative concept of the liquid-fuelled family within the Generation-IV International Forum. Given the harsh working conditions to which the MSFR is subjected, in terms of thermal load and fast neutron fluence, it is essential to investigate the reactor behaviour in nominal steady state operating conditions and during transient scenarios. This work is focused on assessing the behaviour of the confinement wall in a MSFR under the preliminary design conditions set by current studies. A step-by-step approach is proposed: first, multiphysics simulations coupling neutronics and thermal-hydraulics in OpenFOAM are performed on a 3D domain representative of the primary loop. The outcomes provide representative working conditions to be employed within an Abaqus thermo-mechanical model of a confinement shell simulated in a second step. Overall, the multiphysics and thermo-mechanical models and the material correlations form the foundation of a consistent approach to developing an explorative thermo-mechanical analysis of the component.</div></div>","PeriodicalId":20617,"journal":{"name":"Progress in Nuclear Energy","volume":"192 ","pages":"Article 106189"},"PeriodicalIF":3.2,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145736229","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":"Large language model-assisted digital twin for remote monitoring and control of advanced reactors","authors":"Zavier Ndum Ndum ,&nbsp;Doyeong Lim ,&nbsp;John Ford ,&nbsp;Simon Adu ,&nbsp;Jian Tao ,&nbsp;Yassin Hassan ,&nbsp;Yang Liu","doi":"10.1016/j.pnucene.2025.106172","DOIUrl":"10.1016/j.pnucene.2025.106172","url":null,"abstract":"<div><div>In this paper, we present a novel framework for real-time autonomous monitoring and control of advanced small-scale nuclear reactors by integrating a simulator-based digital twin (DT) with a domain-knowledge-enhanced large language model (LLM). The framework’s architecture, featuring robust bi-directional connectivity via the OPC-UA industrial protocol, was demonstrated on a lead-cooled fast reactor (LFR) case study. The LFR demonstration leverages a customized, MATLAB-Simulink-based simulator with natural circulation and burnup modeling capabilities, which has been validated against the System Analysis Module (SAM) code.</div><div>The system employs a hybrid supervisory methodology that incorporates both a traditional rate-limiting Reference Governor (rl-RG) and a novel, tool-centric LLM agent. The LLM agent’s primary capability involves processing incoming sensor data streams, invoking the simulator and related customized tools to obtain physics-based results, and interpreting this data to understand the current system status. Augmented with custom-built retrieval and diagnostic subroutines, the LLM agent then explains the reactor’s state and generates context-aware, quantitative recommendations for management actions, such as reactivity control and power maneuvers. We found that the control signals recommended by the LLM agent successfully matched those generated by the traditional rl-RG. Furthermore, the framework includes an intuitive, multi-tab graphical user interface that enhances human-machine interaction by enabling real-time transient visualization, interactive LLM queries, and detailed transient analysis. This research highlights the transformative potential of AI-enhanced, DT-based control frameworks for advanced reactors and demonstrates its utility as a robust educational and training tool.</div></div>","PeriodicalId":20617,"journal":{"name":"Progress in Nuclear Energy","volume":"192 ","pages":"Article 106172"},"PeriodicalIF":3.2,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145736227","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":"Uncertainty estimation of bifurcated solutions in the Rayleigh–Bénard problem for advanced nuclear reactors applications","authors":"Fadel M. Nasr ,&nbsp;Mauricio Tano ,&nbsp;Yousry Azmy","doi":"10.1016/j.pnucene.2025.106170","DOIUrl":"10.1016/j.pnucene.2025.106170","url":null,"abstract":"<div><div>Multiphysics models of nuclear reactors frequently comprise nonlinear systems of equations. The nonlinear nature of these models could lead to solution bifurcations, where a small change in a certain parameter, e.g., the thermophysical properties of the coolant, can lead to a sudden change in the system’s behavior. At the point in parameter space where this happens, called a <em>critical point</em>, the Jacobian matrix of the model’s nonlinear operator becomes singular potentially permitting multiple solutions to coexist. In this paper, we perform uncertainty estimation (UE) in a parameter range that includes bifurcated solutions within the context of Rayleigh–Bénard problem. We perform this analysis assuming uncertain temperature difference, and tilt angle for the iterative solution algorithm with a unit Prandtl number (<span><math><mrow><mi>P</mi><mi>r</mi><mo>=</mo><mn>1</mn></mrow></math></span>). Also, we perform this analysis under uncertain thermophysical properties for both FLiBe molten salt and liquid sodium as working fluid. We deploy two approaches to compute statistical moments for the resulting distributions of selected flow-field variables. The first approach is the blind computation of the mean and the standard deviation without any consideration of solution bifurcation, while the second approach utilizes <span><math><mi>k</mi></math></span>-means clustering to cluster each branch’s solutions together and compute separate statistical moments for each branch. The statistical distributions are obtained by perturbing the selected parameters about nominal values that correspond to a solution on one of the valid branches, and that solution is used as initial guess for the iterative solution algorithm. We found that perturbation of any parameter when its nominal value is close to its critical point always leads to branch jumping, <em>i.e., the iterations converge to a solution on a branch different from the branch of the initial guess</em>. This produces a statistical ensemble comprised of fundamentally different solutions leading to wrong mean values and uncertainty estimates, whereas clustering provides an efficient way to deal with this type of computation. This work is important for developing Gen IV nuclear systems because many of these systems rely on natural convection for cooling especially in accident conditions.</div></div>","PeriodicalId":20617,"journal":{"name":"Progress in Nuclear Energy","volume":"192 ","pages":"Article 106170"},"PeriodicalIF":3.2,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145736228","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":"Study on the neutronic effects of annular metallic fuel irradiation swelling in a fast reactor core","authors":"Wenhua Yang ,&nbsp;Liang Zhang ,&nbsp;Shouhua Sun,&nbsp;Shuai Jin,&nbsp;Yixing Xu,&nbsp;Jin Lei,&nbsp;Yixiong Sun,&nbsp;Wenbin Zhao","doi":"10.1016/j.pnucene.2025.106181","DOIUrl":"10.1016/j.pnucene.2025.106181","url":null,"abstract":"<div><div>The metallic fuel is a fast reactor fuel with good application prospects. Due to the anisotropic irradiation swelling of the metallic fuel slug, the spatial distribution of fissile materials in the core is changed, and the reactor neutronics performance is affected by the changes of neutron energy spectrum and neutron leakage rate of the core. In this paper, the Monte Carlo code RMC is used to establish the calculation model of a lead bismuth eutectic cooled fast reactor (LFR) with annular slug metallic fuel. The neutronics calculation of the core under different fuel swelling and different fuel burnup conditions is carried out. The quantitative calculation of the influence of three factors on k_eff, including radial swelling, axial swelling and fuel temperature rise, was performed. The influence of irradiation swelling on the neutronics parameters of the core and its change with fuel burnup are analyzed. The results show that the radial irradiation swelling of the core introduces positive reactivity, while the axial swelling and the rise of the fuel temperature caused by the fuel swelling introduce negative reactivity. There is a linear relationship between the axial elongation of the core and the introduced reactivity. For every 1 % axial elongation of the UZr and UPuZr fuel slug, the introduced reactivity is about −100 pcm. Considering the irradiation swelling of the fuel, the absolute values of the fuel axial expansion reactivity coefficient and fuel temperature reactivity coefficient increases by 35 % and 16 % respectively, and the core reactivity decreases by about 300 pcm ∼ 500 pcm. Combined with the irradiation swelling approximate model of annular metallic fuel, an approximate evaluation model of reactor reactivity caused by irradiation swelling under different burnup was obtained.</div></div>","PeriodicalId":20617,"journal":{"name":"Progress in Nuclear Energy","volume":"192 ","pages":"Article 106181"},"PeriodicalIF":3.2,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145736225","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":"A review of Monte Carlo-based multiphysics coupling in nuclear reactor analysis","authors":"Shanfang Huang ,&nbsp;Guodong Liu ,&nbsp;Ying He ,&nbsp;Xingyu Zhao ,&nbsp;Zhigang Li ,&nbsp;Yugao Ma ,&nbsp;Meiming Qiu ,&nbsp;Yongtang Wang ,&nbsp;Haisheng Chen ,&nbsp;Junren Hou ,&nbsp;Kaiwen Li ,&nbsp;Hao Luo ,&nbsp;Chuan Lu ,&nbsp;Kan Wang","doi":"10.1016/j.pnucene.2025.106178","DOIUrl":"10.1016/j.pnucene.2025.106178","url":null,"abstract":"<div><div>The operation of nuclear reactors involves a complex interplay among multiple physical processes. Accurate reactor simulation requires the implementation of multiphysics coupling. Neutronics holds a particularly distinctive role in simulation, and can be solved via deterministic or Monte Carlo (MC) methods. Although research on deterministic-based coupling started earlier, MC-based coupling methods have been increasingly applied in recent years for both analyses of conventional reactors and designs of advanced reactors, due to their high fidelity. In view of this, this paper provides a comprehensive review of MC-based multiphysics coupling in nuclear reactors. Multiphysics coupling issues in representative reactors such as light water reactors, heat pipe-cooled reactors, and high-temperature gas-cooled reactors are systematically presented. Furthermore, multiphysics coupling technologies including cross-section treatments, coupling methods, iteration strategies, data mapping, data transfer, and convergence criteria are extensively discussed. Challenges and future exploration are also enumerated. This review indicates that while MC-based coupling demonstrates superior aptitude for simulation of advanced reactors, current research remains predominantly focused on methodological studies. Leveraging high-performance computing resources and artificial intelligence, the development of advanced algorithms such as tight, transient and full-loop coupling will accelerate the deployment. This comprehensive analysis thereby establishes the review as both a guide for newcomers and an up-to-date reference for researchers.</div></div>","PeriodicalId":20617,"journal":{"name":"Progress in Nuclear Energy","volume":"192 ","pages":"Article 106178"},"PeriodicalIF":3.2,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145681133","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":"Influence of network modifiers on the physical, structural, elastic, thermal properties of lead boroaluminate glasses for advanced radioactive waste management","authors":"M. Vijayakumar ,&nbsp;J. Inico Valanarasi ,&nbsp;K. Ramachandran ,&nbsp;M.S. Al-Buriahi ,&nbsp;Nada Alfryyan ,&nbsp;P. Devendran ,&nbsp;K. Maheshvaran","doi":"10.1016/j.pnucene.2025.106187","DOIUrl":"10.1016/j.pnucene.2025.106187","url":null,"abstract":"<div><div>In this study, a series of europium ions incorporated lead boroaluminate glasses containing a composition of 69B₂O₃+5Al₂O₃+10PbO+15MO+1Eu₂O₃ (where M = Li₂O, Na₂O, K₂O, MgO, CaO, SrO in wt%) were synthesized and characterized to evaluate their potential for radiation shielding applications. The influence of various alkali and alkaline earth modifiers on physical, structural, thermal and elastic properties was systematically examined. Density showed a clear compositional dependence, increasing from 3.155 g/cm³ (K) to 3.897 g/cm³ (Sr), while the molar volume varied between 18.375 and 25.416 cm³/mol, reflecting the combined effects of cation size and field strength on network packing. The refractive index increased steadily from n_d = 1.632 (Li) to n_d = 1.881 (Sr), consistent with enhanced polarizability in heavier modifier-containing glasses. FTIR spectral analysis revealed significant structural changes, including the transformation of BO₃ to BO₄ units and a reduction in non-bridging oxygens, confirming enhanced polymerization. Mechanical studies showed that Sr²⁺- and Ca²⁺-rich glasses exhibited superior Young's, shear, and bulk moduli, reflecting better mechanical strength and rigidity. Thermal analysis through TG/DSC indicates the well-defined glass transition and crystallization events, with T_g and ΔT values strongly dependent influenced by the modifiers. Radiation shielding performance was evaluated using parameters such as mass attenuation coefficient (MAC), mean free path (MFP), half-value layer (HVL), electron density (N_eff) and effective atomic number (Z_eff). The radiation-shielding performance improved across the series, with MAC decreasing from 0.090 to 0.063 cm²/g, HVL reducing from 3.23 to 3.04 cm, and MFP shortening from 5.02 to 4.11 cm at 1 MeV while incorporating different modifiers from Li to Sr in the present compositions. Glasses containing Ca and Sr demonstrated enhanced photon interaction probabilities and reduced penetration depths compared to conventional shielding concretes. Moreover, buildup factor analysis and fast neutron removal cross-sections (FNRC) confirmed the dual-mode shielding capability of these glasses. The performance of the prepared glasses is benchmarked against commercial glass types such as RS 253, RS 360, RS 520, and RS G18/G19 and shielding concretes. The findings establish that careful selection of modifier oxides, especially Sr²⁺ and Ca²⁺, significantly enhances both structural and shielding efficiency, positioning these glasses as promising alternatives for compact and efficient radiation shielding materials in the advance nuclear waste management amenities.</div></div>","PeriodicalId":20617,"journal":{"name":"Progress in Nuclear Energy","volume":"192 ","pages":"Article 106187"},"PeriodicalIF":3.2,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145681060","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":"Experimental study on discharge behavior in automatic depressurization system: High pressure two phase discharge characteristics of pipeline","authors":"Zhengrun Shang ,&nbsp;Dufeng Lv ,&nbsp;Zhongning Sun ,&nbsp;Zhaoming Meng ,&nbsp;Pei Yu","doi":"10.1016/j.pnucene.2025.106184","DOIUrl":"10.1016/j.pnucene.2025.106184","url":null,"abstract":"<div><div>To investigate the high pressure two phase discharge characteristics within the multi-stage pipelines of automatic depressurization system (ADS) under actual operating conditions, this study conducted experimental research on high pressure two phase discharge in multi-stage pipelines. The results shows that with an increase the number of depressurization stages, the pressure drop percentage of the discharge main pipeline increases, and the pressure drop percentage of ADS valve package decreases. Additionally, the position of the maximum pressure drop percentage in the valve package migrates upstream with the increase of depressurization stages. When the equilibrium quality is 90∼100 % and the pressure is 2–13.6 MPa, the equilibrium quality along the flow direction initially decreases and then increases, and as the inlet pressure increases, the inflection point gradually moves downstream. In the other conditions, the equilibrium quality shows an upward trend. When the equilibrium quality is 10–90 %, the pressure is 0–13.6 MPa and the equilibrium quality is 0–10 %, the pressure is 2–13.6 MPa, the equilibrium quality changes significantly along the pipeline. And other conditions is not obvious.</div></div>","PeriodicalId":20617,"journal":{"name":"Progress in Nuclear Energy","volume":"192 ","pages":"Article 106184"},"PeriodicalIF":3.2,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145681056","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}