Nuclear Engineering and Technology最新文献

{"title":"A RAMI analysis of the neutron activation system (NAS) for the HCCP-TBM","authors":"Myungho Kim,&nbsp;Chang Shuk Kim,&nbsp;Youngmin Lee,&nbsp;Mu-Young Ahn","doi":"10.1016/j.net.2025.103708","DOIUrl":"10.1016/j.net.2025.103708","url":null,"abstract":"<div><div>The Neutron Activation System (NAS) is a vital diagnostic component of the Helium-Cooled Ceramic Pebble (HCCP) Test Blanket Module (TBM) under development for the ITER project. This study presents the first detailed RAMI (Reliability, Availability, Maintainability, and Inspectability) analysis specifically applied to the NAS, aiming to ensure it can reliably measure neutron flux and spectrum to support tritium breeding validation and efficiency. By evaluating potential failure modes and their impacts, the analysis identified critical components with high risk, such as the disposal bin, vacuum pump, capsule loader, and transfer station. To address these issues, targeted mitigation strategies, including design improvements and enhanced maintenance protocols, were proposed, which effectively reduced the criticality levels of these components. The study also emphasized the importance of spare parts optimization and proactive maintenance to maintain high system availability over a projected 20-year operation. The results underscore the importance of integrating RAMI analysis in the early design phase to identify and mitigate risks, thereby ensuring long-term stability and reliability of diagnostic systems like the NAS in fusion energy applications.</div></div>","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"57 10","pages":"Article 103708"},"PeriodicalIF":2.6,"publicationDate":"2025-05-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144106748","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":"Comparison of CNN-based deep learning architectures for unsteady CFD acceleration on small datasets","authors":"Sangam Khanal ,&nbsp;Shilaj Baral ,&nbsp;Joongoo Jeon","doi":"10.1016/j.net.2025.103703","DOIUrl":"10.1016/j.net.2025.103703","url":null,"abstract":"<div><div>CFD acceleration for virtual nuclear reactors or digital twin technology is a primary goal in the nuclear industry. This study compares advanced convolutional neural network (CNN) architectures for accelerating unsteady computational fluid dynamics (CFD) simulations using small datasets based on a challenging natural convection flow dataset. The advanced architectures such as autoencoders, UNet, and ConvLSTM-UNet, were evaluated under identical conditions to determine their predictive accuracy and robustness in autoregressive time-series predictions. ConvLSTM-UNet consistently outperformed other models, particularly in difference value calculation, achieving lower maximum errors and stable residuals. However, error accumulation remains a challenge, limiting reliable predictions to approximately 10 timesteps. This highlights the need for enhanced strategies to improve long-term prediction stability. The novelty of this work lies in its fair comparison of state-of-the-art CNN models within the RePIT framework, demonstrating their potential for accelerating CFD simulations while identifying limitations under small data conditions. Future research will focus on exploring alternative models, such as graph neural networks and implicit neural representations. These efforts aim to develop a robust hybrid approach for long-term unsteady CFD acceleration, contributing to practical applications in virtual nuclear reactors.</div></div>","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"57 10","pages":"Article 103703"},"PeriodicalIF":2.6,"publicationDate":"2025-05-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144204325","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":"Inspection of lead aprons damage and evaluation of transmission rate with a 99mTc point-source","authors":"Nazenin İpek Işıkcı ,&nbsp;Mohammad Abuqbeitah ,&nbsp;Nami Yeyin ,&nbsp;Sinem Akyol ,&nbsp;Mustafa Demir","doi":"10.1016/j.net.2025.103689","DOIUrl":"10.1016/j.net.2025.103689","url":null,"abstract":"<div><div>The intent was to inspect the damage to lead aprons worn by radiation practitioners and experimentally measure the relative transmission rates for undamaged and damaged aprons.Fluoroscopy and X-ray scans were made for 281 lead aprons collected from various departments of a large-capacity hospital. Dose rate measurements were obtained using an ionization chamber detector and ^99mTc point source. The transmission rates of the undamaged and damaged aprons were calculated and statistically evaluated. Big tears and crack, besides unknown ones named type 1, type 2, type 3, and type 4. Only 14.5 % aprons were counted as damaged and 32 % were used in the operation room unit. The transmission rate of the undamaged aprons was determined as 50.88 %. The transmission rates calculated for Big tears, cracks, type 1, type 2, type 3, and type 4 damages were 91.30 %, 62.75 %, 53.22 %, 58.10 %, 57.88 %, and 55.54 %, respectively. The study revealed that aside from common damages like tears and cracks, various damages and defects may significantly affect radiation transmission. This is to conclude that periodic fluoroscopy and X-ray scans are essential to explore such invisible damages and enhance radiation protection among radiation workers. Future studies are recommended to investigate preventive measures for apron damage.</div></div>","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"57 10","pages":"Article 103689"},"PeriodicalIF":2.6,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947973","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":"Numerical simulation of radon ventilation optimization in filling stope of trackless Z-shaped roadway","authors":"Yongjun Ye ,&nbsp;Xuanli Yao ,&nbsp;Daijia Chen ,&nbsp;Ning Zhou","doi":"10.1016/j.net.2025.103691","DOIUrl":"10.1016/j.net.2025.103691","url":null,"abstract":"<div><div>In order to study the laws of radon reduction ventilation in a stope with trackless Z-shaped filling method, the actual geometric structure, ventilation parameters, and radon exhalation rate of the exposed surface of this type of stope are determined. The air flow rate distribution, average radon concentration and the volume proportion exceeding the stipulated limit in stopes of different heights were studied by CFD method for the direct ventilation structure and the improved structure with adjustable air curtain. The results show that: 1) For the existing ventilation structure, with the increase of the height of the stope, the air flow rate into the workspace of the stope gradually decreases, and is lower than the required value for radon reduction in the stope, resulting in the average radon concentration in the stope greatly exceeding the stipulated limit. 2) For the improved structure with an adjustable air curtain at the upper mouth of the Z-shaped ramp, the air flow rate can be effectively allocated to the workspace of the stope, and the average radon concentration and the volume proportion exceeding the stipulated limit can be reduced. 3) Based on the numerical simulation results, the relation between the air flow rate of the workspace and the total air flow rate, the height of the stope, and the area ratio of adjustable air curtain to ramp is established, which provides a reference for optimizing the air flow rate distribution of radon reduction ventilation by adjusting the area ratio of adjustable air curtain to ramp.</div></div>","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"57 10","pages":"Article 103691"},"PeriodicalIF":2.6,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144069155","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":"In-depth numerical investigation on three-dimensional flow phenomena in a MONJU wire-wrapped 169-pin fuel bundle using vortex core identification","authors":"Seongchul Park ,&nbsp;Koji Morita ,&nbsp;Jae-Ho Jeong","doi":"10.1016/j.net.2025.103698","DOIUrl":"10.1016/j.net.2025.103698","url":null,"abstract":"<div><div>This investigation presents a novel computational approach to analyzing three-dimensional flow phenomena within a MONJU wire-wrapped 169-pin fuel assembly. Complex vertical flow patterns generated by wire spacers have been investigated using RANS simulations with an SST turbulence model, introducing an innovative vortex structure identification methodology based on critical point theory.</div><div>Numerical results show excellent agreement with experimental measurements from JNC, achieving validation across identical pin configurations. The study reveals distinct flow patterns between interior and edge subchannels, identifying periodic vortex formation synchronized with wire spacer positioning. Edge subchannels have enhanced flow characteristics, with velocity profiles showing marked differences from interior regions. Results demonstrate significant variations in both axial and tangential flows across subchannel types, with edge subchannels showing higher velocities and intensified turbulence patterns due to longitudinal vortex structures.</div><div>Longitudinal vortex structures in the edge subchannels have the opposite direction to the rotation of the wire-spacer, as confirmed through vortex identification analysis. These structures exist over approximately 20 % of the wire-spacer pitch length, with negative normalized helicity values validating our hypothesis from previous studies. While corner subchannels also show vortex structures, normalized helicity values indicate these are primarily local separation vortices. Inner subchannel structures generally consist of separation vortices, but at wire-spacer onset points, longitudinal vortices are also generated for certain periods and lengths. The analysis validates numerical predictions within 2 % of experimental data, with edge regions demonstrating 16 % higher axial velocities and 12 % stronger tangential flows compared to interior subchannels. This comprehensive investigation advances our understanding of complex flow dynamics in wire-wrapped fuel assemblies, contributing valuable insights for nuclear reactor design optimization.</div></div>","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"57 10","pages":"Article 103698"},"PeriodicalIF":2.6,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144195946","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":"Methodology to quantify the efficacy of iodine thyroid blocking via Level 3 PSA to support emergency planning","authors":"Jia Hao Tang ,&nbsp;Sung-yeop Kim","doi":"10.1016/j.net.2025.103701","DOIUrl":"10.1016/j.net.2025.103701","url":null,"abstract":"<div><div>Iodine thyroid blocking (ITB) is an important aspect of the emergency protective action critical in safeguarding the population from adverse health effects from radioiodine that may potentially be released in a nuclear accident. Efficacy and impact of ITB has been dependent on qualitative assessment and expert judgement. To better evaluate the influence of ITB, this study aims to provide a methodology to tap into the results from iodine biokinetic models and couple them with Level 3 PSA MACCS code. In this methodology, ITB efficacy is determined from plume exposure time data derived from Level 3 PSA and the efficacy curve from an iodine biokinetic model. As a result, acute radiation doses can be obtained to provide an informative analysis of ITB. This study also showcases three applications of the methodology to evaluate ITB distribution strategies and incorporation into emergency action plans. The results suggest that pre-distribution is preferred for the population at a close distance from the release site. It is also noted that timely activation of the ITB strategy is a critical factor in ensuring efficacy. Finally, potential improvements to emergency action plans regarding the incorporation of ITB by considering the time points of accident sequences are suggested.</div></div>","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"57 10","pages":"Article 103701"},"PeriodicalIF":2.6,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144184978","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":"Radon and thoron in the ambient air of the caves in Bohol Island, Philippines","authors":"Angelo A. Panlaqui ,&nbsp;Florencio C. Ballesteros Jr. ,&nbsp;Kristine Marie R. Dean ,&nbsp;Chutima Kranrod ,&nbsp;Shinji Tokonami","doi":"10.1016/j.net.2025.103702","DOIUrl":"10.1016/j.net.2025.103702","url":null,"abstract":"<div><div>Radon and thoron concentrations in the ambient air were investigated in the caves of Bohol Island, Philippines. The study focused on Hinagdanan, Batungay, and Princess Manan-aw Caves to establish the baseline data on current radon and thoron levels and estimate the effective doses absorbed by tourists and workers during tour operations, specifically due to radon and its progeny. Radon and thoron were measured using a CR-39-based detector called the Raduet, which was placed along the cave pathways. Radon concentration inside the caves ranges from 127 to 1829 Bq m⁻³, while thoron concentration varies from 28 to 1574 Bq m⁻³. Results showed that radon levels in all three caves exceeded the recommended safety limit (300 Bq m⁻³), which may have been influenced by cave structures affecting natural ventilation. Despite the high radon concentrations in these caves, tourists are generally safe due to low exposure time. However, the estimated annual effective dose for cave guides was found to vary from 0.77 to 46.27 mSv y⁻¹. If uncontrolled, doses to occupationally exposed workers due to radon and thoron may exceed the country's national dose limit (20 mSv y⁻¹) and may increase the risks of health effects.</div></div>","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"57 10","pages":"Article 103702"},"PeriodicalIF":2.6,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144106750","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":"Imaginaries of the resilient second nuclear era: Nuclear paradox resolution and a feasible atomic priesthood","authors":"Juan Chen ,&nbsp;Isaac Yap","doi":"10.1016/j.net.2025.103695","DOIUrl":"10.1016/j.net.2025.103695","url":null,"abstract":"<div><div>The enduring philosophical and political struggle between embracing nuclear energy as a climate solution and an economic catalyst, and resisting it over risks of weapons proliferation and catastrophic accidents, has been a prominent fixture since the aftermath of Hiroshima and Nagasaki. Termed as the nuclear paradox, this dual framing of nuclear energy often oscillates between promise and peril depending on which aspect of its duality appears more immediate, leaving society to navigate the difficult trade-offs. This study re-examines the structural shortcomings of the first nuclear era and outlines the conditions necessary for a more resilient second phase of nuclear development in the context of today's evolving energy market. It argues that the Liquid Fluoride Thorium Reactor (LFTR), through its distinctive reactor design and fuel cycle, offers a comprehensive response to long-standing concerns about safety, economic viability, proliferation, and waste permanence—exemplified by the ill-fated concept of the Atomic Priesthood. The analysis concludes with concrete policy recommendations to accelerate LFTR research and implementation, contributing to the realization of a more secure and sustainable nuclear energy future.</div></div>","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"57 10","pages":"Article 103695"},"PeriodicalIF":2.6,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144189521","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":"Food surface radiation sterilization","authors":"S.Yu. Sokovnin","doi":"10.1016/j.net.2025.103690","DOIUrl":"10.1016/j.net.2025.103690","url":null,"abstract":"<div><div>The proposed methodology entails the utilization of surface sterilization using a nanosecond electron beam. This approach has demonstrated efficacy in the sterilization of products characterized by inedible shells, such as eggs, or sterility from pathogens throughout the volume under standard manufacturing or processing conditions (e.g., pieces of meat and meat products, animal feed pellets, etc.). Importantly, the primary product is shielded from direct electron beam irradiation, thereby preventing any adverse alterations, including the embryo which is not affected. The application and successful implementation of the suggested technology are illustrated through specific examples.</div></div>","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"57 10","pages":"Article 103690"},"PeriodicalIF":2.6,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143937474","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":"Design characteristics of nuclear steam supply system and passive safety system for Innovative Small Modular Reactor (i-SMR)","authors":"Sang Gyu Lim,&nbsp;Hyun Suk Nam,&nbsp;Do Hwan Lee,&nbsp;Sang Won Lee","doi":"10.1016/j.net.2025.103697","DOIUrl":"10.1016/j.net.2025.103697","url":null,"abstract":"<div><div>In response to the growing global climate crisis, nuclear power, particularly through small modular reactors (SMRs), is emerging as a potential solution for sustainable energy production. This paper presents an innovative SMR (i-SMR) design being developed in the Republic of Korea, which integrates proven technologies from existing pressurized water reactors while emphasizing enhanced safety, cost-effectiveness, and operational flexibility. The i-SMR features a fully passive safety system, achieving a core damage frequency of 1E-9, thus significantly reducing the necessity for public evacuation during potential accidents. The i-SMR design incorporates several key elements, including a boron-free operation, a helical coil steam generator, an in-vessel control rod drive mechanism, and a canned-motor reactor coolant pump within an integrated nuclear steam supply system. This paper explores the design characteristics and the detailed operating mechanism of the passive safety system, comprising the passive emergency core cooling system, passive auxiliary feedwater system, and passive containment cooling system. Safety performance analyses were conducted for a loss-of-coolant accident using the Multi-dimensional Analysis of Reactor Safety (MARS) code. The analysis results demonstrate the performance and the thermal-hydraulic behavior of the passive safety system with key phenomena affecting the performance.</div></div>","PeriodicalId":19272,"journal":{"name":"Nuclear Engineering and Technology","volume":"57 10","pages":"Article 103697"},"PeriodicalIF":2.6,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144184976","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}