Volume 4: Student Paper Competition最新文献_第5页

Liquid Film Behavior of Bottoming Liquid Jet in a Shallow Pool Measured by 3D-LIF 用3D-LIF测量浅池底液射流液膜行为

Volume 4: Student Paper Competition Pub Date : 2021-08-04 DOI: 10.1115/icone28-64733

Sota Yamamura, H. Yoshida, Naoki Horiguchi, A. Kaneko, Y. Abe

{"title":"Liquid Film Behavior of Bottoming Liquid Jet in a Shallow Pool Measured by 3D-LIF","authors":"Sota Yamamura, H. Yoshida, Naoki Horiguchi, A. Kaneko, Y. Abe","doi":"10.1115/icone28-64733","DOIUrl":"https://doi.org/10.1115/icone28-64733","url":null,"abstract":"\u0000 When the core meltdown accident occurs in the nuclear plant, molten corium falls into a coolant pool of the lower plenum. It is considered that the molten corium jet is broken up, cooled, and solidified with fuel-coolant interaction (FCI). However, the coolant pool could be a shallow condition by the leakage and evaporation of the coolant. In this situation, it is considered that the corium jet bottoms and spreads without the jet breakup. From the viewpoint of safety, understanding a jet behavior and estimating a cooling behavior are needed.\u0000 The purpose of this study is to clarify the mechanism of the liquid jet behavior in a shallow pool as the fundamental process for estimating the cooling behavior in the real machine. In this paper, we discuss the spreading behavior of the liquid jet after bottoming. The jet injection experiment was conducted using test fluids. By using the 3D-LIF method, the 3D visualization of the liquid jet was Successfully implemented. From the visualization result, the following behaviors were seen. After bottoming, the jet spread radially with the liquid film. As the jet spreading behavior, the liquid film was rolled up to the inside, and the vortex was formed. After a certain time, the vortex was broken. Then the flow and the number density of the fragment were changed.","PeriodicalId":108609,"journal":{"name":"Volume 4: Student Paper Competition","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130353418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Preliminary Design of a Fuel Element With Divergent Hot Gas Channel In Particle Bed Reactor for Nuclear Thermal Propulsion 核热推进用颗粒床堆发散式热气通道燃料元件的初步设计

Volume 4: Student Paper Competition Pub Date : 2021-08-04 DOI: 10.1115/icone28-64771

Zhao Liang, Yu Ji, Jun Sun, Chenrui Mao, Lei Shi

{"title":"Preliminary Design of a Fuel Element With Divergent Hot Gas Channel In Particle Bed Reactor for Nuclear Thermal Propulsion","authors":"Zhao Liang, Yu Ji, Jun Sun, Chenrui Mao, Lei Shi","doi":"10.1115/icone28-64771","DOIUrl":"https://doi.org/10.1115/icone28-64771","url":null,"abstract":"\u0000 The nuclear thermal propulsion (NTP) system can shorten the travel time in deep space exploration and reduce the initial mass of the launch vehicle due to its superior characteristics including high specific impulse and large thrust. Particle bed reactor (PBR) is one of the most appropriate reactor concepts to equip the NTP systems. To make the best use of PBR, the thermal-hydraulic design of the fuel element should be carefully considered and a flow-power matching technology should be developed. In this paper, a novel design employing a divergent hot gas channel is proposed to achieve a uniform flow distribution with lower maximum temperature and pressure drop. Through the analysis of the 1D modified momentum equation in the inlet plenum and hot gas channel, the model of pressure drop is established. Then, the differential equation of the ideal cross-section of the hot gas channel is derived. At last, the flow and heat transfer process in the fuel element with divergent hot gas channel is simulated by using computational fluid dynamics (CFD) code, and the reduction of pressure drop and temperature verifies the theoretical model.\u0000 This study shows that the proposed design of the divergent hot gas channel can provide a new idea for thermal-hydraulic optimization of the PBR fuel element.","PeriodicalId":108609,"journal":{"name":"Volume 4: Student Paper Competition","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123804429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dynamic Model of the VVER-1000 Reactor for Seismic and LB LOCA Evaluation 用于地震和LB LOCA评估的VVER-1000反应堆动态模型

Volume 4: Student Paper Competition Pub Date : 2021-08-04 DOI: 10.1115/icone28-65756

Oleksii Ishchenko, V. Filonov, Y. Dubyk

{"title":"Dynamic Model of the VVER-1000 Reactor for Seismic and LB LOCA Evaluation","authors":"Oleksii Ishchenko, V. Filonov, Y. Dubyk","doi":"10.1115/icone28-65756","DOIUrl":"https://doi.org/10.1115/icone28-65756","url":null,"abstract":"\u0000 The assessment of seismic and dynamic strength for the VVER-1000 reactor with emphasis on fuel assemblies interaction is carried out based on experience for Ukrainian NPPs. Evaluation of fuel assembly structural response to externally applied forces is based on NUREG-800 “Standard Review Plan”, item 4.2 “Design of fuel systems”. The analysis considered two types of events: Safety Shutdown Earthquake (SSE) and Large break Loss Of Coolant Accident (LB LOCA). As LB LOCA for the VVER-1000 – “Maximum design accident” Recirculation Line Break is considered. For the analysis of the initial dynamics, the 3D CFD model (ANSYS CFX) of the VVER-1000 was adapted to account for the two-phase flow. To take into account the transience of the phase transition during depressurization, a special model of interphase exchange is proposed, which takes into account not only the nonequilibrium temperature, but also the features of the pressure change by analogy with cavitation. For full dynamic analysis, it is necessary to develop an analytical and/or FEM model of the reactor, which will include reactor elements, their masses stiffness and inertia characteristics. The developed model is validated against experimental data of natural frequencies of fuel assembles, for uncompressed and compressed working position, also with and without fluid influence. The seismic analysis consider the available response spectra for NPP site with 3-component seismic impact of SSE level. Another important issue is to analyze reactor elements interaction and in case of need, to account for the non-linear behavior of the model. The seismic and LOCA impact at the location of fixation of the fuel assemblies (lower and upper support plates) is calculated by taking into account the dynamic response of the reactor system as a whole. After demonstrating the seismic/dynamic stability of the fuel assemblies and the reactor internals, a justified conclusion is provided on preserving the safety factor for fuel assembles at both loadings.","PeriodicalId":108609,"journal":{"name":"Volume 4: Student Paper Competition","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121167647","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Heat Transfer Performance for Helium Gas Flowing in a Minichannel With Different Inner Diameters 不同内径小通道内氦气的换热性能

Volume 4: Student Paper Competition Pub Date : 2021-08-04 DOI: 10.1115/icone28-65691

Feng Xu, Qiusheng Liu, M. Shibahara

{"title":"Heat Transfer Performance for Helium Gas Flowing in a Minichannel With Different Inner Diameters","authors":"Feng Xu, Qiusheng Liu, M. Shibahara","doi":"10.1115/icone28-65691","DOIUrl":"https://doi.org/10.1115/icone28-65691","url":null,"abstract":"\u0000 The high heat load on the first wall of the helium cooled blanket is removed by tube flow of helium gas. Heat transfer augmentation is considered to be acquired by downsizing of channels. Therefore, this paper experimentally studied the influence of inner diameter on the heat transfer performance of helium gas flowing in a minichannel. The helium gas flowed in the small platinum tubes with the inner diameters of 0.8 mm and 1.8 mm, respectively. The heat generation rate of the tube was controlled by a heat input subsystem and raised with an exponential equation. The surface temperature and heat flux of the tubes were obtained under a wide range of e-folding time at different flow velocities. The heat transfer coefficients of different inner diameter tubes were compared at the same conditions. The heat transfer performance of the 0.8 mm-diameter tube was compared with a classical correlation. The experimental results showed that the heat transfer performance in the minichannel is better than a conventional large-diameter tube. The heat transfer coefficients of the 0.8 mm-diameter tube were higher than those of the 1.8 mm-diameter tube. The heat transfer process was enhanced with reducing the inner diameter of the minichannel. The heat transfer process was divided into two parts including transient and quasi-steady-state regions.","PeriodicalId":108609,"journal":{"name":"Volume 4: Student Paper Competition","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127037736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

System Design for Ammonia Nuclear Thermal Propulsion 氨核热推进系统设计

Volume 4: Student Paper Competition Pub Date : 2021-08-04 DOI: 10.1115/icone28-64359

Chenrui Mao, Yu Ji, Jun Sun, Zhaoyu Liang, Lei Shi

引用次数: 0

Improved Wet Scavenging Schemes for Air Dispersion Modeling of Cs-137 in the Fukushima Accident 改进湿扫法模拟福岛事故中铯-137的空气扩散

Volume 4: Student Paper Competition Pub Date : 2021-08-04 DOI: 10.1115/icone28-64621

Shuhan Zhuang, Shengjiang Fang, Xinwen Dong

{"title":"Improved Wet Scavenging Schemes for Air Dispersion Modeling of Cs-137 in the Fukushima Accident","authors":"Shuhan Zhuang, Shengjiang Fang, Xinwen Dong","doi":"10.1115/icone28-64621","DOIUrl":"https://doi.org/10.1115/icone28-64621","url":null,"abstract":"\u0000 Wet scavenging process is critical for air dispersion modeling of Cs-137 in the Fukushima Daiichi Nuclear power plant (FDNPP) accident. Although intensively investigated, wet scavenging simulation is still subject to uncertainties caused by the biases in wet scavenging modeling and meteorological input. To reduce these uncertainties, the on-line coupled modeling feature of the Weather Research and Forecasting-Chemistry (WRF-Chem) model was utilized and both the in-cloud and below-cloud scavenging processes are considered. In this study, the in-cloud scheme Environ and below-cloud scheme Baklanov are combined with each other to form Environ-Bakla to simulate the wet deposition of Cs-137. The model is systematically compared with a previous WRF-Chem model with a single below-cloud scheme Baklanov, based on both the cumulative deposition and ambient concentration of Cs-137 based on the FDNPP accident observation. The results demonstrate that the in-cloud scavenging scheme substantially improves the cumulative deposition simulation in regions with light rain like Tochigi, Nakadori etc. With respect to the atmospheric concentration, the inclusion of in-cloud scavenging doesn’t necessarily improve the performances and the Environ-Bakla only shows fair performance under plume events with no rain or light rain.","PeriodicalId":108609,"journal":{"name":"Volume 4: Student Paper Competition","volume":"199 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125305481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Wall Materials Effects on Sheltered Indoor Doses From an SMR Hypothetical Accident Release SMR假想事故释放后，墙体材料对遮蔽室内剂量的影响

Volume 4: Student Paper Competition Pub Date : 2021-08-04 DOI: 10.1115/icone28-62097

Yamato Sugitatsu, S. Revankar

{"title":"Wall Materials Effects on Sheltered Indoor Doses From an SMR Hypothetical Accident Release","authors":"Yamato Sugitatsu, S. Revankar","doi":"10.1115/icone28-62097","DOIUrl":"https://doi.org/10.1115/icone28-62097","url":null,"abstract":"\u0000 Small modular reactors (SMRs) are expected as a suitable candidate to fulfill energy needs in the future. The regulation of the emergency planning zone (EPZ) has been a controversial issue. The possibility of smaller EPZs because of their small core size and passive safety functions has still under discussion. The major emergency responses to radiological incidents in the early phase are evacuation from the area and sheltering-in-place within a building. Comparison between the dose incurred during evacuation and that with sheltering-in-place is necessary to consider the proper protective actions. This study focuses on effect of wall materials on indoor doses for sheltered population from small modular reactor severe accident. The source term came from loss of coolant accident or station blackout, and the time change of air concentration and the ground deposition data was calculated with RASCAL, a software developed by NRC to provide dose projection around the plant. Then general one-story and two-story houses were set up, and 6 wall materials were selected for calculating indoor doses. Cloudshine and groundshine were calculated with Monte Carlo methods, and the shielding function of each house was evaluated by comparing the indoor dose with outdoor dose. The result will be a basis for calculating the radiological dose for sheltered cases in case of nuclear emergency for SMR, which will be valuable to have a more effective emergency planning.","PeriodicalId":108609,"journal":{"name":"Volume 4: Student Paper Competition","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117199264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Study on Buckling Strength and Post Buckling Behaviors of Reactor Vessel Lower Heads 反应堆容器下封头屈曲强度及后屈曲行为研究

Volume 4: Student Paper Competition Pub Date : 2021-08-04 DOI: 10.1115/icone28-65553

Masatoshi Murohara, A. Yamazaki, Takuya Sato, N. Kasahara

引用次数: 0

Characteristics of Two-Phase Flow in Packed Bed Systems 填料床系统的两相流特性

Volume 4: Student Paper Competition Pub Date : 2021-08-04 DOI: 10.1115/icone28-64955

Noriaki Yasugi, Akito Fujitsu, Naoya Odaira, D. Ito, K. Ito, Yasushi Saito

{"title":"Characteristics of Two-Phase Flow in Packed Bed Systems","authors":"Noriaki Yasugi, Akito Fujitsu, Naoya Odaira, D. Ito, K. Ito, Yasushi Saito","doi":"10.1115/icone28-64955","DOIUrl":"https://doi.org/10.1115/icone28-64955","url":null,"abstract":"\u0000 Two-phase pressure drop in the debris has been studied by many researchers in relation to the debris cooling characteristics during a severe accident in a nuclear reactor. However, its flow regime transition of the two-phase flow in the debris has not been well understood, which strongly affects the interfacial drag and the pressure drop. Conventional models for gas-liquid two-phase flow pressure drop have not been established well to evaluate interfacial drag accurately. In this study, high-speed imaging of a two-dimensional network model was performed to clarify the effect of flow pattern on interfacial drag and pressure drop. Normally it would be very difficult to visualize such two-phase flow behavior in an ordinary packed bed due to the reflection/refraction of light and/or overlapping bubbles, even if the test section is made of transparent materials. Therefore, in this study, a test section, which simulates two-dimensional network of porous structures, was fabricated to avoid the overlapping bubbles. By using a high-speed imaging of the two-dimensional network model, two-phase flow pattern in the porous structure have been identified. From the experimental results, it was suggested that the interfacial drag term should be modified in the gas-liquid two-phase flow pressure drop model.","PeriodicalId":108609,"journal":{"name":"Volume 4: Student Paper Competition","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132098627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Using Monte Carlo Method and Adaptive Sampling to Estimate the Limit Surface 用蒙特卡罗法和自适应采样估计极限曲面

Volume 4: Student Paper Competition Pub Date : 2021-08-04 DOI: 10.1115/icone28-64484

Lixuan Zhang, Zhijian Zhang, He Wang, Yuhang Zhang, Dabin Sun

{"title":"Using Monte Carlo Method and Adaptive Sampling to Estimate the Limit Surface","authors":"Lixuan Zhang, Zhijian Zhang, He Wang, Yuhang Zhang, Dabin Sun","doi":"10.1115/icone28-64484","DOIUrl":"https://doi.org/10.1115/icone28-64484","url":null,"abstract":"\u0000 In the research on the risk-informed safety margin characterization (RISMC) methodology, how to estimate the limit surface is important. Using the reduced Order Models (ROMs) to simulate calculations can obtain results more quickly and estimate the limit surface. For example, we use ROMs instead of Complex simulation model, Parameters that are critical to the safety of nuclear power plants, such as the peak temperature of the fuel cladding, can be calculated relatively quickly. Using Monte Carlo method to analyze nuclear accident is low efficiency and poor accuracy. To get relatively accurate results, a large amount of simulation experiments is needed. Based on adaptive sampling, the samples which will cause failure will be acquired more easily. Adaptive sampling uses the calculation results of the previous step to guide the next step of sampling, which can quickly obtain the samples points near the failure edge.\u0000 This article will introduce the definition of the limit surface and use the Monte Carlo method and the adaptive sampling to estimate the limit surface through ROMs. And compare the calculation results of the two methods and the number of samples required. The two methods are verified by a case.","PeriodicalId":108609,"journal":{"name":"Volume 4: Student Paper Competition","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124500395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0