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Development of CONTHAC-3D and hydrogen distribution analysis of HPR1000

nuclear science and Techniques 2024年第2期35卷 210-221页

作者： Hui Wang Jing-Jing Li Yuan Chang Gong-Lin Li Ming Ding China nuclear Power Engineering Co.LTD. Beijing 100084China fundamental science on nuclear safety and Simulation Technology laboratory Harbin 100049China

An in-house code,CONTHAC-3D,was developed to calculate and analyze thermal-hydraulic phenomena in containments during severe accidents.CONTHAC-3D is a three-dimensional computational fluid dynamics code that can be applied to predict gas flow,diffusion,and steam condensation in a containment during a severe hypothetical accident,as well as to obtain an estimate of the local hydrogen concentration in various zones of the containment.CONTHAC-3D was developed using multiple models to simulate the features of the proprietary systems and equipment of HPR1000 and ACP100,such as the passive cooling system,passive autocatalytic recombiners and the passive air cooling system.To validate CONTHAC-3D,a GX6 test was performed at the Battelle Model Containment facility.The hydrogen concentration and temperature monitored by the GX6 test are accurately predicted by CONTHAC-3D.Subsequently,the hydrogen distribution in the HPR1000 containment during a severe accident was studied.The results show that the hydrogen removal rates calculated using CONTHAC-3D for different types of PARs agree well with the theoretical values,with an error of less than 1%.As the accident progresses,the hydrogen concentration in the lower compartment becomes higher than that in the large space,which implies that the lower compartment has a higher hydrogen risk than the dome and large space at a later stage of the accident.The amount of hydrogen removed by the PARs placed on the floor of the compartment is small;therefore,raising the installation height of these recombiners appropriately is recommended.However,we do not recommend installing all autocatalytic recombiners at high positions.The study findings in regard to the hydrogen distribution in the HPR1000 containment indicate that CONTHAC-3D can be applied to the study of hydrogen risk containment.

关键词： Hydrogen risk mitigation Pressurized water reactor HPR1000 Thermal hydraulic CONTHAC-3D

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Trial application of the envelope method to the potential ambiguity problem

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nuclear science and Techniques 2024年第1期35卷 73-80页

作者： Li-Yuan Hu Yu-Shou Song fundamental science on nuclear safety and Simulation Technology laboratory Harbin Engineering UniversityHarbin 150001China College of nuclear science and Technology Harbin Engineering UniversityHarbin 150001China Key laboratory of nuclear safety and Advanced nuclear Energy Technology Ministry of Industry and Information TechnologyHarbin 150001China

The optical potential ambiguity is a long-standing problem in the analysis of elastic scattering data.For a specific collid-ing system,ambiguous potential families can lead to different behaviors in the nearside and farside scattering components.By contrast,the envelope method can decompose the experimental data into two components with negative and positive deflection angles,respectively.Hence,a question arises as to whether the comparison between the calculated nearside(or farside)component and the derived positive-deflection-angle(or negative-deflection-angle)component can help analyze the potential ambiguity problem.In this study,we conducted a trial application of the envelope method to the potential ambiguity problem.The envelope method was improved by including uncertainties in the experimental data.The colliding systems of 16O+28Si at 215.2 MeV and 12C+12C at 1016 MeV were considered in the analyses.For each colliding system,the angular distribution experimental data were described nearly equally well by two potential sets,one of which is“surface transpar-ent”and the other is refractive.The calculated angular distributions were decomposed into nearside and farside scattering components.Using the improved envelope method,the experimental data were decomposed into the positive-deflection-angle and negative-deflection-angle components,which were then compared with the calculated nearside and farside components.The capability of the envelope method to analyze the potential ambiguities was also discussed.

关键词： Elastic scattering Optical potential ambiguities Envelope method Nearside/farside decomposition

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Effects of counter-current driven by electron cyclotron waves on neoclassical tearing mode suppression

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Chinese Physics B 2024年第5期33卷 501-509页

作者：高钦郑平卫 School of Resource environment and safety Engineering University of South ChinaHengyang 421001China Demonstration Base for International science and Technology Cooperation on nuclear Energy and nuclear safety University of South ChinaHengyang 421001China

Through theoretical analysis,we construct a physical model that includes the influence of counter-external driven current opposite to the plasma current direction in the neoclassical tearing mode(NTM).The equation is used with this model to obtain the modified Rutherford equation with co-current and counter-current contributions.Consistent with the reported experimental results,numerical simulations have shown that the localized counter external current can only partially suppress NTM when it is far from the resonant magnetic surface.Under some circumstances,the Ohkawa mechanism dominated current drive(OKCD)by electron cyclotron waves can concurrently create both co-current and counter-current.In this instance,the minimal electron cyclotron wave power that suppresses a particular NTM was calculated by the Rutherford equation.The result is marginally less than when taking co-current alone into consideration.As a result,to suppress NTM using OKCD,one only needs to align the co-current with a greater OKCD peak well with the resonant magnetic surface.The effect of its lower counter-current does not need to be considered because the location of the counter-current deviates greatly from the resonant magnetic surface.

关键词： driven current neoclassical tearing mode modified Rutherford equation electron cyclotron waves

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Applications of mercury stable isotopes for tracing volcanism in the geologic record

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science China Earth sciences 2024年第5期67卷 1436-1458页

作者： Qing GONG Ming-Xing LING Wang ZHENG State Key laboratory of nuclear Resources and environment East China University of TechnologyNanchang 330013China School of Earth System science Institute of Surface-Earth System ScienceTianjin UniversityTianjin 300072China

Mercury(Hg)enrichments in ancient sediments have been used as a proxy of volcanism,especially large igneous province(LIP)eruptions.However,considering the existence of other potential Hg sources besides volcanoes and the diverse factors(e.g.,organic matters,clay minerals,sulfide minerals and Fe oxides)that can affect Hg sequestration,there are considerable uncertainties to simply regard sedimentary Hg anomalies as signatures of volcanic activities.Mercury stable isotopes,a promising tool for tracing the origins and transformations of Hg,have been increasingly used for determining the causes of Hg spikes and understanding the geochemical behavior of Hg in the geologic record.To date,lots of researches have applied Hg concentrations and Hg isotopes to identify LIP volcanisms linking with significant geological events such as mass extinctions,ocean anoxic events and other environmental perturbations that mainly occurred in the Phanerozoic.However,the results in previous studies clearly show that not all Hg enrichments are derived from volcanic inputs,which emphasize the need for more caution in using Hg as a fingerprint of volcanism.With a better understanding of Hg isotopes in the future,there will be important implications for Hg isotopes to reconstruct volcanic activities in the rock records and their impacts on biological evolution.

关键词： Mercury stable isotopes Large igneous province Mass extinction event Ocean anoxic event

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3D robust anisotropic diffusion filtering algorithm for sparse view neutron computed tomography 3D image reconstruction

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nuclear science and Techniques 2024年第3期35卷 13-29页

作者： Yang Liu Teng-Fei Zhu Zhi Luo Xiao-Ping Ouyang School of nuclear science and Engineering North China Electric Power UniversityBeijing 102206China State Key laboratory of nuclear Resources and environment East China University of TechnologyNanchang 330013China State Key laboratory of Intense Pulsed Radiation Simulation and Effect Xi’an 710024China

The most critical part of a neutron computed tomography(NCT) system is the image processing algorithm,which directly affects the quality and speed of the reconstructed images.Various types of noise in the system can degrade the quality of the reconstructed images.Therefore,to improve the quality of the reconstructed images of NCT systems,efficient image processing algorithms must be used.The anisotropic diffusion filtering(ADF) algorithm can not only effectively suppress the noise in the projection data,but also preserve the image edge structure information by reducing the diffusion at the image edges.Therefore,we propose the application of the ADF algorithm for NCT image reconstruction.To compare the performance of different algorithms in NCT systems,we reconstructed images using the ordered subset simultaneous algebraic reconstruction technique(OS-SART) algorithm with different regular terms as image processing algorithms.In the iterative reconstruction,we selected two image processing algorithms,the Total Variation and split Bregman solved total variation algorithms,for comparison with the performance of the ADF algorithm.Additionally,the filtered back-projection algorithm was used for comparison with an iterative algorithm.By reconstructing the projection data of the numerical and clock models,we compared and analyzed the effects of each algorithm applied in the NCT system.Based on the reconstruction results,OS-SART-ADF outperformed the other algorithms in terms of denoising,preserving the edge structure,and suppressing artifacts.For example,when the 3D Shepp–Logan was reconstructed at 25 views,the root mean square error of OS-SART-ADF was the smallest among the four iterative algorithms,at only 0.0292.The universal quality index,mean structural similarity,and correlation coefficient of the reconstructed image were the largest among all algorithms,with values of 0.9877,0.9878,and 0.9887,respectively.

关键词： NCT OS-SART Sparse-view Anisotropic diffusion filtering

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Modeling and Simulation of Lithium Vacuum Evaporation Process Using COMSOL Multiphysics

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Journal of Thermal science 2024年第1期33卷 86-100页

作者： LIAN Xuexin ZHONG Dawen Beijing Key laboratory of Passive nuclear Power safety and Technology North China Electric Power UniversityBeijing 102206China

Based on the COMSOL Multiphysics simulation software,this study carried out modeling and numerical simulation for the evaporation process of liquid metal lithium in the vacuum free molecular flow state.The motion of lithium atoms in the evaporation process was analyzed through a succession of studies.Based on the available experimental values of the saturated vapor pressure of liquid metal lithium,the relationship between saturated vapor pressure and temperature of liquid lithium in the range of 600 K-900 K was obtained.A two-dimensional symmetric model(3.5 mm×20 mm) was established to simulate the transient evaporation process of liquid lithium at wall temperatures of 750 K,780 K,800 K,810 K,825 K,and 850 K,respectively.The effects of temperature,the evaporation coefficient,back pressure,and length-to-diameter ratio on the evaporation process were studied;the variation trends and reasons of the molecular flux and the pressure during the evaporation process were analyzed.At the same time,the evaporation process under variable wall temperature conditions was simulated.This research made the evaporation process of liquid lithium in vacuum molecular flow clearer,and provided theoretical support for the space reactor and nuclear fusion related fields.

关键词： free molecular flow saturated vapor pressure vacuum evaporation liquid lithium metal

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A functionalized activated carbon adsorbent prepared from waste amidoxime resin by modifying with H_(3)PO_(4) and ZnCl_(2) and its excellent Cr(Ⅵ)adsorption

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 585-598页

作者： Chunlin He Yun Liu Mingwei Qi Zunzhang Liu Yuezhou Wei Toyohisa Fujita Guifang Wang Shaojian Ma Wenchao Yang School of Resources Environment and MaterialsGuangxi UniversityNanning 530004China State Key laboratory of Featured Metal Materials and Life-cycle safety for Composite Structures Guangxi UniversityNanning 530004China School of nuclear science and Technology University of South ChinaHengyang 421000China School of nuclear science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Key laboratory of New Low-carbon Green Chemical Technology Education Department of Guangxi Zhuang Autonomous RegionNanning 530004China

With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.

关键词： waste amidoxime resin mesoporous adsorbent H_(3)PO_(4)and ZnCl_(2)processing Cr(VI)adsorption electroplating wastewater

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The biochemical behavior and mechanism of uranium(Ⅵ)bioreduction induced by natural Bacillus thuringiensis

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Journal of environmental sciences 2024年第2期136卷 372-381页

作者： Shunzhang Chen Junyuan Gong Yanxia Cheng Yuqi Guo Feize Li Tu Lan Yuanyou Yang Jijun Yang Ning Liu Jiali Liao Key laboratory of Radiation Physics and Technology of the Ministry of Education Institute of Nuclear Science and TechnologySichuan UniversityChengdu 610064China

For a broader understanding of uranium migration affected by microorganisms in natural anaerobic environment,the bioreduction of uranium(Ⅵ)(U(Ⅵ))was revealed in Bacillus thuringiensis,a dominant bacterium strain with potential of uranium-tolerant isolated from uranium contaminated soil.The reduction behavior was systematically investigated by the quantitative analysis of U(Ⅳ)in bacteria,and mechanism was inferred from the pathway of electron transmission.Under anaerobic conditions,appropriate biomass and sodium lactate as electron donor,reduction behavior of U(Ⅵ)induced by B.thuringiensis was restricted by the activity of lactate dehydrogenase,which was directly affected by the initial pH,temperature and initial U(Ⅵ)concentration of bioreduction system.Bioreduction of U(Ⅵ)was driven by the generation of nicotinamide adenine dinucleotide(NADH)from enzymatic reaction of sodium lactate with various dehydrogenase.The transmission of the electrons from bacteria to U(Ⅵ)was mainly supported by the intracellular NADH dehydrogenase-ubiquinone system,this process could maintain the biological activity of cells.

关键词： Uranium Bacillus thuringiensis Bioreduction Electron transmission

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Building a domain-specific compiler for emerging processors with a reusable approach

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science China(Information sciences) 2024年第1期67卷 20-38页

作者： Mingzhen LI Yi LIU Bangduo CHEN Hailong YANG Zhongzhi LUAN Depei QIAN State Key laboratory of Software Development environment School of Computer science and Engineering Beihang University

High-performance computing and deep learning domains have been motivating the design of domain-specific processors.Although these processors can provide promising computation capability,they are notorious for exotic programming paradigms.To improve programming productivity and fully exploit the performance potential of these processors,domain-specific compilers(DSCs) have been proposed.However,building DSCs for emerging processors requires tremendous engineering efforts because the commonly used compilation stack is difficult to be reused.Owing to the advent of multilevel intermediate representation(MLIR),DSC developers can leverage reusable infrastructure to extend their customized functionalities without rebuilding the entire compilation stack.In this paper,we further demonstrate the effectiveness of MLIR by extending its reusable infrastructure to embrace a heterogeneous many-core processor(Sunway processor).In particular,we design a new Sunway dialect and corresponding backend for the Sunway processor,fully exploiting its architectural advantage and hiding its programming complexity.To show the ease of building a DSC,we leverage the Sunway dialect and existing MLIR dialects to build a stencil compiler for the Sunway processor.The experimental results show that our stencil compiler,built with a reusable approach,can even perform better than state-of-the-art stencil compilers.

关键词： domain-specific compiler emerging processor reusable dialect performance optimization MLIR

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Why lowland riparian trees are difficult to use for streamflow reconstruction

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Journal of Forestry Research 2024年第3期35卷 219-230页

作者： Xiaomei Peng Shengchun Xiao Bao Yang Quanyan Tian Vladimir V.Shishov Key laboratory of Ecological safety and Sustainable Development in Arid Lands Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000People's Republic of China School of Geography and Ocean science Nanjing UniversityNanjing 210023People's Republic of China Institute of fundamental Biology and Biotechnology Siberian Federal UniversityKrasnoyarskRussia 660041

Existing streamflow reconstructions based on tree-ring analysis mostly rely on species from upland,mainly montane areas,while lowland species(generally plain)areas are rarely used.This limits the understanding of streamflow change history in the lowlands,which is an important basis for water resource management.This study focused on Populus euphratica stands located along the main stream,eastern and western tributaries in the lower reaches of the Heihe River basin(HRb),in arid northwestern China.We investigated how streamflow regulation interferes with ripar-ian trees in lowlands when they used for streamflow recon-struction.Tree-ring width chronologies were developed and analyzed in conjunction with meteorological and hydrologic observation data.The results show streamflow regulation leads in sharp fluctuations in the streamflow allocation between the eastern tributaries and western tributaries.This resulted in instability of the correlation between streamflow at the two tributaries and at the Zhengyixia hydrologic station,with corresponding fluctuations in radial growth of poplar trees on the banks of the two tributaries and at the station.Streamflow regulation altered the natural patterns of seasonal streamflow below the station,changing the time window of poplar response.This study provides useful insight into tree-ring width based streamflow reconstruction in the lowlands.

关键词： Tree-ring width-Dendrochronology Populus euphratica The Ejina Oasis Streamflow

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