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SSRN 2022年

作者： Li, Wenhan Ma, Zengyi Deng, Lilin Huang, Qianming Zhai, Zian Huang, Bochen Liu, Ting Wang, Shuang Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China State Key Laboratory of Clean Energy Utilization Institute for Thermal Power Engineering Zhejiang University Hangzhou310027 China

In this study, chemical speciation distribution and thermal stability of heavy metals (As, Cd, Cr, Cu, Pb, Se, Zn, and Hg) along flue gas cleaning systems were investigated in a hazardous waste incinerator located in Zhejiang, china. The chemical speciation and thermal stability of heavy metals, environmental risk evaluation, and morphological and mineralogical characteristics of incineration residues were assessed before and after heat treatments at different temperatures. The results showed that As and Cr in the raw incineration residues mainly fractionated as the residual form with the proportion of over 48.9% and 74.5%, respectively, whereas most of Se was associated with the oxidizable and residual fraction. The chemical speciation of Cu and Pb in bag filter ashes was related to the chlorine content in the waste, and high chlorine availability favored the formation of acid soluble Cu and Pb. The residual fraction of Hg (over 68.0%) was the most dominant in bag filter ashes, which might exist in the form of HgS. During heat treatments at different temperatures, the vaporization of heavy metals increased with increasing temperature. As, Cr and Se showed high thermal stability due to the fact that As, Cr and Se were involved in the crystallization reaction, and heat treatment would promote the transformation from the mobile fractions into residual fraction. Hg and Cd displayed the worst thermal stability, and high temperature heat treatment would contribute to secondary volatilization from the incineration residues. Cu, Pb and Zn had moderate thermal stability, and heat treatment would cause the volatilization of the mobile fractions or transformation from the mobile fractions into residual fraction. With the increase of heat treatment temperature, the environmental risk of incineration residues displayed a decreasing trend and reached the medium risk level or below after heat treatment at 1200 °C without any additives or pretreatments. © 2022, The Authors. All ri

关键词： Heavy metals

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Experimental Study on Surface Characteristics and Thermal Conductivity of New Zirconium Alloy with Oxide Layer

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SSRN 2022年

作者： Zhong, Lei Chen, Deqi Yu, Hongxing Liu, Haidong Chen, Mingjing Liu, Hanzhou Deng, Jian Ding, Shuhua Wu, Dan Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China Key Laboratory of Low-grade Energy Utilization Technologies and Systems Chongqing University Ministry of Education Chongqing 400044 China

The surface properties and thermal conductivity of oxide layer formed on the new zirconium alloy due to high temperature steam oxidation are studied in this paper. The thickness of oxide layer, surface wettability and thermal conductivity are measured. The effects of oxidation temperature and time on the wettability and thermal conductivity of zirconium alloy are analyzed. The results show that zirconium on the surface is fully oxidized to ZrO2 , and the difference of surface wettability is caused by different surface morphology. The characteristics of oxide layer surface cracks will affect the surface wettability. At the same oxidation temperature, with increasing time duration, the size and number of oxide layer cracks increase. The change of thermal conductivity is the result of competition among factors such as the development of recrystallization process, the increase of oxide layer thickness and the influence of pores and cracks. © 2022, The Authors. All rights reserved.

关键词： Wetting

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CostFM: A High Cost-Performance Fingerprint Management Mechanism for Shared SSDs

CostFM: A High Cost-Performance Fingerprint Management Mecha...

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IEEE International Conference on Computer design: VLSI in Computers and Processors, (ICCD)

作者： Hao Liu Mengting Lu Fang Wang Wenpeng He Wuhan National Laboratory for Optoelectronics Key Laboratory of Information Storage System School of Computer Science and Technology Huazhong University of Science and Technology Ministry of Education of China Wuhan China Cloud Intelligence Group Alibaba Co. Hangzhou China

As the storage and I/O demand of contemporary computer systems grow, SSDs with deduplication are widely deployed as shared storage devices to provide high performance in cloud platforms where diverse tenant workloads are collocated. However, existing global and fixed fingerprint management schemes are inefficient in the multi-tenant environment. Contention for in-memory fingerprint cache, embedded in DRAM to speed up fingerprint lookups, results in decreased cache utilization, and abundant fingerprint lookups into the backend flash memory degrade the system performance. Besides, a fixed cache replacement policy for all the tenants fails to capture the diverse characteristics, further increasing the lookup *** paper introduces CostFM, a novel fingerprint management mechanism highlighted by two notable features. First, it provides a benefit-aware cache allocation scheme, which estimates the cache hit gains of each tenant and uses dynamic programming to find the optimal cache allocation scheme, avoiding the cache contention for the fingerprint resource and improving cache utilization. Second, it applies a user-based policy model that captures access characteristics to select the suitable cache management policy for each tenant, boosting overall cache efficiency. Extensive experimental results show that CostFM decreases the average request latency by up to 30%, and it also reduces the fingerprint writes into the flash memory by up to 4.7x.

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STUDY ON AUTOMATIC DEPRESSURIZATON system OF SMR

STUDY ON AUTOMATIC DEPRESSURIZATON SYSTEM OF SMR

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2020 International Topical Meeting on Advances in Thermal Hydraulics, ATH 2020

作者： Yin, Shasha Sun, Yan Li, Yi Yang, Hongfa Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Sichuan Chengdu China

ISBN: (纸本)9780894487774

Small modular reactor (SMR) is highly cared and researched by people all over the world. There are many differences during reactor operating between the small modular reactor and the traditional large-scale pressurized water reactor, because of the differences in structure and design issues for both reactors. This means that more and better research especially on SMR will be needed. The continued improvements in designing conception of SMR, the research of SMR get to be more in depth and detail. Passive safety system is commonly accepted in the present study, and developed into an indispensable system for the advance nuclear reactor. However, automatic depressurization system (ADS) as an important part of a passive safety system also is a unique system compared with conventional PWR. So ADS system is worthy of comprehensive and in-depth study. In this paper, the severe accident analysis model was established based on the design characteristics of the small modular nuclear. Then, the severe accident process, the thermalhydraulic phenomena and the system safety were researched. Then, based on the results of the severe accident process for SMR, analyze the depressurization capability of ADS system during a station blackout initiated severe accident in SMR, and analysis the effect on accident process. Finally, this paper proposed the optimization and improvement of the automatic depressurization system (ADS). The results of this study are the necessary foundations for the development of small modular reactor severe accident prevention and mitigation measures. © ATH 2020 - International Topical Meeting on Advances in Thermal *** rights reserved.

关键词： Pressurized water reactors

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Study on Uniaxial Tension and Cyclic Deformation Behavior of TA16 at Room Temperature and High Temperature

Study on Uniaxial Tension and Cyclic Deformation Behavior of...

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作者： Shao, Xuejiao Juan, Du kuang, Linyuan Lu, Yuechuan Lu, Jiang Yu, Mingda Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

TA16 is a new type of titanium alloy material, which is widely used in pipeline systems of aerospace, ship and nuclear reactor with high temperature and high pressure. In this paper, the basic mechanical properties and cyclic deformation characteristics of TA16 were obtained by uniaxial tensile test and cyclic loading test at room temperature and high temperature. The Chaboche constitutive model can reasonably describe the cyclic plastic cumulative effect of materials and is provided in ANSYS which is a commercial finite element analysis software. The constitutive model of Chaboche presents a very important evolution criterion of follow-up hardening for ratchet simulation. Based on steady cyclic stress-strain curves which is got by strain control at different temperatures, the material parameters of Chaboche model are obtained by least multiplication fitting for TA16 at room and high temperatures. The constitutive model can used in elastic and elastic finite element analysis of TA16 materials. The experiment results show that TA16 exhibits slight cyclic softening under symmetrical strain cycles, and obvious ratcheting behavior under asymmetric stress cycles. When ratcheting strain of the structure reaches a certain saturation state, plastic accumulation will lead to accidental damage of the structure and lead to serious consequences. The stable cyclic stress-strain curves of TA16 at room temperature and high temperature are simulated by Chaboche model. The simulation results are in good agreement with the experimental results, which provides the basic data for the finite element simulation of cyclic deformation behavior of TA16 titanium alloy structure. © Springer Nature Switzerland AG 2020.

关键词： Constitutive models

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Using Lock-Free design for Throughput-Optimized Cache Eviction 25

Using Lock-Free Design for Throughput-Optimized Cache Evicti...

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Abstracts of the 2025 ACM SIGMETRICS International Conference on Measurement and Modeling of Computer systems

作者： Chao Dong Fang Wang Hong Jiang Dan Feng Key Laboratory of Information Storage System (Wuhan National Laboratory for Optoelectronics) Engineering Research Center of data storage systems and Technology (School of Computer Science and Technology) Ministry of Education of China Huazhong University of Science and Techonolgy Wuhan Hubei China Department of Computer Science and Engineering University of Texas at Arlington Arlington Texas USA

ISBN: (纸本)9798400715938

This paper presents a practical approach to cache eviction algorithm design, called Mobius, that optimizes the concurrent throughput of caches and reduces cache operation latency by utilizing lock-free data structures, while maintaining high cache hit ratios. Mobius includes two key designs. First, Mobius employs two lock-free FIFO queues to manage cache items, ensuring that all cache operations are executed efficiently in concurrency. Second, Mobius integrates a consecutive detection mechanism that merges multiple modifications during eviction into a single operation, thereby reducing data races. The implementation of Mobius in CacheLib and RocksDB highlights its high concurrency in both synthetic and real-world workloads.

关键词： cache eviction policy

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A simplified two-node coarse-mesh finite difference method for pin-wise calculation with SP3

A simplified two-node coarse-mesh finite difference method f...

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2020 International Conference on Physics of reactors: Transition to a Scalable Nuclear Future, PHYSOR 2020

作者： Zhao, Wenbo Yu, Yingrui Chai, Xiaoming Ning, Zhonghao Zhang, Bin Cai, Yun Liu, Kun Peng, Xingjie Yu, Junchong Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China

ISBN: (纸本)9781713827245

For accurate and efficient pin-by-pin core calculation of SP3 equations, a simplified two-node Coarse Mesh Finite Difference (CMFD) method with the nonlinear iterative strategy is proposed. In this study, the two-node method is only used for discretization of Laplace operator of the 0th moment in the first equation, while the fine mesh finite difference (FMFD) is used for the 2nd moment flux and the second equation. In the two-node problem, transverse flux is expanded to second-order Legendre polynomials. In addition, the associated transverse leakage is approximated with flat distribution. Then the current coupling coefficients are updated in nonlinear iterations. The generalized eigenvalue problem from CMFD is solved using Jacobi-Davidson method. A protype code CORCA-PIN is developed. FMFD scheme is implemented in CORCA-PIN as well. The 2D KAIST 3A benchmark problem and extended 3D problem, which are cell homogenized problems with strong absorber, are tested. Numerical results show that the solution of the simplified two-node method with 1×1 mesh per cell has comparable accuracy of FMFD with 4×4 meshes per cell, but cost less time. The method is suitable for whole core pin-wise calculation. © The Authors, published by EDP sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://***/licenses/by/4.0/).

关键词： Nonlinear equations

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Structure topology optimization design and shock resistance study on nuclear power safety DCS cast aluminum cabinet

Structure topology optimization design and shock resistance ...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Dongwei, Wang Mingxing, Liu Xiao, Wu Hao, Yan Zhiqiang, Wu Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

ISBN: (纸本)9780791883761

Offshore floating nuclear power plant (FNPP) is characterized by its small and mobility, which is not only able to provide safe and efficient electric energy to remote islands, but to the oil and gas platforms. The safety digital control system (DCS) cabinet, as a carrier for the electronic devices, plays a significant role in ensuring the normal operation of the nuclear power plant. To satisfy the requirements of cabinet used in the sea environment, such as well rigidity, shock load resistance, good seal and corrosion resistance, etc, more and more attention is focused on the cast aluminum cabinet. However, the cast aluminum structure may cause larger weight of cabinet, which inevitability affects the mobility of cabinet, and increases the carried load of ship as well. Therefore, seeking for an effective approach to design a light weight cast aluminum cabinet for the offshore FNPP is definitely necessary. In this work, a frame of cast aluminum cabinet with lightweight is obtained successfully via structure topology optimization design, it is found that the weight of the frame can be reduced to 50% after optimization iterations. Subsequently, the natural frequency of the optimized cast aluminum cabinet is calculated by using ABAQUS, it is seen that the first mode frequency of the frame is beyond 30 Hz, which can meet the basic stiffness requirement. Accordingly, dynamic design analysis method (DDAM) is performed to verify the ability of the optimized cast aluminum cabinet in resisting sudden shock load, and the shock response characteristics of the cabinet are determined. Numerical results support that the optimized frame of cabinet possesses good resistance to high level shock. However, for the assembled cast aluminum cabinet, the vertical shock circumstance turns out to be the most critical condition, high stress and deformation regions occurs at the bracket and column. Reinforcements are proposed to make the bracket stiffer in this shock loading condition. Copyri

关键词： Finite element method

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Theoretical exploration of heat transfer characteristics of liquid metals

Theoretical exploration of heat transfer characteristics of ...

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2020 Transactions of the American Nuclear Society, ANS 2020

作者： Shen, Yaou Peng, Shinian Yan, Mingyu Zhang, Yu Deng, Jian Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610041 China

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Research on thermal diffusion coefficient calculation for subchannels with spacer grid using CFD methodology 14

Research on thermal diffusion coefficient calculation for su...

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14th International Nuclear Fuel Cycle Conference, GLOBAL 2019 and Light Water reactor Fuel Performance Conference, TOP FUEL 2019

作者： Chen, Xi Du, Sijia Liu, Yu Qian, Libo Liu, Lili Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

Thermal Diffusion Coefficient (TDC) is one of the most important parameters in subchannel analysis codes. Abundant research results demonstrate that TDC is mainly determined by the structures of fuel assembly, especially by the mixing vanes of spacer grids. Traditionally, TDC is acquired by thermal-hydraulic tests. However, hydraulic tests cost a great deal of money and need long time, and it's impossible to test every grid design. Another new way to obtain coefficients economically and fast is really needed for decades. Recently, with great development of Computational Fluid Dynamics, CFD has been validated as an analysis method for nuclear engineering, especially for single phase calculation. This paper established CFD methodology in TDC calculation for a 5x5 rod bundle with spacer grids. Firstly, CFD simulations were carried out to get sunchannel exit temperature including different conditions, such as different temperature, pressure, and flow rate. Then subchannel code CORTH was used to make subchannel analysis with varied TDC. Finally, we compared the TDC using CFD method with that come from tests, and validation results show that the methodology was right. In conclusion, the feasibility of TDC calculation methodology is preliminarily validated, which provided references for developments and design of new fuel assemblies. Copyright © GLOBAL 2019 - International Nuclear Fuel Cycle Conference and TOP FUEL 2019 - Light Water reactor Fuel Performance *** rights reserved.

关键词： Computational fluid dynamics

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