• Title/Summary/Keyword: Nuclear Engineering

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Assessment of ECCMIX component in RELAP5 based on ECCS experiment

  • Song, Gongle;Zhang, Dalin;Su, G.H.;Chen, Guo;Tian, Wenxi;Qiu, Suizheng
    • Nuclear Engineering and Technology
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    • v.52 no.1
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    • pp.59-68
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    • 2020

  • ECCMIX component was introduced in RELAP5/MOD3 for calculating the interfacial condensation. Compared to other existing components in RELAP5, user experience of ECCMIX component is restricted to developmental assessment applications. To evaluate the capability of the ECCMIX component, ECCS experiment was conducted which included single-phase and two-phase thermal mixing. The experiment was carried out with test sections containing a main pipe (70 mm inner diameter) and a branch pipe (21 mm inner diameter) under the atmospheric pressure. The steam mass flow in the main pipe ranged from 0 to 0.0347 kg/s, and the subcooled water mass flow in the branch pipe ranged from 0.0278 to 0.1389 kg/s. The comparison of the experimental data with the calculation results illuminated that although the ECCMIX component was more difficult to converge than Branch component, it was a more appropriate manner to simulate interfacial condensation under two-phase thermal mixing circumstance, while the two components had no differences under single-phase circumstance.

  • https://doi.org/10.1016/j.net.2019.07.007 인용 PDF KSCI

Parallelization and application of SACOS for whole core thermal-hydraulic analysis

  • Gui, Minyang;Tian, Wenxi;Wu, Di;Chen, Ronghua;Wang, Mingjun;Su, G.H.
    • Nuclear Engineering and Technology
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    • v.53 no.12
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    • pp.3902-3909
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    • 2021

  • SACOS series of subchannel analysis codes have been developed by XJTU-NuTheL for many years and are being used for the thermal-hydraulic safety analysis of various reactor cores. To achieve fine whole core pin-level analysis, the input preprocessing and parallel capabilities of the code have been developed in this study. Preprocessing is suitable for modeling rectangular and hexagonal assemblies with less error-prone input; parallelization is established based on the domain decomposition method with the hybrid of MPI and OpenMP. For domain decomposition, a more flexible method has been proposed which can determine the appropriate task division of the core domain according to the number of processors of the server. By performing the calculation time evaluation for the several PWR assembly problems, the code parallelization has been successfully verified with different number of processors. Subsequent analysis results for rectangular- and hexagonal-assembly core imply that the code can be used to model and perform pin-level core safety analysis with acceptable computational efficiency.

  • https://doi.org/10.1016/j.net.2021.06.029 인용 PDF KSCI

Water film covering characteristic on horizontal fuel rod under impinging cooling condition

  • Penghui Zhang;Bowei Wang;Ronghua Chen;G.H. Su;Wenxi Tian;Suizheng Qiu
    • Nuclear Engineering and Technology
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    • v.54 no.11
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    • pp.4329-4337
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    • 2022

  • Jet impinging device is designed for decay heat removal on horizontal fuel rods in a low temperature heating reactor. An experimental system with a fuel rod simulator is established and experiments are performed to evaluate water film covering capacity, within 0.0287-0.0444 kg/ms mass flow rate, 0-164.1 kW/m2 heating flux and 13.8-91.4℃ feeding water temperature. An effective method to obtain the film coverage rate by infrared equipment is proposed. Water film flowing patterns are recoded and the film coverage rates at different circumference angles are measured. It is found the film coverage rate decreases with heating flux during single-phase convection, while increases after onset of nucleate boiling. Besides, film coverage rate is found affected by Marangoni effect and film accelerating effect, and surface wetting is significantly facilitated by bubble behavior. Based on the observed phenomenon and physical mechanism, dry-out depth and initial dry-out rate are proposed to evaluate film covering potential on a heating surface. A model to predict film coverage rate is proposed based on the data. The findings would have reliable guide and important implications for further evaluation and design of decay heat removal system of new reactors, and could be helpful for passive containment cooling research.

  • https://doi.org/10.1016/j.net.2022.06.027 인용 PDF KSCI