Investigation of Core Thermohydraulics in Fast Reactors—Interwrapper Flow during Natural Circulation

Kamide, Hideki; Hayashi, Kenji; Isozaki, Toshikuni; Nishimura, Masahiro

doi:10.13182/nt01-a3160

Cited by 29 publications

(6 citation statements)

References 4 publications

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“…The SSC code solves the overall behaviour of LMFBR plant thermal-hydraulics by using a network of one-dimensional objects that simulate pipes, pumps, core, intermediate heat exchanger, SG, etc. Using these calculated results as the boundary conditions, the 3D behaviour of sodium flow in the upper plenum and core are solved by CFD codes such as the AQUA code, the ASFRE(single phase) and the SABENA(two phase) codes [56]. Recently, JNC has been coupling a CFD code with a subchannel code to simulate the thermal-hydraulic behaviour of the core in more detail.…”

Section: Japanmentioning

confidence: 99%

Experimental Studies into the Non-Isothermal Mixing of Incompressible Liquid Counterflows in a Y-junction

Rayzapov

Sobornov

Dmitriev

et al. 2023

YadEn

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The OECD is a unique forum where the governments of 30 democracies work together to address the economic, social and environmental challenges of globalisation. The OECD is also at the forefront of efforts to understand and to help governments respond to new developments and concerns, such as corporate governance, the information economy and the challenges of an ageing population. The Organisation provides a setting where governments can compare policy experiences, seek answers to common problems, identify good practice and work to co-ordinate domestic and international policies.

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Section: Japanmentioning

confidence: 99%

Experimental Studies into the Non-Isothermal Mixing of Incompressible Liquid Counterflows in a Y-junction

Rayzapov

Sobornov

Dmitriev

et al. 2023

YadEn

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“…In contrast, the ability of CFD to simulate geometrical effects directly makes it easier to argue that experiments performed for other designs (and thus in different geometrical configurations) will provide a useful contribution for validating the new tool. Thanks to these arguments, multi-scale/CFD tool may thus rely on a growing experimental database for validating coupled effects: for the effect of pool thermal-hydraulics on natural convection, TALL-3D [25] (SET), CIRCE-HERO [26] (IET) and E-SCAPE [27] (IET) may be considered; for the effect of inter-wrapper flow on S/A cooling, THEADES [28] (SET), PLANDTL-1 [29] (IET) and PLANDTL-2 [30] (IET) are available or will be in the near future; -CLEAR-S [31] (IET) will present an interesting case where it will be possible to validate the effect of pool TH and inter-wrapper flow on global natural convection at the same time; for integral validation, PHENIX [24], EBR-II [32] and FFTF [33] tests are or will be available in the short-term.…”

Section: Validation Stepmentioning

confidence: 99%

VVUQ of a thermal-hydraulic multi-scale tool on unprotected loss of flow accident in SFR reactor

Marie

Marrel

et al. 2021

EPJ Nuclear Sci. Technol.

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Within the framework of the French 4th-generation Sodium-cooled Fast Reactor safety assessment, methodology on VVUQ (Verification, Validation, Uncertainty Quantification) is conducted to demonstrate that the CEA's thermal-hydraulic Scientific Computation Tools (SCTs) are effective and operational for design and safety studies purposes on this type of reactor. This VVUQ-based qualification is a regulatory requirement from the French Nuclear Safety Authority (NSA). In this paper, the current practice of VVUQ approach application for a SFR accidental transient is described with regard to the NSA requirements. It constitutes the first practical, progressively improvable approach. As the SCT is qualified for a given version on a given scenario, the transient related to a total unprotected station blackout has been selected. As it is a very complex multi-scale transient, the SCT MATHYS (which is a coupling of the CATHARE2 tool at system scale, TrioMC tool at component scale and TrioCFD tool at local scale) is used. This paper presents the preliminary VVUQ application to the qualification of this tool on this selected transient. In addition, this work underlines some feedback on design and R&D aspects that should be addressed in the future to improve the SCT.

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“…Norihiro DODA*, Ayako ONO* and Masaaki TANAKA* heat removal, Subchannel, Computational fluid dynamics © The Japan Society of Mechanical Engineers One is the thermal stratification in the upper plenum of the RV (Kamide, et al, 1998a(Kamide, et al, , 2001. While hot sodium at lower density flowing out from the fuel subassemblies occupies the upper part of the upper plenum, cold sodium with higher density provided from the D-DHX accumulates in the lower part of the upper plenum.…”

Section: Introductionmentioning

confidence: 99%

“…At the lower power fuel subassemblies under low flowrate conditions in NC, the cold sodium flow penetrates the upper neutron shielding region due to the strong negative buoyancy force. The IWF (Kamide, et al, 1998a(Kamide, et al, , 2017Weinberg, et al, 1995;Momoi, et al, 1997) is well known as that the cold sodium provided from the D-DHX flows down into the narrow gap between fuel subassemblies (interwrapper gap) and removes the heat from the core through the wrapper tubes. These two phenomena have a direct cooling effect on the heat in the fuel subassemblies, reducing the maximum temperature in the core.…”

Section: Introductionmentioning

confidence: 99%

Core thermal-hydraulics analysis during dipped-type direct heat exchanger operation in natural circulation conditions

Hamase

Miyake

Imai

et al. 2022

Mechanical Engineering Journal

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A direct reactor auxiliary cooling system (DRACS) under natural circulation (NC) conditions with a dipped-type direct heat exchanger (D-DHX) in the upper plenum of a reactor vessel (RV) has been investigated for enhancing the safety of sodium-cooled fast reactors. Studies of the past have revealed that core-plenum interactions, which consists of penetration of the coolant from D-DHXs into the subassemblies and the narrow gap between them (IWF: inter-wrapper flow), and the heat transfer through a wrapper tube among subassemblies (radial heat transfer), occurred and increased core cooling performance during the DRACS operation. Therefore, a multidimensional thermal-hydraulics analysis model in the RV using a computational fluid dynamics (CFD) code (RV-CFD model) was developed to evaluate the core cooling performance. For the design study, the RV-CFD model must simulate reasonable calculation costs while maintaining accuracy. In this study, the subchannel analysis method using the CFD code for fuel subassemblies (subchannel CFD model) was applied to the RV-CFD model. In the subchannel CFD model, the porous media approach was used to consider local geometry in the fuel subassembly, and the effective heat conductivity coefficients in a diffusion term of the energy equation were set to fit the actual radial thermal diffusion between subchannels. Two numerical simulations were compared to the experimental data obtained from the sodium experimental apparatus PLANDTL-1. In the first case, the focus was only the radial heat transfer without the D-DHX operation. In another case with the D-DHX operation, the IWF noticeably occurred, and the focus was on the core-plenum thermal interaction. The calculated sodium temperature in the core correlated well with the experimental results. The RV-CFD with subchannel CFD model was validated for core-plenum interactions during the DRACS with the D-DHX operation under NC conditions.

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Investigation of Core Thermohydraulics in Fast Reactors—Interwrapper Flow during Natural Circulation

Cited by 29 publications

References 4 publications

Experimental Studies into the Non-Isothermal Mixing of Incompressible Liquid Counterflows in a Y-junction

Experimental Studies into the Non-Isothermal Mixing of Incompressible Liquid Counterflows in a Y-junction

VVUQ of a thermal-hydraulic multi-scale tool on unprotected loss of flow accident in SFR reactor

Core thermal-hydraulics analysis during dipped-type direct heat exchanger operation in natural circulation conditions

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