Three-Dimensional Transport Correction in Fast Reactor Core Analysis

As the first developmental step of the sodium-cooled fast reactor (SFR) in China, the pool-type China Experimental Fast Reactor (CEFR) is equipped with the openings and inter-wrapper space in the core, which act as an important part of the decay heat removal system. The accurate prediction of coolant flow in the reactor core calls for complete three-dimensional calculations. In the present study, an investigation of thermal-hydraulic behaviors in a 180° full core model similar to that of CEFR was carried out using commercial Computational Fluid Dynamics (CFD) software. The actual geometries of the peripheral core baffle, fluid channels and narrow inter-wrapper gap were built up, and numerous subassemblies (SAs) were modeled as the porous medium with appropriate resistance and radial power distribution. First, the three-dimensional flow and temperature distributions in the full core under normal operating condition are obtained and quantitatively analyzed. And then the effect of inter-wrapper flow (IWF) on heat transfer performance is evaluated. In addition, the detailed flow path and direction in local inter-wrapper space including the internal and outlet regions are captured. This work can provide some valuable understanding of the core thermal-hydraulic phenomena for the research and design of SFRs.

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Experimental Study on the Effect of Core Support Frame on Seismic Behavior of Fast Reactor Core

Volume 9: Seismic Engineering ◽

10.1115/pvp2020-21385 ◽

2020 ◽

Author(s):

Shinichiro Matsubara ◽

Akihisa Iwasaki ◽

Hidenori Harada ◽

Tomohiko Yamamoto

Keyword(s):

Fast Reactor ◽

Three Dimensional ◽

Reactor Core ◽

Vertical Direction ◽

Vertical Displacement ◽

Test Results ◽

Core Element ◽

Vibration Behavior ◽

Seismic Experiment ◽

Core Elements

Abstract The fast reactor core is composed of hundreds of core elements that self-stand on the lower support plate, and core elements does not have support to constrain vertical displacement in order to avoid effects such as thermal elongation. When an earthquake occurs, the group vibration behavior including the rising of core elements in the vertical direction, the collision with adjacent core elements in the horizontal direction, and the fluid structure interaction is observed. The three dimensional core group vibration analysis code (REVIAN-3D) for evaluating these has been constructed. In this study, to grasp and estimate the group vibration behavior with and without a core former under the earthquake motion, seismic experiment of hexagonal multi bundle model using core element mock-up was conducted. These test results show that the presence of the core former decrease the horizontal displacements and increases core compaction. And the test results are used for the verification data of the analysis code REVIAN-3D.[1]

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Few-group condensation via two-material coexisting ring model for fast reactor core analysis

Annals of Nuclear Energy ◽

10.1016/j.anucene.2015.04.017 ◽

2015 ◽

Vol 83 ◽

pp. 172-180

Author(s):

Jong Hyuck Won ◽

Nam Zin Cho

Keyword(s):

Fast Reactor ◽

Reactor Core ◽

Core Analysis ◽

Ring Model

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Towards spatial kinetics in a low void effect sodium fast reactor: core analysis and validation of the TFM neutronic approach

EPJ Nuclear Sciences & Technologies ◽

10.1051/epjn/2017008 ◽

2017 ◽

Vol 3 ◽

pp. 17 ◽

Cited By ~ 6

Author(s):

Axel Laureau ◽

Laurent Buiron ◽

Bruno Fontaine

Keyword(s):

Fast Reactor ◽

Reactor Core ◽

Core Analysis ◽

Sodium Fast Reactor ◽

Void Effect

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Effect of Deformation of Core Elements of Fast Reactor Core to the Seismic Response

Volume 8: Seismic Engineering ◽

10.1115/pvp2019-93769 ◽

2019 ◽

Author(s):

Akihisa Iwasaki ◽

Shinichiro Matsubara ◽

Kazuteru Kawamura ◽

Hidenori Harada ◽

Tomohiko Yamamoto

Keyword(s):

Thermal Expansion ◽

Fast Reactor ◽

Seismic Analysis ◽

Three Dimensional ◽

Reactor Core ◽

Axial Direction ◽

Vertical Displacement ◽

Analysis Model ◽

The Core ◽

Core Elements

Abstract Core elements of a fast reactor are self-standing on the core support structure and not restrained in the axial direction. When the earthquake occurs, it is necessary to consider vertical behavior and horizontal displacement of the core elements simultaneously. In the core seismic analysis, a three dimensional core vibration behavior was evaluated by considering fluid structure interaction, collision with adjacent core elements and vertical displacement and verified by a series of vibration tests. But the evaluation had a assumption of straightness of each core elements which may be bowed due to thermal expansion and swelling under restraint of the horizontal direction between the upper pad and lower structure (Entrance Nozzle). If the core elements are deformed in its plant operation, they may push each other against its adjacent core elements. The large horizontal interference forces may work to decrease the vertical displacement of the core elements. In this study, to grasp and estimate the behavior under the deformed core elements under the earthquake motion, a three dimensional seismic analysis model consist of all of core elements with consideration of the effect of deformed core elements were prepared, analyzed and verified by hexagonal-matrix tests with 37 core elements and single row mock-up models with 7 core elements. These test results show that the rising displacements decrease with increased deformation and no rising occurs when the deformations exceed a threshold. In this paper, the effect of bending deformation due to thermal expansion and swelling on the rising displacement of the core elements was shown by seismic experiments.

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Analysis of Seismic Experiment of Hexagonal Multi Bundle Model Using Core Assembly Mock-Up

Volume 9: Seismic Engineering ◽

10.1115/pvp2020-21386 ◽

2020 ◽

Author(s):

Akihisa Iwasaki ◽

Shinichiro Matsubara ◽

Hidenori Harada ◽

Tomohiko Yamamoto

Keyword(s):

Fast Reactor ◽

Three Dimensional ◽

Reactor Core ◽

Vertical Direction ◽

Horizontal Displacement ◽

Vertical Displacement ◽

The Core ◽

Vibration Behavior ◽

Seismic Experiment ◽

Core Elements

Abstract The fast reactor core is composed of hundreds of core elements that stand independently on the core support plate, but does not have support to constrain vertical displacement in order to avoid effects such as thermal elongation. When the earthquake occurs, the group vibration behavior is shown, including the rising of core elements in vertical direction, the collision with adjacent core elements in horizontal direction, and the fluid structure interaction. The three dimensional core group vibration analysis code (REVIAN-3D) was constructed to evaluate them. In the case of fast reactor cores in Japan, the horizontal displacement of core elements at the outermost periphery is restricted by the core former (core barrel). However, since there is no core former in fast reactors other than Japan and the boundary conditions are different from those in Japan, the vibration behavior also differs. In this study, to grasp and estimate the group vibration behavior with and without a core former under the earthquake motion, seismic experiment of hexagonal multi bundle model using core assembly mock-up was conducted [1]. These test results show that the horizontal displacements are larger and impact force between pads of core assembly mock-up is smaller without the core former. In this paper, the analysis was verified by group vibration tests with and without a core former.

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