Numerical simulation for the control rod assembly drop time evaluation in a LFR

Emmanuel Maurice Arthur; Chaodong Zhang; Seth Kofi Debrah; Stephen Yamoah; Lei Wang

Heliyon (Nov 2022)

Numerical simulation for the control rod assembly drop time evaluation in a LFR

Emmanuel Maurice Arthur,
Chaodong Zhang,
Seth Kofi Debrah,
Stephen Yamoah,
Lei Wang

Affiliations

Emmanuel Maurice Arthur: Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031, China; School of Nuclear and Allied Sciences, University of Ghana, Box AE 1, Kwabenya, Accra, Ghana; Nuclear Power Institute, Ghana Atomic Energy Commission, Box LG 80, Accra, Ghana
Chaodong Zhang: Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031, China
Seth Kofi Debrah: School of Nuclear and Allied Sciences, University of Ghana, Box AE 1, Kwabenya, Accra, Ghana; Nuclear Power Institute, Ghana Atomic Energy Commission, Box LG 80, Accra, Ghana
Stephen Yamoah: School of Nuclear and Allied Sciences, University of Ghana, Box AE 1, Kwabenya, Accra, Ghana
Lei Wang: Corresponding author.; Key Laboratory of Neutronics and Radiation Safety, Institute of Nuclear Energy Safety Technology, Chinese Academy of Sciences, Hefei, Anhui 230031, China; School of Nuclear and Allied Sciences, University of Ghana, Box AE 1, Kwabenya, Accra, Ghana; Nuclear Power Institute, Ghana Atomic Energy Commission, Box LG 80, Accra, Ghana; School of Computer Science, Hefei Normal University, Hefei, Anhui, 230601, China; Nuclear Power Ghana, P. O. Box KA 9152, KIA-Airport-Accra, Ghana

Journal volume & issue: Vol. 8, no. 11
p. e11540

Abstract

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During scram, the Control Rod Assembly (CRA) is quickly dropped into the core and as well, if any of the operating limits are exceeded, the CRA is dropped into the core within a stipulated time to shut down the reactor power as soon as possible. In this study, the Computational Fluid Dynamics (CFD) approach was used to investigate the CRA drop dynamics of a lead-based research reactor. To simulate the flow field around the CRA in the guide tube, a 3-dimensional model of the CRA in the LBE-filled guide tube was developed and discretized; and the averaged Navier-Stokes equations coupled with the dynamic mesh method were adopted. Considering the large mesh deformation in the LBE coolant domain while the CRA drops, the recently developed FSI method in the CFX code, namely the rigid body approach, was adopted, which falls under the monolithic method. In this method, the translational CRA wall, which is partially immersed in the LBE, was set as a rigid body. It has the advantage of updating and improving the mesh quality through the mesh and re-meshing technique during the process of computation. Compared with the results of the work done in the available literature, the CFD model proved to be applicable and reliable. From the results, the inherent high density among the LBE flow characteristics had the most influence on the drop time. The mass of the CRA impacts its driving force so that the drop time reduces when the CRA mass is increased. In conclusion, the method used in this study can be applied to compute and predict significant parameters which can serve as a reference for a suitable design of the CRA and its drive mechanism in the case of modification for safety.

Published in Heliyon

ISSN: 2405-8440 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Science: Science (General); Social Sciences: Social sciences (General)
Website: https://www.cell.com/heliyon/home

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