Effect of asymmetric airflow on liquid film behavior and emergency core coolant bypass in the downcomer geometry of a nuclear reactor pressure vessel

Choi, Chi-Jin; Cho, Hyoung Kyu

doi:10.1016/j.icheatmasstransfer.2020.104765

Cited by 2 publications

(1 citation statement)

References 22 publications

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“…As a radioactive material barrier that contains the core and withstands irradiation, the structural integrity of the pressure vessel is of great significance to the safe operation of the reactor. Therefore, in the process of repairing, refueling, and decommissioning of nuclear plants, we need to clean and decontaminate the pressure vessels [18]. Visual inspection is then performed to determine whether there are cracks, defects, etc., to ensure the integrity of the pressure vessel.…”

Section: Introductionmentioning

confidence: 99%

Design and Development of Underwater Radioactive Material Cleaning Robot Applied in Pressure Vessel

Zhang

2022

ARME

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This paper designed and developed an underwater robot for radioactive material cleaning and other operations, instead of manual methods. Since radioactive substances exist in a pressure vessel, the interior of which is filled with water, and the working environment of the robot is underwater. Its working method is as follows: the inner wall of the pressure volume is cleaned by the cleaning and grinding tools mounted on both sides of the fuselage, and the radioactive material dropped from the bottom of the pressure vessel is cleaned by the robotic arm mounted on the bottom of robot. At the same time, sensors such as cameras, thermometers, and sonars mounted on the robot can return video images and information data inside the pressure vessel. Under the nuclear environment, the underwater robot can improve the cleaning efficiency of the inner wall of the pressure vessel, and reduce the radioactive radiation received by the staff, and control the production of secondary and tertiary wastes. The test results show the effectiveness and practicability of the underwater robot, meanwhile the robot can also be used for cleaning up other underwater radioactive environments.

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Section: Introductionmentioning

confidence: 99%

Design and Development of Underwater Radioactive Material Cleaning Robot Applied in Pressure Vessel

Zhang

2022

ARME

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Numerical Investigations of Liquid Film Offtake by Transverse Gas Flow in a Downcomer Annulus Geometry

Choi

Cho

2022

Front. Energy Res.

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Advances in computational power have enabled the application of computational fluid dynamics (CFD) to nuclear reactor safety analyses, which require accurate predictability for two-phase flow in complex geometries. This study is aimed at validating CFD simulation of liquid film off-take in a 1/10-scale downcomer of a reactor pressure vessel under emergency core coolant (ECC) bypass conditions. Even though different flow regimes can exist simultaneously in real flow, the traditional two-phase flow models used in CFD have a disadvantage with respect to regime dependency. In this study, VOF–slip, which is a hybrid model that combines volume-of-fluid (VOF) and mixture models and is offered in STAR-CCM+ 15.04, was used to simulate the film off-take phenomenon. The key parameters in the simulation were found to be the droplet diameter and interface turbulence damping coefficient. A parametric study was performed to determine the value of the parameters that yield a reasonable liquid film thickness and ECC bypass fraction which were measured at the Seoul National University (SNU) experiment facility. For the conditions of the SNU experiment, the droplet diameter was found to be 150 μm, and the interface turbulence damping coefficient was found to be in the range of 0–30. The validation results confirmed that the VOF–slip model can describe the behavior of the liquid film and the unresolved droplet appropriately. This resulted in an improvement in predicting the ECC bypass fraction in comparison to the results using the conventional VOF model.

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Effect of asymmetric airflow on liquid film behavior and emergency core coolant bypass in the downcomer geometry of a nuclear reactor pressure vessel

Cited by 2 publications

References 22 publications

Design and Development of Underwater Radioactive Material Cleaning Robot Applied in Pressure Vessel

Design and Development of Underwater Radioactive Material Cleaning Robot Applied in Pressure Vessel

Numerical Investigations of Liquid Film Offtake by Transverse Gas Flow in a Downcomer Annulus Geometry

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