Pressurized Water Nuclear Reactor Downcomer Flow SimulationAljaž Kekec
, 2021, diplomsko delo
Opis: In the diploma thesis the flow pattern and conditions in the downcomer of a pressurized water nuclear reactor were simulated, to study coolant mixing inside the primary circuit. This was done using computational dynamics software Ansys CFX. The nuclear reactor in Krško (Slovenia) was used as a basis for the model. The downcomer geometry was simplied for a more feasible study. Three separate simulations were done: one with normal conditions, one with loss of coolant accident conditions and one with a modified geometry. The flow was then studied at different condition at the same levels using velocity contours. The results showed that the axial velocity profiles at the downcomer outlet are not completely uniform.
Ključne besede: Nuclear Power Plant, Pressurized Water Reactor, Downcomer, Flow simulation, Ansys CFX
Objavljeno: 13.10.2021; Ogledov: 134; Prenosov: 14
Celotno besedilo (2,49 MB)
Simulacija toka v prelivnem vodu tlačnika tlačnovodne jedrske elektrarneMelanija Zala Vračko
, 2019, diplomsko delo
Opis: V diplomski nalogi sem naredila simulacijo toka v prelivnem vodu tlačnika tlačnovodne jedrske elektrarne tekom izlivne nezgode. Simulacija je bila narejena s pomočjo programa ANSYS CFX. Za ta program sem razvila primeren vhodni model. Rezultate, ki jih je izračunal program ANSYS CFX, sem primerjala z rezultati, ki so bili izračunani s sistemskim programom RELAP5. Iz rezultatov, izračunanih s programom RELAP5, sem tudi dobila robne pogoje za simulacijo. Primerjava je potrdila, da so rezultati, dobljeni s programom ANSYS CFX smiselni. Analiza rezultatov je omogočila vpogled v tok v prelivnem vodu na lokalni strani.
Ključne besede: jedrska elektrarna, prelivni vod, simulacija toka, računska dinamika tekočin
Objavljeno: 12.02.2020; Ogledov: 594; Prenosov: 108
Celotno besedilo (2,62 MB)
Simulation of flow conditions in nuclear power plant reactor pressure vessel lower plenum experimental facilityBlaž Kamenik
, 2019, magistrsko delo
Opis: The flow conditions during the experiment LIVE2D on reactor core melt behaviour in the lower plenum of a reactor pressure vessel, performed at the Karlsruhe Institute of Technology (Germany), were simulated with a Computational Fluid Dynamics computer code. In this hypothetical severe accident scenario in a pressurized water reactor nuclear power plant, the melt is divided into an oxidic layer and a metallic layer on top of it, and the oxidic layer is volumetrically heated due to decay heat. In the experiment, oil and salt were used as simulant materials for metallic and oxidic melt, respectively. The main goal of performed simulations was to investigate the so-called “focusing effect”, where a thin layer of the reactor vessel steel wall is exposed to high heat flux. Due to the length of experiment, which exceeds 100 hours, only intervals of the melt behaviour were simulated. Four cases were simulated. The first case investigated different boundary conditions for the oil layer behaviour for layer thickness 35 mm. The second case investigated the same conditions with added modelling of the reactor vessel steel wall and salt crust from the lower layer. The third case used similar modelling as the second case to investigate the oil layer behaviour for layer thickness 75 mm. The fourth case investigated both salt and oil layers for oil layer thickness 75 mm. Different analytical and numerical calculations were performed to determine heat losses from simulant liquids to the surroundings, which played an important part in the experiment.
Ključne besede: nuclear power plant, severe accident, reactor core melt, lower plenum, heat flux focusing effect
Objavljeno: 17.09.2019; Ogledov: 556; Prenosov: 99
Celotno besedilo (6,83 MB)