Search for dissertations about: "pressure vessel reactor"

Showing result 1 - 5 of 14 swedish dissertations containing the words pressure vessel reactor.

2. 1. Radiation Induced Precipitation in Reactor Pressure Vessel Steel Welds

   Author : Kristina Lindgren; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; precipitation; irradiation damage; low alloy steel; reactor pressure vessel; atom probe tomography;

   Abstract : Radiation induced clustering and precipitation affect the mechanical properties of the reactor pressure vessel (RPV) of a nuclear power plant, i.e. the material becomes embritteled. The combination of low Cu (0. READ MORE

4. 2. Thermo-mechanical Assessment of Reactor Pressure Vessels of Light Water Reactors During Severe Accidents

   Author : Hongdi Wang; Walter Villanueva; Sevostian Bechta; Weimin Ma; Artem Kulachenko; Michael Fitzpatrick; KTH; []
   Keywords : Severe accident scenario; reactor pressure vessel; in-vessel melt retention; failure analysis; finite element analysis; validations; Scenario för svåra haverier; reaktortank; in-vessel retention; feleffektsanalys; Finite Element Analyser; validering; Physics; Fysik;

   Abstract : The reactor pressure vessel (RPV) is one of the crucial safety barriers designed to isolate the reactor core, safeguarding against potential radioactive releases into the environment during a severe accident. The assessment of RPV behaviour and its failure is necessary to predict the characteristics of melt release into the reactor pit and succeeding ex-vessel accident progression. READ MORE

5. 3. Modelling and Simulation of Reactor Pressure Vessel Failure during Severe Accidents

   Author : Peng Yu; Weimin Ma; Walter Villanueva; Sevostian Bechta; Florian Fichot; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; RPV failure; thermo-fluid-structure coupling; creep modelling; melt pool heat transfer; severe accident; CFD; FEA; transIVR;

   Abstract : This thesis aims at the development of new coupling approaches and new models for the thermo-fluid-structure coupling problem of reactor pressure vessel (RPV) failure during severe accidents and related physical phenomena. The thesis work consists of five parts: (i) development of a three-stage creep model for RPV steel 16MND5, (ii) development of a thermo-fluid-structure coupling approach for RPV failure analysis, (iii) performance comparison of the new approach that uses volume loads mapping (VLM) for data transfer with the previous approach that uses surface loads mapping (SLM), (iv) development of a lumped-parameter code for quick estimate of transient melt pool heat transfer, and (v) development of a hybrid coupling approach for efficient analysis of RPV failure. READ MORE

6. 4. The Effective Convectivity Model for Simulation and Analysis of Melt Pool Heat Transfer in a Light Water Reactor Pressure Vessel Lower Head

   Author : Chi Thanh Tran; Tomas Lefvert; Harri Tuomisto; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; light water reactor; hypothetical severe accident; accident progression; accident scenario; core melt pool; heat transfer; turbulent natural convection; heat transfer coefficient; phase change; mushy zone; crust; lower plenum; analytical model; effective convectivity model; CFD simulation; Thermal energy engineering; Termisk energiteknik;

   Abstract : Severe accidents in a Light Water Reactor (LWR) have been a subject of intense research for the last three decades. The research in this area aims to reach understanding of the inherent physical phenomena and reduce the uncertainties in their quantification, with the ultimate goal of developing models that can be applied to safety analysis of nuclear reactors, and to evaluation of the proposed accident management schemes for mitigating the consequences of severe accidents. READ MORE

7. 5. Effects of Irradiation and Thermal Ageing on the Nanoscale Chemistry of Steel Welds

   Author : Kristina Lindgren; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; spinodal decomposition; thermal ageing; low alloy steel; reactor pressure vessel; irradiation damage; atom probe tomography; core barrel; clustering;

   Abstract : Structural materials of nuclear power plants degrade during operation due to thermal ageing and irradiation from the reactor core. Effects on the materials are an increase in hardness and tensile strength, and a decrease in ductility and fracture toughness, i. e. embrittlement. READ MORE