Sökning: "RPV failure"

Hittade 5 avhandlingar innehållade orden RPV failure.

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

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

    Sammanfattning : 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. LÄS MER

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

    Författare :Hongdi Wang; Walter Villanueva; Sevostian Bechta; Weimin Ma; Artem Kulachenko; Michael Fitzpatrick; KTH; []
    Nyckelord :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;

    Sammanfattning : 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. LÄS MER

  4. 3. Antiretroviral drug resistance and treatment outcomes of human immunodeficiency virus type-1 : implications for low and middle income countries

    Författare :Amanda Häggblom; Karolinska Institutet; Karolinska Institutet; []
    Nyckelord :;

    Sammanfattning : My thesis contains comprehensive studies of antiretroviral treatment (ART) naïve and experienced patients from the beginning of the Swedish HIV-1 epidemic. Paper I was the first study to describe the ART usage and occurrence acquired drug resistance mutations (DRM) at a population level in Sweden over time and we used data derived between 1997-2011. LÄS MER

  5. 4. Informing Severe Accident Management Guidelines for a Pressurized Water Reactor with MELCOR Simulations

    Författare :Nan Zhao; Sevostian Bechta; Jinho Song; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Severe accident management guidelines SAMG ; SAMG verification validation; numerical simulation; SAMG entry condition; SAMG actions; primary-side bleed feed.; Kärnenergiteknik; Nuclear Engineering;

    Sammanfattning : Severe accident management guidelines (SAMGs) play an important role in the hierarchical structure of the defense-in-depth (DiD) principle of reactor safety. Among different methods to verify and validate the effectiveness of SAMG on mitigating severe accident consequences, the approach of numerical simulations using best-estimate computer codes was extensively applied to evaluate the SAMG and SAM actions. LÄS MER

  7. 5. Investigations of passive safety systems in LWRs : melt coolability with bottom coolant injection, light gas effects on a passive containment cooling system

    Författare :Domenico Paladdino; KTH; []
    Nyckelord :;

    Sammanfattning : The key objectives in introducing passive features in thesafety systems for Light Water Reactor (LWR) are to increasetheir reliability, to simplify the design of the plants and toimprove performance and economics. Component and integralsystem tests in scaled facilities are required for optimizingthe design and for certification of these safety systems. LÄS MER