Sökning: "Ma Weimin"

Visar resultat 1 - 5 av 14 avhandlingar innehållade orden Ma Weimin.

  1. 1. CFD Study of Molten Pool Convection in a Reactor Vessel during a Severe Accident

    Författare :Boshen Bian; Walter Villanueva; Sevostian Bechta; Weimin Ma; Shuisheng He; KTH; []
    Nyckelord :Severe accident; Corium; Natural convection; Turbulence; Scalability; Direct numerical simulation DNS .; Svåra haverier; härdsmälta; naturlig konvektion; turbulens; skalbarhet; direkt numerisk simulering DNS .; Physics; Fysik;

    Sammanfattning : During severe accidents in nuclear reactors, the core and internal structures can melt down and relocate into the reactor pressure vessel (RPV) lower head (LH) forming there a stratified molten corium pool. The pool generally consists of superheated oxidic and metallic liquid layers imposing thermo-mechanical loads on the RPV wall. LÄS MER

  3. 2. MELCOR Capability Development for Simulation of Debris Bed Coolability

    Författare :Yangli Chen; Weimin Ma; Michael Buck; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Severe accident; coolability; MELCOR; COCOMO; surrogate modeling; coupling codes; uncertainty analysis.; Kärnenergiteknik; Nuclear Engineering;

    Sammanfattning : The severe accident management (SAM) strategy for a Nordic boiling water reactor (BWR) employs cavity flooding prior to vessel failure, so that the core melt (corium) discharged from the vessel could fragment and form a particulate debris bed. The key to the success of this SAM strategy is the coolability of ex-vessel debris beds. LÄS MER

  4. 3. An Experimental Study on the Dynamics of a Single Droplet Vapor Explosion

    Författare :Roberta Concilio Hansson; Weimin Ma; Geroges Berthoud; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; steam explosions; radiography; melt preconditioning; noncondensable gas; Low energy physics; Lågenergifysik;

    Sammanfattning : The present study aims to develop a mechanistic understanding of the thermal-hydraulic processes in a vapor explosion, which may occur in nuclear power plants during a hypothetical severe accident involving interactions of high-temperature corium melt and volatile coolant. Over the past several decades, a large body of literature has been accumulated on vapor explosion phenomenology and methods for assessment of the related risk. LÄS MER

  5. 4. Experimental Study on Steam Explosions in Chemical Solutions and Seawater

    Författare :Yucheng Deng; Weimin Ma; Sevostian Bechta; Andrei Komlev; Renaud Meignen; KTH; []
    Nyckelord :Severe accident; fuel coolant interactions; steam explosion; chemical additives; seawater; Svåra haverier; bränsle-kylmedelsinteraktioner; ångexplosion; kemiska tillsatser; havsvatten; Kärnenergiteknik; Nuclear Engineering;

    Sammanfattning : Steam explosions may be encountered in severe accidents of light water reactors (LWRs), which are thermal detonations caused by rapid and intense vaporization of the coolant upon its direct contact with the core melt (corium). Motivated by the interest in understanding and mitigation of severe accident progression, many studies have been conducted to investigate the steam explosion phenomena during severe accidents. LÄS MER

  7. 5. Sensitivity and Uncertainty Analysis of Boiling Water Reactor Stability Simulations

    Författare :Ivan Gajev; Weimin Ma; Tomasz Kozlowski; Kostadin Ivanov; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; BWR Stability; Sensitivity; Uncertainty; SRA - Energy; SRA - Energi;

    Sammanfattning : The best estimate codes are used for licensing of Nuclear Power Plants (NPP), but with conservative assumptions. It is claimed that the uncertainties are covered by the conservatism of the calculation. LÄS MER