Sökning: "thermal-hydraulics"

Visar resultat 11 - 15 av 15 avhandlingar innehållade ordet thermal-hydraulics.

1. 11. 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

3. 12. Numerical Investigations on Debris Bed Coolability and Mitigation Measures in Nordic Boiling Water Reactors

   Författare :Zheng Huang; Weimin Ma; Florian Fichot; KTH; []
   Nyckelord :Severe accident; Debris bed; Coolability; Quench; Oxidation; MEWA code; Coupled analysis; Svåra haverier; Grusbädd; Kylbarhet; Kylning; Oxidering; MEWA program; Kopplad analys; Physics; Fysik;

   Sammanfattning : This thesis is aiming at coolability assessment of particulate debris beds formed in hypothetical severe accidents of Nordic boiling water reactors (BWRs) which may employ either lower drywell flooding or control rod guide tubes (CRGT) cooling as severe accident management strategies. For this purpose, quench and cooling limit (dryout) of debris beds after their formation from fuel coolant interactions were investigated by numerical simulations using the MEWA code. LÄS MER

4. 13. Validation and Application of CFD to Safety-Related Phenomena in Lead-Cooled Fast Reactors

   Författare :Marti Jeltsov; Pavel Kudinov; Walter Villanueva; Dmitry Grishchenko; Afaque Shams; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Verification; Validation; Calibration; Sensitivity Analysis; Uncertainty Analysis; CFD; STH; Code Coupling; Liquid Lead Coolant; LFR; SGTL R; Bubble transport; Core voiding; Seismic Sloshing; Melting Solidification; Physics; Fysik;

   Sammanfattning : Carbon-free nuclear power production can help to relieve the increasing energy demand in the world. New generation reactors with improved safety, sustainability, reliability, economy and security are being developed. Lead-cooled fast reactor (LFR) is one of them. LÄS MER

5. 14. Development, validation and application of an effective convectivity model for simulation of melt pool heat transfer in a light water reactor lower head

   Författare :Chi Thanh Tran; Truc-Nam Dinh; Florian Fichot; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; 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.; Other physics; Övrig fysik;

   Sammanfattning : Severe accidents in a Light Water Reactor (LWR) have been a subject of the research for the last three decades. The research in this area aims to further understanding of the inherent physical phenomena and reduce the uncertainties surrounding their quantification, with the ultimate goal of developing models that can be applied to safety analysis of nuclear reactors. LÄS MER

7. 15. Analysis methodology for RBMK-1500 core safety and investigations on corium coolabiblty during a LWR sever accidnet

   Författare :Audrius Jasiulevicius; KTH; []
   Nyckelord :RBMK. Light water reactor. Core analysis; transient analysis; reactor dynamics;

   Sammanfattning : This thesis presents the work involving two broad aspectswithin the field of nuclear reactor analysis and safety. Theseare: - development of a fully independent reactor dynamics andsafety analysis methodology of the RBMK-1500 core transientaccidents and - experiments on the enhancement of coolabilityof a particulate bed or a melt pool due to heat removal throughthe control rod guide tubes. LÄS MER