Sökning: "Transient boiling"

Visar resultat 11 - 15 av 15 avhandlingar innehållade orden Transient boiling.

1. 11. Experimental and analytical study of thermal mixing at reactor conditions

   Författare :Mattia Bergagio; Henryk Anglart; Horst-Michael Prasser; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; High-cycle thermal fatigue; Hilbert-Huang transform; large eddy; WALE; rainflow; inverse heat conduction; adjoint conjugate gradient; Energy Technology; Energiteknik; Fysik; Physics;

   Sammanfattning : High-cycle thermal fatigue due to turbulent mixing of streams at distinct temperatures is an interdisciplinary issue affecting safety and life extension of existing reactors together with the design of new reactors. It is challenging to model damage and thermal loads arising from the above mixing. LÄS MER

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

   Författare :Chi Thanh Tran; Tomas Lefvert; Harri Tuomisto; KTH; []
   Nyckelord :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;

   Sammanfattning : 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. LÄS MER

4. 13. 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

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. 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