Sökning: "boiling water reactors"

Visar resultat 6 - 10 av 40 avhandlingar innehållade orden boiling water reactors.

  1. 6. Novel Diagnostics and Computational Methods of Neutron Fluxes in Boiling Water Reactors

    Författare :John Loberg; Michael Österlund; Thomas Smed; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Void; BWR; neutron fluxes; channel bow; MCNP; 2D 3D; Physics; Fysik;

    Sammanfattning : The focus in this thesis is to improve knowledge of the BWR related uncertainties void, channel bow, and control rods. The presence of void determines the moderation of neutrons in BWRs. A high void fraction is less efficient in moderating neutrons than a low one. LÄS MER

  3. 7. Noise Applications in Light Water Reactors with Traveling Perturbations

    Författare :Victor Dykin; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Green s function technique; transit times; decay ratio; cross-correlation function; void fraction; global and regional instabilities; propagating density perturbation; BWR stability; reduced order models; non-white driving force; local component; Monte Carlo; space-dependent neutron noise; density wave oscillations;

    Sammanfattning : Neutron noise induced by perturbations traveling with the coolant of light water reactors (LWRs) is investigated. Different methods to simulate the effect of propagating perturbations are considered. The studies are performed in both open- and closed-loop systems and summarized in three chapters. LÄS MER

  4. 8. 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

  5. 9. 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

  7. 10. On Fuel Coolant Interactions and Debris Coolability in Light Water Reactors

    Författare :Sachin Thakre; Weimin Ma; Florian Fichot; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; severe accident; fuel-coolant interactions; melt jet fragmentation; steam explosion; debris bed coolability; uncertainty analysis; Energiteknik; Energy Technology;

    Sammanfattning : During the case of a hypothetical severe accident in a light water reactor, core damage may occur and molten fuel may interact with water resulting in explosive interactions. A Fuel-Coolant Interactions (FCI) consists of many complex phenomena whose characteristics determine the energetics of the interactions. LÄS MER