Sökning: "UO2"

Visar resultat 11 - 15 av 44 avhandlingar innehållade ordet UO2.

  1. 11. Development of Encapsulated UN-UO₂ Accident Tolerant Fuel

    Författare :Diogo Ribeiro Costa; Pär Olsson; Janne Wallenius; Simon Middleburgh; Magnus Limbäck; Denise Adorno Lopes; Ho Jin Ryu; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Accident tolerant fuel; UN-UO2 composite fuel; coating technology; powder coating; chemical vapour deposition CVD ; physical vapour deposition PVD ; UN spheres; spark plasma sintering; Kärnenergiteknik; Nuclear Engineering;

    Sammanfattning : Accident tolerant fuels (ATFs) are designed to endure a severe accident in the reactor core longer than the standard UO2-Zr alloy systems used in light water reactors (LWRs). Composite fuels such as UN-UO2 are being considered as an ATF concept to address the lower oxidation resistance of the UN fuel from a safety perspective for use in LWRs, whilst improving the in-reactor behaviour of the UO2 fuel. LÄS MER

  3. 12. Studies of reactions occurring in the AUC-process : from UF₆ to sintered UO₂ pellets

    Författare :Lars Hälldahl; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This study has been carried out to investigate the influence of process parameters upon the material characteristics during the conversion of UFg to UO2 powder, and the importance of variation in these charcteristics for the final quality of the sintered pellets. The first process step is a precipitation of ammonium uranyl carbonate (AUC) from UFg, ammonia and carbon dioxide. LÄS MER

  4. 13. Experimental studies of radiation-induced dissolution of UO2 : The effect of intrinsic solid phase properties and external factors

    Författare :Alexandre Barreiro Fidalgo; Mats Jonsson; David Shoesmith; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Oxidation; dissolution; uranium dioxide; gadolinium; bentonite; sulfide; hydrogen; gamma radiation; radiolysis; hydrogen peroxide; hydroxyl radical; repository; Kemi; Chemistry;

    Sammanfattning : Dissolution of the UO2 matrix is one of the potential routes for radionuclide release in a future deep geological repository for spent nuclear fuel. This doctoral thesis focuses on interfacial reactions of relevance in radiation-induced dissolution of UO2 and is divided in two parts:In the first part, we sought to explore the effects of solid phase composition:The impact of surface stoichiometry on the reactivity of UO2 towards aqueous radiolytic oxidants was studied. LÄS MER

  5. 14. Oxidative dissolution of doped UO2 and H2O2 reactivity towards oxide surfaces : A kinetic and mechanistic study

    Författare :Kristina Nilsson; Mats Jonsson; Mats Johansson; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Oxidative dissolution; UO2; ADOPT; H2O2; Spent Nuclear Fuel.; Kemi; Chemistry;

    Sammanfattning : Oxidative dissolution of std. UO2 and UO2 doped with Cr2O3 and Al2O3, i.e. ADOPT, induced by H2O2 and γ radiation has been the main focus in this licentiate thesis. LÄS MER

  7. 15. Development and Applications of some Radioanalytical Procedures: Analysis of β- and α-Emitting Radionuclides Using Radiometric and ICP-MS Detection Methods

    Författare :Henrik Ramebäck; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; diffusion; plutonium; 90Sr; curium; uranium; 99Tc; bentonite clay; analysis; UO2 fuel; leaching; americium; neptunium;

    Sammanfattning : Analyses of radionuclides are important in environmental monitoring and in research. However, as in the analysis of many other species, interferences may be a problem. In a-spectrometric detection, 238Pu interferes with 241Am, owing to their similar decay energies. LÄS MER