Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 18 of 18 for “"Zirconium alloys"”.
-
Subcritical crack growth in zirconium alloys
Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1982.
-
Electrochemical study of corrosion phenomena in zirconium alloys
Shadow corrosion of zirconium alloy fuel cladding in BWR environments, the phenomenon in which accelerated corrosion is experienced when the cladding surface is in close proximity to other metals, has become a potentially life-limiting issue for BWR fuel. Recent results from experimentation at MIT, …
-
Characterization of hydrides and delayed hydride cracking in zirconium alloys
… to fill some of the missing gaps in the study of zirconium hydrides with state-of-art experiments, cutting edge tomographical technique, and a novel numerical algorithm. A new hydriding procedure is proposed. The new anode material and solution combination overcomes many drawbacks of the AECL …
-
Cracking of zirconium alloys at constant load with and without applied potentials
Cladding materials, namely Zircaloy-2 (Zr-2) and Zircaloy-4 (Zr-4), were tested for evaluation of their resistance to stress corrosion cracking (SCC), delayed hydride cracking (DHC), and localized corrosion (pitting and crevice) in neutral and acidic environments at ambient temperature and 90°C. …
-
High temperature steam oxidation of titanium-coated Zircaloy-2 and Titanium-Zirconium Alloys
… the manifestation of uncontrolled oxidation of zirconium and 3) strong resilience against nuclear bombardment (alpha, beta, gamma, fission products, etc.). The research project was centered on selecting a potential additive not previously looked into for solving the problem of high temperature …
-
Predicting the equilibria of point defects in zirconium oxide : a route to understand the corrosion and hydrogen pickup of zirconium alloys
The performance of zirconium alloys in nuclear reactors is compromised by corrosion and hydrogen pickup. The thermodynamics and kinetics of these two processes are governed by the behavior of point defects in the ZrO₂ layer that grows natively on these alloys. In this thesis, we developed a …
-
Microstructure-informed modeling of hydrogen diffusion in zirconium polycrystals
Zirconium alloys are widely used in the core of various types of nuclear reactors. During service, the hot water coolant reacts with zirconium and releases hydrogen atoms that ingress into the lattice of the metal alloy. With time, hydrogen concentration exceeds its terminal solid solubility limit …
-
Mode I Fracture Testing on Zirconium Foils Under Plane-stress Condition
Zirconium alloys are commonly used in nuclear reactor in-core components due to their good mechanical properties and low neutron-absorption cross-section. Especially for CANada Deuterium Uranium (CANDU) reactors, zirconium alloys serve as the main structural material for fuel channels. In order to …
-
Estudo do processamento termomecânico de liga experimental de zircônio e seu efeito nas propriedades mecânicas e formação de hidretos
Zirconium alloys are used in components of nuclear reactors, particularly in the fuel element, for their excellent properties of corrosion resistance, mechanical resistance, thermal conductivity and low neutron absorption. The interaction with hydrogen during the operation of the reactor leads to …
-
Atomic scale diffusion in complex systems from first principles
… scale transport is crucial to development of new alloys. First principles calculations coupled with advanced diffusion models can accurately predict atomic scale transport mechanisms of point defects in solids. In this work, we examine transport of six solutes - Sn, Cr, Fe, Be, Al and Ni in HCP …
-
Safety of light water reactor fuel with silicon carbide cladding
… cladding - an emerging option to replace the zirconium alloy cladding - are assessed. Its behavior under accident conditions is examined with an integrated approach of experiments, modeling, and simulation. High temperature (1100°C~1500°C) steam oxidation experiments demonstrated that the …
-
Evaluation of multilayer silicon carbide composite cladding under loss of coolant accident conditions
… (SiC) has been proposed as an alternative to zirconium alloys used in current light water reactor (LWR) fuel cladding because it exhibits superior corrosion characteristics, high-temperature strength, and a 1000°C higher melting temperature, all of which are important during a loss of coolant …
-
Silicon carbide performance as cladding for advanced uranium and thorium fuels for light water reactors
… ongoing interest in replacing the fuel cladding zirconium-based alloys by other materials to reduce if not eliminate the autocatalytic and exothermic chemical reaction with water and steam at above 1,200 °C. The search for an accident tolerant cladding intensified after the Fukushima events of …
-
Application of advanced fuel concepts for use in innovative pressurized water reactors
… (PWR) environment. In the switch from a UO2 with zirconium-based cladding to any other combination, there is a multitude of questions that need to be answered. This work examines three of these knowledge gaps: (1) the disposition of weapons-grade plutonium in thorium and silicon carbide cladding, …
-
Influence of zirconium hydride on the biaxial creep behavior of Zircaloy-4 cladding for interim dry storage of spent nuclear fuel
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2019-12-01
-
Investigation effect of external stress on hydrogen solvus in a zircaloy-4 fuel cladding alloy: application of in situ diffraction technique and mesoscale phase-field simulation
… reactors (LWRs). However, the formation of the zirconium hydride phase in the cladding significantly degrades its mechanical properties by reducing the local ductility and initiating crack propagation. Therefore, one of the current fuel performance modeling efforts is to simulate the degradation …
-
Predicting the Influence of Hydrogen on Zirconium
The corrosion process that ensues when the alloys of zirconium used as structural components and fuel claddings in nuclear reactors react with the heavy water used as coolant in the CANDU® reactors results in the production of hydrogen or deuterium. Some of this hydrogen enters the alloy and causes …
-
Modelización microscópica del daño por irradiación en metales hcp (a-Zirconio) : efecto de la anisotropía en la difusión y evolución de defectos
… directions). This study has focused on hcp α-Zirconium (c/a 1.594, lower than ideal 1.633). The aim of this thesis is the creation of a new and original model for the understanding of the microscopic evolution (defect diffusion) in hcp metals, mainly zirconium, using a kinetic Monte Carlo …