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Jacek Jagielski

Publications and source records attributed to Jacek Jagielski.

3 recordsLinked to original sources

Preliminary Structural Study of Chromium Coatings for Nuclear Applications

Following the Fukushima Daiichi disaster, an increasing number of studies concentrate on the development of Accident Tolerant Fuel (ATF) cladding materials for nuclear fuel, aiming to prevent the oxidation of zirconium during incidents such as Loss of Coolant Accident (LOCA) and to effectively lower the amount of heat and hydrogen released during emergency core cooling (ECC). Zirconium alloy cladding with a protective chromium (Cr) coating is considered one of the promising candidates, largely due to its relatively short timeline for deployment in nuclear power plants. In this study, Cr-coated and uncoated Zircaloy-4 claddings were evaluated using high temperature X-ray diffraction (HT-XRD) in vacuum over a temperature range from RT to 1100oC. The temperatures corresponding to the formation of oxide phases are >200oC and >600oC for the uncoated and Cr-coated samples, respectively. SEM and TEM characterisation of the sub-surface in Cr-coated specimen after HT-XRD revealed Fe segregation, formation of Zr(Fe,Cr)2 Laves phase and nano-bubbles at the former Cr / Z4 interface.

cond-mat.mtrl-sci

Surface and in-depth structural changes in nuclear graphite irradiated with noble gases described with Raman imaging

4th Generation high-temperature gas-cooled nuclear reactors (HTGR) are regarded as possible sources of industrial heat in Poland and Europe, allowing for a substantial reduction of the dependency on gas and coal import. It is mainly due to their safety of use, reliability and economy in a current energetic crisis. In this work, graphite, as a primary construction material and neutron moderator in HTGR, was evaluated before and after ion irradiation since its properties depend on the material's structure and purity. Commercial graphite materials (IG-110, NBG-17) and the laboratory's in-home material were chosen for the exemplary samples. The structural damage in HTGR was simulated with energetic Ar+ and He+ ions with fluencies from 1E12 to 2E17 ion/cm2. Raman imaging was chosen to assess radiation damage build-up: the crystallites' evolution, occurrence and types of defects. The recorded evolution showed stronger disordering of the material with heavier Ar+ ions than with He+.

cond-mat.mtrl-sci

Van der Waals interlayer potential of graphitic structures: from Lennard-Jones to Kolmogorov-Crespy and Lebedeva models

The experimental knowledge on interlayer potential of graphenites is summarized and compared with computational results based on phenomenological models. Besides Lennard-Jones approximation, the Mie potential is discussed, Kolmogorov-Crespy model and equation of Lebedeva et al. An agreement is found between a set of reported physical properties of graphite (compressibility along c-axis under broad pressure range, Raman frequencies for bulk shear and breathing modes under pressure, layer binding energies), when a proper choice of model parameters is made. It is argued that the Kolmogorov-Crespy potential is the preferable one for modelling. A simple method of fast numerical modelling, convenient for accurate estimation of all these discussed physical properties is proposed. It is useful in studies of other van der Waals homo/heterostructures.

cond-mat.mes-hall