Cladding Materials Research Articles

In-situ observation of damage evolution in Mo-SiCf/SiC heterogeneous composite

Innovative metal-SiCf/SiC heterogeneous structure composites are promising accident tolerance fuel cladding materials for the Gen IV advanced reactors. The mechanical damage of these composites is a critical issue for their safe application. In this work, the damage process and mechanism of the Mo-SiCf/SiC cladding are revealed by combining In-situ C-ring test and Finite Element Analysis. The results show that the mirco-cracks originate from the pores in the outermost side of the SiCf/SiC layer, and propagate along the fiber bundles boundaries. At the same time, the “bamboo joint”-like damage occurs in the SiCf/SiC layer during C-ring test due to the periodic pore distribution. The fact that the formation of the main crack in SiCf/SiC layer prior to the fracture of Mo layer indicate the Mo-SiCf/SiC cladding can maintain the hermeticity and structure integrity until the sample fails completely. Moreover, the C-ring strength of the Mo-SiCf/SiC cladding is 360 MPa, which is much higher than 201 MPa of SiCf/SiC cladding. Overall, the Mo-SiCf/SiC cladding structure exhibits better crack growth resistance and higher strength compared to SiCf/SiC cladding. Meanwhile this work will provide technical support and theoretical basis for the structural design of cladding materials for advanced nuclear energy systems.

Effects of different cladding materials on orbital angular momentum modes propagating in photonic crystal fibers.

With the development of orbital angular momentum (OAM) photonic crystal fibers (PCFs) for more efficient communication, fiber claddings are important to the performance. In this paper, the influence of S i O 2 and four new optical materials, which are amethyst, SSK2, SF11, and LaSF09, as cladding materials, on the OAM mode characteristics is studied based on a common PCF for OAM transmission. In addition, the effective index difference, dispersion, confinement loss, and other properties of OAM modes transmitted in the five materials are derived by the finite element method. After in-depth analysis, universal rules can be obtained as guidelines for optimization of PCF in the future for improving the efficiency of optical fiber communication. Through chart analysis, it can be concluded that when materials of high effective refractive indices are used as cladding materials for PCF, the dispersion, nonlinear coefficient, confinement loss, mode purity, and other properties are significantly improved. Lower dispersion and confinement loss are more conducive to long-distance communication transmission. The decrease in nonlinear coefficient represents a better effect in suppressing nonlinear effects, and the increase in numerical aperture and mode purity respectively improves the transmission efficiency and stability of OAM communication. These conclusions provide universal rules for high-quality communication in the future.

Cast-rolling force model of multi-roll solid–liquid cast-rolling bonding process for fabricating metal cladding materials

Based on twin-roll casting technology and multi-roll groove rolling technology, a Multi-Roll Solid-Liquid Cast-Rolling Bonding (MRSLCRB) process was proposed to fabricate Cu/steel cladding bars, which processes the advantages of short flow and high-efficiency. However, it is a typical 3-D thermal-fluid-mechanics coupled problem, and determining cast-rolling force is difficult during the equipment design. Therefore, the geometrical evolution of the cast-rolling area was studied, laying the foundation to establish contact boundary equations and analyze mechanical schematics and metal flow. Then, a 3-D steady-state thermal-fluid coupled simulation model, including casting roll, substrate bar, and cladding metal, was established. The Kissing Point (KP) height, average outlet temperature, and process window were predicted, and simulation results of the three-roll layout indicate that the KP distribution along the circumferential direction can be considered uniform. Hence, the engineering cast-rolling force model was derived based on the differential element method and plane deformation hypothesis. The accuracy was verified by the 3-D finite element model, and the influences of process layouts and technological parameters on the cast-rolling force were analyzed. Through the indirect multi-field coupled analysis method, the temperature–pressure evolution and reasonable process window can be predicted, which provides a significant basis for guiding equipment design and improving product quality.

Effects of Zr and/or Ti addition on the morphology, crystal and metal/oxide interface structures of nanoparticles in FeCrAl-ODS steels

FeCrAl oxide dispersion strengthened (ODS) steel is one of the most promising candidate cladding materials for Generation IV nuclear reactors due to its superior high temperature strength and excellent resistance to creep, corrosion and irradiation. The morphologies of matrix grains and oxides, the crystal and metal/oxide interface structures of nanoparticles in two FeCrAl ODS steels, i.e., 3.3Al–0.5Zr (Fe–15Cr–2W–3.3Al–0.5Zr–0.35Y2O3) and 3.7Al–0.1Ti–0.6Zr (Fe–15Cr–2W–3.7Al–0.1Ti–0.6Zr–0.35Y2O3), were studied by transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) and high resolution transmission electron microscopy (HRTEM). The average matrix grain sizes of 3.3Al–0.5Zr ODS steel and 3.7Al–0.1Ti–0.6Zr ODS steel are 1.01 and 0.97 μm, respectively. The dispersion morphology of oxides in 3.7Al–0.1Ti–0.6Zr ODS steel is much better, relative to that of 3.3Al–0.5Zr ODS steel. Crystal & interface structures of 88 and 171 oxides in 3.3Al–0.5Zr ODS steel and 3.7Al–0.1Ti–0.6Zr ODS steel were characterized, respectively. The proportions of Y–Zr–O, Y–Al–O, Y–Cr–O, ZrO2 and Y2O3 in 3.3Al–0.5Zr ODS steel are 77.2%, 9.1%, 2.3%, 2.3% and 2.3%, respectively and, however, the proportions of Y–Zr–O, Y–Ti–O, Y–Al–O and ZrO2 in 3.7Al–0.1Ti–0.6Zr ODS steel are 86.5%, 8.3%, 3.5% and 1.7%, respectively. The much better dispersion morphology of oxides in 3.7Al–0.1Ti–0.6Zr ODS steel, relative to that of 3.3Al–0.5Zr ODS steel, is due to the much higher proportion of Y–Zr–O, the considerably lower proportion of Y–Al–O and the fairly high number fraction of Y–Ti–O. The mechanisms of the formation and polymorphic transition of various kinds of oxides and, moreover, the strengthening mechanisms in both ODS steels were discussed.

Effect on Surface Properties of H13 Mold Steel Cladding Layer by Scanning Strategy

Laser cladding technology is used to clad the surface layer of H13 mold steel with Ni60A metal powder coating to solve the failure problem. The study used JMatPro software to extract and fit the thermophysical property parameters of the substrate and the clad material, and then used ANSYS APDL software to qualitatively analyze the distribution of melt pool morphology, nodal temperature versus time course curve and residual stress magnitude during the laser cladding process. Based on the results of the minimum residual stress in the cladding, reasonable scan paths were derived for the preparation of metal coatings on the surface layer of the die steel. The results show that the maximum peak temperature of the cladding process is 2515°C using short path scanning. The cladding layer can form a good metallurgical bond with the substrate at this temperature, with a stress of 406.68 MPa in the scanning direction and 284.45 MPa perpendicular to the scanning direction, which is significantly smaller than the residual stresses of other scanning methods. The residual stress values for the different strategies are from largest to smallest: spiral scan > block scan > long path scan > short path scan.

Deep energy retrofits using different retrofit materials under different scenarios: Life cycle cost and primary energy implications

Deep energy retrofits of existing buildings can contribute to achieving a renewable-based society, though they are mostly lacking in the EU. To understand the cost and primary energy savings of deep energy retrofits, all life cycle phases, including construction, operation, maintenance and end-of-life, must be considered. The initial building without retrofit must be analysed over its remaining lifetime covering energy operation, maintenance and end-of-life implications that change with a retrofit. Such a method is applied to a multifamily building retrofitted to two passive house standards limiting annual final heat use to 50 and 30 kWh/m2. Energy improvements to the building envelope are analysed considering different versions of initial cladding materials and retrofit materials, and different economic and electricity supply scenarios. A retrofit to 50 kWh/m2 is profitable for all economic scenarios while the 30 kWh/m2 version is profitable for most of the scenarios giving net primary energy savings of 57–60% and 63–72%, respectively, compared to the non-retrofitted building. The cost of different retrofit materials is similar, while the primary energy use is much lower for wood-based materials. The changed costs and primary energy use for the non-retrofit building, in maintenance and end-of-life phases, varies depending on assumed initial cladding materials.

Molybdenum isotopes separation using squared-off optimized cascades

Recently molybdenum alloys have been introduced as accident tolerating materials for cladding of fuel rods. Molybdenum element has seven stable isotopes with different neutron absorption cross section used in various fields, including nuclear physics and radioisotope production. This study presents separation approaches for all intermediate isotopes of molybdenum element by squared-off cascades using a newly developed numerical code with Salp Swarm Algorithm (SSA) optimization algorithm. The parameters of cascade including feed flow rate, feed entry stage, cascade cut, input feed flow rate to gas centrifuges (GCs), and cut of the first stage are optimized to maximize both isotope recovery and cascade capacity. The squared off and squared cascades are studied, and the efficiencies are compared. The results obtained from the optimization showed that for the selected squared off cascade, Mo94 in four separation steps, Mo95 in five steps, Mo96 in six steps, Mo97 in seven steps, and Mo98 in two steps are separated to the desired concentrations. The highest recovery factor is obtained 63% for Mo94 separation and lowest recovery factor is found 45% for Mo95.

Impact of oxidized HANATM and Zircaloy-4 cladding materials under high temperature on the coolability of light water reactors

In this study, oxidized HANATM and Zircaloy-4 exposed to steam at a temperature of 1200 °C for a duration of 136–1536 s were characterized, and their coolability under nuclear accident conditions was discussed. Under the given environmental oxidization conditions, the differences in the surface conditions and effective thermal properties of oxidized HANATM and Zircaloy-4 resulted in different degrees of coolability. For different oxidation resistances of these cladding materials, the reduction in their thermal conductivity by oxidation showed a difference, resulting in different heat transport phenomena that determine the Leidenfrost temperature, TL. However, TL did not increase further after the oxide layer reached an equivalent cladding reacted (ECR) of at least 24%, which is the penetration depth of the oxide layer. A 1-D transient heat transfer analysis based on the droplet behavior showed that TL did not increase even after reaching the penetration depth of the oxide layer. The analysis results also indicated that the delay in the heat transfer in the oxide layer did not affect TL after reaching the penetration depth of the oxide layer.

Uniaxial tensile properties of pre-stretched ethylene-tetrafluoroethylene (ETFE) foil

The ETFE foil is a type of good cladding material in the field of architecture and its uniaxial tensile properties are important considerations in the design analysis. In engineering application, the stress of ETFE foil may exceed the first and second yield stress under external load and the large plastic deformation is usually observed. Previous studies mainly focus on its uniaxial tensile properties along the uniaxial pre-stretching direction after the uniaxial pre-stretching stress is over the yield stress. Uniaxial pre-stretch will cause the ETFE film to compress in the other direction due to Poisson’s ratio, while the uniaxial tensile properties perpendicular to the uniaxial pre-stretching direction is still unknown. Besides, the study on its uniaxial tensile properties along the biaxial pre-stretching direction after the biaxial pre-stretching stress is over the yield stress is also quite limited. In order to investigate this issue, the uniaxial pre-stretching tests, the asynchronous biaxial pre-stretching tests and the synchronous biaxial pre-stretching tests were performed to make the uniaxial stress and the biaxial stress reach over the first and second yield stress respectively. Square specimens for subsequent uniaxial tensile tests were prepared from these pre-stretching tests and the uniaxial tensile stress–strain curves of specimens of different pre-stretching tests were obtained. The uniaxial tensile test results demonstrate that in some cases the bearing capacity of ETFE foil was strengthened after pre-stretching tests while in many cases both the uniaxial pre-stretching and the biaxial pre-stretching lowered the bearing capacity of ETFE foil. Additionally, the pre-stretching strain correlates strongly with the bearing capacity of pre-stretched ETFE foil and the relationship between them is discussed.

Residual stress release during laser cladding process: A review

Laser cladding technology has attracted substantial attention in cutting-edge areas of metal surface repair and remanufacturing research. Nevertheless, excessive residual stress of cladding is the primary obstacle that hinders its practical application in aerospace, engineering machinery, and other industries. Herein, a comprehensive review of recent advances in the residual stress release in laser cladding is provided in three sections. The first section covers how various laser parameters and material characteristics affect residual stress. The second section discusses the effect and comparison of matching heat treatment methods before and after the laser cladding process on residual stress. The final section focuses on a brand-new concept and technique to release the residual stress during the cladding process via phase transformation. We hope that this review will be a reference for theoretical research and implementation of new laser cladding materials and technologies and present possible scientific solutions and prospects for the ideal reduction in residual stress during the cladding process.

An investigation of bimetallic tube fabrication through a novel friction stir extrusion based technology for automotive applications

The bimetallic tubular component fabrication through a novel friction stir backward extrusion (FSBE) process has been proposed in this article. During the extrusion process, the bonding occurs between the substrate and cladding material due to diffusion. The frictional heat generated during the process leads to softening and extrusion of solid clad material that forms a layer on the substrate material. Different sets of materials have been used for feasibility testing. The results show that the process is capable of uniform cladding and void-free bonding for different sets of material. Energy dispersive spectroscopy (EDS) line scan and area mapping were performed at the interface to understand the diffusion pattern. At the interface, intermetallic compounds (IMCs) were confirmed via spot EDS and X-ray diffraction (XRD) analyses. Strong metallurgical bonding occurs between the substrate and the cladding material due to the interdiffusion of the materials, and the flattening test was performed to check the bonding efficacy. Thus, this process opens new opportunities for the fabrication of bimetallic tubular components, which can be used in electrical, structural, lightweight, and corrosion-resistance applications.

Steady-state and power transient critical heat flux experiments of FeCrAl and Zircaloy claddings under saturated pool boiling

FeCrAl and Zircaloy cladding tubes are vertically placed in the saturated pool boiling chamber to perform steady-state and power-transient critical heat flux (CHF) experiments. Three FeCrAl-variants, including FeCrAl-C26M, FeCrAl-B126Y, and FeCrAl-B136Y, are tested to compare their pool boiling thermal performances with traditional Zircaloy claddings including Zirlo, Zr705, and Zircaloy-4. In the steady-state pool boiling experiments, it was confirmed that FeCrAl alloys have higher pool boiling CHF values than Zircaloys. Among these tested materials, FeCrAl-C26M has the highest pool boiling CHF, but the FeCrAl-C26M nucleate boiling heat transfer coefficient is less than that of FeCrAl-B136Y. It reconfirms that CHF is enhanced on the post-CHF oxidized samples. However, as the cycling number of post-CHF oxidization increases, the CHF enhancement becomes less appreciable due to the limited physics contributions of the oxide layer. It is noteworthy that the finalized CHF enhancement can vary a lot between different cladding materials. For example, in three Zircaloy variants, their saturated pool boiling CHF results converge to 980 kW/m2 on the post-CHF oxidized samples. In three FeCrAl variants, their pool boiling CHF results are finalized to 1400 kW/m2. This CHF enhancement difference could be possibly attributed to the chemical constituents of oxide layers presented on cladding surfaces. The Fuchs-reactivity initiated accident transients are simulated by direct current programmable power supply to characterize thermal responses of different claddings to various pulse-width power transients. It is found that the heat transfer coefficients show monotonically increasing parametric trend with respect to faster power-transient rates, i.e., shorter pulse widths. Different from the steady-state pool boiling, the transition boiling regime is phenomenologically reflected in the power-transient pool boiling curve. This potentially implies that power-transient CHF featured by surface temperature overshoot may indicate transient thermal-safety margins not so accurately as the power-transient maximum heat flux. The difference gap of power-transient maximum heat flux between various cladding materials can be gradually closed by the progressive increasing of power transient rates.

Effect of Cladding Material and Date of Transplanting on Growth and Yield of Greenhouse Broccoli During Winter in High Altitude Ladakh, India

Broccoli is a cool-season crop. The optimum temperature for initiation of flowering and head growth is 15-20°C. Due to subfreezing temperatures at night, the crop is not traditionally cultivated in winter in the high-altitude Ladakh region. We found that growing broccoli in a passive solar greenhouse in winter is feasible. The choice of greenhouse cladding material and the date of transplanting are important factors that need to be considered. The mean marketable head weight of the cv. Fiesta and KTS-1 in a passive solar trench greenhouse with polycarbonate cladding material transplanted on 8 September were 403±106 and 169±100 g, respectively. Delayed transplanting on 8 October did not produce any marketable head. Covering the greenhouse with a polyethylene sheet did not result in marketable heads on both transplanting dates. We anticipate our study to be a starting point for researchers and the farming community to optimize the greenhouse production of broccoli during freezing winter-months in high-altitude regions.

Unveiling the characteristics of the residual point defects of collision cascade in Zr-xNb binary system: A molecular dynamics study

Zirconium-based alloys are commonly used as fuel cladding materials for light-water reactors. As an alloying element, niobium can further improve the performance of Zr alloys. However, the mechanism of the Nb effect on the irradiation damage (e.g., the irradiation-induced precipitation of Nb-rich clusters) of the alloy is still unclear and should resort to atomic-scale modeling. In this work, we unveiled the characteristic of the residual point defects produced at the end of the collision cascade caused by primary knock-on atoms (PKAs) in the Zr-xNb binary alloy through many molecular dynamics simulations. The effects of PKA directions (<0001> and <101¯0>), PKA energies (2 keV, 5 keV, 10 keV, 20 keV, 30 keV, and 50 keV), temperatures (300 K, 600 K, and 800 K), and the initial Nb contents in the alloy (cNb = 0 at.%, 0.5 at.%, 1 at.%, and 2 at.%) on the remaining Frenkel pairs, the displaced atoms, the composition of these point defects, the size and number of clusters, and the composition of the clusters with different-size have been studied. Several concepts were clarified from these simulation results. A special focus of this work is on the Nb proportion in the point defects and their clusters. It is worth emphasizing that the interstitial-Nb proportion in the interstitials and their clusters is far greater than the initial Nb content in the alloy, which can be the nucleate center of Nb-rich precipitation particles. This distinct feature may be solving the experimental puzzle of radiation-induced Nb precipitates/clusters of Nb-containing Zr alloys.

High-velocity laser accelerated deposition (HVLAD): An experimental study

A versatile solid-state cladding technique named high-velocity laser accelerated deposition (HVLAD), which is capable of creating highly uniform coverage on various surfaces, is reported here. The method is a non-thermally driven, mechanically based process that relies on laser peening (LP) technology which has been used for commercial applications for decades. In HVLAD, a high-intensity laser is used to accelerate, propel, and deposit small areas of a thin film in a controlled step-by-step manner onto a substrate. This process can be repeated until a desired thickness of material is deposited onto the substrate. This technique does not generate any large variations in temperature between the thin film and the substrate material. Instead, it employs intense laser pulses with energies up to 50 J for a duration of 8–50 ns to create a plasma generated pressure wave which accelerates the thin film in the order of a few hundred meters per second into the substrate material. Two cladding methods were evaluated in this study including the confined method, which incorporates a confining water media and a vinyl tape overlay, and the unconfined method which does not. High speed and thermal imaging cameras showed no macrolevel melting or significant temperature increase in the clad or substrate material during the cladding process, however signs of microlevel melting and re-solidification were observed at the interface primarily in specimens cladded using the unconfined method. Grain structures in adjacent areas to the clad location remained preserved using both methods, and no signs of any phase or alloy composition changes, except for at the interface, were observed. The effects of a confining media (water) and vinyl tape in the process were studied both analytically and experimentally and a change in the deposition mechanism was observed. With further research and development this technique has the ability to be used to deposit a variety of coatings without any limitations dictated by their strength on complex geometries in a cost-effective manner. The HVLAD process can be implemented to deposit corrosion, wear, thermal, and even impact-resistant coatings with strong bonding on a wide range of substrates.

Influence of multi-layer laser cladding depositions and rail curvature on residual stress in light rail components

Rapid deterioration of critical rail components due to wear and fatigue is a significant challenge faced by the railway industry. Laser cladding has been applied to straight and curved light rail substrates which are particularly prone to these methods of degradation using a Stellite 21 hardfacing alloy. The influence of multi-layer cladding depositions, grinding-based finishing procedures and substrate rail grade on residual stress was analyzed using non-destructive neutron diffraction techniques. As cladding is a thermal process, microstructural changes from the heat inputs can result in a high internal stress state which reduces the loading capacity whilst a high hardness increases the likelihood of brittle failure. Stellite laser cladding depositions were found to result in low tensile residual stresses within the cladding layer, which become compressive in the heat affected zone (HAZ). Repeated thermal inputs from multi-layer cladding depositions did not negatively impact the hardness or microstructure after double layer laser cladding and increased the residual stress to 100 MPa at the cladding surface after grinding. Laser cladding on a curved rail substrate also produced increased internal stress after cladding due to higher strains resulting from the rail geometry but remained below the yield limit of the cladding and substrate material. These outcomes were compared to current literature indicating this critical combination of low internal strain and a cladding and HAZ hardness complementing the substrate material is difficult to achieve. Therefore, ensuring laser cladding is compatible with a variety of light rail components is essential in developing viable maintenance techniques to recondition critical railway infrastructure to avoid disruptive replacement procedures.

Dynamic Precipitation of Laves Phase in FeCrAl Alloy with Zr Addition

FeCrAl alloy is one of potential candidates for accident‐tolerant‐fuel (ATF)‐cladding materials due to its excellent oxidation and corrosion resistance at accident temperature, combining good mechanical properties at service temperature. Alloying strategy is an important way for improving comprehensive properties of FeCrAl alloy through the precipitation of fine Laves phase. Zr alloying can stabilize the Laves phase due to its lower diffusion coefficient and solubility in body‐centered‐cubic ferrite matrix. Herein, it is found that Zr addition changes the dynamic precipitation features of Laves phase in FeCrAl alloy during high‐temperature deformation, from only one type of Fe2M (M = Nb, Mo, Ta) Laves phase to Fe2Zr combining Fe2M‐type Laves phase. The Fe2Zr‐type Laves phase precipitates dynamically first, and the interface precipitates between which with ferrite matrix creates more nucleation sites for subsequent precipitation of Fe2M Laves phase. The results can be possibly applied for alloy design and microstructure tailoring in series of FeCrAl alloys used for ATF cladding in the near future.

BIM to BEM Transition for Optimizing Envelope Design Selection to Enhance Building Energy Efficiency and Cost-Effectiveness

This article focuses on developing an energy simulation model through Building Information Modeling (BIM) and Building Energy Modeling (BEM)to optimize energy in building design in Vietnam. Reducing the energy consumption in buildings will help reduce operating costs, impact the environment, and increase the efficiency of buildings. However, there is limited research on buildings with complex structures and configurations, detailed surface design, and envelope construction, especially in simulating details through BIM. The author proposes converting from BIM to BEM to simulate energy in buildings and optimize the factors related to building construction in the envelope design of the building. These factors include wall cladding materials, mirror materials, the window ratio on the walls, and other details. This study has effectively created an energy model for a public building, allowing for the calculation of the Energy Intensity Index (EUI) and annual energy costs for various scenarios. By altering factors associated with the design and construction process, the system has the potential to decrease both energy intensity and usage costs for the building. The study results will help designers and building managers improve and enhance energy efficiency in building projects.

A Neutronics Study of the Initial Fuel Cycle Extension in APR-1400 Reactors: Examining Homogeneous and Heterogeneous Enrichment Design

AbstractIn this study, we conducted a neutronics analysis of a soluble-free-boron APR-1400 reactor core. Our goal was to explore the possibility of extending the fuel life cycle from 18 to 24 months. To achieve this, we examined both homogeneous and heterogeneous fuel enrichment designs while maintaining the original fuel geometries of the reactor. The proposed fuel enrichments for the homogeneous reactor core were 3.0%, 3.5%, 4.0%, 4.5%, and 4.95%. For the heterogeneous reactor core, they were (3.6%, 4.0%, 4.5%, and 5.0%) and (3.4%, 3.8%, 4.5%, and 5.0%). To suppress excess reactivity at the beginning of the fuel cycle (BOC), we applied an Integral Fuel Burnable Absorber as a thin coating layer on the outer surface of the fuel pellets. The coating was distributed uniformly throughout the core. In addition, we also studied the use of selected cladding materials as a replacement for the conventional zircaloy used in the fuel rods. The neutronics calculations for the modified APR-1400 core configuration were performed using the Serpent 2.1.31 Monte Carlo reactor physics code. We evaluated the behavior of the APR-1400 core by analyzing the effective multiplication factor, flux spectrum, pin power distribution, and radial power profile. Both the homogeneous and heterogeneous cores were compared with the reference APR-1400 core configuration. Our results indicate that it is possible to extend the fuel cycle to up to 24 months in both the homogeneous and heterogeneous cores. We also conducted a thorough analysis of the initial cycle for heterogeneous cores to consider more realistic scenarios.

Neutronic and Thermal hydraulic evaluation of accident tolerant cladding materials in a WWER1000

The concept of Accident Tolerant Fuel (ATF) claddings is developed to improve the safety of light water reactors (LWRs). The main objective of this work is neutronic and Thermal Hydraulic (TH) analysis of potential cladding materials in a WWER1000. In this analysis, the ZrC, TiC, SiC and FeCrAl are evaluated as enhanced alternatives for traditional Zircaloy-4. For neutronic analysis, Monte Carlo particle transport method is used. For thermal hydraulic analysis, the performance of the materials in unmitigated small break LOCA is evaluated by MELCOR. Assessments show that ATFs can delay the failure of reactor pressure vessel (RPV) and core melting by reducing the heat generated from oxidation reaction. The TiC and FeCrAl claddings are more reliable in the accident, but they are not desirable from the perspective of the Neutronics. The calculations demonstrate that ZrC and SiC can be excellent alternatives to the Zircaloy-4. Also, simulations show using TiC and FeCrAl as a 0.1 mm thick covering of the Zircaloy-4 improves the multiplication factor, but it is not sufficient.