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Electron Microscopy of Oxide Formed on Nickel Alloy X-750 in Simulated Boiling Water Reactor Environment

Electron Microscopy of Oxide Formed on Nickel Alloy X-750 in Simulated Boiling Water Reactor Environment

The environment of a nuclear reactor is hostile and the materials used have to withstand harsh and corrosive working conditions. Nickel alloy X-750 has been extensively used in the nuclear industry for the last 30 years. The good corrosion properties and the high strength at elevated temperatures made this material a good choice for springs, bolts, guide pins and spacer grids in boiling water reactors (BWRs). The focus of this thesis is on the spacer grid corrosion. A spacer grid is a metal lattice that holds the nuclear fuel in position. It is critical to limit the corrosion of the spacer grids so that the fuel is held stable for safety purposes and also since corrosion and dissolution of the alloy can lead to spread of radiation in the closed water system and consequently an increased risk of radiation exposure for maintenance workers at nuclear plants. A BWR operates at 286°C under a pressure of 70 bar, and the radiation induces radiolysis of the water, making it corrosive. Significant corrosion of alloy X-750 has been observed under these conditions. In order to study the high temperature water corrosion of alloy X-750, this aggressive environment was simulated in an autoclave system. In this thesis, the connection between the corrosion performance and the effect of pretreatments and the impact of iron content of the alloy is studied. The evolution of the oxide growth was studied by exposing the specimens in a temporal range from 2 h to 840 h. The samples have been studied with a set of complementary characterization techniques (mainly electron microscopy, but also X-ray diffraction and atom probe tomography), and focused ion beam milling has been used for sample preparation. Pre-oxidation treatment results in the formation of a thin multi-layer oxide, which improves the corrosion properties of the alloy, leading to contained dissolution of the metal. The oxide formed is composed of an outer layer of trevorite (NiFe 2 O 4 ), a Cr-rich middle
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Effect of temperature on hydrogen embrittlement susceptibility of alloy 718 in Light Water Reactor environment

Effect of temperature on hydrogen embrittlement susceptibility of alloy 718 in Light Water Reactor environment

the majority of Nb and Ti is tied up in the age hardening precipitates. However, in the B material, these elements are dissolved in the matrix, where they may exert their maximum effect in promoting the dissolution of hydrogen in the ma trix. Tensile tests showed that mechanical properties were almost comparable with only a slight decrease of YS and UTS when samples were hydrogen precharged. Elongation to failure decreased from 15% to 12% in presence of hydrogen. The value of EF was 20% that was slightly below but comparable to EF measured in LWR environment {27%) for A samples. For C samples, fracture surface observations revealed a ductile fracture with large dimples without hydrogen whereas dim ples were very small in presence of hydrogen {Fig. 4). This was consistent with the observations carried out for A samples, tested at 300 •c after exposure in LWR environment.
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Thermomechanical fatigue of hollow specimens in a light water reactor environment - latest test results and analysis

Thermomechanical fatigue of hollow specimens in a light water reactor environment - latest test results and analysis

A thin-walled hollow specimen was analysed using the same cyclic hardening material model to understand the strain amplitudes experienced during isothermal fatigue [r]

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Oxidation kinetics of 316l stainless steel in the pressurised water reactor environment

Oxidation kinetics of 316l stainless steel in the pressurised water reactor environment

This research project aims to contribute towards an overall PWSCC initiation model for austenitic stainless steel by characterising the one component, namely the kinetics of intergranular oxidation as a function of time, temperature and material condition. It is known that oxidation preferentially propagates down grain boundaries of austenitic structural materials when exposed to high temperature primary water [11,12]. Since PWSCC propagates as an intergranular crack, an oxidised grain boundary will form a preferred initiation site for such a crack and therefore it is generally agreed that intergranular oxidation forms a precursor from which PWSCC can initiate [8,11,13–15]. However, to the authors knowledge, there is no quantitative study that has measured the growth of intergranular oxidation in austenitic stainless steel. This type of model will therefore form part of the surface reactivity category described above. While the mechanism of intergranular oxidation may be quite different from stress corrosion cracking it forms a necessary part of the time taken to create the environment necessary for cracking to propagate.
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Iot Based Digitalization Of Mining Process Using Sages System

Iot Based Digitalization Of Mining Process Using Sages System

the iot most likely has turned out to be a standout amongst the most prominent systems administration ideas that can possibly bring out numerous advantages. be that as it may, iot has brought a few interchanges difficulties. principle correspondence conventions that permits the usage of an iot stage, to decide their computational burden, overhead what's more, organize transfer speed [6] wireless sensor networks-wsn have become popular in industries for measurement of process parameter temperature, vibration & humidity for the past few years, research & development efforts have increased to implement wsn technology in nuclear industry also for this wireless hardware & software must have a record of reliable performance along with verification &validation testing. In order to prove the robustness of wsn technology & to gain enough experience before deploying wsn in nuclear reactor environment several hardware and software developments, experimental wsn deployments have been carried out in indira gandhi centre for atomic research- with nodes communicating using zigbee standard and the performance results specific to the configured transceiver, have been analyzed and used in various experimental deployments, this paper describes about the test network setup & performance analysis of the network
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Effects of H2:CO2 ratio and H2 supply fluctuation on methane content and microbial community composition during in-situ biological biogas upgrading

Effects of H2:CO2 ratio and H2 supply fluctuation on methane content and microbial community composition during in-situ biological biogas upgrading

timepoint by performing non-metric multidimensional scaling (NMDS) ordination on the Bray–Curtis dis- tances (Fig.  4b), a metric which considers both the spe- cies present in a sample as well as their abundance. The PCA analysis allows assessment of the similarity in reac- tor environment for the different reactor timepoints (Fig. 4a), whereas the NMDS analysis evaluates similarity in the microbial community composition across reactor timepoints (Fig.  4b), and comparing the process param- eter PCA plot with the microbial community, NMDS plot allows for inference of the process parameters that corre- spond to changes in microbial community composition. The characteristics of each reactor environment changed over the time course of the experiment (Fig.  4a), as did the microbial community composition (Fig.  4b) in the reactors. The reactor timepoints were grouped into (1) start-up phase (days 4 and 9), (2) inhibition phase (day 30), (3) experimental phase (days 37, 44, 45 and 52), (4) stable phase (days 59, 66 and 70) and (5) end phase (day 81). The timepoints cluster together by phase and form a continuum from start-up phase to end phase, which indicates that the reactor conditions and the microbial community gradually changed over time. The two main principle components (PC) explain 84% of the variation in the process parameter data, and the NMDS ordina- tion has a stress of 0.16 which indicates that the plot provides an acceptable two-dimensional representa- tion of the Bray–Curtis distances (Fig. 4b). The CO 2 and
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Performance and Energy Consumption Analysis of UV-H2O2 Photoreactors Using Computational Fluid Dynamics

Performance and Energy Consumption Analysis of UV-H2O2 Photoreactors Using Computational Fluid Dynamics

Shao [8] and Hofman et al. [9] performed numerical computations for a 4-lamp closed vessel UV reactor using three different cross-flow configurations (staggered, squared and trapezoidal) to investigate the role of reactor hydraulics on UV dose distribution. Among the three cases examined, the staggered lamp arrangement (e.g., UV lamps positioned with a relative vertical offset in the flow direction) predicted a UV dose distribution with the highest mean UV dose and the lowest variance.

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Systematic design of chemical reactors with multiple stages via multi objective optimization approach

Systematic design of chemical reactors with multiple stages via multi objective optimization approach

All the reactors in this study are treated as a plug-flow system to simplify the mathematical representation for optimization purpose. As the optimization step that is adopted in this work is a time-consuming process, the choice of this simpler representation will be justified front the point of view of minimizing the complexity of mathematical model solution. If required, the results can be further validated by simulating the reactor system with more complicated mathematical model later. However, the effort is being made also to validate the approach by comparing the obtained solutions with industrial reactor design that is simulated by the same mathematical model that is used for optimization. The following mathematical models are adopted to represent the corresponding reactor systems in this study:
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Reactor Laboratory Manual

Reactor Laboratory Manual

27 REACTOR LABORATORY FORD NUCLEAR REACTOR EXPERIMENT NO., 7 REACTOR POWER MEASUREMENT OBJECT s To measure the thermal neutron flux throughout one coolant channel in the core of the Ford[r]

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Comparison of Small Modular Reactor and Large Nuclear Reactor Fuel Cost

Comparison of Small Modular Reactor and Large Nuclear Reactor Fuel Cost

In this paper, five SMRs based on LWRs were chosen. All SMR reactors in the study are still in pre-build or pre-licensing stages, so the design characteristics are nominal and subject to change by their designers. The five other PWR-derived designs for near term land deployment in this study are: NuScale, mPower, SMART, the Westinghouse SMR, and HI-SMUR. The NuScale power reactor is a 45 MWe reactor based on a PWR design to be installed underground with up to six units sharing a common housing [9]. The B&W mPower reactor was announced to be installed in modules of 125 MWe with a long operating cycle between refuelings [10]. The South Korean SMART (System-integrated Modular Advanced ReacTor) is being developed by KAERI with a thermal power of 330 MWt to be used for both electric generation and water desalination or other process heat applications [11]. The Westinghouse Small Modular Reactor (W-SMR) builds upon the design concepts of the much larger AP1000 reactor currently under construction in China and the United States. The Westinghouse SMR was announced to be a 200 MWe integral pressurized water reactor using a derivative of AP 1000 fuel [12]. Holtec Inherently Safe Modular Underground Reactor, (HI-SMUR) was announced to be a 140 MWe reactor design does not require coolant pumps as it relies on natural convection. It does not depend on off-site power for safe shutdown and thus qualifies as inherently safe. As its name implies, the HI-SMUR is to be built underground [13]. The HI-SMUR is not considered an integral PWR because its steam generators are not in- tegrated into the reactor vessel.
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Uncertainty Quantification in Nuclear Reactor Modeling using Stochastic Sampling with the Virtual Environment for Reactor Applications.

Uncertainty Quantification in Nuclear Reactor Modeling using Stochastic Sampling with the Virtual Environment for Reactor Applications.

Uncertainty quantification is an important component of model development. In uncertainty quantification, uncertainties in the inputs to a model are propagated through the model, and the resulting uncertainty in the model output is analyzed. The various methods for uncertainty quantification can be divided into two classes: statistical methods and deterministic methods. Stochastic sampling, a statistical method, is exclusively used in this study. The model is the Virtual Environment for Reactor Applications (VERA). The uncertain inputs to the model are the multigroup cross sections and fuel rod manufacturing parameters. One thousand perturbed multigroup cross section libraries were generated. These perturbed cross section libraries were used with a variety of benchmark problems based on the Three Mile Island Unit 1 Pressurized Water Reactor, the Peach Bottom Unit 2 Boiling Water Reactor, and the Watts Bar Unit 1 Pressurized Water Reactor. When only considering the uncertainty in the effective neutron multiplication factor due to cross section uncertainty, the relative standard deviation for all cases was determined to be approximately 0.5 – 0.6 %.
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Seismic Fragility Capacity of Equipment (Electric Panel Test)

Seismic Fragility Capacity of Equipment (Electric Panel Test)

At first, JNES selected more than ten kinds of electric panels used in safety systems and investigated the expected failure mode, influence level on CDF, the structural feature and so on. Consequently, JNES narrowed the electric panels down to eight panels as representatives for the actual equipment tests. A main control board, a reactor auxiliary control board, a logic circuit control panel, an instrumentation rack, a reactor protection rack, a reactor control center, a power center and a metal-clad switchgear (6.9kV) were tested.

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Disinfection of Low UV Transmittance Fluids: Fundamentals and Applications

Disinfection of Low UV Transmittance Fluids: Fundamentals and Applications

In general, a bench-lab scale collimated beam reactor (CBR) is used for studying the disinfection of microorganisms with UV light. For the opaque fluids that have high absorption (such as apple juice, orange juice, wine) and scattering coefficients (such as milk) even with the stirring bar, a uniform fluence cannot be guaranteed. This is an important requisite to calculate the microbial inactivation rate. Since the collimated beam test procedure is not appropriate for these food products because of the weak penetration of UV light through the sample, unless special procedure was adopted like we seen in chapter two. It was necessary to develop another lab-scale reactor in order to provide adequate mixing and uniform dose delivery to the fluid. This reactor can be based on Taylor-Couette flow.
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Enhancement of Hydrogen and Methanol Production using a Double Fluidized-bed Two Membranes Reactor

Enhancement of Hydrogen and Methanol Production using a Double Fluidized-bed Two Membranes Reactor

configurations. As it can be seen in Fig. 3 (a), controlling the temperature of exothermic side in the DFTMR is easier due to lower hot spot. There is not a sudden increase of temperature for this system at reactor entrance like CR. Furthermore, in the second region, the continually reduced temperature in this bed provides increasing thermodynamic equilibrium potential. Thus, the most favorable exothermic temperature profile seems to belongs to DFTMR system owing to simultaneous heat transfer with permeation side in the inner tube and reacting gas in the endothermic side and also using a fluidization concept.
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Applications of Anaerobic Baffled Reactor in Wastewater Treatment using Agriculture Wastes

Applications of Anaerobic Baffled Reactor in Wastewater Treatment using Agriculture Wastes

In the anaerobic baffled reactor (ABR) process, baffles are used to direct the flow of wastewater in an up-flow mode through a series of sludge blanket reactors. The sludge in the reactor rises and falls with gas production and flow. But moves through the reactor at a slow rate. Various modifications have been made to the ABR to improve performance. The modifications include, 1) changes to the baffle design, 2) hybrid reactors where a settler has been used to capture and return solids, or, 3) packing has been used in the upper portion of each chamber to capture solids (Barber and Stuckey, [3]). Though granulated sludge is not considered essential for the operation and performance of the ABR process. Several studies have been done with the ABR process at bench and pilot scale for a wide range of wastewaters and temperatures as low as 13 o C.
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Heat Transfer Strategies in Itaconic Acid Production by Using Aspergillus Terreus MTCC 479

Heat Transfer Strategies in Itaconic Acid Production by Using Aspergillus Terreus MTCC 479

different configuration reactors with a configuration volume of 100 ml and 2 batch reactors. Aspergillus terreus species were found to give a maximum yield of itaconic acid in 100 ml batch reactor than 2 reactor indicating that the 100 ml reactor was most suited for the production of itaconic acid. A. terreus has produced maximum itaconic acid of 27 g/lt (Figure) under optimized conditions (Table). The present observed results were found to be in consonance with the reports of Prucssc et al., (1998).

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Neutron-gamma flux and dose calculations in a Pressurized Water Reactor (PWR)

Neutron-gamma flux and dose calculations in a Pressurized Water Reactor (PWR)

Abstract . The present work deals with Monte Carlo simulations, aiming to determine the neutron and gamma responses outside the vessel and in the basemat of a Pressurized Water Reactor (PWR). The model is based on the Tihange-I Belgian nuclear reactor. With a large set of information and measurements available, this reactor has the advantage to be easily modelled and allows validation based on the experimental measurements. Power distribution calculations were therefore performed with the MCNP code at IRSN and compared to the available in-core measurements. Results showed a good agreement between calculated and measured values over the whole core. In this paper, the methods and hypotheses used for the particle transport simulation from the fission distribution in the core to the detectors outside the vessel of the reactor are also summarized. The results of the simulations are presented including the neutron and gamma doses and flux energy spectra. MCNP6 computational results comparing JEFF3.1 and ENDF-B/VII.1 nuclear data evaluations and sensitivity of the results to some model parameters are presented.
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Simulation Model for Biodiesel Production using Plug Flow reactor: Non Isothermal Operation

Simulation Model for Biodiesel Production using Plug Flow reactor: Non Isothermal Operation

The following assumptions were made for the modeling of plug flow reactor. (1) The reactor is operated at steady state (2) The reaction is a liquid phase reaction, density is constant so the volumetric flow rate at the inlet is equal to that of the outlet (3) The reaction is carried out in a non-isothermal condition (4) The work term is negligible (5) The specific heat capacity is constant (6) The summation of the energy is negligible, compared to the enthalpy.

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10th International Symposium on Continuous Flow Reactor Technology for Industrial Applications157-165

10th International Symposium on Continuous Flow Reactor Technology for Industrial Applications157-165

Matthew Bio’s (Snapdragon Chemistry) presentation was on ‘Automation of Experimentation: Chemical Process Development in the Era of Industry 4.0’. He commented that with a batch process, you design the chemistry to fit the reactor, with flow you can design the reactor to fit the chemistry. A key element in moving from laboratory reactors to productions in flow was analysis (at-line) and control strategy. He highlighted the importance of automation. For fast reaction process development, he used the Matteson reaction as a case study and showed evidence of how poor mixing can occur for fast reactions and how to optimise reaction parameters. Pump pulsation could be a problem in this respect. He also showed a production reactor setup which could fit inside a fume cupboard. The strategy employed was reaction design (route and reagent, kinetic analysis, heat flow analysis) to laboratory reactor (optimisation of reactor and process and characterisation of process) to production reactor (confirm design space, set control space for GMP manufacture).
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Techno-economic assessment of chemical looping reforming of Natural Gas for Hydrogen production and power generation with integrated CO 2 capture

Techno-economic assessment of chemical looping reforming of Natural Gas for Hydrogen production and power generation with integrated CO 2 capture

Figure 4: For different oxidation reactor outlet temperature (T-OX) (a) Methane conversion in the fuel reactor. 367[r]

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