Steel Container Research Articles

Roles of Radiolytic and Externally Generated H2 in the Corrosion of Fractured Spent Nuclear Fuel.

A 2-D model for the corrosion of spent nuclear fuel inside a failed nuclear waste container has been modified to determine the influence of various redox processes occurring within fractures in the fuel. The corrosion process is driven by reaction of the fuel with the dominant α radiolysis product, H2O2. A number of reactions are shown to moderate or suppress the corrosion rate, including H2O2 decomposition and a number of reactions involving dissolved H2 produced either by α radiolysis or by the corrosion of the steel container vessel. Both sources of H2 lead to the suppression of fuel corrosion, with their relative importance being determined by the radiation dose rate, the steel corrosion rate, and the dimensions of the fractures in the fuel. The combination of H2 from these two sources can effectively prevent corrosion when only micromolar quantities of H2 are present.

NOx emissions and the component changes of ternary molten nitrate salts in thermal energy storage process

The objective of this work is to investigate the NOx emissions from HITEC (ternary molten nitrates of 7wt.%NaNO3-53wt.%KNO3-40wt.%NaNO2) in thermal energy storage (TES) process and the effects of 45# carbon steel (1045, ASTM) on NOx emission as well as the component changes in HITEC. Referring to the national environmental protection standard (HJ479-2009) in China, NOx emissions in tail gases were measured in one hour for heating the molten salts in a quartz glass boat during TES process. Furthermore, the concentrations of nitrate and nitrite ion in molten salts samples were determined, and chemical thermodynamic calculations of related reactions were carried out to explain the mechanism of NOx emissions. The results show that HITEC contained in a quartz glass or carbon steel container in air atmosphere can release NOx in the operating temperature range, which were caused by several reactions between nitrate and SiO2 or Fe. The concentrations of NOx emissions increase with the rise of temperature. In the practical application, NOx emission is acceptable since the amount of NO2 or NO will dramatically decreased in the liquid salts by reacting with NaNO2.

Enhancement and Prediction of Adhesion Strength of Copper Cold Spray Coatings on Steel Substrates for Nuclear Fuel Repository

Thick copper coatings have been envisioned as corrosion protection barriers for steel containers used in repositories for nuclear waste fuel bundles. Due to its high deposition rate and low oxidation levels, cold spray is considered as an option to produce these coatings as an alternative to traditional machining processes to create corrosion protective sleeves. Previous investigations on the deposition of thick cold spray copper coatings using only nitrogen as process gas on carbon steel substrates have continuously resulted in coating delamination. The current work demonstrates the possibility of using an innovative surface preparation process, forced pulsed waterjet, to induce a complex substrate surface morphology that serves as anchoring points for the copper particles to mechanically adhere to the substrate. The results of this work show that, through the use of this surface preparation method, adhesion strength can be drastically increased, and thick copper coatings can be deposited using nitrogen. Through finite element analysis, it was shown that it is likely that the bonding created is purely mechanical, explaining the lack of adhesion when conventional substrate preparation methods are used and why helium is usually required as process gas.

Thermal Hydraulic Analysis of China Spallation Neutron Source Target System Under Abnormal Situations

The analysis of thermal hydraulic performance under three abnormal conditions is very important for the design of China spallation neutron source (CSNS) target system, which could provide some important information for developing an emergency plan. In this study, we first introduce the design of the CSNS target system and create a three-dimensional physical model, calculate the heat source and decay heat distribution using the MCNPX 2.5 Monte Carlo code and the CINDER’90 activation code, and simulate and analyze the temperature distribution in the tungsten target and the steel container under normal operation using fluent. By using the same model, the thermal hydraulic characteristics are analyzed under three different abnormal conditions including power failure, off-center of proton beam, and cooling water failure. The results show that in order to keep the cooling water temperature below the boil point at normal operating pressure, the emergency power for the cooling water should start immediately after power failure. The maximum temperature of the beam window and the up plate increases by about 8 °C when the offsetting distance of proton beam is 5 mm along z direction. The cooling water will not effectively take all away the heat when the flow rate of the cooling water drops below 72% of the normal setpoint.

Thermo-mechanical behaviour during encapsulation of glass in a steel vessel

Quantitative numerical simulations and qualitative evaluations are conducted to elucidate thermo-mechanical behaviour during pouring and solidification of molten glass into a stainless-steel cylindrical container. Residual stress and structural integrity in this casting/vitrification process is important because it can be used for long-term storage of high-level nuclear wastes. The predicted temperature and stress distributions in the glass and container agree well with previous measurements of the temperature histories and residual stresses. Three different thermal-stress models are developed using the finite-element method and compared. Two simple slice models were developed based on the generalized plane strain assumption as well as a detailed two-dimensional axi-symmetric model that adds elements according to the stages of pouring glass into the stainless steel container. The results reveal that mechanical interaction between the glass and the wall of the stainless steel container generates residual tensile stresses that approach the yield strength of the steel. Together, these results reveal important insights into the mechanism of stress generation in the process, the structural integrity of the product, and accuracy of the modelling-tool predictions.

Identification of dangerous hoisting loads based on vibration characteristics

The dynamical behaviors of steel ropes and containers caused by different dangerous hoisting loads are theoretically and experimentally investigated to improve the hoisting safety in coal mines. Subsequently, the identification method is studied. The modal analysis technique based on Ritz Series and the Dempster–Shafer evidence theory is respectively employed during the study on vibration and identification. The vibration characteristics are apparently different with different categories and severities of dangerous loads. The different dynamical behaviors could be used as the basis of identification. The Dempster–Shafer evidence theory efficiently reduces uncertainty during the identification process of dangerous hoisting loads. Outcomes of this study might make a significant contribution to the hoisting safety in coal mines.

A Small-scale Model to Assess the Risk of Leachables from Single-use Bioprocess Containers through Protein Quality Characterization.

Leachables from single-use systems often exist in small quantities and are difficult to detect with existing analytical methods. The presence of relevant detrimental leachables from single-use bioprocess containers (BPCs) can be indirectly detected by studying the stability of monoclonal antibodies via changes by size exclusion chromatography, capillary electrophoresis sodium dodecyl sulfate, and visible/sub-visible particles using a small-scale stress model containing high surface area-to-volume ratio at elevated temperature alongside with an appropriate control (e.g., glass vials or stainless steel containers). These changes in protein quality attributes allowed the evaluation of potential risks associated with adopting single-use bioprocess containers for storage as well as bag quality and bag differences between earlier and later batches. These leachables appear to be generated during the bag sterilization process by gamma irradiation. Improvements in protein stability after storage in "preheated" bags indicated that these leachables may be thermally unstable or volatile. The effect of surfactant levels, storage temperatures, surface area-to-volume ratios, filtration, and buffer exchange on leachables and protein stability were also assessed.

Thermal stress analysis of PCM containers for temperature smoothing of waste gas

This article develops an analytical and numerical approach to evaluate thermal stress in a phase change material (PCM) system, used for temperature smoothing of waste gas of Electric Arc Furnace, in which the PCM is encapsulated in a cylindrical steel container. Thermal analysis shows that temperature distribution in the PCM system can be considered as uniform at any time instant according to the lumped capacitance method; the thermal behaviour of PCM system is thus simulated as a sequence of steady state analyses. Mechanical analysis adopts an axialsymmetric plane analytical model to compare elastic thermal stress distribution for different stainless steels and to identify AISI 316 as the most suitable material for the PCM container. A simple two-bars model and a stress index are also used to allow a physical understanding and a satisfactory interpretation of the PCM system response. Mechanical analysis shows that thermal stresses exceed the yield point of both stainless steels used in the container. A finite element elastic-plastic model is then developed to estimate the extension of the plastic zone. Finally, an alternative PCM system geometry based on concentric pipes is designed to keep the maximum stresses in the PCM container below the yielding point. A sensitivity analysis shows that the most relevant design parameters of the alternative geometry are the diameter of inner pipe and thickness of the external pipe.

Tritium permeation characterization of Al2O3/FeAl coatings as tritium permeation barriers on 321 type stainless steel containers

Accurate tritium transport properties of prospective tritium permeation barriers (TPBs) are essential to tritium systems in fusion reactors. By passing a temperature and rate-controlled sweeping gas over specimen surfaces to carry the permeated tritium to an ion chamber, the gas-driven permeation of tritium has been performed on 321 type stainless steel containers with Al2O3/FeAl barriers, to determine the T-permeation resistant performance and mechanism of the barrier. The tritium permeability of the Al2O3/FeAl coated container was reduced by 3 orders of magnitude at 500–700 °C by contrast with that of the bare one, which meets the requirement of the tritium permeation reduction factor (PRF) of TPBs for tritium operating components in the CN-HCCB TBM. The Al2O3/FeAl barrier resists the tritium permeation by the diffusion in the bulk substrate at a limited number of defect sites with an effective area and thickness, suggesting that the TPB quality is a very important factor for efficient T-permeation resistance.

Assessing the Thermal Performance of Phase Change Material in a Photovoltaic/Thermal System

Photovoltaic/ thermal (PV/T) systems refer to systems which integrate photovoltaic and solar thermal technologies and have the added advantage of producing both electrical and thermal energy. This study has been carried out to experimentally investigate the application of phase change material (PCM) in a thermal system under the climatic conditions of Ireland. In this system, a stainless steel container of PCM was integrated with a PV panel. PCM absorbs heat generated by the PV during daylight hours. Water is piped through the PCM and absorbs heat stored by the PCM. The application of the PCM alone was found to regulate the temperature of the PV panel by approximately 5°C under climatic conditions of Ireland. This paper presents a method to assess the performance of a photovoltaic/thermal system with integrated PCM taking into account the useful heat energy gained by the water, stored by the PCM and the delay in available heat factor.

Introducing Donor Milk in a Neonatal Intensive Care Unit: A Developing Country's Perspective.

To replace 75% of formula feeds by donor human milk (DHM) feeds in the first three days of life in neonates admitted to the neonatal intensive care unit (NICU). It was a prospective observational study in the NICU in a resource-limited set up in India. All neonates admitted during December 2013 and August 2014, were included in the study without any exclusion. Expressed DHM was administered within 2-3h of manual expression without refrigeration or pasteurization. It was left standing at room temperature in a covered stainless steel container prior to use. Prospective entries of 2 hourly neonatal feeds, for first 3 d of life, (36 entries) were made in the charts. Main outcome was the desired percentage replacement of formula feeds. Total 168 neonates were admitted to the NICU over the study period. Their median [Interquartile range (IQR); Range] gestation and birth weight was 37 (36, 38; 24-42) wk and 2300 (2100, 2700; 500-2950) g respectively. A total of 4136/6027 (68.6%) charted feeds were of human milk and 1891(31.4%) were of formula milk. Thus, 68.6% of formula feeds were replaced by DHM. Neonates weighing ≤2kg were at a lower risk of getting >25% formula feeds. A simple low cost method was effective in replacing a significant proportion of formula feeds by DHM in the first three days of life for neonates in a resource poor set up.

ChemInform Abstract: On the Fluorination of Plutonium Dioxide by Ammonium Hydrogen Fluoride.

AbstractFollowing a literature survey on published PuF3 syntheses in view of its use within the fuel cycle of advanced molten salt fast nuclear reactors, the authors′ own method comprises fluorination of PuO2 with NH4HF2 (Ni crucible in stainless steel container, 350 °C, 24 h, 92% yield).

옹기가 빵 품질에 미치는 영향

How do we use onggi, Korean earthenware, for container of dough during fermentation instead of stainless steel container? How does it affect the flavor of bread if onggi tray is used in baking instead of steel tray? We tried to confirm those. As a result, the characteristics of onggi made positive effect on dough in fermenting room. The time, when the temperature of the center in the dough is equilibrated to that of surface on the dough, take shorter in onggi than in stainless steel. It could make the temperature of dough maintained evenly with little deviation, which could result in shorter fermentation time. Volume and surface color of the bread baked on onggi tray were better than on steel tray. The bread baked on onggi tray got higher score on overall acceptability in sensory test than on steel tray. Therefore, if onggi is used during baking, it could produce better quality of bread like making positive effect on fermented foods.

Analysis of the structural response and failure of containers subjected to internal blast loading

A series of small-scale internal blast experiments were conducted to assess the structural response and failure mechanisms of metal containers subjected to internal blast loading for the enhancement of Vulnerability/Lethality (V/L) modelling. The experiments examined welded steel containers, both fully enclosed and flanged, against a range of charge sizes detonated internally. The deformation and strain profiles of the containers were measured and compared with the numerical simulation results. The numerical simulations replicated the deformation and strains at the centre of the containers with a reasonable degree of accuracy. However, initial numerical simulations using shell elements significantly under-predicted strain values at the welded joints where failure of the containers occurred. Metallographic analysis of the welded joints and the high-speed imagery post-experiment indicated that failure occurred due to large strains in the heat affected zone and weld bead interface, where the material strength is reduced. To perform these assessments, a refined geometrical model, using Lagrangian elements, was required. Results from the numerical simulations highlighted that the quasi-static overpressure was the key parameter from the blast wave in determining the maximum deformation of the container, enabling simplified loading conditions for the Lagrangian analysis. Simulations using Lagrangian elements for the container improved the accuracy of the edge strain measurements but still under predicted the experimental results, which highlighted the inability of these models to account for weld defects such as porosity and lack of fusion which act as stress concentrators, assisting ultimate failure of welded containers.

INFLUENCE OF MAGNETIC FIELDS OF VARYING INTENSITY ON THE MORPHOLOGICAL VARIABILITY OF LONG-LEGGED WOOD FROG LARVAE (RANA MACROCNEMIS) AFTER THE EXPOSURE PERIOD FROM NEURULA TO HATCHING

Aim. The aim is to study morphological diversity of long-legged wood frog larvae after continuous exposure to a magnetic field of varying intensity during embryonic development from neurula to leaving the egg membranes. Methods. We have created hypermagnetic conditions by increasing the tension of the natural magnetic field. Petri dish with fragments of laid eggs has been placed in a low carbon steel container (20,5x17x9). Outside, the container has been covered with a shell made of sheet copper. Results. Rana macrocnemis, obtained in the first experiment, compared with the control specie, showed a significant increase in tail and body length. The second experiment showed an increase in tail and body length. The third experiment, compared to the control specie, showed no difference. The fourth experiment showed an increase in tail and body length. The fifth experiment also showed an increase in tail and body length. Conclusions. The effect of magnetic fields on the embryonic development period from neurula to hatching showed that the length of the trunk is a more stable feature, the tail length increases in the experiments, and only in the third experiment it remained unchanged compared to control species.

Diffusion Coatings as Corrosion Inhibitors

Abstract Corrosion is the cause of irretrievable loss of huge amounts of metals and alloys. The harmful effects of corrosion can be reduced significantly by applying appropriate methods of corrosion protection. One method to protect metals against corrosion is the formation of diffusion coatings on them. High corrosion resistance is typical for the boride diffusion layers. Aluminothermy is one of the main methods for diffusion saturation of the surface of metal products with various elements, including boron, and under certain conditions with aluminum, too. Samples of steel 45 were put to aluminothermic diffusion saturation with boron in a pressurized steel container at a temperature of 1100K, for 6 hours in powdered aluminothermic mixtures. The content of В2О3 in the starting mixtures decreased from the optimum - 20% to 0%, and the content of Al and the activator - (NH4)2.4BF3 is constant, respectively 7% and 0.5%. Al2O3 was used as filler. The borided samples were tested for corrosion resistance in 10% HCl for 72 hours. The results show that their corrosion resistance depends on the composition of the starting saturating mixture (mainly on the content of В2О3), and respectively on the composition, structure, thickness and degree of adhesion of the layer to the metal base.

Corrosion behaviour of 304L stainless steel and 5754 aluminium alloy for intermediate‐level radioactive waste containers

300 series stainless steels are the most common materials used in the manufacture of container for the intermediate storage of low‐ and intermediate‐level radioactive wastes. Today, aluminium alloys are being considered as an alternative as they would enable gamma measurements to be performed directly through the container. However, reactions which occur during storage, lead to the formation of corrosive species. An investigation and comparison of the corrosion behaviour of a 5754 aluminium alloy container with that of a 304L stainless steel container was realised. Samples were introduced in corrosive environment during several months and then characterised by SEM. Results allow or not to validate the use of this aluminium alloy as nuclear container material.

Alteration of expandable clays by reaction with iron while being percolated by high brine solutions

Bentonites are suitable candidates as buffer and backfill materials in HLW-repositories. A target of this research is to define the mineralogical alteration of bentonite caused by its interaction with iron powder, which simulates the contact of bentonite with a steel container. Compacted MX80 bentonite and Friedland clay (raw density of 1.6g/cm3) were used as the initial materials for clay/iron interaction experiments (10wt.% of iron) involving percolation with NaCl or Mg-rich IP21 solution. These experiments were conducted at 25°C, 60°C, and 90°C and a suite of analytical techniques was applied to identify the mineralogical transformations. Smectite was the main phase and was fully expandable in all reaction products, though the octahedral and tetrahedral compositions were altered. “Illitization” was found as a main process of smectite alteration and was caused by the percolation component of these experiments. Smectitization occurred only when Fe-oxidation was considerable. The alteration of smectite was mainly driven by the high alkaline pH-value resulting from Fe-corrosion. Different interstratified phases like kaolinite–smectite–dioctahedral vermiculite, berthierine–saponite, chlorite–saponite–trioctahedral vermiculite, and cronstedtite–saponite–trioctahedral vermiculite interstratifications were identified as neo-formed phases which were formed in minor amounts. Cementation of particles by Fe- or Si-precipitation was assumed to reduce swelling pressure and permeability.

Synthesis of Biodegradable Mg-Zn Alloy by Mechanical Alloying: Effect of Milling Time

Magnesium (Mg) is one such promising light weight metal, which is currently utilized for bio-engineering applications. Mg possesses a number of attractive characteristics that make Mg-based materials potential candidates to serve as implants for load-bearing applications in the medical industry due to its good biocompatibility and biodegradability. However, Mg and its alloys are susceptible to suffer attack in chloride containing solutions, e.g. the human body fluid or blood plasma. Thus, alloying with other metal elements is the most effective tool to improve mechanical properties and corrosion resistance of Mg. In this current work, binary Mg-Zn alloy was produced using mechanical alloying (MA) followed by compaction and sintering. The aim of this work was to study the effect of milling time on binary magnesium-zinc (Mg-Zn) alloy synthesized by mechanical alloying. A powder mixture of Mg and Zn with the composition of Mg-10wt%Zn was milled in a planetary mill under argon atmosphere using a stainless steel container and balls. Milling process was carried out at 250rpm for various milling times i.e. 1, 2, 5, 10 and 15hours. 3% n-heptane solution was added prior to milling process to avoid excessive cold welding of the powder. Then, as-milled powder was compacted under 400MPa and sintered in a tube furnace at 350°C in argon flow. The refinement analysis of the x-ray diffraction patterns shows the presence of Mg-Zn solid solution and formation of MgZn2 when Mg-Zn powder was mechanically milled for 2hours and further. A prolonged milling time has increased the density and microhardness of the sintered Mg-Zn alloy.

Development of Biodegradable Mg-Ti Alloy Synthesized Using Mechanical Alloying

The aim of this work was to study the effect of milling time on binary magnesium-titanium (Mg-Ti) alloy synthesized by mechanical alloying. A powder mixture of Mg and Ti with the composition of Mg-15wt%Ti was milled in a planetary mill under argon atmosphere using a stainless steel container and balls. Milling process was carried out at 400 rpm for various milling time of 2, 5, 10, 15 and 30 hours. 3% n-heptane solution was added prior to milling process to avoid excessive cold welding of the powder. Then, as-milled powder was compacted under 400 MPa and sintered in a tube furnace at 500 °C in argon flow. The refinement analysis of the x-ray diffraction patterns shows the presence of Mg-Ti solid solution when Mg-Ti powder was mechanically milled for 15 hours and further. Enhancements of Mg-Ti phase formation with a reduction in Mg crystallite size were observed with the increase in milling time. A prolonged milling time has increased the density and hardness of the sintered Mg-Ti alloy.