This study presents a comparative analysis of several commercial removable materials for radioactive decontamination of steel surfaces using 241Am as representative radionuclide. The selection ...criteria of removable coatings for this study included a history of application, commercial availability, easy handling conditions and different composition and formulation. Carbon steel and stainless steel coupons were utilized as common industrial materials, and the experimental series were expanded to include the rusting treatment of these surfaces as it is common for decommissioned nuclear facilities. Radionuclide 241Am was deposited on the coupon surfaces and used to evaluate decontamination efficiency of the removable coatings, which were pre-screened for the ease of application and removal from the surface. Selected coatings were characterized with Fourier-transform infrared spectroscopy and thermogravimetric analysis, decontamination efficiencies for different types of steel surfaces, and potential enhancement of the removal efficiencies of the select removable coatings via amendment with EDTA. Across all the coatings, decontamination efficiencies for stainless steel (both pristine and with oxidizing treatment) were higher than for pristine carbon steel, which in turn were higher than for rusted carbon steel. Amendment with EDTA improved removal efficiency of a removable coating. CC Strip coating exhibited easy handling and high decontamination efficiency, (up to 97% when EDTA-amended), but its drying time was the longest, and thermal analysis indicated higher release of energy during thermal decomposition compared to the other coatings. Hydrogel-based DeconGel coating, even though not the easiest in handling among the rest of materials, exhibited high decontamination efficiency, efficient drying at the ambient temperature leading to the loss of about 80 wt% due to solvent evaporation, and extremely low heat released during thermal decomposition; therefore, it is considered a preferable choice for the considered factors.
Display omitted
•Commercial strippable coatings for radioactive decontamination were investigated.•Stainless steel: removed up to 98% 241Am from pristine and rusted surfaces.•Carbon steel: removed up to 68–90% 241Am from pristine and rusted surfaces.•Coatings exhibited different properties impacting their practical applications.
The demander of enterprise internal contain information comes from many aspects. Different information demand subjects have different motives. This article first conducts a theoretical and systematic ...analysis of the demand drivers for internal contain based on big data analysis, and then conducts a statistical analysis of the internal contain quality and information disclosure of listed companies in my country in 2018 based on big data. Finally, combined with big data, put forward targeted regulatory recommendations. As for some listed companies in our country, the requirements of internal control level are not high and the accuracy of control related information exists, we need to make outstanding contributions to this research.
For the first time, we combine depth‐specific soil information obtained from the quantitative inversion of ground‐based multicoil electromagnetic induction data with the airborne hyperspectral ...vegetation mapping of 1 × 1‐m pixels including Sun‐induced fluorescence (F) to understand how subsurface structures drive above‐surface plant performance. Hyperspectral data were processed to quantitative F and selected biophysical canopy maps, which are proxies for actual photosynthetic rates. These maps showed within‐field spatial patterns, which were attributed to paleo‐river channels buried at around 1‐m depth. The soil structures at specific depths were identified by quantitative electromagnetic induction data inversions and confirmed by soil samples. Whereas the upper plowing layer showed minor correlation to the plant data, the deeper subsoil carrying vital plant resources correlated substantially. Linking depth‐specific soil information with plant performance data may greatly improve our understanding and the modeling of soil‐vegetation‐atmosphere exchange processes.
Plain Language Summary
Plants interact with soil. This is intuitive, although we know little about the subsurface structure because we cannot see it. At first glance, all soil may look the same, yet healthy plants can survive beside withered ones. We investigate the soil‐plant interaction in an agricultural field situated in an area characterized by ancient (paleo‐) river channels. These channels formed in sandy‐gravelly material due to melting water after last glaciation, were then filled up with fine aeolien sediments, overlaid with soils up to 1 m thick, and are no longer visible at the surface. However, crops grow in meandering/braiding patterns that can be seen on satellite images, for example. To explain this, the subsurface structural geometry must be known. We combine ground‐based electromagnetic induction data inversion results with airborne hyperspectral measurements to reveal the soil depths driving plant performance (photosynthetic activity and growth). Contrary to expectations, the deeper subsoil and not the plowing layer controls plant performance at the investigated site. Plants above the buried paleoriver channels find nutrients and water, whereas the surrounding plants in gravelly soil suffer, especially during drought. These results improve our understanding of soil‐plant interaction, which may improve soil‐vegetation‐atmosphere exchange process modeling and harvest predictability.
Key Points
Soil structures at depth were obtained by quantitative 3‐D electromagnetic induction data inversions not by apparent electrical conductivity maps
Deeper subsoil characteristics correlate with airborne Sun‐induced fluorescence data indicating soil moisture effects on plant performance
Quantitative inverted electrical conductivity model together with plant data help to inform and improve soil‐vegetation‐atmosphere models
The nitrogen fertilizer has a critical role in the plant growth and development processes by which the plant derives nitrogen which is in one content of cells. As a key element in the formation of ...many compounds whereas the most important are amino acids that compose the protein. Therefore, Nitrogen considers as important for growth and plant development and consequently for the increased outcomes. The Forage grass plants respond well to nitrogen fertilization and collect about half of the nitrogen absorbed by the plant during various stages of plant grains growth. Nitrogen positively affects the photosynthesis rate by increasing the rate of chlorophyll amount in the leaves, as it is the main element in the increase and composition of the dry matter of the plant, the size and capacity of the grin, and the final crops of grains as each ton of grain crops such as maize contain about 16 kg of nitrogen.
Food allergy is a major public health concern with avoidance of the trigger food(s) being central to management by the patient. Food information legislation mandates the declaration of allergenic ...ingredients; however, the labelling of the unintentional presence of allergens is less defined. Precautionary allergen labelling (PAL) was introduced by the food industry to help manage and communicate the risk of reaction from the unintended presence of allergens in foods. In its current form, PAL is counterproductive for consumers with food allergies as there is no standardized approach to applying PAL. Foods with a PAL often do not contain the identified food allergen while some products without a PAL contain quantities of common food allergens that are capable of inducing an allergic reaction. Integrated Approaches to Food Allergen and Allergy Risk Management (iFAAM) was an EU‐funded project that aimed to improve the management of food allergens by the food industry for the benefit of people with food allergies. Within iFAAM, a clinically validated tiered risk assessment approach for food allergens was developed. Two cross‐stakeholder iFAAM workshops were held on 13‐14 December 2016 and 19‐20 April 2018. One of the objectives of these workshops was to develop a proposal to make PAL effective for consumers. This paper describes the outcomes from these workshops. This provides the basis for the development of more informative and transparent labelling that will ultimately improve management and well‐being in consumers with food allergy.
Ultrafiltration membrane's efficiency and antifouling properties can be enhanced by blending with benign tailor made inorganic nano-materials. Carbon adhered Fe3O4 hollow nanotube, nanosheet ...synthesized from iron alkoxide using iron (III) acetate source refluxed with methanol. The prepared Fe3O4 (nanotubes & nanosheets) were characterised by PXRD, FE-SEM, TEM, FT-IR and elemental analysis. Polymer nanocomposite membranes were prepared by blending PVDF (14 wt%)/Fe3O4 (2 wt%)/DMF and characterised in detail. PVDF/Fe3O4 (hollow nanotube) composite membrane showed enhanced flux property and antifouling efficiency confirmed by BSA rejection and molecular weight cut-off (MWCO). The biofilm formation studies of PVDF/Fe3O4 hollow nanotube composite membrane were evaluated using E. coli, fresh water Bacillus subtilis and marine Bacillus bacteria showed excellent control of biofilm growth by PVDF/Fe3O4 (hollow nanotube) membrane. The antifouling studies of PVDF blank and PVDF/Fe3O4 (holow nanotube) with B. subtilis and P. aeruginosa showed 0.943 ± 0.02, 0.932 ± 0.01 A.U for PVDF blank and 0.88 ± 0.02 and 0.802 ± 0.02 A.U, and this indicates the significant antifouling control arise from the Fe nanomaterial.
Display omitted
•Synthesis of carbon adhered iron oxide hollow nanomaterial (tube, sheet).•Characterization by PXRD, FE-SEM and HR-TEM.•Preparation of PVDF ultrafiltration composition membrane using iron oxide nanomaterial.•Effect of nanomaterial on membrane's flux and antibiofouling property.
•Containment pressure and hydrogen distribution are evaluated by the MELCOR code during SBO, SBO-LBLOCA and SBO-SBLOCA.•The minimum number of required HARs is predicted to reduce the hydrogen ...concentration below the ignition limit.•The possibility of the hydrogen ignition by HARs is also investigated.•A new spray system with optimized characteristics and HARs are proposed for the mitigation systems during a severe accident.•The containment pressure during the SBO accident is more than the other accidents.
Investigation of Severe Accidents (SAs) to manage containment pressure and hydrogen production are the objectives of the present work. A novel SA management (SAM) strategy for containment pressure management is evaluated during Station Black-Out (SBO), Station Black-Out with Large Break Loss of Coolant Accident (SBO-LBLOCA) and Station Black-Out with Small Break Loss of Coolant Accident (SBO-SBLOCA) in the WWER1000/V446 nuclear reactor by tuning the spray parameters using MELCOR1.8.6 code and CONTAIN2.0 code for validation. Results show that the spray system with 0.44 m3/s flow rate, droplet temperature of 55 °C and duration about 7955 s associated with 49 Hydrogen Auto-catalyst Recombiners (HARs) can keep the containment integrity against overpressure during the course of the SAs. The peak containment pressure during the SBO, SBO-LBLOCA and SBO-SBLOCA decreased from 0.92, 0.52, 0.66 MPa to 0.43, 0.38, and 0.37 MPa by the proposed mitigation strategy, respectively.
•Modeling of RELAP5/SCDAP and CONTAIN containment are prepared for VVER 1000/V446.•Double-ended loss of coolant accident is simulated.•The core degradation map and hydrogen generation are ...evaluated.•Distribution of H2, O2, N2, and H2O (liquid and steam) are investigated in the containment cells.
In this paper, a double-ended loss of coolant accident with station blackout condition is modeled for VVER-1000/V446 using RELAP5/SCDAP mod3.4 as a best estimate nuclear code. Besides, the cells of containment rooms are modeled exactly according to safety reports of this reactor using the CONTAIN 2.0 computer code. The breaks mass flow rates of coolant in liquid and vapor phases, hydrogen generation rate, and oxidation heat generation data are extracted from RELAP5/SCDAP code and used as the input data for CONTAIN code.
The hydrogen, vapor and liquid water release to the containment through the break. It can lead to the pressure of containment increases and failure can occur due to overpressure. The containment pressure and temperature in the containment dome are evaluated during the one day. In addition, the local hydrogen generation and mixture gases are investigated in the cells of containment after 24 h.
The suppression pool is an important component in a boiling water reactor nuclear power plant. Under design-basis, loss-of-coolant accident conditions, pressure in the containment increases. Gas ...flows from the drywell to the wetwell after the normally submerged connecting vents between the drywell and the wetwell have been purged of water through a vent clearing process so that the suppression pool may prevent pressure in the containment from exceeding the designed pressure limit. To analyze such complicated thermal-hydraulic behavior of the suppression pool under a specific accident, an advanced reasonable model should be developed. The SPARC-90 model used in MELCOR calculates the mass and energy transfer between the bubbles of the injected gas and the suppression pool, which is affected by distance efficiency and subcooling efficiency. The dedicated vent flow model used in CONTAIN can well simulate the vent clearing time, that is, the time required for the liquid level on either side of the suppression pool to drop to the level at which the vent begins to clear. However, it is necessary and better to combine them into one integrated code. This paper presents a newly developed suppression pool model based on the self-developed severe accident analysis code Integrated Severe Accident Analysis (ISAA), which combines the advantages of the dedicated vent flow model and the SPARC-90 model to analyze the suppression pool's thermal-hydraulic behavior. The simulation results of the developed suppression pool model shows reasonableness compared with the result in the CONTAIN 2.0 code manual. The good agreement between the simulation results and the analysis results from the COLUMBIA power station final safety analysis report demonstrates the rationality and effectiveness of the developed model, although future improvement is needed.
PDF
