Accidental Release Research Articles

Experimental and numerical characterization of hydrogen jet fires

Compressed hydrogen gas is considered the most convenient and robust technological solution for long-term storage. However, several safety concerns are still under investigation. This work presents an experimental and numerical characterization of the jet flame produced after the accidental release from a high-pressure tank containing pure hydrogen at pressures ranging from 90 to 450 bar and release diameters ranging from 1 to 5 mm. Results are expressed in terms of temperature history and flame length. The complete set of measurements has been reported in the supplementary materials. Both integral and discrete models were employed. Besides, the computational fluid dynamic was integrated with finite reaction rate and accurate thermodynamic properties (from the ab initio approach) and showed excellent agreement with experimental data.

Wildlife trade and the establishment of invasive alien species in Indonesia: management, policy, and regulation of the commercial sale of songbirds

In Southeast Asia, mynas (genus Acridotheres) are amongst the most invasive bird species. Information is largely lacking as to where they have established themselves. The spread of invasive, non-native mynas is partially or largely driven by the massive trade in these species as songbirds. While preventing unintentional introductions early is the most effective management option, these species continue to be traded in bird markets throughout the region. We focus on the trade of native and non-native species of mynas, and the establishment of non-native mynas on the Indonesian islands of Java, Bali, and Lombok. Between 2016 and 2019, through field surveys and use of citizen science data (e.g., Burungnesia, iNaturalist, birding reports), we assessed where non-native mynas have been recorded in the wild on these three islands; through bird market surveys we established in which cities these birds are traded. We recorded common myna in Yogyakarta, one of our three survey areas. Combining all records, the areas where alien invasive mynas are established are Greater Jakarta (common and jungle myna), Yogyakarta (common myna), Bali (common and bank myna) and Lombok (common and Javan myna). Two-thirds of the records come from farmlands, home gardens and urbanised areas. In the bird markets, we recorded ~ 23,000 mynas of five species for sale, with Greater Jakarta, Bali and Lombok standing out as areas with high numbers of potentially invasive alien species offered for sale. Restrictions on the sale of wild-caught birds are not adhered to. Well-intended policies concerning the breeding and sale of legally protected species, whereby 10% of the stock is bred to be released in the wild, exacerbate the risk of the establishment of non-native species. We surmise that one of the most effective ways to reduce the risk of the accidental or deliberate release of potentially invasive alien mynas (and indeed other birds) into the wild is for governments and conservationists to work more closely with the retailers who hold the key to informing and educating consumers.

Multicomponent gas mixture parametric CFD study of condensation heat transfer in small modular reactor system safety

Safety is always the primary concern for designing and analyzing nuclear reactor systems. The requirements for the safety margin for advanced small modular reactor (SMR) systems are targeted even higher than the conventional commercial large-scale nuclear reactors incorporating the passive and inherent safety systems. The SMR systems are designed with the condensation passive containment cooling system (PCCS), which plays a critical role in removing reactor heat during a steam release accident case. However, the presence of non-condensable gas (NCG), like air, reduces the heat transfer performance. This physics phenomenon becomes multifactorial for nuclear reactor containment during a fuel failure accident case that releases hydrogen gas. Besides, the mixture component of steam-air-hydrogen varies in reactor accident cases, which needs simulation and validation keeping parameters of importance. Reviews showed that previous studies for SMR’s PCCS did not cover the condensation heat transfer (CHT) in the presence of multicomponent NCG mixture parametric computational fluid dynamics (CFD) simulation and validation, making a research gap in the SMR design safety. A comprehensive CHT parametric CFD study was performed for SMR PCCS to fill this research gap. This study used experimental data as simulation 3D physics domain inlet and outlet boundary conditions. However, the wall boundary conditions were constant temperature, curve-fit, and annular coolant for verifying the turbulence models. Parametric simulations were performed, verified, and optimized for steam-NCG mixtures. The multicomponent gases, multiphase mixtures, and fluid film condensation models were applied with associated turbulence models. The results of the parametric study were evaluated for realistic reactor conditions. Results showed that parametric study provided critical insight about the dependency of multicomponent gas mixture parameters that supports reactor safety design, analysis, and licensing.

Development of swine Fc conjugated Serotype O Foot and mouth disease virus like particles

Abstract Foot-and mouth disease virus (FMDV) cause a highly contagious infection in cloven-hoofed animals. The current conventional FMD vaccines are produced by chemical inactivated virulent FMDV virions, but conventional FMD vaccines risky and limitation such as respect to accidental release of FMDV and high-level biosafety facilities were required to handle FDMV. FMDV virus like particle (VLP) could be alternative choice for future vaccine against FMDV because of efficacy and safety. Receptor for Fc portion of antibody play and important role in the activation of immune response for infection of virus and bacteria. Therefore, immunization with a complex of virus antigen and Fc has the potential to be an improved. Here we report our vaccine studies with Fc conjugated serotype O FMDV VLP for alternative FMDV vaccine.

Identifying the vagal bronchopulmonary afferents responsible for eliciting the cough response to inhaled sulfur dioxide in mice

Among the three major types of vagal sensory nerves innervating the lung and airways, C‐fibers and rapidly adapting receptors (RARs or irritant receptors) are known to possess the properties and functions of “cough receptors”, but their relative roles in regulating cough reflex responses to inhaled irritants are not yet clearly defined. To address this question, we have recently carried out a series of studies in a mouse cough model, in which the intra‐pleural pressure was continuously recorded by a surgically implanted telemetry sensor. Sulfur dioxide (SO2), a common irritant gas, was chosen for the study because its widespread use as a chemical agent in various industrial operations has led to severe lung injuries in workers in numerous incidences resulting from accidental release of high concentrations of SO2 in industrial facilities. Inhalation of SO2 (300 and 600 ppm) consistently and reproducibly elicited coughs in a concentration‐dependent manner in awake mice moving freely in a recording chamber. The cough frequency increased rapidly after the onset of the SO2 inhalation challenge, which continued for the remaining duration of 8‐min exposure. In the current study, single‐fiber electrophysiological recording of vagal afferent activity in anesthetized mice showed that the high concentration of SO2 (600 ppm) evoked a sustained stimulatory effect on C‐fibers for the entire duration (8 min) of the inhalation challenge. However, in sharp contrast, inhalation of SO2 at the same concentration and duration generated a distinct and consistent inhibitory effect on both phasic RARs and slowly adapting receptors. Their respiratory cycle‐related phasic discharge declined progressively and/or ceased completely within 1‐3 min after the onset of the SO2 inhalation challenge, which gradually recovered after >15 min following the termination of the SO2 inhalation. In a small percentage of RARs that displayed no phasic activity during eupneic breathing and often exhibited sensitivity to certain inhaled irritants, the same SO2 inhalation challenge did not evoke any significant stimulatory effect. Taken together, these observations suggest that stimulation of bronchopulmonary C‐fibers is primarily responsible for triggering airway irritation and coughing in response to the SO2 inhalation challenge.

Oceanic Radionuclide Dispersion Method Investigation for Nonfixed Source from Marine Reactor Accident

Radionuclide dispersion model, which is of critical importance to the emergency response of severe nuclear accident, is used to estimate the consequences arising from accidental or routine releases and to predict areas of high contamination. It is difficult to evaluate the radioactive consequence accurately and rapidly for the accidental release of radionuclides from marine reactor because of the complex mobility feature in the sea. Based on CFD method, a finite-volume, three-dimensional regional oceanic dispersion model was developed in this paper to simulate the dispersion of radionuclides originating from marine reactor. The simulated dose variation of 137Cs presented good agreement with the monitoring data of marine radioactive pollution caused by Fukushima Dai-ichi nuclear accident, which demonstrated the validity of the method. A severe accident scenario of marine reactor was simulated and analyzed, which indicates that the regional oceanic dispersion model can provide dose assessment for nuclear emergency response.

Atmospheric dispersion modeling for an accidental release from a SLOWPOKE-2 research reactor: a case study.

Atmospheric dispersion modeling was performed for a postulated design basis accident at a SLOWPOKE research reactor. The MCNP-5 computer code was used to estimate the neutron flux spectrum which was then used in the ORIGEN-S code to perform core depletion calculations and determine the radiological source term. The HotSpot health physics code was then used to model the atmospheric transport of the radioactive material released to estimate the resulting doses to the population downwind of the reactor. The highest total effective dose (TED) for a release from the reactor's exhaust stack in predominant meteorological conditions, stability class C, was 0.37mSv, while a maximum TED of 4.29mSv was estimated for a release at ground level. Ground deposition was estimated to be 3900kBq/m2. It was shown that any hypothetical release of radioactive material resulting from such an accident would have no significant adverse effect on the municipal water reservoir close to the reactor.

Accidental release in the bunkering of LNG: Phenomenological aspects and safety zone

The continuous increase in consciousness on properties and models characterizing cryogenic fuels has opened a new era for the supply of alternative sources of energy, especially in the naval sector. However, practical insights providing comprehensive indications for the development of safe and optimized procedures are still missing or lacking. In this perspective, a preliminary investigation on the commonly adopted procedure was integrated with a 3-dimensional representation of a typical port area in computational fluid dynamics (CFD) simulations implementing sub-models suitable for cryogenic conditions. At first, different scenarios were selected as representative for possible release conditions: Unloading Operation (UO), Shore to Ship (STS), and Truck to Ship (TTS) bunkering operations. This study indicates that TTS can be the most critical scenario because of the simultaneity of bunkering and disembarking procedures. The numerical analysis was devoted to the quantification of the safety distance in the case of the absence of an ignition source. The area where skin and eyes' frostbite are possible is assessed, as well, based on the combination of estimated temperature and local wind speed. The resulting safety distances were compared against estimations deriving by discrete and integral models without obstacles, demonstrating that neglect obstacles lead to non-conservative results. Indeed, a local increase in mixing effectiveness, limiting the flammable area within the channel between quayside and ship, was identified and characterized in this work. Besides, it was found that only under certain circumstances for TTS operations a flammable cloud can potentially reach passengers. Hence, the installation of barriers and mitigation systems (e.g., water curtains) is strongly recommended.

Reduced Genotoxicity of Gold Nanoparticles With Protein Corona in Allium cepa.

Increased usage of gold nanoparticles (AuNPs) in biomedicine, biosensing, diagnostics and cosmetics has undoubtedly facilitated accidental and unintentional release of AuNPs into specific microenvironments. This is raising serious questions concerning adverse effects of AuNPs on off-target cells, tissues and/or organisms. Applications utilizing AuNPs will typically expose the nanoparticles to biological fluids such as cell serum and/or culture media, resulting in the formation of protein corona (PC) on the AuNPs. Evidence for PC altering the toxicological signatures of AuNPs is well studied in animal systems. In this report, we observed significant genotoxicity in Allium cepa root meristematic cells (an off-target bioindicator) treated with high concentrations (≥100 µg/ml) of green-synthesized vanillin capped gold nanoparticles (VAuNPs). In contrast, protein-coated VAuNPs (PC-VAuNPs) of similar concentrations had negligible genotoxic effects. This could be attributed to the change in physicochemical characteristics due to surface functionalization of proteins on VAuNPs and/or differential bioaccumulation of gold ions in root cells. High elemental gold accumulation was evident from µ-XRF mapping in VAuNPs-treated roots compared to treatment with PC-VAuNPs. These data infer that the toxicological signatures of AuNPs are influenced by the biological route that they follow to reach off-target organisms such as plants. Hence, the current findings highlight the genotoxic risk associated with AuNPs, which, due to the enhanced utility, are emerging as new pollutants. As conflicting observations on the toxicity of green-synthesized AuNPs are increasingly reported, we recommend that detailed studies are required to investigate the changes in the toxicological signatures of AuNPs, particularly before and after their interaction with biological media and systems.

Good Medical Entomology Laboratories Practices (GMELP) in India: A Concept Note

Vectors of malaria, filaria, dengue, chikungunya, zika, japanese encephalitis, and kala-azar play an important role in the disease transmission in different eco-settings with variable climatic conditions. Ticks, mites, and fleas also pose a threat to new emerging and re-emerging vector-borne diseases, i.e. Kyasanur Forest Disease (KFD), Crimean Congo Hemorrhagic Fever (CCHF), scrub typhus, and other rickettsioses. Now, the time has come that field oriented entomological work has to shift from open, field based towards closed medical entomological laboratories for undertaking molecular research and pathogen/ virus detection among vector species handling them by minimising human risks. It is imperative to note that there is a strong need for a standard protocol for effective medical entomological laboratory practices while handling the pathogen carrying vector species under laboratory conditions. This may help to prevent the transmission of pathogens/ viruses in case of accidental release of vectors carrying pathogens/ viruses from the entomology laboratories. Such protocols would always help the scientists to minimise risks working in closed conditions. Though, there are guidelines/ procedures available for developing medical entomology laboratory, having facilities for insect rearing, its handling and equipment, however, no specific published protocol or guidelines exist presently in the Indian context. In the present manuscript, the need for a standard protocol for arthropod containment levels (ACLs 1- 4) along with the appropriate bio-safety levels based on the risk potential of pathogen carried by the vector species has been discussed for its application at the ground by the respective health authorities/ institutions.The presence of Standard Operating Procedures (SoPs) and guidelines on Good Medical Entomology Laboratory Practices (GMELP) would help the professionals working in a medical entomology laboratory to minimise risks. There is a need to develop and follow Good Medical Entomology Laboratory Practices (GMELP) for handling the vectors (Arthropods) carrying the pathogens/ viruses at the national/ state/ district level as well as by the research institutes, medical colleges, and universities. The present concept note shall help to provide a guiding principle to develop standard operating procedure (SoP)/ Guidelines for GMELP.

THE USE OF BIO-MOLECULAR SUBSTANCE OF MARINE BIOTA AS AN ALTERNATIVE EARLY INDICATOR OF OIL POLLUTED ENVIRONMENT: A NEW APPROACH FOR MONITORING CONSIDERATION

THE USE OF BIO-MOLECULAR SUBSTANCE OF MARINE BIOTA AS AN ALTERNATIVE EARLY INDICATOR OF OIL POLLUTED ENVIRONMENT: A NEW APPROACH FOR MONITORING CONSIDERATION

Trench Fires Resulting from Accidental Releases from Tanker Trucks: Assessing the Thermal Effect on Roadside Territory

The risk posed by spill and subsequent fire during road transportation of flammable liquid is considered in the paper. Attention is paid to a pool fire than can occur in roadside terrain. Circumstances and road situations increasing the likelihood of a spill and fire accident are analysed. The problem under study is an assessment of thermal radiation induced by a roadside pool fire. This study applied a pool fire model known as a trench fire to a roadside situation. The trench fire is considered to be a likely type of a pool fire due to presence of roadside ditches and other oblong low areas along the road. The estimation of the thermal radiation from trench fires is carried out in the deterministic way due to actual lack of systematic uncertainty modelling related to pool fires. Deterministic models developed for estimating the radiation of pool and trench fires are presented and illustrated by a transportation case study. The case study reveals that the thermal radiation emitted by a trench fire can endanger objects positioned in the intermediate vicinity to the road. Further spread of fire into more distant locations is possible only through the domino effect. Incorporation of the thermal radiation models into a transportation risk assessment is discussed in brief. Findings of this study are viewed as knowledge that can be used for refining the estimation of risk posed by transportation of hazardous materials.

Release estimation of pollutants in river by the variational analysis approach

After accidental release of pollutants in rivers, the release estimation of the pollutant is necessary for the dealing of this accident. With the increase of people's attention to river pollution, the monitoring data of river pollution will become more and more abundant and diversified. At this point, data assimilation approaches will be more advantageous. In this paper, a new model called variational analysis inverse model (VAIM) based on the variational data assimilation is proposed to solve the pollutant release estimation problem. In the framework of the variational analysis, the conjugate gradient method and one-dimensional imprecise line search Wolfe-Powell conditions are combined to solve this problem. The implicit finite difference scheme is adopted to solve the one-dimensional advection-dispersion equation. Some synthetic cases are conducted to evaluate the robustness of the proposed model under the effect of the observational error and the effect of initial estimates for release rates in the iteration. Results show that VAIM successfully recovers the accurate release. There are only slight differences among estimated releases by VAIM under different initial estimates. Field tracer experiments are used to evaluate the practicability of VAIM. Results show that the relative error between the estimated release and the real release in the field tracer experiment is only 1.2%. In conclusion, VAIM is a release estimation method with high accuracy and will play an important role in river pollution management.

Fission product isotope ratios as event characterization tools– Part II: Radioxenon isotopic activity ratios

Abstract Air sampling for radioxenon has been recommended as part of the verification system for a Comprehensive Nuclear-Test-Ban Treaty. Xenon isotopic activity ratios are used as a basis for confirming nuclear detonation, and discriminating between nuclear reactor accidental release and nuclear explosion. The primary purpose of this work is to use the available data on explosions, accidental reactor releases and laboratory experiments and simulations, in order to define the most probable scenarios for nuclear reactor accidental release, and for emission from underground nuclear detonations, to calculate the relevant radioxenon isotopic activity ratios in each scenario and to assess their use as event characterizing tools.

Ensemble Data Assimilation of Concentration Measurements Following the Accidental Release of a Contaminant in the Ocean: Method Testing in an Idealized Setting

Ensemble Data Assimilation of Concentration Measurements Following the Accidental Release of a Contaminant in the Ocean: Method Testing in an Idealized Setting

Fission product isotope ratios as event characterization tools Part I: Particulate debris, isotopic activity ratios

Abstract The main goal of this work is to develop quantitatively reliable tools that can be used to identify the origin of a nuclear event, e. g. discriminate between a nuclear explosion and an accidental reactor release. A model has been developed, which takes into account the wide range of conditions and parameters, which may exist in connection with nuclear events. Using the model, specific isotope activity ratios are defined, promising to be effective in event characterization, while reducing the influence of various nuclear scenarios to a minimum. Besides, an attempt was made to quantify the concept of “short irradiation reactor” and to set its limits, as related to an event characterization method.

Operational Modeling of North Aegean Oil Spills Forced by Real-Time Met-Ocean Forecasts

Over the latest decades, oil marine pollution has posed a vital threat for global ocean health, since spillages of any scale are related to environmental, social and financial impacts. The worldwide increase in oil and gas demand, and the parallel rise in oil and gas production, exploiting particularly coastal and offshore marine deposits, have significantly increased the risk of accidental oil release to the sea. In the present study, an operational oil spill model was applied to test the oil dispersive properties and to reveal the relative magnitude of weathering processes, after an accidental oil spill release along the main tanker transportation route in the North Aegean Sea. Numerical simulations were implemented using the OpenOil transport and fate numerical model, a subclass of the OpenDrift open-source trajectory framework. This model integrates algorithms with several physical processes, such as oil entrainment, vertical mixing, oil resurfacing and oil emulsification. The oil dispersion model was coupled to real-time met-ocean forecasts received from NOAA-GFS and CMEMS. Present simulation results have focused on the impact of turbulent kinetic energy, induced by the background flow field, on the horizontal spreading of particles, as well as on the evolution of oil mass balance and oil mass properties.

Accumulation and Speciation of Cobalt in Paracentrotus lividus.

Since the first human release of radionuclides on Earth at the end of the Second World War, impact assessments have been implemented. Radionuclides are now ubiquitous, and the impact of local accidental release on human activities, although of low probability, is of tremendous social and economic consequences. Although radionuclide inventories (at various scales) are essential as input data for impact assessment, crucial information on physicochemical speciation is lacking. Among the metallic radionuclides of interest, cobalt-60 is one of the most important activation products generated in the nuclear industry. In this work, a marine model ecosystem has been defined because seawater and more generally marine ecosystems are final receptacles of metal pollution. A multistep approach from quantitative uptake to understanding of the accumulation mechanism has been implemented with the sea urchin Paracentrotus lividus. In a well-controlled aquarium, the day-by-day uptake of cobalt and its quantification in different compartments of the sea urchin were monitored with various conditions of exposure by combining ICP-OES analysis and γ spectrometry. Cobalt is mainly distributed following the rating intestinal tract ≫ gonads > shell spines. Cobalt speciation in seawater and inside the gonads and the intestinal tract was determined using extended X-ray absorption fine structure (EXAFS). The cobalt inside the gonads and the intestinal tract is mainly complexed by the toposome, the main protein in the sea urchin P. lividus. Complexation with purified toposome was characterized and a complexation site combining EXAFS and AIMD (ab initio molecular dynamics) was proposed implying monodentate carboxylates.

Assessment of genetically modified maize DP4114 × MON 810 × MIR604 × NK603 and subcombinations, for food and feed uses, under Regulation (EC) No 1829/2003 (application EFSA-GMO-NL-2018-150).

Maize DP4114 × MON 810 × MIR604 × NK603 (four‐event stack maize) was produced by conventional crossing to combine four single events: DP4114, MON 810, MIR604 and NK603. The GMO Panel previously assessed the four single maize events and one of the subcombinations and did not identify safety concerns. No new data on the single maize events or the assessed subcombination were identified that could lead to modification of the original conclusions on their safety. The molecular characterisation, comparative analysis (agronomic, phenotypic and compositional characteristics) and the outcome of the toxicological, allergenicity and nutritional assessment indicate that the combination of the single maize events and of the newly expressed proteins in the four‐event stack maize does not give rise to food and feed safety and nutritional concerns. The GMO Panel concludes that the four‐event stack maize, is as safe as the comparator and the selected non‐GM reference varieties. In the case of accidental release of viable grains of the four‐event stack maize into the environment, this would not raise environmental safety concerns. The GMO Panel assessed the likelihood of interactions among the single events in nine of the maize subcombinations not previously assessed and concludes that these are expected to be as safe as the single events, the previously assessed subcombination and the four‐event stack maize. Post‐market monitoring of food/feed is not considered necessary. The post‐market environmental monitoring plan and reporting intervals are in line with the intended uses of the four‐event stack maize. The GMO Panel concludes that the four‐event stack maize and its subcombinations are as safe as the non‐GM comparator and the selected non‐GM reference varieties with respect to potential effects on human and animal health and the environment.

Real-time risk assessment model for hazmat release accident involving tank truck

The main objective of this paper is to develop a real-time risk assessment model for havzmat release accidents involving a tank truck. The proposed model can make full use of multiple real-time data and static data for the purpose of quantifying the risk of hazmat release faced by the tank truck at each moment in the driving process. In order to achieve the above function, we improve the risk quantification method in ARAMIS (Accidental Risk Assessment Methodology for Industries System) for real-time risk assessment. For quantifying the possibility, a fuzzy comprehensive evaluation method based on fuzzy rules is used to synthesize multiple evaluation indicators; For quantifying the intensity and vulnerability, a “potential impact zone” model based on the Gaussian plume model is proposed to describe the influence range of toxic gas leak, and point of interest (POI) data is used to identify critical targets. Through the analysis of the road test results, the effectiveness of the proposed model is verified. The significance of this study is to provide a real-time risk quantification tool for tank trucks, which can be programmed and embedded into various driving auxiliary or safety management systems in the future.