Re-Aerosolization of Dense Metal Oxide Simulating Radiological Contamination from Military Clothing

Radiological contamination from nuclear accidents or the terrorist use of a Radiological Dispersal Device (RDD) are events that first responders must be prepared for. It is currently assumed that removal of the victims clothing will remove 80-90 of contamination. Many RDD radioisotopes produce dense aerosols that would then contaminate victim clothing and re-aerosolize during clothing removal. A series of experiments were conducted during which clothing was contaminated with a dense aerosol simulating the radioisotope of Strontium 90. Compared to background, there was statistically significant re-aerosolization from the clothing. This demonstrates inhalation hazards from re-aerosolization of RDD contamination

Methodology for the Construction of a Virtual Environment for the Simulation of Critical Processes

There is a growing trend in education and training towards the use of online and distance learning courses. This delivery format provides flexibility and accessibility; it is also viewed as a way to provide education in a more effective way to a broader community. Online courses are comfortable, they are built under the missive of “anyone, anywhere, anytime”. Everyone can participate from home or workplace. Online courses can be developed in a variety of ways, for example, using a LMS (Learning Management System), a LCM (Learning Content System), or a Web 2.0 tool (or some mixture). These options, however, show limitations in terms of communication and interaction levels that can be achieved between students. Most learning systems are asynchronous and don't allow an effective real-time interaction, collaboration and cooperation. Whilst they typically have synchronous chats and whiteboards, these capabilities are often sterile and don’t stimulate the appropriate interactions that enhance learning. A rich interaction does not necessarily involve just verbal exchange since there is an huge learning value to be gained from interacting with the learning content in a more visual and practical way. For instance, imagine the learning benefits from collaborating on a 3D construction jointly and in real-time? Imagine watching the impact of soil erosion, or building and walking inside an heart model or a car engine? All this is possible in a 3D immersive virtual world. Students can engage at a distance building content in real-time, collaboratively and interactively. On the net there can be found an array of virtual worlds, however we have chosen Second Life® (SL®) to show how teaching and learning can be enhanced through the use of this platform. Second Life® is immersive, enabling users to interact, communicate and collaborate as if in the real world. SL® is a model of the real world, it shows an accurate physics simulation and it includes a meteorological and gravitational system; as such, anything can be modelled and simulated. Each user in the environment is represented by an avatar with all the features of a human being and avatars can manipulate the environment. Scientific experiments can be held in a very safe and controlled environment, and can be directly conducted by the scientist in charge. Scientific fields such as architecture, history, medicine, biology, sociology, programming, languages learning among many others can all be tested and researched through this virtual world.info:eu-repo/semantics/publishedVersio

The HotSpot Code as a Tool to Improve Risk Analysis During Emergencies: Predicting I-131 and CS-137 Dispersion in the Fukushima Nuclear Accident

Conventional and non-conventional emergencies are among the most important safety and security concerns of the new millennium. Nuclear power and research plants, high-energy particle accelerators, radioactive substances for industrial and medical uses are all considered credible sources of threats both in warfare and in terror scenarios. Estimates of potential radiation releases of radioactive contamination related to these threats are therefore essential in order to prepare and respond to such scenarios. The goal of this paper is to demonstrate that computational modeling codes to simulate transport of radioactivity are extremely valuable to assess expected radiation levels and to improve risk analysis during emergencies helping the emergency planner and the first responders in the first hours of an occurring emergency

The free license codes as decision support system (DSS) for the emergency planning to simulate radioactive releases in case of accidents in the new generation energy plants

The radiological risk is related to a wide range of activities, beginning with the medical and military ones and including those connected to the industrial and research activities such as nuclear fusion. A valid tool to predict the consequences of the accidents and reduce the risk is represented by computing systems that allow modeling the evolution of a possible release of radioactive materials over time and space. In addition to proprietary codes there are free license codes, like Hot-Spot, that allow providing a set of tools to simulate diffusion in case of accidents involving radioactive materials and analyze the safety and security of the facilities in which the radioactive material is manipulated. The case studies scenario’s consists in two simulations accidents scenario the first to biomass plant and the second at nuclear fission plant. The simulation of the radioactive contamination have been conducted with the code HOT SPOT, a free license code. The results of the simulation and data discussion will be presented in this work by the authors

Tellurium Behavior and Management in the Liquid Phases in the Containment During a Severe Nuclear Reactor Accident

No industry is immune to accidents; however, the consequences and the probability are the parameters to consider when assessing the risks. When considering nuclear power, two of the highest-level accidents have occurred during the course of the commercial use of nuclear energy. The consequences of these events were the release of radioactive material to the environment and increased radiation dose to the people. Severe nuclear accident research is therefore crucial in both minimizing the consequences and assessing the effects of the potential releases. The lessons learned from previous nuclear reactor accidents have resulted in higher safety standards, more accurate source term assessment, and improvements in accident management actions. Yet, there are still uncertainties about the behavior of radionuclides during a severe nuclear reactor accident that need to be addressed.\ua0One of the elements released in a severe reactor accident is tellurium. It has several radioactive isotopes that can potentially cause an increased dose in the population if released. Moreover, many of the tellurium isotopes decay to iodine and therefore contribute to the iodine source term. The behavior and release of tellurium have been investigated in the fuel and the reactor system during the past decades. However, the released species, including tellurium, are subjected to different management actions after entering the containment including the containment spray system. The removal efficiency of the spray system towards tellurium species formed under various conditions has been unclear. In this work, the effectiveness was investigated in relation to tellurium species under various atmospheres and in the presence of cesium iodide. In addition, the effect of the chemical composition of the spray was also examined. The spray system was found to be relatively effective in all conditions tested. Moreover, the increase in chemical content of the spray solution increased the removal efficiency. \ua0After being removed from the containment atmosphere, the species, including various tellurium compounds, may enter the containment sump. Due to the complex chemistry of tellurium, it is difficult to predict the behavior under different redox conditions and especially under irradiation. This work therefore investigated the behavior of tellurium dioxide was investigated in simplified containment sump conditions in relation to dissolution, redox reactions and interactions with water radiolysis products. The results indicate that radiolysis products have a significant effect on tellurium chemistry in both reducing and oxidizing manner depending on the solution composition. The redox reactions also affect the solubility of tellurium both by increasing and decreasing it depending on the prevailing conditions. The results show that the current information used to assess tellurium source term needs to be re-evaluated for both severe accident management as well as for severe accident code validation purposes

Dust tracking techniques applied to the STARDUST facility: First results

An important issue related to future nuclear fusion reactors fueled with deuterium and tritium is the creation of large amounts of dust due to several mechanisms (disruptions, ELMs and VDEs). The dust size expected in nuclear fusion experiments (such as ITER) is in the order of microns (between 0.1 and 1000 μm). Almost the total amount of this dust remains in the vacuum vessel (VV). This radiological dust can re-suspend in case of LOVA (loss of vacuum accident) and these phenomena can cause explosions and serious damages to the health of the operators and to the integrity of the device. The authors have developed a facility, STARDUST, in order to reproduce the thermo fluid-dynamic conditions comparable to those expected inside the VV of the next generation of experiments such as ITER in case of LOVA. The dust used inside the STARDUST facility presents particle sizes and physical characteristics comparable with those that created inside the VV of nuclear fusion experiments. In this facility an experimental campaign has been conducted with the purpose of tracking the dust re-suspended at low pressurization rates (comparable to those expected in case of LOVA in ITER and suggested by the General Safety and Security Report ITER-GSSR) using a fast camera with a frame rate from 1000 to 10,000 images per second. The velocity fields of the mobilized dust are derived from the imaging of a two-dimensional slice of the flow illuminated by optically adapted laser beam. The aim of this work is to demonstrate the possibility of dust tracking by means of image processing with the objective of determining the velocity field values of dust re-suspended during a LOVA

Region-specific radioecological evaluation of accidental releases of radionuclides from ESS

Gadolinium-148 is one of the radionuclides of most concern that will be produced in the tungsten target of the European Spallation Source (ESS), as a by-product of the spallation reaction used by the facility to produce neutrons. Since 148Gd a pure alpha emitter, it is both very radiotoxic and difficult to measure. With its half-life of 75 years, it will remain in the environment for a long time if released from the facility during normal operation or after an accident. There are still uncertainties regarding the amounts that actually will be produced by spallation in the tungsten targets of the facility. As Gd-148 does not occur naturally in the environment, there is no information available about its analysis in environmental samples but a few studies provide data from irradiated target material analysed by alpha spectroscopy or inductively coupled plasma mass spectrometry (ICP-MS). This report is a continuation of the SSM project as described in the SSM report 2020:08, entitled “Identifying radiologically important ESS-specific radionuclides and relevant detection methods” that focused on the ESS-related radionuclides that will be the most relevant to study and monitor in the environment as well as the analytical techniques to detect them. The present report focuses on the rare earth elements (REEs), including their radioactive isotopes, in particular Gd-148, and is intended to highlight the knowledge gaps that exist regarding their fate in the specific environment of the ESS area. In the first part of the report, the available literature on radioecological models was reviewed, with emphasis on ESS-related radionuclides. The existing modelling programmes were surveyed as well as the most relevant environmental parameters and experimental radioecological data required to build models specific to the ESS.In the second part of the report, the area in the vicinity of the ESS was surveyed to identify the important producers of foodstuff, what plant species are grown in the area and also the local husbandry and hunting practices, in order to identify critical pathways after a radioactive dispersion into the environment in connection with a potential accident at the ESS. In the third part of this report, after a thorough literature review and preliminary assays, we propose to investigate the use of ICP-MS for assessment of Gd-148 in the event of an accidental release, knowing that this analytical technique is already used for the measurement of stable Gd and REEs in the environment. The existing methods to extract REEs from environmental samples (soil, water, plants, and animal products) and to properly assess their concentration are described in the form of a literature review. The presented examples of methods were selected to fit the type of environment found around the ESS facility and the local agricultural and horticultural practices. A pilot study was also conducted to test extraction and measurement methods on the specific type of soil around ESS. These results are presented at the end of this report

Focal Spot, Summer 2003

https://digitalcommons.wustl.edu/focal_spot_archives/1094/thumbnail.jp