Radioactive Dispersion Research Articles

Management of Casualties from Radiation Events

Radiation events such as nuclear war, nuclear reactor incidents, and the deployment of a radioactive dispersal device (dirty bomb) are all significant threats in today’s world. Each of these events would bring significant challenges to clinicians caring for patients with burns and traumatic injuries who are also contaminated or irradiated. The result of a nuclear exchange in a densely populated area could result in thousands of patients presenting with trauma, burns, and combined injury (trauma and burn in an irradiated patient). In this review, we will discuss the three major types of ionizing radiation: alpha, beta, and gamma, and their respective health hazards and biological effects. Additionally, we will discuss the types of burn injuries in a nuclear disaster, caring for the contaminated patient, and managing the combined injury of burn trauma with acute radiation syndrome. The reader will also be left with an understanding of how to prioritize lifesaving interventions, estimate the absorbed dose of radiation, and predict the onset of acute radiation syndrome. While some animal models for morbidity and mortality exist, there is limited modern day human data for patients with combined injury and burns associated with a nuclear disaster due to the infrequent nature of these events. It is extremely important to continue multidisciplinary research on the prevention of, preparedness for, and the response to nuclear events. Furthermore, continued exploration of novel treatments for radiation induced burns and the management of combined injury is necessary.

Comparative study on gradient-free optimization methods for inverse source-term estimation of radioactive dispersion from nuclear accidents

In this study, we rigorously assess the performance of three gradient-free optimization algorithms—Ensemble Kalman Inversion (EKI), Particle Swarm Optimization (PSO), and Genetic Algorithm (GA)—for estimating source terms in diverse radionuclide release scenarios. Our analysis encompasses both single and multiple sources with varying radionuclide compositions, delving into the influence of decay constants and radioactivity on source estimation accuracy. Although estimating a single radionuclide from a single source exhibits outstanding results, estimating multiple radionuclides from a single source proves more arduous due to the limited information available for discerning gamma dose rates. Contrary to expectations, increasing the number of observation stations does not consistently improve the likelihood of finding accurate solutions in ill-posed inverse problems. Impressively, under our simulation settings, EKI demonstrates competitive performance in terms of convergence, accuracy, and runtime compared to PSO and GA, with GPU parallelization further bolstering computational efficiency. We explore strategies for enhancing source term estimation, including incorporating prior information, applying uncertainty removal techniques, and optimizing observation placement. Additionally, this study underscores the intricate role of relative error in determining multi-radionuclide estimation accuracy from gamma dose measurements. By employing the Gaussian plume model under steady-state conditions, our research lays the groundwork for future applications of Lagrangian dispersion models with real-time data integration. The insights gleaned from our study promise to advance environmental radioactivity monitoring and catalyze the development of cutting-edge, real-time source estimation technologies in full-scale systems.

Baseline radioactivity in the five candidate sites for the second nuclear power plant in Bangladesh and concomitant hazards assessment

ABSTRACT To meet the increasing energy demands and foresee the shortage of fossil fuels as a source of energy, the Government of the People’s Republic of Bangladesh has decided to install a second Nuclear Power Plant in the southern region of Bangladesh. This study was conducted to assess the baseline radioactivity using the High Purity Germanium (HPGe) detector of the five candidate sites to construct a nuclear power plant in the southern regions of Bangladesh and to evaluate the associated radiological hazard parameters. This pioneering study demonstrates that the mean activity concentrations (range) of 226Ra, 232Th, and 40K in forty-five soil samples collected from the five candidate sites were 28.95 ± 2.72 (2.65–48.75), 30.10 ± 2.95 (10.35–46.65), and 278.82 ± 25.78 (126.05–418.61) Bqkg−1. The evaluated area poses insignificant radiological concerns regarding mean absorbed dose rate, radium equivalent activity, annual effective dose, external and internal hazard indices, and excess lifetime cancer risk values. This study revealed a thorough picture of radioactive dispersion in soil samples from Bangladesh’s southern areas, allowing policymakers to take appropriate measures in identifying viable candidate sites for constructing a Nuclear Power Plant. Moreover, the data of this study can be used as a reliable source of baseline radioactivity in the particular area.

Using ARGOS to simulate radioactive dispersion in the atmosphere from Fangchenggang nuclear power plant to Viet Nam

In this study, ARGOS software was used to simulate the atmospheric radioactive emissions from Fangchenggang nuclear power plant to Viet Nam. The simulated cases are hypothetical accidents with hypothetical source terms equivalent to level 6 of the International Nuclear and radiological Event Scale (INES). The results show the possibility of using ARGOS in simulating atmospheric dispersion, assessing radiation dose to humans from the Fangchenggang nuclear power plant accident to Viet Nam in some accident situations. Furthermore, the obtained results contribute to forecasting and supporting emergency response when an accident occurs in nuclear power plants.

Sensitivity study of risk to future generations from geological disposal of radioactive waste in high strength rock in the UAE

The United Arab Emirates (UAE) Government's Policy is to institute a safe and permanent geological disposal facility (GDF) for the final disposal of higher activity radioactive wastes (HAW). The UAE has yet to identify or decide on a disposal site, and geological data specific to the characterisation of a GDF host rock either lacks sufficient details or is not available in the public domain. However, initial screenings of geological environments in the UAE give an indication of potential suitable host rock formations. This paper presents the results of a study into the factors that influence the risk to future generations from the disposal of Spent Nuclear Fuel (SNF) in a deep underground geological disposal facility. For the purpose of this study the GDF was assumed to be in a High Strength Rock (HSR) geological environment in the Khor Fakkan (KF) Block. GoldSim's Contaminant Transport code was used to model the potential dispersion of radioactivity from a GDF. which enabled the calculation of risk to future generations. The GDF radiological source term was based on the UAE's forecasted SNF inventory. The model created from GoldSim emphasizes the transport of radionuclides through the GDF's engineered barrier systems (EBS), through the surrounding geosphere and into the biosphere. Once in the biosphere the radiation dose to the reference receptor is determined via ingestion from well drinking water, or inhalation through atmospheric dispersion. The paper explores the factors that influence the assessment of risk to people both now and in the future. The analyses presented in this paper are not meant to be used in site selection decision making or in the assessment of the suitability of the location to host a GDF for nuclear waste. The selection of a disposal site in the UAE would depend on a more detailed analysis of site-specific conditions.

Assessment of Radioactivity Dispersion Model for Surface Water

Uranium is an element commonly found in natural groundwater can be measured up to 100-500 µg per L without impact from mining. Determination of radionuclide concentrations by dispersion in the surface water is based on several mathematical models. In this paper, the main purpose of this research is to estimate the distribution of radionuclide contamination in the water body under laboratory conditions. The simplest approach in deriving radioactivity dispersion was evaluated by a laboratory-scale glass tank (60 x 60 x 60 cm) which was used for dispersion measurements in the laboratory. The box model transition test has taken into account several parameters; these are mixing ratio, transit time and decay to predict radionuclide concentrations in the water at the location of interest. Radioactive solution (650 Bq/liter) was released in the box and samples were taken from 10 cm intervals every 5 minutes. Results show that radioactivity dispersion can be predicted briefly by using this model for surface waters. Laboratory water tank measurements show that radioactivity dispersion of uranium-bearing solution in surface water compatible with the equation. Measured transition time in the field is the most valuable information that improves the ability to predict the transport and dispersion in surface water.

Modeling on 137Cs Radioactive Dispersion in Gosong Coast as The Candidate Location for Nuclear Power Plant

The study of radioactive dispersion in the ocean should be conducted to prepare the construction of nuclear power plant (NPP) in Gosong Coast, West Kalimantan. This study estimated the distribution of 137Cs radioactive from various scenarios of radioactive waste dumping if nuclear emergency is occurred during NPP’s operation. These scenarios were distinguished based on their volume discharges of radioactive waste into the ocean, included 10 m3 (Scenario I), 50 m3 (Scenario II), and 100 m3 (Scenario III). Model dispersions were constructed for 15 days by Delft3D-Flow module. The simulation showed that ocean current directions were not significantly different among spring and neap tide, instead the ocean current during the spring period dominantly increased rather than neap period. Ocean currents at Gosong Coast flowed parallel to the shoreline towards Singkawang Coastal Area during ebb tide. Meanwhile, during flood tide, ocean currents at Gosong Coast flowed offshore through Burung Archipelagic. The dispersed model showed the distribution of 137Cs radioactive for 15 days reaching to coastal areas of Burung Archipelagic, Singkawang, and Southern Sambas Coast. Each scenario of the disposal system did not influence the marine pollution of the West Kalimantan Sea.

Radiological Consequences Modelling for a Land Based Operations Environment

Radiological Dispersive Devices (RDD) are often portrayed as weapons used by radical (asymmetric) forces, however they can also be used in a regular war. In this study, a hypothetical scenario where an asymmetric force contaminates the battlefield, by detonating an RDD prior to the soldier’s arrival without being detected, is simulated. The software HotSpot was used due to its speed and conservative results which can help inform the decisions made by the commanding officers. HotSpot performs a Gaussian simulation of the radioactive dispersion in the environment. The plumes that arise from the explosion are considered to be affected by the atmospheric conditions. In this study, those conditions are represented by the Pasquill-Gifford stability classes. The results of the simulation show that remaining stationary, if the contaminated area size is not affected by the PG class variation, may increase the radiological risk. It is better to move the soldiers around in order to avoid additional exposure, however that may also be a challenge for various reasons including changes in the shape of the contaminated area. Nevertheless, the variations in local PG classes gain importance as the distance from the release point increases.

Impact of boundary layer simulation on predicting radioactive pollutant dispersion: A case study for HANARO research reactor using the WRF-MMIF-CALPUFF modeling system

Wind plays an important role in cases of unexpected radioactive pollutant dispersion, deciding distribution and concentration of the leaked substance. The accurate prediction of wind has been challenging in numerical weather prediction models, especially near the surface because of the complex interaction between turbulent flow and topographic effect. In this study, we investigated the characteristics of atmospheric dispersion of radioactive material (i.e. 137Cs) according to the simulated boundary layer around the HANARO research nuclear reactor in Korea using the Weather Research and Forecasting (WRF)-Mesoscale Model Interface (MMIF)-California Puff (CALPUFF) model system. We examined the impacts of orographic drag on wind field, stability calculation methods, and planetary boundary layer parameterizations on the dispersion of radioactive material under a radioactive leaking scenario. We found that inclusion of the orographic drag effect in the WRF model improved the wind prediction most significantly over the complex terrain area, leading the model system to estimate the radioactive concentration near the reactor more conservatively. We also emphasized the importance of the stability calculation method and employing the skillful boundary layer parameterization to ensure more accurate low atmospheric conditions, in order to simulate more feasible spatial distribution of the radioactive dispersion in leaking scenarios.

Enhancing Radiation Detection by Drones through Numerical Fluid Dynamics Simulations.

This study addresses the optimization of the location of a radioactive-particle sensor on a drone. Based on the analysis of the physical process and of the boundary conditions introduced in the model, computational fluid dynamics simulations were performed to analyze how the turbulence caused by drone propellers may influence the response of the sensors. Our initial focus was the detection of a small amount of radioactivity, such as that associated with a release of medical waste. Drones equipped with selective low-cost sensors could be quickly sent to dangerous areas that first responders might not have access to and be able to assess the level of danger in a few seconds, providing details about the source terms to Radiological-Nuclear (RN) advisors and decision-makers. Our ultimate application is the simulation of complex scenarios where fluid-dynamic instabilities are combined with elevated levels of radioactivity, as was the case during the Chernobyl and Fukushima nuclear power plant accidents. In similar circumstances, accurate mapping of the radioactive plume would provide invaluable input-data for the mathematical models that can predict the dispersion of radioactivity in time and space. This information could be used as input for predictive models and decision support systems (DSS) to get a full situational awareness. In particular, these models may be used either to guide the safe intervention of first responders or the later need to evacuate affected regions.

Deposition velocities of some natural radionuclides from the atmosphere at Ninh Thuan and Dong Nai of Vietnam

The deposition velocities of Be-7, K-40, Th-232, U-238 and Pb-210 radionuclides from the atmosphere at Ninh Thuan and Dong Nai monitoring stations of Vietnam were investigated. The deposition velocity was calculated based on it’s specific radioactivity in aerosols and deposition density in fallout samples. The data of the deposition velocities of radionuclides from the atmosphere are needed as input data for the models to simulate atmospheric radioactive dispersion and assess the public dose around nuclear facilities. The radioactivity of Be-7, K-40, Th-232, U-238 and Pb-210 nuclides in aerosols and fallout samples were analyzed by using a low level background gamma spectrometer equipped with HPGe detector of high resolution. The results show that the deposition velocities of Be-7, K-40, Th-232, U-238 and Pb-210 nuclides from the air are in ranges of 0.04÷1.71; 1.84÷27.46; 1.46÷23.63; 0.80÷26.13 and 0.06÷1.53 (cm/s), with average values of 0.55; 13.81; 8.22; 8.12 and 0.58 (cm/s), respectively. The deposition velocities of the radionuclides in the survey areas are comparable with those found in tropical and subtropical regions and these results could be served as the database of the World radioactive transport parameters.

Formulation of turbulence diffusion relationships under stable atmospheric conditions and its effect on pollution dispersion

In this article, we formulate Monin–Obukhov similarity theory (MOST)-based relationships, for normalized standard deviations of wind velocity components under the local scaling framework, and investigate their applicability under stable and highly stable atmospheric conditions. We used the fast response data collected using an ultrasonic anemometer over a flat terrain of Kalpakkam in India and a complex hilly terrain at Cadarache, France, for arriving at these formulations. The study shows that after filtering of the submesoscale motions from the sonic anemometer data, the turbulence diffusion relationships follow local scaling, under stable conditions. The study further indicates that these relationships follow similar behavior for the sites taken for this study. At neutral conditions, the values of the scaled standard deviations are found to be 1.9 ± 0.07, 1.8 ± 0.06 and 1.3 ± 0.02, for longitudinal, crosswind and vertical component, respectively, for the complex terrain and 1.8 ± 0.03, 1.9 ± 0.06 and 1.1 ± 0.04, respectively, for the flat terrain. The research also investigates the effect of the new diffusion relationships in simulating atmospheric dispersion, using the Lagrangian particle dispersion model FLEXPART-WRF. Simulations using these new diffusion relationships show a higher dose estimate relative to the model default Hanna’s method, in the case of radioactivity dispersion. Detailed comparisons of the simulated dose rate estimates against measurements using Environmental Radiation Monitors (ERM) indicate that the new relationships give better correlation (r2 = 0.62) under stable conditions over model default relationships (r2 = 0.50).

Radioactive dispersion in groundwater resulting from postulated accident at a proposed nuclear power plant, northwestern coast of Egypt

Egypt announced a nuclear power program to secure and diversify the country's energy supply. The radiation risks to workers, public and to the environment that may arise from these applications have to be assessed and if necessary, controlled. The radioactivity concentration of groundwater has been predicted for 50 years after a postulated accident at a proposed Nuclear Power Reactor at El-Negila, Northwestern Coast of Egypt. The accident is assumed to be resulting from a loss of coolant accident (LOCA) of a 1000 MWe Nuclear Power Reactor of the pressurized water type. The radioactive releases were estimated and a conservative estimate of dispersion in air and the consequent contaminant transport of radioactive pollutants through groundwater around the reactor were modeled. Of greatest interest in terms of long term radiation contamination hazard of the surface are 137Cs and 90Sr isotopes as their radiological significance increased with time. The analysis results from RASCAL code are used as the input data to MODFLOW-MT3D model, to predict radioactive contamination of groundwater for 50 years of simulation. Two scenarios for groundwater dispersion are assumed. The 1stscenario considered no pumping, while the second scenario assumes stressing of the system through pumping wells. The results of groundwater modeling show that the radioactive concentration of 137Cs and 90Sr were higher at the point source location of the released source term compared to WHO limits on drinking water borne radionuclides and decreased in all directions during 50 years of simulation indicating radionuclides retention in the aquifer matrix taking into consideration that 90Sr was retained more than 137Cs. Applying the 2nd scenario revealed that still low concentrations appear in a pumping well at the coast for both 137Cs and 90Sr, due to the fact that several factors affect the dispersion in groundwater (half life time, dispersion, adsorption-desorption).

Robotic Dispersal Technique for 35 GBq of 140La in an L-polygon Pattern.

In 2018, Defence Research and Development Canada, in partnership with Natural Resources Canada, led a field trial of survey and mapping of a large dispersion of radioactivity using Unmanned Aerial Vehicles (UAVs). The intent was to disperse La material in a 3,200 m L-polygon with an approximate activity level of 10 MBq m and to measure the radioactive material using sensors carried by UAVs. Due to the potential radiological hazard to personnel, the activity was approved only if Unmanned Ground Vehicles (UGVs) were able to completely handle and disperse the material remotely. One UGV was equipped with a traditional agricultural sprayer to disperse the material, and one UGV was equipped with a force feedback manipulator arm. Due to the freezing temperatures during dispersal, the 35 GBq of La was dispersed non-uniformly as one sprayer boom failed to perform as tested. However, rough analysis of the electronic dosimetry on the UGV concluded that 99% of the material was dispersed on the ground. The dosimeter placed closest to the robot manipulator arm, used for dispersal of material, indicated a contact dose of 33.5 mSv. The electronic dosimeter placed where the driver would have sat on the sprayer vehicle if it were not unmanned indicated a dose of 22.3 mSv. Thus, the use of UGVs for material dispersion substantially reduced the external exposure to personnel. The use of UGVs eliminated the potential of internal exposure as well. The Radiation Safety Officer received the highest dose at approximately 3 μSv, with the majority of the exposure coming from the handling of the Type A container.

THE STUDY OF ATMOSPHERIC DISPERSION MODEL ON ACCIDENT SCENARIO OF RESEARCH REACTOR G. A. SIWABESSY USING HOTSPOT CODES AS A NUCLEAR EMERGENCY DECISION SUPPORT SYSTEM

G.A. Siwabessy Multipurpose Reactor (RSG-GAS) is a research reactor with thermal power of 30 MW located in the Serpong Nuclear Area (KNS), South Tangerang, Banten, Indonesia. Nuclear emergency preparedness of RSG-GAS needs to be improved by developing a decision support system for emergency response. This system covers three important aspects: accident source terms estimation, radioactive materials dispersion model into the atmosphere and radiological impact visualization. In this paper, radioactive materials dispersion during design basis accident (DBA) is modeled using HotSpot, by utilizing site-specific meteorological data. Based on the modelling, maximum effective dose and thyroid equivalent dose of 1.030 mSv and 26 mSv for the first 7 days of exposure are reached at distance of 1 km from the release point. These values are below IAEA generic criteria related to risk reduction of stochastic effects. The results of radioactive dispersion modeling and radiation dose calculations are integrated with Google Earth Pro to visualize radiological impact caused by a nuclear accident. Digital maps of demographic and land use data are overlayed on Google Earth Pro for more accurate impact estimation to take optimal emergency responses.Keywords: G.A. Siwabessy research reactor, Nuclear emergency, Atmospheric dispersion model, Decision support system, HotSpot codes

First measurement using COUNTERFOG device: Nuclear and radiological scenario

Nowadays, radioactive materials are widely used in medicine, agriculture, industry and scientific research. This implies a growing accessibility and their potential use for criminal or terrorist purposes, i.e. as Radioactive Dispersion Device (RDD) or as Radiation Emission Device (RED). In light of these new threats, currently there are no countermeasures available that can respond quickly and automatically to mitigate their possible consequences. Therefore, the need arises to design and to implement new countermeasure systems that will act in the face of a CBRNE (Chemical, Biological, Radiological, Nuclear and Explosives) incident, even in the presence of fire. This is the main goal of the COUNTERFOG project, which proposed a countermeasure system based on the generation of a fog that interact with the dispersed aerosols. The objectives of the project range from the design and manufacture of nozzles able to generate the required fog, to planning and execution of the experimental procedure to evaluate its effectiveness. This work presents the results of the application of the COUNTERFOG system to the cleaning of RN surrogates, dispersed in the environment simulating the detonation of a RDD device.

User Interface of Atmospheric Dispersion Simulations for Nuclear Emergency Countermeasures

In the event of a nuclear emergency, evacuation experts will have very limited time to make life saving decisions. Therefore, it is very important to provide these experts with knowledge of plume characteristics which are generated by an intuitive user interface; backed by simulations of radionuclide dispersions to better assist experts in evacuation planning. This study aims to verify the effectiveness of the user interface that can provide a one year meteorological and dispersion data based on WSPEEDI-II library. Such a user interface might be beneficial to risk and crisis management planning in case of a radioactive dispersion.

In field application of differential Die-Away time technique for detecting gram quantities of fissile materials

In the frame of Chemical, Biological, Radiological, and Nuclear defense European activities, the ENEA, the Italian National Agency for New Technologies, Energy and Sustainable Economic Development, is proposing the Neutron Active Interrogation system (NAI), a device designed to find transuranic-based Radioactive Dispersal Devices hidden inside suspected packages. It is based on Differential Die-Away time Analysis, an active neutron technique targeted in revealing the presence of fissile material through detection of induced fission neutrons. Several Monte Carlo simulations, carried out by MCNPX code, and the development of ad-hoc design methods, have led to the realization of a first prototype based on a 14 MeV d–t neutron generator coupled with a tailored moderating structure, and an array of helium-3 neutron detectors. The complete system is characterized by easy transportability, light weight, and real-time response. First results have shown device’s capability to detect gram quantities of fissile materials.

Radioactive dispersion analysis for hypothetical nuclear power plant (NPP) candidate site in Perak state, Malaysia

Malaysia is planning to build a nuclear power plant (NPP) by 2030 to diversify the national electricity supply and resources. Selection of an NPP site must consider various factors, especially nuclear safety consideration to fulfil the nuclear safety objectives. Environmental Risk Assessment Analysis is a part of safety requirements by the International Atomic Energy Agency (IAEA) prior to the NPP commissioning process. Risk Assessments Analysis (RIA) is compulsory for the NPP site evaluation. One of RIA methods are Radioactive Dispersion Analysis using probabilistic risk analysis software. It is also important to perform studies to estimate the impact to the neighbouring population in the case of a nuclear accident at the power plant. In the present work, aimed to study the impact of a hypothetical nuclear accident by simulating the dispersion pattern of radionuclides originated from a candidate site at Manjung, Perak. The work has been performed using the HotSpot Health Physics codes. Two types of radionuclides have been considered namely 137 Cs and 131 I. In calculations, the initial concentration of radioactive materials of Fukushima Daiichi accident data are used which are 2.06 x 10 16 Bq and 1.68 x 10 17 Bq respectively for the two radionuclides. The result shows that the dispersion distance obtained from both software are not the same. It shows that 137 Cs and 131 I can be dispersed as far as 16 km and 80 km away from the site during radiological accident respectively, reaching major towns in Perak. Using HOTSPOT, the estimated total effective dose equivalent (TEDE) for 137 Cs and 131 I at major towns in Perak such as Lumut and Sitiawan are 1.2 mSv and 9.9 mSv. As for Taiping, Ipoh, Kampar, and Teluk Intan the estimated TEDE is around 0.2 mSv and 1.6 mSv respectively. In conclusion, the dispersion can reach as far as 80 km from the site. However, estimated annual effective dose is not more than 1 mSv limit, which is considered acceptable in the point of view of radiological health risk for human and the environment.

The ability to use FLEXPART in simulation of the long-range radioactive materials dispersed from nuclear power plants near Vietnam border

FLEXPART is a Lagrangian transport and dispersion model suitable for the simulation of a large range of atmospheric transport processes. FLEXPART has been researched and applied in simulation of the long-range dispersion of radioactive materials. It can be applicable to the problem of radioactive materials released from the nuclear power plants impact on Vietnam. This report presents simulation of radioactive dispersion from the accident assumed Fangchenggang and Changjiang nuclear power plants in China with the FLEXPART, using meteorological data from the National Centers for Environmental Prediction (NCEP). The results of simulations and analyzing showed good applicability of FLEXPART for a long-range radioactive materials dispersion. The preliminary simulation results show that the impact of the radioactive material dispersion in Vietnam varies by the well-known characteristics of the monsoon of our country. Winter is the time when the dominant northeast winds up radioactive dispersion most towards our country, its sphere of influence extends from the Northeast (Quang Ninh) to North Central (Da Nang).