Enhancing Resilience through Nuclear Emergency Preparedness at El Dabaa Site

. Te research utilized advanced PCTRAN and RASCAL software to evaluate the potential radiological impacts of hypothetical accidents, specifcally loss-of-coolant accident (LOCA) and long-term station blackout (LTSBO), at the El Dabaa Nuclear Power Plant. Over a span of ten years, comprehensive meteorological data were meticulously analyzed to assess the dispersion of radioactive substances within a 40-kilometer radius across all four seasons. Te outcomes revealed that only in the case of LTSBO did the radiological levels surpass the limits set by the Environmental Protection Agency (EPA). Notably, during spring, LTSBO exhibited a maximum total efective dose equivalent (TEDE) value of 13 millisieverts (mSv) at a distance of 3.2kilometers, and the highest thyroid dose (TD) recorded was 63mSv at 8kilometers. Tese signifcant fndings play a crucial role in shaping strategies related to the distribution of potassium iodide (KI) and further enhance the overall preparedness and evacuation planning protocols.


Introduction
Te El Dabaa nuclear plant will be situated in Marsa Matrouh governorate, approximately 320 kilometers northwest of Cairo and west of Alexandria, Egypt.It comprises four VVER-1200 nuclear power units.Te construction of the plant will be undertaken by Rosatom's subsidiary company, in collaboration with the Korea Hydro and Nuclear Power (KHNP) [1].During normal operation, reactors release minimal radionuclides [2,3].However, severe accidents involving core meltdown or surpassing design limits can result in substantial radionuclide release [2,3].After a signifcant accident, radionuclides can pose risks to plant staf, public health, and the environment [4].Te extent of radionuclide release and the seriousness of the event that caused it determine how serious the threat is [3,5].Given the potentially lethal nature of nuclear radiation, assessing potential radiological hazards resulting from catastrophic accidents is essential [6].Tis evaluation should consider the vulnerability of the plant's safety mechanisms [3].Past incidents at Tree Mile Island, Chernobyl, and Fukushima Daiichi have shown how nuclear accidents can lead to extensive radioactive pollution locally, regionally, and globally [5].Consequently, when considering the establishment of a new nuclear facility, the signifcance of developing emergency readiness programs becomes imperative [6].Ensuring readiness requires vital details such as site locations, plume arrival times at key spots, and background radiation levels.Tis level of preparedness relies on sophisticated tools such as dispersion models and detailed meteorological databases, encompassing wind speed and direction for precise forecasting [5].Simulation emerges as an indispensable tool for providing early decision support in emergency scenarios, facilitating the evaluation of accident consequences [5].Diverse software tools are leveraged to assess the impact of radiological and nuclear incidents, with a specifc emphasis on atmospheric dispersion modeling.Prominent examples encompass MLDP (Modèle Lagrangien de Dispersion de Particules d'ordre), NAME (Numerical Atmospheric-dispersion Modeling Environment), RATM (Regional Atmospheric Transport Model), FLEXPART (Flexible Particle Dispersion Model), SPEEDI (System for Prediction of Environmental Emergency Dose Information), WSPEEDI (Worldwide SPEEDI), RIMPUFF (Risø Mesoscale PUFF model), ADMS (Atmospheric Dispersion Modeling System), JRODOS (Java-based Real-time Online Decision Support), HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory), HotSpot (Gaussian Plume Model), RASCAL (Radiological Assessment System for Consequence Analysis), PC CREAM (Consequences of Releases to the Environment Assessment Methodology), and others.Tese tools collectively contribute to a comprehensive understanding of atmospheric transport and dispersion, which are crucial factors in predicting the radiological impact during potential nuclear emergencies [7][8][9].Gaussian plume models remain extensively employed for risk assessment and emergency responses.Tese models fnd application in various software, including "Radiological Assessment System for Consequence Analysis," RASCAL [10,11].PCTRAN, short for "Personal Transient Computer Analyzer," simulates nuclear power plant transients and accidents on personal computers.Its user-friendly graphical interface enables direct interaction with simulation elements.It is an easy operation, faster-than-real-time execution and suitable for various plant types, and is recognized by the International Atomic Energy Agency (IAEA) [12,13].
As Egypt's nuclear involvement poses signifcant challenges, demanding strong emergency strategies at local and national levels [14,15].Te aim of this study is to enhance strategies for public safety and environmental protection as well as improve emergency response planning and decisionmaking by integrating PCTRAN-modeled transient and accident sequences, encompassing both design basis accidents (DBA) and beyond design basis accidents (BDBA), into RASCAL.

Literature Review of Previous Studies
Nuclear power plants are commonly viewed as environmentally friendly energy sources with a minimal carbon footprint, making them a promising solution to the escalating global energy demand [16].Nevertheless, the apprehension of a signifcant or severe accident occurring in a nuclear power plant has, to some extent, impeded the growth and development of this industry among the general population [17].Te Fukushima Daiichi nuclear accident in 2011 underscored the susceptibility of nuclear facilities to natural disasters, particularly when lacking essential safety features.Te extensive release of radioactive materials into seawater and soil following this incident triggered signifcant concerns among researchers [18,19].Tis paper conducted a thorough examination of the Fukushima accident, focusing on the release and dispersion of radioactivity in the environment.It delves into the repercussions on public health, the economy, energy policies, international relations, and the development of light water reactor (LWR) fuel [20].Tis paper outlined the variations in safety preparations at Chernobyl and Fukushima Daiichi, providing recommendations for enhancing safety culture, decontamination practices, and disaster planning.Additionally, it addressed the necessity for implementing a high-level national emergency response system to efectively manage nuclear accidents [21].In this paper, showcase outcomes derived from the efcient RASCAL 4.2 code applied to the Fukushima Daiichi accident are presented.By leveraging comparable Nuclear Power Plants (NPPs) already cataloged in the RASCAL database of U.S. NPPs and incorporating tailored accident event sequences for each unit at Fukushima, the released Source Term into the atmosphere is assessed [22].
In a series of PCTRAN-based studies, Omar and Hasan [23] conducted a comparative loss of coolant accident (LOCA) analysis, investigating severity in the VVER 1200 plant's hot and cold legs.Te study explored break size impact, simulating various scenarios, including station blackout (SBO) and emergency core cooling system (ECCS) malfunction.Similarly, Fyza et al. [24] used PCTRAN to analyze thermal-hydraulic parameters of the VVER-1200 plant during a LOCA with ofsite power loss.Additionally, Akter et al. [25] used PCTRAN for a reactor transient simulation, focusing on turbine trips and anticipated transient without scram (ATWS) events in AP-1000 and VVER-1200 reactors.Furthermore, Tanim et al. [26] conducted a fault consequences analysis using PCTRAN.Te study explored various faults, including feedwater loss, steam generator tube rupture (SGTR), and coolant break.Factors such as reactivity, steam/feedwater fow, pressure, and more were analyzed through transient behavior analysis.
In the realm of RASCAL studies, Bakr [15] used probabilistic safety assessment (PSA) to establish emergency zones for the El-Dabaa NPP.A severe accident scenario for the VVER-1200 reactor was simulated, considering varied atmospheric patterns and probabilities.Additionally, Abd El-Hameed and Kim [27] utilized the RASCAL code to analyze radioactive material release from the VVER-1200 reactor in diverse scenarios.Output data were utilized in a machine learning classifcation and regression tree (CART) model to predict material quantities based on specifc parameters at the El Dabaa site.Moreover, Khai and Cuong [28] used RASCAL to evaluate radiation doses resulting from radioactive release at Ninh Tuan 1 NPP.Teir focus was on INES-level 7 nuclear accidents, encompassing scenarios involving station blackout (SBO) and loss of LOCA incidents.Furthermore, Faisal et al. [29] investigated a VVER-1200 reactor's station blackout (SBO) incident using RASCAL.Lastly, Shiuli et al. [30] undertook a VVER-1200 radiological safety analysis using RASCAL and HOTSPOT codes.Tey examined reactor accidents at diferent international nuclear event scale (INES) levels (5, 6, and 7) due to SBO and loss of LOCA incidents, analyzing emergency response at the Rooppur site during both dry and rainy seasons.In contrast to previous RASCAL studies where accident sequence scenarios were either assumed by authors or simulated using general pressurizer water reactor (PWR) descriptions, this study takes a distinct approach.Te accident scenario transients will be implemented by directly using the transient responses of VVER-1200 reactor systems using PCTRAN.Tis approach aims to ofer a more precise and specifc representation of accident situations.

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Science and Technology of Nuclear Installations

Methodology
In this study, the methodology includes four procedures, as illustrated in Figure 1.
(1) Te frst procedure involves meteorological data analysis, where a 10-year dataset of meteorological information was gathered and organized into categories corresponding to the four distinct seasons.(2) Te second procedure involves the analysis of accident scenario event sequences.Tis step utilizes the PCTRAN-VVER 1200 data as input into the RAS-CAL software to simulate LOCA with and without emergency core cooling system (ECCS) and LTSBO.(3) Te third procedure encompasses calculation of source term and corresponding doses.(4) Te fourth procedure is the radiological assessment to evaluate potential impacts, by comparing dose results against established guidelines to determine appropriate actions.

Weather Data.
A detailed examination was carried out on temperature, wind speed, precipitation, stability classifcation, and wind direction data spanning a ten-year period.
Quartiles and median values were employed since the data deviated from a normal distribution, helping to capture representative values for each condition.Te outcomes of this analysis are presented in Table 1.

RASCAL. Te latest version of the "Radiological As-
sessment System for Consequence Analysis," known as RAS-CAL 4.3.4,is a specialized tool developed by the U.S. NRC's Protective Measures Team to assess the impact of radioactive accidents.Tis comprehensive system comprises seven distinct tools, with a focus on consequence assessment.Notably, the four core tools include Source Term to Dose (STDose), Field Measurement to Dose (FMDose), Radionuclide Data Viewer, and Decay Calculator.Among these, STDose and FMDose are pivotal for independent radiation dose predictions, aiding in decision-making during nuclear incidents.RASCAL 4.3.4employs the STDose model, a key component, to estimate radiation exposure downstream.Tis involves diverse dose pathways such as inhalation, ground shine, and cloud shine.Equation (1) in RASCAL represents the fundamental Gaussian puf model, applying the superposition principle to extend the onedimensional solution of the difusion equation to three dimensions.Tis mathematical approach forms the basis for modeling the dispersion of radioactive materials and calculating radiation doses in the afected areas.
where Q is the amount of unconfned radioactive material released during the accident, measured in becquerels (Bq) or grams (g).σ is the dispersion parameter, which depends on the distance from the release point.It is used in conjunction with a transport device to pass through the puf's centre (x 0 , y 0 , and z 0 ).Te dispersion parameter is measured in meters (m).χ is the concentration of the radioactive material in the atmosphere, measured in becquerels per cubic meter (Bq/ m 3 ) or grams per cubic meter (g/m 3 ).Tis represents the amount of radioactive material present in the air at a specifc location and time.
As the transport model exclusively calculates air concentration and ground surface concentration for a unit release, it becomes necessary to adjust these values for each radionuclide using the dose model.Radiologic decay leads to the depletion of each radionuclide in the source term over the assessment period.Te outcome is then multiplied by the cumulative air concentration calculated for a unit release, considering whether the material is depositing or nondepositing, as appropriate for that particular radionuclide [31].Te early phase TEDE, as outlined by the Environmental Protection Agency (EPA), encompasses cloudshine dose, inhalation CEDE, and the groundshine dose accumulated within the initial 96 hours following the commencement of the release into the environment.Te Tyroid Committed Dose Equivalent represents a 50-year committed dose to an adult man, encompassing contributions from all radionuclides.Tese dose equivalents are calculated by summing over all radionuclides of the products of the exposure to each radionuclide during the 15-minute period, the radionuclide and organ-specifc dose conversion factor, and the breathing rate [10,32].In the early phase, doses can be derived by either using the average air concentration during the radioactive plume's passage or ground concentration immediately after its transit.Tis assumes measurement accuracy for plume radiation and considers exposure to both plume and surface radiation over the plume's passage and the following 96 hours.Te method assumes constant plume concentration during passage.Tis forms the basis for estimating early-phase incident doses.Te main aim is to evaluate whether radionuclide concentrations could lead to doses exceeding Protective Action Guides (PAGs) set by the U.S. Environment Protection Agency (EPA) which appropriate protective actions [10,33].

PCTRAN.
Tis study utilized PCTRAN-VVER1200, a specialized Nuclear Transient Accident Simulator developed by Micro Simulation Technology.PCTRAN, an acronym for "Personal Transient Computer Analyzer," is a PC-based program designed for simulating transient events and accidents across various reactor models, such as PWR, BWR, advanced AREVA EPR, Westinghouse AP1000, and GE ABWR [2].PCTRAN has been efectively utilized by the IAEA as a training platform.Its adaptability and wide applicability make it invaluable for nuclear power safety analysis and training [34].Past PCTRAN studies primarily focused on simulating fault scenarios within a VVER-1200 reactor, investigating their efects on key parameters Science and Technology of Nuclear Installations including reactivity, steam and feedwater fow, and pressure.Tis current study takes a step further by examining the radiological consequences of these scenarios, extending the analysis to environmental radiation protection considerations.Te transient sequence in the PCTRAN fle is crossreferenced with prior research about LOCA without ECCS, the timing of events in this study is compared with a 2800 m 2 large break LOCA from [23], revealing only minor diferences in timing, measured in seconds.For instance, in the referenced study, core exposure takes place after 27.5 seconds, whereas in this study, with a slightly larger 3000 m 2 break, core exposure occurs in just 25 seconds.Tis validation process for some of study's scenarios confrms the accuracy of the transient behavior analysis by aligning it with these comparative studies.However, the core inventory (source-term) is evaluated by integrating the transient responses of reactor systems from PCTRAN into the RASCAL software.Te analysis covered three accident scenarios at El Dabaa NPP.

Hypothetical Accident Scenarios. Tis study involves the simulation of diverse accident scenarios, encompassing
Beyond Design Basis Accidents (BDBA) along with Design Basis Accident (DBA) at EL Dabaa NPP Unit-1.Tese simulations replicate events modeled in PCTRAN and integrate them into the RASCAL software.Te study follows predefned accident sequences and malfunctions, aiming to explore the radiological consequences associated with these scenarios [34,35].

Scenario-1 (S1).
In this scenario, a cold leg undergoes a signifcant large break, leading to a sizable 3000 cm 2 opening for the discharge of reactor coolant.Te ECCS remains operational, without any error for activation.

Scenario-2 (S2).
In this scenario, a Large Break Loss of Coolant Accident (LBLOCA) is simulated in a cold leg.Unlike the previous scenario S1, ECCS functionality is not considered in this case.

Scenario-3 (S3).
In this scenario, a LTSBO is simulated, resulting in a total loss of alternating current (AC) power.Additionally, it is assumed that the turbine-driven auxiliary feedwater pump is not available.
Te VVER-1200, which stands for "Water-Water Energetic Reactor 1200," belongs to the category of Generation-III + pressurized water type nuclear reactors.Table 2 shows  the VVER-1200 reactor's technical parameters for simulation.It features enhanced safety measures compared to earlier models.Te reactor is designed with fve levels of engineering safety barriers aimed at preventing the release of radiation into the environment.Notably, the VVER-1200 incorporates advanced passive safety mechanisms capable of functioning during prolonged SBO events or interruptions in cooling water supply to the reactor core.Tese passive safety systems can operate for approximately 72 hours during an SBO scenario.In case of a severe accident, a contemporary core catcher is used to contain molten materials, efectively preventing contamination of soil, water, or the environment.Tis design substantially reduces the likelihood of environmental impact resulting from both design and beyond design basis accidents in this type of nuclear power plant [38].Nonetheless, it remains essential to conduct pre-estimations of potential risks associated with accidents in nuclear power plants.Such assessments are crucial in ensuring preparedness for nuclear and radiological emergencies, while also safeguarding the well-being of workers and public from potential health hazards.Table 3 shows all simulated accident scenarios' event sequences.Applying all the transients from PCTRAN into RASCAL presented certain limitations.As indicated in Table 3, radionuclide emissions from the reactor core initiate after an 8-hour interval, corresponding with the default delay duration of 8 hours (default value) for LTSBO as set by the SOARCA RASCAL study [10].Also, the maximum value can be simulated for steam fow rate into RASCAL is 1.0E + 06 kg/hr.Furthermore, another limitation concerns the timing of core exposure during LTSBO, a scenario not encountered in transients modeled by PCTRAN.In Figure 2, the core remaining covered throughout the simulation for 15 hr and the diesel generator starting automatically (D/G A) after a 60.0-second delay (postreactor scram within 26 sec).Additionally, the high-pressure safety injection system and spray system activate only after 3.5 hours.

Source Term Investigation.
Te study source term is divided into eight groups, selected from prior literature with a primary focus on VVER 1000 and VVER 1200 [3,39].Tese groups include noble gases, halogens, alkali metals, tellurium group, Ba/Sr group, noble metals, cerium group, and lanthanides.Figure 3 displays the source term groups' activity in Becquerel (Bq) for all scenarios.Te contribution of radionuclides to the source term is infuenced by several signifcant factors, including fssion product yield, the nuclide's physical state, chemical activity, its reaction to reduction mechanisms, and most importantly, the severity of the accident [3].As shown in Figure 3, the dominant contributors to the source term are noble gases and halogens, constituting total activity 5.1E + 17 Bq and 7.1E + 15 Bq, respectively.Te contributions from other groups are 4.8E + 15 Bq for all scenarios.In a previous study [29], using RASCAL for LTSBO, the activities of certain radionuclides from diferent groups, such as I-131, Cs-137, Mo-99, and Sr-90, were reported as 2.3E + 15 Bq, 2.8E + 14 Bq, 9.6E + 14 Bq, and 1.1E + 12 Bq, respectively.In the present study, the corresponding activity levels for these radionuclides are 1.5E + 15 Bq, 2.0E + 14 Bq, 6.4E + 14 Bq, and 7.8E + 11 Bq, respectively.Tis divergence arises from the diferent initial conditions including average burn up, primary coolant mass, and steam generator water mass in addition the availability of the spray system.In a prior study by Shiuli et al. [30], which considered LOCA concurrent with SBO, the activity of I-131 was noted as 1.6E + 15 Bq, and for Cs-137, it was 2.6E + 15 Bq.Conversely, for the LOCA scenario without ECCS in this current study, the activities were found to be lower at 3.1E + 13 Bq for I-131 and 4.0E + 12 Bq for Cs-137.Tis disparity in activity levels between the two scenarios can be attributed to the difering accident severities, with Shiuli et al's study [30] indicating a more severe accident due to the absence of AC power.

Total Efective Dose Equivalent.
Te maximum dose values in millisieverts (mSv) were calculated within a 25mile radius (40.2 km) from the nuclear plant.Te data were presented graphically in Figure 4, where (a), (b), and (c) represented scenarios S1, S2, and S3, respectively.Tese scenarios were tested under diferent weather conditions outlined in Table 1.In each graph, it was observed that the most intense radiation exposure occurred at a distance of about 0.4 km from the release point.As the distance increased beyond this point, radiation exposure gradually decreased.In case of LOCA with ECCS  Notably under S3 scenario (c), radiation exposure levels near the release point were signifcantly higher, reaching 340 mSv, 180 mSv, 230 mSv, and 240 mSv for fall, spring, summer, and winter, respectively.As distance increased, the radiation exposure decreased, with a maximum value above the limits of 11 mSv during fall, 13 mSv during spring, 4.8 mSv during summer, and 10 mSv during winter at 3.2 km.For all seasons, at 40 km, the values were much lower than the PAGs limits.

Tyroid Committed Dose Equivalent.
Te highest dose values for thyroid dose (TD) in mSv were also computed within a 40.2 km from the nuclear plant.Tese fndings were visually depicted in Figure 5, with panels (a), (b), and (c) corresponding to scenarios S1, S2, and S3, respectively.As a worst-case scenario particularly scenario S3 (c) the TD reached 3.8E + 03 mSv, 2.0E + 03 mSv, 2.2E + 03 mSv, and 2.9E + 09 mSv during fall, spring, summer, and winter, respectively, at 0.4 km.As the distance from the release point increased, radiation exposure diminished, but still remained concerning.At 4.8 km, the maximum values exceeded the prescribed limits, with readings of 6.1E + 01 mSv in fall, 9.9E + 01 mSv in spring, and 8.2E + 01 mSv in winter.Furthermore, in the context of scenario S2, a noteworthy observation is that the thyroid dose (TD) surpasses the limits only at a distance of 0.4 km from the release point.Specifcally, during fall and spring, the TD was measured at 100 mSv, which is double the prescribed limits.However, during the summer and winter seasons, these values were Science and Technology of Nuclear Installations slightly lower at 76 mSv and 56 mSv, respectively.On the contrary, in scenario S1, it is crucial to emphasize that across all seasons, the recorded values were signifcantly below the limits stipulated by Protective Action Guides (PAGs).
Variations arise from facility-specifc factors such as source term, operational conditions, the presence of safety systems afecting release activity, and the implementation of mitigation measures.Tese results underscore the importance of taking into account precise accident scenarios and the corresponding weather conditions when evaluating the potential impact of radiation.
In the early stage of a severe nuclear incident, critical measures are used to mitigate consequences and manage the crisis efectively.PAGs are pivotal in guiding decisions, ensuring public health and safety.Regulatory authorities develop these PAGs, founded on scientifc and technical evaluations [40].Accurate evaluation of radiation doses from deposited materials, aiding decisions on protective actions and understanding radiological impacts.Table 4 delineates crucial PAG components for early phase of nuclear accidents, along with recommended actions for this study.
Tese fndings highlight that neither the TEDE nor thyroid dose values come close to regulatory limits, as observed in the case of LOCA S1.Tis indicates that there is no immediate need for concern regarding regulatory thresholds for both workers and the general public.For LOCA S2, it is only beyond a distance of 800 meters from El Dabaa unit 1 that some protective actions might be warranted for workers, in line with the "as low as reasonably achievable" (ALARA) principle following an incident.Importantly, there is no requirement for an emergency plan for the public in this scenario, as they remain safe.However, the Long-Term Station Blackout (LTSBO) scenario (S4) raises the necessity for specifc protective measures.Tis is due to the observation that both TEDE and hyroid dose values remain elevated beyond the established limits within an 11 km and 4.8 km, respectively, after 96 hours.LTSBO emerged as the worst-case scenario in all seasons, surpassing ICRP and PAGs regulation limits [41,42].Results in Figure 6 shows that during fall, plume expansion within the early phase range from 70 to 90 degrees covered 3.8 km 2 , with the maximum doses 6.1E − 02 Sv at 4.8 km in 80 degrees.During spring, 1.7 km 2 was covered within 110 and 140 degrees where the expansion of the plume dose limits was 6.3E − 02 Sv reaching 8 km.Summer experienced directional patterns between 130 to 140 with 0.2 km 2 above 50 mSv.In 50-degrees direction, the dose reached 8 km with 5.2E − 02 where the dispersion is directed to the sea.
Te Food and Drug Administration (FDA) has updated its guidelines for the use of stable iodine, referred to as "KI," as a thyroid-blocking agent in radiological   Table 5 shows the potassium iodide (KI) dosages for diferent risk groups and threshold levels of radioactive exposure to the thyroid gland.Te Long-Term Station Blackout (LTSBO) study ofers valuable insights into thyroid dose levels across various seasons, fall, spring, summer, and winter, and considers diferent directions and distances.Tese fndings, presented in Figure 6 and Table 4, serve as the foundation for establishing the distribution of thyroid-blocking tablets.Aligned with the FDA's guidelines, the study proposes a comprehensive plan for distributing these tablets that is applicable throughout all seasons.Te plan outlines varying dosages (ranging from 16 mg to 65 mg) based on weight diferences for individuals aged 1 month to 18 years, as well as pregnant women, within specifed directions and distances.

Conclusion
In conclusion, the study has delved into the critical realm of radiological emergency preparedness by using advanced computational tools to assess potential risks and safety measures at the El Dabaa nuclear site.Tis study utilized advanced PCTRAN and RASCAL software to evaluate the radiological impacts of hypothetical incidents, including LOCA with and without the availability of ECCS and LTSBO, at the El Dabaa NPP.Te integration of advanced tools, including atmospheric dispersion models and high-resolution meteorological databases, is foundational in providing precise projections for radiological events.Over a span of ten years, comprehensive meteorological data were meticulously analyzed to study the dispersion of radioactive substances within a 40-kilometer radius around the El Dabaa NPP throughout all four seasons.Tis research underscores the signifcance of early phase dose assessments and comprehensive risk management strategies during radiological emergencies.It is noteworthy that only LTSBO scenario surpassed the radiological exposure limits set by the EPA.During spring, LTSBO recorded a maximum TEDE of 13 mSv at 3.2 kilometers.Te expansion of thyroid dose plume ranged from 70 to 90 degrees, covering an area of 3.8 square kilometers.Te maximum doses reached 6.1E − 02 Sv at a distance of 4.8 km in the 80-degree direction.During spring, the plume covered 1.7 square kilometers within the range of 110 to 140 degrees, with dose limits extending to 6.3E − 02 Sv up to 8 km.In the summer, directional patterns were observed between 130 to 140 degrees, covering an area of 0.2 square kilometers where doses exceeded 50 mSv.Remarkably, in the 50-degree direction, the dose extended up to 8 kilometers with a value of 5.2E − 02 Sv, and the dispersion was directed towards the sea.Calculated radioactive exposure levels, alongside the recommended use of potassium iodide (KI) for thyroid protection, underscore practical measures for ensuring public health and safety in unforeseen incidents.Te study fndings provide the foundation for devising a distribution plan for thyroid-blocking tablets.Aligned with FDA guidelines, the study suggests a comprehensive plan applicable across all seasons.Tis plan specifes varied dosages (ranging from 16 mg to 65 mg) based on weight diferences for individuals aged 1 month to 18 years and pregnant women residing within specifc directions and distances under worst case scenario.As Egypt embarks on its nuclear journey, this research provides valuable insights for researchers, emergency responders, and policymakers.Enhancing our understanding of radiological risks, safety measures, and potential nuclear incident consequences contributes to public welfare, environmental security, and the efcacy of response planning in emergency scenario.

Figure 1 :
Figure 1: Flowchart for the study procedures.

Table 1 :
Weather data for El Dabaa site.

Table 2 :
Technical specifcations of the VVER-1200 reactor for simulation.

Table 3 :
Sequences of events within accident scenarios.
Figure 2: Te end of LTSBO simulation main view of PCTRAN.

Table 4 :
PAGs and suggested protective actions for study accidents scenarios.

Table 5 :
[41]hold levels of radioactive exposure to the thyroid gland and the recommended dosages of potassium iodide (KI) for various risk groups[41].