Emergency Planning Zone Research Articles

Evolution of zoning philosophy for emergency planning around nuclear power plants

Emergency planning zones (EPZs) serve as vital geographic framework within nuclear emergency preparedness and response (EPR) strategies, facilitating the swift implementation of protective measures across varying levels of urgency during nuclear emergencies. Over the years, nations have undergone thorough reassessments of these zones, in the light of evolving evaluation methods, reactor technology, and lessons learned from accidents, leading to the refinement of methodologies for delineating EPZ distances. Adherence to the International Atomic Energy Agency safety guidelines regarding EPZ size has demonstrated effectiveness in protecting both the public and environment surrounding existing nuclear power plants. As the landscape of nuclear energy evolves with the advent of small modular reactors, characterized by reduced power capacity and innovative safety features, there is enough potential for smaller EPZs. However, the determination of EPZ also depends on national policies, public acceptance, and nuanced risk criteria. This paper seeks to synthesize current insights into the evolution of EPZs and explores avenues for resizing them to accommodate emerging reactor technologies. Its findings hold relevance for reactor designers, risk analysts, and experts in nuclear EPR, offering guidance for future planning and implementation efforts.

Assessment of radiological dose and emergency planning zones of TRIGA Mark-II research reactor of Bangladesh due to a postulated severe accidental condition

Radiological dose and emergency planning zones assessment has been conducted for dry and rainy seasons in Bangladesh for the TRIGA Mark-II research reactor. A postulated severe accident of a plane crash was considered in this analysis. Due to the full collapse of the reactor building and core damage, core inventory radionuclides were released at their highest release fraction. In this instance, doses due to the release of radionuclides such as Xe, Kr, I, and Cs were estimated using two different atmospheric dispersion models utilizing meteorological data collected from the Bangladesh Meteorological Department. The source term analysis has been performed using the ORIGEN 2.1 code. The HotSpot 3.1.2 and RASCAL 4.3 codes were used for the assessment of radiological doses. Based on the results of both the RASCAL 4.3 and HotSpot 3.1.2 codes, the TEDE and thyroid CDE were found to be substantially higher than the allowable limit in a large area. The dose values were compared to the dose standards of the IAEA General Safety Requirements (GSR) Part 7 and the United States Environmental Protection Agency (U.S. EPA) to identify the evacuation, sheltering and iodine prophylactic administration distances for both dry and rainy seasons. The evacuation and sheltering distances were obtained at approximately 2.25–5 km, 4.5–15 km, and 3–6.6 km, 3.7–8.5 km according to U.S. EPA dose criteria in the dry and rainy seasons, respectively. On the other hand, according to IAEA GSR part 7 dose criteria, the evacuation and sheltering distances are obtained at 1.5–3.5 km and 2.5–5.25 km in the dry and rainy seasons, respectively. Thus required emergency protective actions must be undertaken by the local authority to lessen the health impact on the general public.

Design and evaluation of radiation disaster prevention map based on evacuation behavior

An effective disaster prevention map ensures public safety and efficient evacuation during emergencies. Emergency evacuation information design in Taiwan is in its nascent stages. This study focuses on individuals' understanding, behavior, and decision-making during disaster prevention to devise suitable disaster prevention map norms. We examined the Emergency Planning Zone's existing disaster prevention methods and surveyed the community to understand their disaster prevention concepts and needs. We conducted two experiments: the first tested the comprehension of existing disaster prevention maps and identified their issues, while the second evaluated a redesigned map based on Experiment 1's findings. We discovered that all age groups agree on needing accurate, fast information and diverse evacuation route options. Experiment 1 revealed disproportionate assembly point icons on the existing map, leading to navigation difficulties. The map also failed to mark landmarks, road names, and blocked intersections accurately. The redesigned map in Experiment 2 addressed these issues, showing that improving map information design aids recognition and memory, and bridges wayfinding behavior gaps in people with different spatial abilities. We suggest marking evacuation routes on maps, placing corresponding signs on-site, and locating assembly points near landmarks for easier navigation.

Détermination des Zones de Planification des mesures d’urgence (ZPU) autour de sites présentant des risques d’accidents technologiques majeurs

This article presents a methodology to establish the emergency planning zones around a site that presents risks of major technological accidents involving hazardous substances. A process to reduce the impact zones from these accidents is also presented. A concrete example involving an ammonia refrigeration system is included to illustrate the subject. The identification of the emergency planning zones is critical for public safety and is used for the preparation of emergency response plans by the site and the public emergency response organizations.

Analysis of nuclear accident scenarios and emergency planning zones for a proposed Advanced Power Reactor 1400 (APR1400)

Radiological scenario analysis considering potential accidents and the corresponding emergency planning arrangements are based on the estimations of radioactive releases following such accidents. This involves investigating the possible effects on the surrounding population and environment. The current paper hypothesized three accident scenarios in a pressurized water reactor (PWR) proposed to be located in Khor Duweihin on the Western Coast of the Arabian Gulf. HotSpot tool was used to estimate the total effective dose equivalent (TEDE) due to certain released radionuclides of different chemical groups. Initial emergency planning arrangements were defined based on the estimated doses triggered by the hypothetical scenarios considered: loss of coolant accident (LOCA), station blackout (SBO) and steam generator tube rupture (SGTR) in an Advanced Power Reactor 1400 (APR1400). This study established a baseline for an emergency plan that assures the mitigation of radiological consequences due to probable nuclear accidents, involving preparedness based on forecasting the atmospheric dispersion of radionuclides released during potential scenarios in different meteorological conditions.

JRODOS customization for Pakistan and assessment of the consequences of a hypothetical nuclear accident

Since the Chernobyl disaster in 1986, decision support systems and modelling tools have been utilized in response to nuclear and radiological emergencies. The java-based real-time online decision support system (JRODOS) is a decision support tool that can be utilised in response to an emergency in managing off-site radiological consequences. This article documents the customization and use of JRODOS for Pakistan. JRODOS was tailored to the local Pakistan conditions, and a case study of a theoretical nuclear power plant accident was used to assess JRODOS’s feasibility as a decision support tool. A worst-case probabilistic accident scenario was used to identify zones and areas where urgent protective actions, early protective actions and food restriction and other response actions could be required. The areas and distances identified for the implementation of protective and response actions for such a hypothetical accident were found to be in agreement with the emergency planning zones and distances suggested by the International Atomic Energy Agency (IAEA). Additionally, the implications of meteorological and source term input parameters on predicting the radiation doses to members of the public were investigated. It was identified that the output of such tools strongly depends on the availability and accuracy of the input parameters, such as radioactive release and meteorological data. Limitations and uncertainties associated with these tools need to be considered in deciding on protective and other response actions in response to a nuclear accident. As established by the IAEA, protective and other response actions need to be applied on a graded approach, taking into account the protection strategy and uncertainties and limitations in the available information and criteria, based on the conditions at the facility and off-site.

Dose assessment on the impact of accidents with Fukushima nuclear meltdown emission levels at the four nuclear power plants in Taiwan

There is a heated debate for including nuclear power as an important source of energies for pursuing net-zero carbon emission in the coming years. An advanced Gaussian trajectory dispersion model is used to evaluate the consequent impacts of nuclear power plant (NPP) accidents with Fukushima nuclear meltdown emission levels occurring at all of the four power plants (NPP1–NPP4) in Taiwan. Our study indicates the exposure pathway emergency planning zone (EPZ) would be as far as 17, 25, 5 and 17 km downwind from NPP1 to NPP4, respectively, for an event occurring on 11 March 2011. Our study indicates that the percentages of the land in Taiwan becoming permanent evacuation zones (PEZs) are as high as 8%, 13%, 2%, and 11% for an event occurring randomly during a year from 11 March 2011 at NPP1 to NPP4, respectively. The mean percentages of the land for Taipei City becoming PEZs are 35%, 71%, 0% and 48%, respectively. The mean percentages of the land for Kaohsiung City becoming PEZ are 4%, 5%, 5% and 3%, respectively. The analysis shows that for pursuing net-zero carbon emission, the conventional nuclear energy might not be a good choice for Taiwan, since about 2–13% of the Island can be inhabited for more than 30 years while a Fukushima-level nuclear meltdown occurs. The methodology and the trajectory model used here can be applied for other countries for quantifying the EPZ and PEZ for each nuclear power plant to substitute a conventional straight-line-type plume model, such as MACCS2.

Semi-mechanistic analysis of emergency planning zones for 20 MWe lead-cooled fast reactor by hypothetical accidents during Korea's arctic exploration

Small modular reactors or micro modular reactors have been considered as an alternative power source for merchant ships because of minimal carbon emission and a long lifecycle without refueling. Ahead of the operation, however, their emergency planning zones (EPZs) should be optimally set and approved to ensure both radiological safety and cost efficiency in case of nuclear accidents. Thus, the required size of EPZs was analyzed based on semi-mechanistic assumptions for hypothetical accidents with MicroURANUS, a micro modular fast reactor type of 20-MW lead-bismuth-cooled, used to power an icebreaker during Korea's Arctic missions. For meteorological data, actual icebreaker data acquired in 2020s Artic exploration were utilized. The results showed that EPZ sizes, rationalized in terms of stability class, wind directions, and inherent radioprotection design, ranged within the assumed icebreaker boundary. When comparing various regulations among countries and the International Atomic Energy Agency, dose criteria of Korea (10 mSv/2 d) were found to be strictest. Since major contribution to the whole-body dose was from noble gases (over 96%), a high-quality air filtration system in addition to external shielding would significantly reduce hazards. The emergency situation could be successfully controlled without evacuation and sheltering, avoiding overestimated socioeconomic costs.

Comparative Analysis of Emergency Planning Zone and Control Room Habitability for Potential Nuclear Reactor Deployment in Ghana.

Following the recent surge in harnessing clean energy sources to fast-track carbon neutrality, renewable and nuclear energies have been the best-rated sources of clean energy. Even though renewable energy presents an almost insignificant risk to public health and the environment, they are insufficient to support the growing demand for the high energy required for industrialization. Despite the competitive potential of nuclear energy to meet these demands, public concerns about its safety have significantly hindered its mass deployment in developing countries. Therefore, one of the primary considerations in commissioning a nuclear power plant is the establishment of emergency planning zones based on the reactor type and other siting criteria. Based on Ghana’s reactor type assessment (RTA), four reactor designs were considered in this study which are APR1400, HPR1000, VVER1200, and Nuscale Power Module. Using the NRC’s SNAP/RADTRAD and RASCAL codes, this research sought to investigate radionuclide doses released at the Exclusion Area Boundary (EAB), Low Population Zone (LPZ), Control room (CR), and the 16 km recommended public safe zone during Fuel handling Accidents (FHA), Rod Ejection Accident (REA), and Long-Term Station Blackout (LTSBO). The results revealed that reactors’ power contributed to the source term activities and offsite consequences during REA and LTSBO, while FHA was predominantly affected by the number of fuel assemblies and a fraction of damaged fuel. Additionally, the accidents considered in this study followed a similar trend of impact in decreasing order of reactor power and the number of fuel assemblies; APR1400 < VVER1200 < HPR1000 < Nuscale. Nevertheless, all the doses were within regulatory limits.

Pre-conceptual high temperature gas cooled microreactor design utilizing two-phase composite moderators. Part II: Design space and safety characteristics

This work expands on a pre-conceptual microreactor design based on a High Temperature Gas-Cooled Reactor (HTGR) platform generated in the companion paper of this study. Here, power, coolant inlet temperature, and coolant outlet temperature are varied to outline an operable design space associated maximum allowable component temperatures and coolant pressure drop for a given microreactor design. Calculations show that beryllium- and hydride-based composite moderators have a smaller operating design space than graphite because of a lower allowable moderator temperature under the conservative upper limits employed for this study. Power below 6MWth was considered to be undesirable for all designs because of a limited inlet/outlet temperature range. Reactivity Temperature Coefficients (RTC) are calculated to illustrate an inherent safety feature of HTGRs and are fed into a Depressurized Loss of Forced Coolant (DLOFC) without active intervention accident simulation, considered to be a bounding case for fuel temperatures in a HTGR. RTC calculations showed that all designs would expect to have a negative isothermal coefficient through their entire operating cycle and DLOFC calculations showed no case exceed their maximum temperature limits. An additional accident that simulates the release of fission products is performed to compare expected minimum Emergency Planning Zone (EPZ) size for all designs. EPZ calculations showed a marginally smaller achievable size for the composite moderators because of a lower concentration of relevant nuclides due to a more thermal spectrum

Nuclear Accident Emergency Response System: Radiation Field Estimation and Evacuation

In this paper, a nuclear accident emergency response system based on unmanned aerial vehicles (UAVs) and bus collaboration is designed for radiation field estimation and evacuation. When a nuclear accident occurs, the radiation field is estimated firstly using the measurements acquired by UAVs. Based on the Cramer–Rao Lower Bound (CRLB), the coordinate optimization combined with UAV routing is formulated as a nonconvex mixed integer nonlinear programming (MINLP) problem to maximize the estimation accuracy. Further, a two-stage solution procedure based on genetic algorithm (GA) is proposed to solve the above problem. Then, taking the predicted radiation field as input, personnel in the emergency planning zone (EPZ) are evacuated to shelters by buses. The evacuation routing problem for minimizing both the total radiation exposure and evacuation time is formulated as a mixed integer linear programming (MILP) problem, which is solvable with efficient commercial solvers, such as Gurobi and CPLEX. The simulation results indicate that the system can provide effective help for emergency management under the nuclear accident scenarios.

Traffic management for large-scale evacuation with public transportation and calculation of appropriate operating ratio

In 2013, the International Atomic Energy Agency (IAEA) changed the recommended maximum range of the Emergency Planning Zone (EPZ) to 30 km, and the Kori Nuclear Power Plant in Republic of Korea has also expanded the EPZ to 30 km, following the recommendation. As a result, metropolitan cities with a high population density are contained within the EPZ, and evacuating millions of people should be considered if the 30 km range of evacuation is to take place. This study proposes an evacuation plan using buses (public transportation) to transport people outside of the EPZ, quickly and efficiently. To verify the appropriate mode share ratio of buses that can guarantee the right of vulnerable road users and reduce traffic congestion, a model was built simulating the Kori Nuclear Power Plant in Ulsan Metropolitan City. The scenarios were established by changing the mode share ratio of buses and passenger cars by 10%. Considering a large-scale network analysis at the city level, a cell transmission model was applied to calculate the evacuation time in each scenario. The result shows that the optimal mode share ratio of buses is 40%, with a total evacuation time of 132 min, considering feasible bus fleets in Ulsan Metropolitan City.

Semi-Mechanistic Analysis of Emergency Planning Zones for 20 Mwe Lead-Cooled Fast Reactor by Hypothetical Accidents During Korea's Arctic Exploration

Semi-Mechanistic Analysis of Emergency Planning Zones for 20 Mwe Lead-Cooled Fast Reactor by Hypothetical Accidents During Korea's Arctic Exploration

Machine Learning-Based Classification and Regression Approach for Sustainable Disaster Management: The Case Study of APR1400 in Korea

During nuclear accidents, decision-makers need to handle considerable data to take appropriate protective actions to protect people and the environment from radioactive material release. In such scenarios, machine learning can be an essential tool in facilitating the protection action decisions that will be made by decision-makers. By feeding machines software with big data to analyze and identify nuclear accident behavior, types, and the concentrations of released radioactive materials can be predicted, thus helping in early warning and protecting people and the environment. In this study, based on the ground deposition concentration of radioactive materials at different distances offsite in an emergency planning zone (EPZ), we proposed classification and regression models for three severe accidents. The objective of the classification model is to recognize the transient situation type for taking appropriate actions, while the objective of the regression model is to estimate the concentrations of the released radioactive materials. We used the Personal Computer Transient Analyser (PCTRAN) Advanced Power Reactor (APR) 1400 to simulate three severe accident scenarios and to generate a source term released to the environment. Additionally, the Radiological Consequence Analysis Program (RCAP) was used to assess the off-site consequences of nuclear power plant accidents and to estimate the ground deposition concentrations of radionuclides. Moreover, ground deposition concentrations at different distances were used as input data for the classification and regression tree (CART) models to obtain an accident pattern and to establish a prediction model. Results showed that the ground deposition concentration at a near distance from a nuclear power plant is a more informative parameter in predicting the concentration of radioactive material release, while the ground deposition concentration at a far distance is a very informative parameter in identifying accident types. In the regression model, the R-square of the training and test data was 0.995 and 0.994, respectively, showing a mean strong linear relationship between the predicted and actual concentration of radioactive material release. The mean absolute percentage error was found to be 26.9% and 28.1% for the training and test data, respectively. In the classification model, the model predicted a scenario (1) of 99.8% and 98.9%, scenario (2) of 98.4% and 91.6%, and scenario (3) of 98.6% and 94.7% for the training and test data, respectively.

Determination of Emergency Planning Zones distances and scaling-based comparison criteria for downsized Nuclear Power Plants

Nuclear Small Modular Reactors (SMR) present innovative features in design and safety compared to existing Nuclear Power Plants (NPP). Some of these features may turn into a reduction in radioactive releases –both in magnitude and frequency.It seems reasonable to think that smaller plants, i.e. featuring lower power levels, should present lower radioactive releases and offsite consequences. However, how small is small enough cannot be addressed through direct comparison. Furthermore, since multiple nuclear sites to compensate for the same amount of power provided by a single, large nuclear site, might be needed, such direct comparison is ill-conceived.Scaling-based criteria to facilitate comparison of radioactive releases between plants of different size –i.e. power– are proposed. Such criteria set limits to radioactive releases and offsite radioactive risk for SMRs so that offsite consequences of replacing large NPPs by a wider set of SMR sites are not exceeded when assessed globally, i.e. in terms of power generation.The first, deterministic-oriented criterion looks at the radioactive source strength of the SMR based on the maximum size of the SMR Emergency Planning Zone (EPZ) in order not to exceed the EPZ of another NPP when normalizing the EPZ to the power generating unit. The second, risk-informed criterion, looks at the sum of the radioactive harm caused by any event considered under probabilistic analysis application weighted by its frequency, i.e. standard definition of risk.Aside from these two scaling-based criteria for offsite nuclear hazard comparison between nuclear sites of different size, this paper presents two different methods for the determination of EPZ distances. The first method is straightforward based on plant-specific data for dose-consequence calculation, whereas the second, inverse method, builds on extrapolating the EPZ distance of a reference, large NPP down to the SMR.The scaling-based criteria and the methods for the determination of the EPZ distance are put into practice in an application exercise for an integral Pressurized Water Reactor (PWR) SMR.

Fate and transport of unruptured tri-structural isotropic (TRISO) fuel particles in the event of environmental release for advanced and micro reactor applications

Advanced nuclear reactor designs and advanced fuel types offer safety features that may reduce environmental consequences in an accident scenario when compared to conventional reactors and fuels. One advanced reactor fuel is tri-structural isotropic (TRISO) fuel particles which are approximately 0.9 mm in diameter. TRISO particle mobility, assuming the particle is unruptured and the encapsulated radionuclides are contained, was explored by a theoretical examination of transport through atmosphere, soil and groundwater, surface water, and non-human biota pathways. TRISO particles are too large and dense to travel in the atmosphere except under extreme conditions. TRISO particles are also too large to penetrate most soil profiles and so cannot be transported to or by groundwater. TRISO particles will settle out of the water column in surface waters and thus the transport will depend on the energy of the water body (e.g., waves or floods). TRISO particles could be transported by non-human biota. The size of TRISO particles could allow them to be intentionally ingested by non-human biota as a gastrolith or mimic something typical in an organism's diet. Generally, TRISO particles will have reduced environmental mobility compared to releases of radionuclides in the event of a conventional nuclear reactor accident. The extent of transport has implications in emergency planning zone designations and other considerations for licensing and deploying TRISO-fueled reactors. Further research and experimental work exploring TRISO particle mobility is required to understand the full environmental mobility of TRISO particles in the environment.

Creation of preventive mass evacuation plan with the use of public transport

The article deals with the planning of the preventive evacuation processes from the point of view of ensuring the mass transportation of inhabitants from hazardous areas, when dangerous substances that are leaking into the surroundings from factories and other industrial facilities (such as nuclear power plants) threaten the inhabitants. The approach presented in this article is based on multi-criteria mixed integer linear programming. Optimisation modelling has not been yet applied in the Czech Republic to create evacuation plans. The main contribution of the article lies in a new type of optimisation approach to evacuation planning when speed of the mass evacuation process is determinative. The mathematical model was applied to the planning of the mass evacuation process in the emergency planning zone which is demarcated around the nuclear power plant Dukovany in the Czech Republic.

大型核动力船舶应急计划区分区策略研究

大型核动力船舶应急计划区分区策略研究

Evaluation of Evacuation Strategies According to the Travel Demand: The Case of Nuclear Research Reactor HANARO’s EPZ

In the event of a nuclear accident, evacuation is the most effective protective action for the public. During the evacuation, total travel time is a key measure to protect the public because it is directly related to the public’s radiation exposure. Thus, strategies that reduce the total travel time are needed for a safer nuclear emergency plan. Many studies on evacuation strategies so far have suggested the methodology of effective routing decisions or delay management. Despite the application of those strategies during evacuation, the effectiveness of those strategies, in reality, varies depending on the level of travel demand. In this study, evacuation strategies based on travel demand levels were evaluated based on the case of the Emergency Planning Zone (EPZ) of HANARO, the nuclear research reactor in the Republic of Korea. As a result, it was confirmed that effective evacuation strategies could be applied differently according to travel demand levels.

Approaches to the Establishment and Justification of the Size of Emergency Planning Areas around NPPs

Emergency planning zones around facilities that use radiation and nuclear technologies are set up in order to prevent or minimize deterministic effects and reduce risks of stochastic effects of radiation exposure in case of nuclear or radiological emergency. In international practice, in order to enhance effectiveness of response to emergencies, it is common to set up emergency planning zones for nuclear facilities in accordance with their level of threat for the environment and public. As the establishment of such zones requires certain material resources, the size of the zones is to be justified.&#x0D; As of today, sanitary-protective zone and monitoring zone in Ukraine could be considered, to a certain extent, as analogues of such emergency planning zones. However, the main functional load of these zones are relevant more for routine operation of nuclear facilities than for the issues of emergency planning and do not have such a specific for the emergency planning zones functions as ensuring necessary infrastructure for conducting such urgent protective actions as evacuation, sheltering, notification, relocation and others in case of severe accidents at NPPs.&#x0D; Absence of transparent numerical criteria for determining the size of emergency planning areas, on one hand, and necessity to determine such areas as required by the key IAEA publication GSR Part 7, as well as due to understanding the importance of emergency planning areas in the state emergency response system, on the other hand, make the task on establishing approaches to the definition of the scope of emergency release, which is a framework for emergency zoning, crucial.&#x0D; The paper proposes to discuss two approaches to defining the scope of the boundary release, according to which the size of the emergency planning areas is to be defined. The paper presents results of assessing the size of the emergency planning areas around NPPs based on the scope and radionuclide composition of the boundary release.