Hypothetical Nuclear Power Plant Research Articles

Bangkok port and coastal regions of Thailand under atmospheric PM2.5 pollution: A hypothetical nuclear power plant accident

The atmospheric transport pathways of 1) a hypothetical accident of aerosol at Ninh Thuan Nuclear Power Plant (NPP) in Vietnam to the coastal area of Thailand and 2) the source of PM2.5 near the area of Bangkok port were selected for case studies. The overviews of atmospheric transport patterns were analyzed using the long-term mean wind and the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model for simulating the transport pathway. The results found that the possible pathway of aerosol from Ninh Thuan NPP to coastal regions of Thailand was present over the entire year, except for the southwest monsoon month. The percentage of aerosol transport reaching the coast of Thailand is highest in the southern coastal part, found in January-April and October-December, with a maximum in January (approximately 84 %). For PM2.5 pollutants on a poor day, strongly positive and negative significant relationships with relative humidity (RH) (r = 0.44, rs = 0.46) and wind speed (r = -0.46, rs = -0.47) were found, respectively. The concentration of PM2.5 is slightly negatively correlated with wind direction. In addition, the upper air transport may bring PM2.5 pollutants from neighboring provinces or Southeast Asia to Bangkok port, Thailand, which appeared in anticyclone form in the upper atmosphere before the day which exceeded the safety level of PM2.5. Highlights The possible pathway of aerosol from Ninh Thuan NPP to coastal regions of Thailand is present over the entire year The percentage of aerosol transport from Ninh Thuan NPP reaching the coast of Thailand is highest in the southern coastal part during the northeast monsoon The exceeding air pollution problem in Bangkok comes from unfavorable meteorological conditions The anticyclone center in the upper atmosphere of Vietnam, Laos, and Cambodia formed before the day, which exceeded the safety level at a poor level

Modeling the Diffusion of Radioactive Materials into the East Sea of Korea: Analysis of Hypothetical Nuclear Power Plant Accident Scenarios and Long-Term Marine Ecosystem Impacts

Min, B.I.; Suh, K.-S.; Park, K.; Kim, J.Y.; Choi, Y., and Kim, S., 2023. Modeling the diffusion of radioactive materials into the East Sea of Korea: Analysis of hypothetical nuclear power plant accident scenarios and long-term marine ecosystem impacts. Journal of Coastal Research, 39(2), 394–400. Charlotte (North Carolina), ISSN 0749-0208. The East Sea is surrounded by South Korea, North Korea, Japan, China, and Russia and is connected to the Northwest Pacific Ocean through three narrow straits. In the East Sea, there are 18 nuclear power plants installed along the coasts of South Korea alone. This study evaluated the long-term diffusion of radioactive materials in the East Sea using a compartment model and described the effect on a marine food chain model. A hypothetical scenario in which soil near the power plant is contaminated and flows into rivers and seas due to rainfall was numerically tested. It took about 2 minutes to calculate the intake dose for 10 years, and there was no significant difference compared to the detailed model.

Long-Term Contamination of the Arabian Gulf as a Result of Hypothetical Nuclear Power Plant Accidents

Long-term consequences of radionuclide contamination of the Arabian Gulf as a result of hypothetical accidents at the Bushehr and Barakah nuclear power plants (NPPs) were studied using a chain of models including the atmospheric dispersion model RIMPUFF, the marine compartment model POSEIDON-R, and the dose model. The compartment model POSEIDON-R is complemented by a dynamic model of the biota food chain that includes both pelagic and benthic organisms. The source terms for the hypothetical releases of the selected radionuclides (134Cs, 137Cs, 106Ru, and 90Sr) in the atmosphere were defined as a fraction of respective reactor inventories available in the literature. Conservative meteorological scenarios for the calculation of the initial depositions of radionuclides were selected. Because the Gulf is shallow, a significant portion of the reactive radionuclides (134Cs, 137Cs, 106Ru) remain in the bottom sediments and continue to contaminate water and benthic organisms for a long period of time. The annual dose due to the consumption of marine products can exceed 1 mSv, whereas the annual dose due to drinking the water from desalination plants is expected to be an order less. The contribution of elements to the dose depends on the type of reactor. This is manifested in differences between the contributions of different marine organisms to the dose.

A Dynamic Risk Framework for the Physical Security of Nuclear Power Plants

This paper describes ongoing work within the Light Water Reactor Sustainability pathway at Idaho National Laboratory (INL) to optimize the security and cost of nuclear power plants. It introduces the dynamic risk assessment tool developed at INL, Event Modeling Risk Assessment using Linked Diagrams (EMRALD). EMRALD is leveraged to optimize the security posture of a nuclear power plant by integrating force-on-force (FOF) simulations and operator mitigation actions, including dynamic and flexible coping strategies (FLEX). To illustrate the methodology, four attack scenarios are modeled in a commercially available FOF simulation tool using a hypothetical nuclear power plant facility. The simulation results provide valuable insights into possible attack outcomes, as well as the probabilistic risk of a core damage event given these outcomes. Safety mitigation procedures are modeled in EMRALD dependent on the attack outcomes by considering human operator uncertainties. The results demonstrate that the number of armed responders can be optimized, while still maintaining the same protection level as the initial security posture. The proposed modeling and simulation framework of integrating FLEX equipment with FOF models enables the nuclear power plants to credit FLEX portable equipment in the plant security posture, resulting in an efficient and optimized physical security system.

Optimal siting of a nuclear power station in Nigeria using fuzzy grey relational analysis

One of the primary causes of Nigeria's underdevelopment is a lack of electricity to power the country's industries. Rather than relying solely on fossil fuels to generate electricity in Nigeria, a variety of other sources, such as nuclear energy, must be considered. A Nuclear Power Plant's (NPP) location is a critical step in its development. This paper thus presents a methodology for resolving the issue of NPP site selection. For this project, the fuzzy Grey Relational Analysis (GRA) method was chosen. To assess the feasibility of the approach, one of Nigeria's six south-south states was chosen as the location of a hypothetical nuclear power plant. According to the findings, the NPP would be best located in Delta State, which had the highest gray relational grade of 0.7897.

Damage and vibrations of nuclear power plant buildings subjected to aircraft crash part II: Numerical simulations

Investigations of large commercial aircraft impact effect on nuclear power plant (NPP) buildings have been drawing extensive attentions, particularly after the 9/11 event, and this paper aims to numerically assess the damage and vibrations of NPP buildings subjected to aircrafts crash. In Part I of present paper, two shots of reduce-scaled model test of aircraft impact on NPP were conducted based on the large rocket sled loading test platform. In the present part, the numerical simulations of both scaled and prototype aircraft impact on NPP buildings are further performed by adopting the commercial program LS-DYNA. Firstly, the refined finite element (FE) models of both scaled aircraft and NPP models in Part I are established, and the model impact test is numerically simulated. The validities of the adopted numerical algorithm, constitutive model and the corresponding parameters are verified based on the experimental NPP model damages and accelerations. Then, the refined simulations of prototype A380 aircraft impact on a hypothetical NPP building are further carried out. It indicates that the NPP building can totally withstand the impact of A380 at a velocity of 150 m/s, while the accompanied intensive vibrations may still lead to different levels of damage on the nuclear related equipment. Referring to the guideline NEI07-13, a maximum acceleration contour is plotted and the shock damage propagation distances under aircraft impact are assessed, which indicates that the nuclear equipment located within 11.5 m from the impact point may endure malfunction. Finally, by respectively considering the rigid and deformable impacts mainly induced by aircraft engine and fuselage, an improved Riera function is proposed to predict the impact force of aircraft A380.

The radiological assessment, hazard evaluation, and spatial distribution for a hypothetical nuclear power plant accident at Baiji potential site

BackgroundThe safety assessment in site selection for a new nuclear power plant is an essential issue for human health. It could be improved by predicting the consequences for a hypothetical accident. This paper is contextual with the nuclear safety regarding the risk upon human health from the hazard constituted by the emission of radioactive material due to a hypothetical nuclear power plant accident. HYSPLIT model used and configured based on terrestrial and meteorological conditions for this purpose.ResultsIt presents an analysis of the time-series and spatial distribution for dispersed radioactive contaminants from a hypothetical accident at Baiji potential site. This is based on the geological and meteorological specifications of the potential site. Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model configured to simulate the atmospheric dispersion of fission emissions, then assesses the public health consequences of a hypothetical nuclear accident. Results indicate that the total individual dose intake by the population living around the potential site from the hypothetical accident exceeded 1 Sv, greater than the allowed dose limits by International Commission on Radiological Protection (ICRP). The probability of cancer incidence at regions on directions of southeast to northeast along 30 km from the potential site was high (0.0378 to 0.00131) risk/person. However, the areas that laid on the west and south-west of the site recorded higher levels of influence compared to regions on other directions. Also, the reduction of exposure dose with the distance from the site presented. The north-direction regions from the Baiji site recorded a rapid reduction of exposure dose to become zero at 40 km distance.ConclusionsFinally, to minimize the radiological impacts on population, emergency procedures are required at the regions that laid on the west and south-west of the site. These countermeasure remedy actions should include evacuation, sheltering, ban the sale of local agriculture productions, and long-range resettlement of the population. Since the plume of radioactive contaminants did not arrive at the regions on east and northeast, 40 km away from Baiji site, these areas could be categorized as a support zone.

Development of fault displacement PRA methodology and its application to a hypothetical NPP

The authors have developed fault displacement (FD) probabilistic risk assessment (PRA) methodology, through application to a hypothetical nuclear power plant (NPP).Core damage frequency (CDF) and its uncertainty of a hypothetical NPP for dip-slip faults and strike-slip faults were evaluated using a probabilistic FD hazard, FD fragilities of building and components, and fault tree and event tree models. Important initiating events, accident sequences, components and structure failures, as well as the range of FD that characterize the core damage risk profile were identified. Through the study, the authors confirmed the feasibility of the methodology, and also identified the important source of uncertainties within the methodology that require further development. Risk insights obtained from the FD PRA can be used to investigate countermeasures to reduce the FD risk.

Tellurium and selenium sorption kinetics and solid fractionation under contrasting estuarine salinity and turbidity conditions

Tellurium (Te) is a Technology Critical Element (TCE) and a relevant product of nuclear fission. It has an unknown environmental biogeochemical cycle, mostly related to current analytical challenges in measuring its ultra-trace dissolved concentrations in complex environmental matrices. It is therefore generally compared to its geochemical pair selenium (Se), which shows a narrow range between diet essentiality and toxicity properties. Batch experiments using isotopically-labelled stable Te and Se were performed with fresh suspended particulate matter (SPM) from the fluvial part of the Gironde Estuary, simulating both estuarine salinity (S = 0 vs S = 32) and turbidity (100 mg L−1 vs 1000 mg L−1) gradients to understand the importance of the particulate phases in Te reactivity under estuarine conditions and verify the resemblance to Se behaviour. These experiments addressed sorption kinetics, sorption isotherms and fractionation from selective extractions of final equilibrated SPM. Results showed a strong, salinity-independent affinity of Te for the particulate phases (log10 Kd ~ 4.9 L kg−1), following a Langmuir-type isotherm. Contrastingly, Se adsorbs clearly less to estuarine SPM (log10 Kd ~ 2.5 L kg−1), following a Freundlich-type isotherm. Both isotherms and selective extractions highlighted differences between Te and Se sequestration. Selective extractions suggested higher mobility of particulate Se in contrast to Te. Based on these results the paper sets a first dispersion scenario on the environmental fate of radioactive Te and Se after hypothetical nuclear power plant accidental releases in coastal aquatic systems such as the Garonne-Gironde fluvial-estuarine system.

Radiological dose assessment due to hypothetical nuclear power plant operation in Mersing, Johor, Malaysia

Malaysia has considered for some time to adopt nuclear power to cater to the increasing demand of electricity following other developed Asian countries such as Japan, Korea, and China. In implementing a nuclear power plant, strict regulations and guidelines by the International Atomic Energy Agency (IAEA) and International Commission on Radiological Protection (ICRP) must be fulfilled before any construction license is given for a new nuclear power program. One of the assessments include the estimation of potential radiological risks to both humans and environment from routine and accidental release of radioactive effluent from the nuclear power plant (NPP). In this work, simulations of radionuclide dispersion from a hypothetical NPP site in Mersing, Johor will be presented. The simulation was performed based on the Lagrangian atmospheric dispersion model using the HYSPLIT software. The radioactive effluent release rate was approximated to the value found in the Fukushima Dai-ichi accident in 2011. Meteorological data of 2017 were utilized in this study. Simulation results showed that the dispersion of radioactive effluent from the hypothetical NPP can potentially affect areas around Johor Bahru district, Singapore, and even some areas in Indonesia.

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.

Hazard-consistent ground motions generated with a stochastic fault-rupture model

Conventional seismic probabilistic risk assessments (PRAs) of nuclear power plants consist of probabilistic seismic hazard and fragility curves. Even when earthquake ground-motion time histories are required, they are generated to fit specified response spectra, such as uniform hazard spectra at a specified exceedance probability. These ground motions, however, are not directly linked with seismic-source characteristics.In this context, the authors propose a method based on Monte Carlo simulations to generate a set of input ground-motion time histories to develop an advanced PRA scheme that can explain exceedance probability and the sequence of safety-functional loss in a nuclear power plant. These generated ground motions are consistent with seismic hazard at a reference site, and their seismic-source characteristics can be identified in detail.Ground-motion generation is conducted for a reference site, Oarai in Japan, the location of a hypothetical nuclear power plant. A total of 200 ground motions are generated, ranging from 700 to 1100cm/s2 peak acceleration, which corresponds to a 10−4 to 10−5 annual exceedance frequency. In the ground-motion generation, seismic sources are selected according to their hazard contribution at the site, and Monte Carlo simulations with stochastic parameters for the seismic-source characteristics are then conducted until ground motions with the target peak acceleration are obtained. These ground motions are selected so that they are consistent with the hazard. Approximately 110,000 simulations were required to generate 200 ground motions with these peak accelerations.Deviations of peak ground motion acceleration generated for 1000–1100cm/s2 range from 1.5 to 3.0, where the deviation is evaluated with peak ground motion accelerations generated from the same seismic source. Deviations of 1.0 to 3.0 for stress drops, one of the stochastic parameters of seismic-source characteristics, are required to obtain these acceleration deviations. A similar tendency can be found for some other seismic-source characteristics, meaning that ground motions obtained in this study cannot be generated by simulations of deterministic fault-rupture models with averaged seismic-source characteristics. Generated ground motions incorporate differences between each seismic-source characteristic, and they are effectively available for PRAs of structures.

A method for estimating 41Ar, 85,88Kr and 131m,133Xe doses to non-human biota

A method is presented for estimating 41Ar, 85,88Kr and 131m,133Xe dose rates to terrestrial wildlife without having to resort to comparisons with analogue radionuclides. The approach can be used to calculate the dose rates arising from external exposures to given ambient air concentrations of these isotopes. Dose conversion coefficient (DCC) values for a range of representative organisms are calculated, using a Monte Carlo approach to generate absorbed fractions based on representing animals as reference ellipsoid geometries. Plume immersion is the main component of the total DCC.DCC values calculated for a human-sized organism are compared with human dose conversion factors from ICRP Publication 119, demonstrating the consistency of the biota approach with that for humans. An example of application is provided for hypothetical nuclear power plant atmospheric discharges with associated exposures to birds and insects. In this example, the dose rates appear to be dominated by 133Xe and 88Kr, respectively. The biota considered would be protected from the effects of noble gas radiation from a population protection perspective.

Ruthenium release from fuel in accident conditions

Abstract During a hypothetical nuclear power plant accident, fission products may be released from the fuel matrix and then reach the containment building and the environment. Ruthenium is a very hazardous fission product that can be highly and rapidly released in some accident scenarios. The impact of the atmosphere redox properties, temperature, and fuel burn-up on the ruthenium release is discussed. In order to improve the evaluation of the radiological impact by accident codes, a model of the ruthenium release from fuel is proposed using thermodynamic equilibrium calculations. In addition, a model of fuel oxidation under air is described. Finally, these models have been integrated in the ASTEC accident code and validation calculations have been performed on several experimental tests.

Improving Evacuation Planning with Sensible Measure of Effectiveness Choices

This paper advocates the importance of selecting appropriate measures of effectiveness (MOE) for evacuation planning and optimization purposes. In addition to evacuation time, which is often the choice MOE used by many practitioners, this paper also presents several increasingly more complex and useful MOEs that consider average evacuee travel time, delay, and temporal–spatial-based exposure risks. By studying a real-world transportation network in the event of a hypothetical nuclear power plant incident, the paper demonstrates that the superiority of one evacuation plan (or an optimization strategy) over others is highly dependent on the MOE selected for evaluation. Optimization efforts based on a single and ill-chosen MOE may not yield the best evacuation plan, as one might expect. The overall space-based or time- and space-based risk exposure may be increased if the optimization process is focused on travel time or some other time-based measure alone. Depending on the specifics of an emergency scenario (e.g., disaster type, risk components, and time constraints), an appropriate MOE should be chosen judiciously to make sure the optimization process for the evacuation plan is not wasted. This paper also demonstrates a multiobjective optimization approach for planning and designing an evacuation plan. With combined space-based risk and the travel time in route searching and traffic assignment, better destination assignment (and improved evacuation efficiency) may be obtained. The findings here should provide insights for future efforts toward assessing, improving, and optimizing evacuation plans.

Probabilistic methodology for turbine missile risk analysis

A methodology has been developed for estimation of the probabilities of turbine-generated missile damage to nuclear power plant structures and systems. Mathematical models of the missile generation, transport, and impact events have been developed and sequenced to form an integrated turbine missile simulation methodology. Probabilistic Monte Carlo techniques are used to estimate the plant impact and damage probabilities. The methodology has been coded in the TURMIS computer code to facilitate numerical analysis and plant-specific turbine missile probability assessments. Sensitivity analyses have been performed on both the individual models and the integrated methodology, and probabilities have been estimated for a hypothetical nuclear power plant case study.