Nuclear Safety Research Articles

Ionic Conduction-Based Polycrystalline Oxide Gamma Ray Detection - Radiation-Ionic Effects.

Newly discovered opto-ionic effects in metal oxides provide unique opportunities for functional ceramic applications. The authors generalize the recently demonstrated grain boundary opto-ionic effect observed in solid electrolyte thin films under ultraviolet (UV) irradiation to a radiation-ionic effect that can be applied to bulk materials and used for gamma-rays (γ-rays) detection. Near room temperature, lightly doped Gd-doped CeO2, a polycrystalline ion conducting ceramic, exhibits a resistance ratio change ≈103 and reversible response in ionic current when exposed to 60Co γ-ray (1.1 and 1.3 MeV). This is attributed to the steady state passivation of space charge barriers at grain boundaries, that act as virtual electrodes, capturing radiation-induced electrons, in turn lowering space charge barrier heights, and thereby exclusively modulating the ionic carrier flow within the ceramic electrolytes. Such behavior allows significant electrical response under low fields, that is, < 2 V cm-1, paving the way to inexpensive, sensitive, low-power, and miniaturizable solid-state devices, uniquely suited for operating in harsh (high temperature, pressure, and corrosive) environments. This discovery presents opportunities for portable and/or scalable radiation detectors benefiting geothermal drilling, small modular reactors, nuclear security, and waste management.

International law obligations for the disposal of Fukushima nuclear-contaminated water under the principles of nuclear safety

The disposal of contaminated water from Japan’s Fukushima nuclear power plant is a significant international nuclear safety issue with considerable cross-border implications. This matter requires compliance not only with the law of the sea but also with the principles of nuclear safety under international law. These principles serve as the overarching tenet of international and China’s domestic nuclear laws, applicable to nuclear facilities and activities. The principle of safety in nuclear activities is fully recognized in international and domestic laws, carrying broad legal binding force. Japan’s discharge of nuclear-contaminated water into the sea violates its obligations under the principle of safety in nuclear activities, including commitments to optimum protection, as low as reasonably practicable, and prevention. The Japanese government and the International Atomic Energy Agency (IAEA) have breached the obligation of optimum protection by restricting the scope of assessments, substituting core concepts, and shielding dissenting views. In the absence of clear radiation standards, they have acted unilaterally without fulfilling the obligation as low as reasonably practicable principle. The discharge of Fukushima nuclear-contaminated water poses an imminent and unpredictable risk to all countries worldwide, including Japanese residents. Japan and the IAEA should fulfill their obligations under international law regarding disposal, adhering to the principles of nuclear safety, including optimum protection, the obligation as low as reasonably practicable, and prevention through multilateral cooperation. Specifically, the obligation to provide optimum protection should be implemented by re-evaluating the most reliable disposal technologies and methods currently available and comprehensively assessing various options. The standard of the obligation as low as reasonably practicable requires that the minimization of negative impacts on human health, livelihoods, and the environment should not be subordinated to considerations of cutting costs and expenses. Multilateral cooperation should be promoted through the establishment of sound multilateral long-term monitoring mechanisms for the discharge of nuclear-contaminated water, notification and consultation obligations, and periodic assessments. These obligations under international law were fulfilled after the accidents at the Three Mile Island and Chernobyl nuclear power plants. The implications of the principles of nuclear safety align with the concept of building a community of shared future for nuclear safety advocated by China. In cases of violations of international law regarding the disposal of nuclear-contaminated water that jeopardize the concept of a community of a shared future for nuclear safety, China can also rely on its own strength to promote the implementation of due obligations through self-help.

Imaging technology based on the interaction between muon and material

Muon imaging technology, as an emerging detection method, is widely used in various fields. Muons can be classified into cosmic ray muons and accelerator muons based on their origins. Cosmic ray muons stand out for wide energy range, strong penetrating power and no artificial radiation. These characteristics make cosmic ray muon imaging technology adept at achieving nondestructive imaging of target objects. Presently, the commonly used imaging methods include scattering and transmission imaging technologies that leverage muon information for imaging. Additionally, muon and muonic secondary particle coincidence imaging technology utilizes information from secondary particles generated during the interaction between muons and target objects for imaging. The accelerator muon, distinguished by its high flux, strong monochromaticity, and adjustable energy, enables rapid and multidimensional imaging of target objects at various depths. Furthermore, it facilitates the analysis of material elements through muonic X-rays. This article provides insights into the production process and physical characteristics of muons, the fundamental principles of muon imaging technology, and its diverse applications across disciplines. It also explores the current development status and emerging trends in fields such as mineral resource exploration, archaeological studies, and nuclear safety.

Establishing a mechanism for international cooperation for Fukushima nuclear-contaminated water monitoring

The Japanese government’s unilateral decision to discharge the nuclear-contaminated water from the Fukushima nuclear power plant into the ocean has caused immense nuclear safety risks. Monitoring the unclear-contaminated water is a starting point to combat these risks and seek remedies for the rights and interests of all concerned parties. The establishment of a mechanism for international cooperation in this respect is necessary to handle the risks of the Fukushima nuclear-contaminated water and to lay the foundation of a framework for tackling any future disposal of nuclear-contaminated water following Japan’s example. At present, the international legal systems in the spheres of nuclear safety and security, marine environmental protection, and other areas, as well as the questioning of the monitoring reports of the International Atomic Energy Agency (IAEA) by the relevant parties, the monitoring practices of historical nuclear accidents, and numerous radioactivity monitoring mechanisms have provided the institutional and practical basis for constructing such a mechanism. The mechanism can be promoted by the IAEA through its existing mechanisms or be jointly initiated by China, the Russian Federation, the Republic of Korea, the Democratic People’s Republic of Korea, and the Pacific Island countries, among other stakeholders. Specifically, this mechanism should consist of three levels: first, the framework of the basic legal system, including the cooperative principles of national sovereignty, interest-relatedness, and procedural fairness, and the signing of the Framework Convention on the Monitoring of Fukushima’s nuclear-contaminated water and its Optional Protocol; second, the organizational structure and its responsibilities, which may include the Conference of Parties as the decision-making body, the Secretariat as the central coordinating body, and the monitoring committees in various fields as specific implementing agencies; and third, specific administrative arrangements, which involve the standardization of monitoring, the management system of monitoring networks and stations, the rules for monitoring procedures, and the rules for the utilization of the monitoring data, etc. With the urgent need for the scientific and fair monitoring of Fukushima’s nuclear-contaminated water, China, as a stakeholder country, can promote the establishment of such a mechanism for monitoring nuclear-contaminated water through the following paths: ① It is necessary to clarify the factors affecting the construction of an international cooperation mechanism for monitoring nuclear-contaminated water so as to ascertain the standpoints of the stakeholders, claims of their interests, contents of their cooperation, and the relevant international relations. ② On the basis of existing practices, China should consider improving the monitoring mechanism to cope with the risks of the discharge of Fukushima’s nuclear-contaminated water by formulating targeted policies and systems, setting up specialized monitoring institutions, and establishing a systematic monitoring network system. ③ This is an effective way for China to actively promote the participation of stakeholders in the construction of an international cooperation mechanism for monitoring nuclear-contaminated water in Fukushima by further innovating the dissemination mechanism to address the risk of Fukushima’s nuclear-contaminated water discharging into the sea and facilitating the identification of issues for international cooperation in monitoring Fukushima’s nuclear-contaminated water based on the concept of a community with a shared future for mankind.

A comprehensive examination of the linear and numerical stability aspects of the bubble collision model in the TRACE-1D two-fluid model applied to vertical disperse flow in a PWR core channel under loss of coolant accident conditions

The one-dimensional Two-Fluid concept uses an area-average approach to simplify the time and phase-averaged Two-Fluid conservation equations, making it more suitable for addressing difficulties at an industrial scale. Nevertheless, the mathematical framework has inherent weaknesses due to the loss of details throughout the averaging procedures. This limitation makes the conventional model inappropriate for some flow regimes, where short-wavelength perturbations experience uncontrolled amplification, leading to solutions that need to be physically accurate. The critical factor in resolving this problem is the integration of closure relations. These relationships play a crucial function in reintroducing essential physical characteristics, thus correcting the loss that occurs during averaging and guaranteeing the stability of the model. To improve the accuracy of predictions, it is essential to assess the stability and grid dependence of one-dimensional formulations, which are particularly affected by closure relations and numerical schemes. The current research presented in the text focuses on improving the well-posedness of the TFM, specifically within the TRACE code, which is widely utilized for nuclear reactor safety assessments. Incorporating a bubble collision model in the momentum equations is demonstrated to enhance the TFM's resilience, especially in scenarios with high void fractions where conventional TFMs may face challenges. The analysis presents a linear stability analysis performed for the transient one-dimensional Two-Fluid Model of system code TRACE within the framework of vertically dispersed flows. The main emphasis is on evaluating the stability characteristics of the model while also acknowledging its susceptibility to closure relations and numerical techniques.

Правовые вопросы безопасности АЭС в зоне военных действий

The article discusses the legal aspects of physical protection and nuclear safety of nuclear power plants located in a combat zone. The existing multilateral international treaties in this area, namely, the 1979 Convention on the Physical Protection of Nuclear Material (CPPNM) and the 2005 Amendment to the 2005 Convention on the Physical Protection of Nuclear Material, do not regulate the physical protection of nuclear facilities located in areas of active combat using conventional weapons. Moreover, the IAEA soft law provisions do not regulate the issues of physical protection of nuclear power plants located in areas of full-scale combat operations. The situation with the Zaporizhzhia Nuclear Power Plant has made the international community and the IAEA face the issue of legal regulation and development of recommendations for the physical protection of nuclear facilities in a war zone. Currently, a new concept for the physical protection of the Zaporizhzhia Nuclear Power Plant is being discussed under the auspices of the IAEA and efforts to prepare a new international treaty on the physical security of nuclear facilities in a war zone are underway.

Legal instruments for deterring nuclear conflict in the current military and political geo-environment

The relevance of this study lies in the need to consider the legal instruments for deterring a nuclear conflict in connection with the crisis of nuclear safety and instability in the current military-political geo-environment. The purpose of this study was to examine international experience in the field of legal consolidation of prohibitive norms of deterrence necessary to prevent nuclear threats. The following general scientific and special methods were employed in the study: analysis, synthesis, deduction, induction, generalisation, as well as formal legal, legal hermeneutics, logical- legal, comparative legal, and historical-legal methods. The study examined the specialised international legal framework of regulatory documents in the field of nuclear safety, safe operation of nuclear facilities and nuclear deterrence, as well as nuclear deterrence strategies and their development depending on the geopolitical situation. Based on the results of the study, it is determined that the legal regulation of nuclear conflict containment is in the form of prohibitory orders consolidated in the relevant international treaties in the field of nuclear and radiation safety. The study highlighted the main international treaties positioned as legal means of nuclear deterrence. The interaction of “soft” and “hard” law in nuclear and radiation safety agreements was considered, as well as the specific features of consolidating such norms in municipal law. The study provided generalising conclusions in terms of nuclear deterrence strategies, specifically, a vision of a new concept in this area, based on technological superiority in non-nuclear means of repelling nuclear strikes and massive precision non-nuclear retaliatory strikes. It was also concluded that attention should be paid to the development of a new international treaty that would combine all the rules prohibiting the use of nuclear energy for military purposes, as well as the rules governing nuclear and radiation safety as integral components of global nuclear security. The practical significance of this study is that its materials can be used for further development of the concepts of non-nuclear or legal nuclear deterrence

Enhancing Nuclear Reactor Safety through ICE Digital Systems and Cyber Integration

This article examines the imperative of enhancing nuclear reactor safety through the Integration of Instrumentation, Control, and Electrical) Digital (ICE) Systems and cybersecurity measures. Focused on advancements within Boiling Water Reactors (BWRs), particularly the BWRX-300, the discussion emphasizes the transformative impact of digital technology on safety protocols. ICE Digital Systems contribute to real-time monitoring, predictive maintenance, and remote operation, optimizing reactor performance. Simultaneously, robust cybersecurity measures are integrated to safeguard against potential cyber threats. The article highlights the synergistic effect of ICE Digital Systems and cybersecurity in fortifying the safety framework of nuclear reactors, ensuring a secure, efficient, and sustainable future for nuclear power.

Asynchronous propagation of atomic force and excited electronic charge in GaAs under proton irradiation

The studies for the interaction of energetic particles with matter have greatly contributed to the exploration of material properties under irradiation conditions, such as nuclear safety, medical physics and aerospace applications. In this work, we theoretically simulate the non-adiabatic process for GaAs upon proton irradiation using time-dependent density functional theory, and find that the radial propagation of force on atoms and the excitation of electron in GaAs are non-synchronous process. We calculated the electronic stopping power on proton with the velocity of 0.1–0.6 a.u., agreement with the previous empirical results. After further analyzing the force on atoms and the population of excited electrons, we find that under proton irradiation, the electrons around the host atoms at different distances from the proton trajectories are excited almost simultaneously, especially those regions with relatively high charge density. However, the distant atoms have a significant hysteresis in force, which occurs after the surrounding electrons are excited. In addition, hysteresis in force and electron excitation behavior at different positions are closely related to the velocity of proton. This non-synchronous propagation reveals the microscopic dynamic mechanism of energy deposition into the target material under ion irradiation.

The European intercomparison of in-vivo monitoring laboratories: the EIVIC-2020 project

The EIVIC project was launched in 2020, and the main goal was the organisation of a European intercomparison of in-vivo monitoring laboratories dealing with direct measurements of gamma-emitting radionuclides incorporated into the body of exposed workers. This project was organised jointly by members of EURADOS Working Group 7 on internal dosimetry (WG7), the Federal Office for Radiation Protection (BfS, Germany) and the Radioprotection and Nuclear Safety Institute (IRSN, France). The objective was to assess the implementation of individual-monitoring requirements in EU Member States on the basis of in-vivo measurements and to gain insight into the performance of in-vivo measurements using whole-body counters. In this context, a total of 41 in-vivo monitoring laboratories from 21 countries, together with JRC (EC) and IAEA participated. The results were submitted in terms of activity (Bq) of the radionuclides identified inside phantoms that were circulated to all participants. The measured data were compared with reference activity values to evaluate the corresponding bias according to the standards ISO 28218 and ISO 13528. In general, the results of the different exercises are good, and most facilities are in conformity with the criteria for the bias and z-scores in the ISO standards. Furthermore, information about technical and organisational characteristics of the participating laboratories was collected to test if they had a significant influence on the reported results.

The Legal Basis for Civil Liability in the Nuclear Field

This study examined the legal basis of civil liability in the nuclear field by assessing the feasibility of fault-based liability, whether it is based on proven fault or presumed fault, to establish civil liability for nuclear damages. Furthermore, the study addressed strict liability as the most suitable solution for establishing liability in the nuclear field, given the inadequacy of fault-based liability in addressing the issues of nuclear incidents and compensation for them. The study recommended the necessity of implementing strict and absolute liability in the nuclear field to protect individuals, society, and the environment from the catastrophic severity of nuclear incidents. It emphasized the importance of focusing on all means of nuclear safety and security to avoid any nuclear incident, and the significance of solidarity among nuclear operators and insurance pools and funds when facing nuclear incidents and addressing the severe damages they cause.

Simultaneous Gamma-Neutron Vision device: a portable and versatile tool for nuclear inspections

This work presents GN-Vision, a novel dual γ-ray and neutron imaging system, which aims at simultaneously obtaining information about the spatial origin of γ-ray and neutron sources. The proposed device is based on two position sensitive detection planes and exploits the Compton imaging technique for the imaging of γ-rays. In addition, spatial distributions of slow- and thermal-neutron sources (<100 eV) are reconstructed by using a passive neutron pin-hole collimator attached to the first detection plane. The proposed gamma-neutron imaging device could be of prime interest for nuclear safety and security applications. The two main advantages of this imaging system are its high efficiency and portability, making it well suited for nuclear applications were compactness and real-time imaging is important. This work presents the working principle and conceptual design of the GN-Vision system and explores, on the basis of Monte Carlo simulations, its simultaneous γ-ray and neutron detection and imaging capabilities for a realistic scenario where a 252Cf source is hidden in a neutron moderating container.

A study on the fracture pattern change of high-burnup fuel cladding failed by pellet-cladding mechanical interaction failure under reactivity-initiated accident conditions

ABSTRACT In a part of the historical reactivity-initiated accident (RIA) simulated tests on high-burnup fuels performed at the Nuclear Safety Research Reactor, the fuel failure caused by pellet-cladding mechanical interaction (PCMI) led to splitting into upper- and lower-part pieces or even fragmentation of the cladding tube. A massive release of fuel fragments accompanied this fracture pattern change from previously known axial cracks and thus identified as a potential concern in safety evaluation regarding core coolability. Dedicated out-of-pile mechanical tests were performed with unirradiated Zircaloy-4 cladding specimens to clarify the condition of such fracture pattern change. The specimens were pre-hydrided and subjected to loading with axial-to-hoop strain ratios of ℇz/ℇθ = 0.5–1.25, simulating the effects of hydrogen embrittlement and pellet-cladding mechanical bonding of high-burnup fuels, respectively. The results indicate that higher biaxiality of the loading and lower ductility (failure strain level) assist the fracture pattern change. This study proposes a conservative criterion that a PCMI failure splits the cladding tube into more than two pieces when strain ratio ℇz/ℇθ >0.75 and a concurrent hoop strain < 1.7% at the failure instant.

Polyhedral Relaxations for Optimal Pump Scheduling of Potable Water Distribution Networks

The classic pump scheduling or optimal water flow (OWF) problem for water distribution networks (WDNs) minimizes the cost of power consumption for a given WDN over a fixed time horizon. In its exact form, the OWF is a computationally challenging mixed-integer nonlinear program (MINLP). It is complicated by nonlinear equality constraints that model network physics, discrete variables that model operational controls, and intertemporal constraints that model changes to storage devices. To address the computational challenges of the OWF, this paper develops tight polyhedral relaxations of the original MINLP, derives novel valid inequalities (or cuts) using duality theory, and implements novel optimization-based bound tightening and cut generation procedures. The efficacy of each new method is rigorously evaluated by measuring empirical improvements in OWF primal and dual bounds over 45 literature instances. The evaluation suggests that our relaxation improvements, model strengthening techniques, and a thoughtfully selected polyhedral relaxation partitioning scheme can substantially improve OWF primal and dual bounds, especially when compared with similar relaxation-based techniques that do not leverage these new methods. History: Accepted by David Alderson, Area Editor for Network Optimization: Algorithms &amp; Applications. Funding: This work was supported by the U.S. Department of Energy (DOE) Advanced Grid Modeling project, Coordinated Planning and Operation of Water and Power Infrastructures for Increased Resilience and Reliability. Incorporation of the PolyhedralRelaxations Julia package was supported by Los Alamos National Laboratory’s Directed Research and Development program under the project Fast, Linear Programming-Based Algorithms with Solution Quality Guarantees for Nonlinear Optimal Control Problems [Grant 20220006ER]. All work at Los Alamos National Laboratory was conducted under the auspices of the National Nuclear Security Administration of the U.S. DOE, Contract No. 89233218CNA000001. This work was also authored in part by the National Renewable Energy Laboratory, operated by the Alliance for Sustainable Energy, LLC, for the U.S. DOE, Contract No. DE-AC36-08GO28308. Supplemental Material: The software that supports the findings of this study is available within the paper and its Supplemental Information ( https://pubsonline.informs.org/doi/suppl/10.1287/ijoc.2022.0233 ) as well as from the IJOC GitHub software repository ( https://github.com/INFORMSJoC/2022.0233 ). The complete IJOC Software and Data Repository is available at https://informsjoc.github.io/ .

Research on Radiation Monitoring Strategy for Spent Fuel Reprocessing Plant Based on Coordination of Nuclear Security Risk and Facility Importance Evaluation

This paper examines a method and scheme for optimizing the allocation of nuclear radiation monitoring resources, based on the analysis of the risk of nuclear security events and the importance of facilities in a spent fuel reprocessing plant. By constructing a nuclear security radiation accident tree for a plant, the importance of different security events was calculated using fuzzy mathematics and expert scoring methods. The importance of each facility was determined by establishing a fuzzy comprehensive decision model, and a resource allocation scheme for nuclear radiation monitoring was proposed based on the importance level of facilities. The research findings demonstrated that the extraction process plant in the main process area, and the centralized control room in the front area of the plant, were of highest importance. Accordingly, three levels of nuclear radiation monitoring programs were established based on the importance of each facility. This study offers theoretical and technical support for the safety management and operation of a spent fuel reprocessing plant. Additionally, the analysis results can serve as a reference for allocating nuclear radiation monitoring resources in various facilities in a reasonable manner.

Development of GPU-Paralleled multi-resolution techniques for Lagrangian-based CFD code in nuclear thermal-hydraulics and safety

In this study, we propose a fully parallelized adaptive particle refinement (APR) algorithm for smoothed particle hydrodynamics (SPH) to construct a stable and efficient multi-resolution computing system for nuclear safety analysis. The APR technique, widely employed by SPH research groups to adjust local particle resolutions, currently operates on a serialized algorithm. However, this serialized approach diminishes the computational efficiency of the system, negating the advantages of acceleration achieved through high-performance computing devices. To address this drawback, we propose a fully parallelized APR algorithm designed to enhance both efficiency and computational accuracy, facilitated by a new adaptive smoothing length model. For model validation, we simulated both hydrostatic and hydrodynamic benchmark cases in 2D and 3D environments. The results demonstrate improved computational efficiency compared to the conventional SPH method and APR with a serialized algorithm, and the model's accuracy was confirmed, revealing favorable outcomes near the resolution interface. Through the analysis of jet breakup, we verified the performance and accuracy of the model, emphasizing its applicability in practical nuclear safety analysis.

The implementation of the environmental impact assessment in Fukushima contaminated water discharge: an analysis of the international legal framework

Japan is discharging nuclear contaminated water from the 2011 Fukushima incident into the sea after treatment with the Advanced Liquid Processing System (ALPS). This process is expected to continue for decades, as planned by the Japanese government. This decision sparks opposition from many countries and international organizations, as well as constant protests from people in Japan and neighboring countries. Although there are no international documents specifically addressing the discharge of contaminants from a nuclear accident, it is found that the LOS Convention, treaties on nuclear safety, and international environmental laws provide the basis and legal framework for requiring Japan to implement environmental impact assessments throughout the entire process of Fukushima contaminated water discharge. First, this paper evaluates the consistency between the measures taken before Japan’s decision to discharge contaminated water into the sea and the requirements under international laws. Second, this paper further examines the substantive and procedural requirements under international law for the entire process of Fukushima contaminated water discharge. It identifies substantive criteria to be applied in assessing the environmental impact of Fukushima contaminated water discharge based on international documents and explores the procedural requirements to assure transparency, prudence, and accountability of the assessment. Finally, given the potential transboundary damage caused by the discharge of nuclear-contaminated water into the sea, this paper proposes that a new multi-stakeholder cooperative mechanism is necessary to achieve effective and credible monitoring and respond to the claims of potentially affected parties. In addition to providing a legal framework for the environmental impact assessment in the Fukushima case, this paper may also contribute to the proper disposal of nuclear contaminants in future nuclear accidents.

Évaluation de la pratique pharmaceutique en établissement de santé : une étude exploratoire comparant les processus en France et au Québec

To ensure compliance with the legal and normative framework, the professional orders, which supervise the practice of pharmacy have established a professional inspection process. In addition to this process, other external organizations also require an accreditation, authorization, certification or validation process for professional practices. The main objective is to identify and compare the methods of evaluating pharmaceutical practice in hospitals in France and Quebec. In order to identify and compare the methods of evaluating pharmaceutical practice in hospitals in France and Quebec, our approach allowed us to identify more organizations in France (i.e., High Authority of Health, Regional Health Agencies, the National Order of Pharmacists, the Nuclear Safety Agency, the Biomedicine Agency and the National Agency for the Safety of Medicines and Health Products) than in Quebec (i.e., Accreditation Canada, Ordre des pharmaciens du Québec and Health Canada). The study highlights the legal framework and applicable standards, the surveyors, the evaluation methods and the particularities for the evaluation of the hospital, the pharmacy department and the members of the department. This study highlights the evaluation processes of pharmaceutical practice in hospitals. In France, as in Quebec, we recognize the importance of the drug circuit in the hospital, the development and operation of a pharmacy department and the practice of pharmacy. While there are more similarities for the assessment of the drug circuit in hospitals and pharmacy department, important differences are observed for the assessment of individuals. We believe that the publication of a comparative analysis can contribute to discussions and exchanges to benefit from the best practices of each country.

Source term analysis and impact study during a hypothetical accident in Haiyang nuclear power plant

Since 2018, the use of AP1000 nuclear technology has been growing due to its advantages in terms of nuclear safety and security. Knowing that the occurrence rate of the serious nuclear reactor accidents has increased due to the natural disasters that the world has encountered in recent decades, such as earthquakes, floods, tsunamis, etc., we propose to carry out an impact study and analyze the consequences of these accidents, with the aim of avoiding exposure of the public and workers to ionizing radiation.This work is divided into two sections: firstly, calculate the source term by using the ORIGEN-JR depletion code, and compare the obtained results with those published in the document AP1000 Design Control. The obtained results are in agreement with the literature. Secondly, starting from the results of the source term calculation, we have evaluated the atmospheric dispersion using health HotSpot code. The Total Effective Doses (TED) is estimated over two meteorological periods: the first period, from April to August, and the second one, from September to March. The simulation results showed that the TED was higher, around 27 Sv at 0.6 km from the source during the April–August period. However, for the second period, the TED is about 8 Sv at 2 km from the source. Generally, the TED of all radionuclide groups exceeds the IAEA annual regulatory limits, which are one millisievert per year (1 mSv/year) for public exposure and twenty millisieverts per year (20 mSv/year) for occupational exposure of workers. Therefore, the probability of risks to workers, the public, and the environment rises. There are generic criteria for acute doses, according to which preventive actions must be taken in all circumstances in order to minimize the serious effects of radionuclides on the population.

Evolution of Legislation Regarding the Use of Nuclear Energy for Peaceful Purposes

The development and use of atomic energy represent one of the greatest achievements of the 20th century, opening new possibilities for global evolution. The United Nations (UN) has formulated the «Millennium Development Goals» and the «Sustainable Development Goals by 2030» to address comprehensive solutions to the social, economic, and environmental challenges facing the planet. In this context, nuclear energy offers unparalleled advantages, but it is essential to consider the risks and challenges associated with its future use and development. Nuclear law serves as a valuable tool for regulating the development of nuclear energy and overcoming these risks and challenges. All countries must strictly fulfill their international obligations, responsibly implement international legal instructions at the national level, and collectively support the international regime and legal framework organized around the United Nations. This, in turn, contributes to the achievement of the shared goal of «atoms for peace and development».&#x0D; The international legal framework on nuclear issues emerged alongside the development of nuclear energy worldwide. It evolves as social, economic, scientific, and technical challenges associated with this development are addressed, thereby contributing to the safe, secure, and sustainable development of peaceful nuclear energy use.&#x0D; The IAEA and the international community have established an almost universal regime of safeguards aimed at detecting and preventing the diversion of nuclear materials from peaceful nuclear activities to the production of nuclear weapons.&#x0D; Based on the results of the conducted research, it has been established that each country not only has the right to use nuclear energy for peaceful purposes but also bears the responsibility and obligation to prevent the proliferation of nuclear weapons and to support nuclear safety and security. All countries should conscientiously fulfill their obligations in accordance with the international legal framework on nuclear safety, fully implement relevant resolutions of the United Nations Security Council, strengthen and expand the existing international legal framework on nuclear safety, and provide institutional guarantees, adhering to universally defined guiding principles for managing international nuclear safety.