IAEA Research Articles

Comparing Coupled Multiphysics Simulations of Pump-Driven Transients for a Pressurized Heavy Water Reactor

Comparison of results for global responses predicted by different multiphysics simulations of benchmark problems may fail to reveal potentially significant local modeling issues. An examination of code interactions in coupled simulations can provide more information, which may help identify potential modeling issues that went unnoticed during verification (and validation) of the individual codes, or may call into question approximations otherwise deemed reasonable at the individual code level. We illustrate this challenge for the case of coupled neutronics/thermal-hydraulic transient simulations using one of the problems and contributed results documented in International Atomic Energy Agency TECDOC-1994. This recently published report documents the specifications of four numerical multiphysics pressurized heavy water reactor (PHWR) transient challenge problems and the results contributed by 10 participants. Our work is based on the pump rundown problem, where TECDOC-1994 suggests that differences in modeling and methods employed in thermal-hydraulics may be the dominant factor in the observed differences. We performed a more detailed assessment with two different multiphysics coupled computational frameworks using NESTLE-C/ARIANT and PUMA/RELAP-5. We also studied a pump seizure transient, a more challenging variant of the pump rundown transient. Several aspects were investigated: comparisons of standalone results, sensitivity to gap modeling, selection of boundary conditions at the pressurizer, and an examination of correlations used in ARIANT and RELAP-5. Our assessment goes beyond the results for global parameters and dives into details of predictions at the channel level. This paper briefly describes the PHWR pump rundown transient problem and a pump seizure variant, the computational methods employed, and the areas investigated, and discusses some selected results.

Towards an international regulatory framework for AI safety: lessons from the IAEA’s nuclear safety regulations

This study explores the necessity and direction of safety regulations for Artificial Intelligence (AI), drawing parallels from the regulatory practices of the International Atomic Energy Agency (IAEA) for nuclear safety. The rapid advancement and global proliferation of AI technologies necessitate the establishment of standardized safety norms to minimize discrepancies between national regulations and enhance the consistency and effectiveness of these rules. The study emphasizes the importance of international collaboration and the engagement of various stakeholders to strengthen the appropriateness of regulations and ensure their continuous updating in response to the evolving risks associated with technological advancements. The paper highlights the critical role of subgoal setting mechanisms in AI’s decision-making processes, underscoring their significance in ensuring the technology’s stability and social acceptability. Improperly tuned subgoal setting mechanisms may lead to outcomes that conflict with human intentions, posing risks to users and society at large. The study draws attention to the hidden risks often embedded within AI’s core decision-making mechanisms and advocates for regulatory approaches to guarantee safe and predictable AI operations. Furthermore, the study acknowledges the limitations of directly applying IAEA’s nuclear safety cases to AI due to the distinct characteristics and risks of the two fields. The paper calls for future research to delve deeper into the need for an independent regulatory framework tailored to AI’s unique features. Additionally, the study emphasizes the importance of accelerating international consensus, developing flexible regulatory models that reflect the situation in each country, exploring harmonization with existing regulations, and researching timely regulatory responses to the fast-paced development of AI technology.

Gamma noise to non-invasively monitor nuclear research reactors

Autonomous nuclear reactor monitoring is a key aspect of the International Atomic Energy Agency’s strategy to ensure nonproliferation treaty compliance. From the rise of small modular reactor technology, decentralized nuclear reactor fleets may strain the capacities of such monitoring and requires new approaches. We demonstrate the superior capabilities of a gamma detection system to monitor the criticality of a zero power nuclear reactor from beyond typical vessel boundaries, offering a powerful alternative to neutron-based systems by providing direct information on fission chain propagation. Using the case example of the research reactor CROCUS, we demonstrate how two bismuth germanate scintillators placed outside the reactor vessel can precisely observe reactor criticality using so called noise methods and provide core status information in seconds. Our results indicate a wide range of applications due to the newly gained geometric flexibility that could find use in fields beyond nuclear safety.

Recurrent medical imaging exposures for the care of patients: one way forward.

Medical imaging is both valuable and essential in the care of patients. Much of this imaging depends on ionizing radiation with attendant responsibilities for judicious use when performing an examination. This responsibility applies in settings of both individual as well as multiple (recurrent) imaging with associated repeated radiation exposures. In addressing the roles and responsibilities of the medical communities in the paradigm of recurrent imaging, both the International Atomic Energy Agency (IAEA) and the American Association of Physicists in Medicine (AAPM) have issued position statements, each affirmed by other organizations. The apparent difference in focus and approach has resulted in a lack of clarity and continued debate. Aiming towards a coherent approach in dealing with radiation exposure in recurrent imaging, the IAEA convened a panel of experts, the purpose of which was to identify common ground and reconcile divergent perspectives. The effort has led to clarifying recommendations for radiation exposure aspects of recurrent imaging, including the relevance of patient agency and the provider-patient covenant in clinical decision-making. CLINICAL RELEVANCE STATEMENT: An increasing awareness, generating some lack of clarity and divergence in perspectives, with patients receiving relatively high radiation doses (e.g., ≥ 100mSv) from recurrent imaging warrants a multi-stakeholder accord for the benefit of patients, providers, and the imaging community. KEY POINTS: • Recurrent medical imaging can result in an accumulation of exposures which exceeds 100 milli Sieverts. • Professional organizations have different perspectives on roles and responsibilities for recurrent imaging. • An expert panel reconciles differing perspectives for addressing radiation exposure from recurrent medical imaging.

Design and dynamic analysis of transport cask for SMR fresh fuel assembly

Transportation of fresh fuel assemblies requires the utilization of transport casks to ensure the internal radioactive material does not affect the environment. In this work, we introduce an innovative design of a transport cask for the fresh fuel assembly of a Small Module Reactor (SMR). The cask is constituted by two containers, supports and various energy-absorbing structures welded at the outer container. The structural integrity of the transport cask under variant scenarios determined by the International Atomic Energy Agency (IAEA) and domestic regulations was numerically evaluated. The detailed 3D model of the cask was created, and the simulations were performed via the Finite Element Method (FEM) using commercial software ABAQUS. Simulation results obtained from static and dynamic analyses indicated that the integrity of the designed transport cask can be assured during normal and accident conditions. The most severe damage during the 9 m drop tests was caused by a horizontal oblique condition and this configuration is recommended to be tested in future experiments.

الإنسانية وأسلحة الدمار الشامل القانون الدولي الإنساني

The present study investigates the humanitarian consequences of the spread of weapons of mass destruction (WMDs). The proliferation of weapons of mass destruction (WMDs) is a significant apprehension on a global scale, as both state and non-state entities endeavor to obtain them. Despite the concerted efforts of developed nations and international organizations, including the United Nations and the International Atomic Energy Agency, the task of managing proliferation has proven to be a challenging one. The present essay delves into the perils associated with the utilization of these armaments on human existence, the ramifications on economic progress, and approaches to avert their proliferation. The regulation of warfare has been increasingly pursued by states and civil societies through the adoption of humanitarian disarmament as a strategy. The humanitarian perspective has been significantly enhanced by multilateral agreements pertaining to the regulation of conventional weapons, such as the 1980 Convention on Certain Conventional Weapons and the 1997 Anti-Personnel Landmine Convention. The article culminates by proposing recommendations to enhance the effectiveness of arms control agreements, advance disarmament efforts, establish novel legal frameworks at the global level, and prioritize non-state entities as potential sources of weapons of mass destruction.

USING THE IAEA MEDICAL ISOTOPE BROWSER FOR SIMULATION THE PRODUCTION OF IODINE-123

The paper presents the results of modeling the production of a medical isotope using the medical isotope browser of the International Atomic Energy Agency. A web application for the production of medical isotopes allows you to obtain the necessary data on a nuclear reaction based on user data: target radionuclide, irradiating particle or irradiating radiation, energy range, irradiation and cooling time. Tabular values and illustrated graphs of the cross section of the nuclear reaction are obtained based on modeling the production of the isotope iodine-123 from tellurium-124; The isotope decay products are presented. The simulation results were compared with the data recommended by the IAEA for this nuclear reaction for the gamma-emitting radionuclide iodine-123. It is shown that gamma-emitting radionuclide iodine-123 is one of the most convenient radionuclides for single-photon emission computed tomography. When experimental methods are not available, modern technologies in the field of computer modeling allow specialists in a narrow profile to use the achievements of world science to solve problems, in this case, for the production of medical isotopes. Modeling approaches for the production of iodine-123 are recommended for the production of other medical isotopes.

CollisionDB: A New Database of Atomic and Molecular Collisional Processes with an Interactive API

The Atomic and Molecular Data Unit of the International Atomic Energy Agency has developed a new database, CollisionDB, to provide an open, free, robust and long-term repository of data on plasma collisional processes. The database contains data on cross sections and rate coefficients for collisions of electrons, photons and heavy particles with atomic and molecular species. A fundamental requirement for this database is the implementation of standardized metadata, which provide an unambiguous description of the collisional data available in peer-reviewed sources. CollisionDB offers both a browser-based search interface and an application programming interface (API) that allows users to filter, process and compare collisional datasets. For this purpose, a Python package PyCollisionDB has been developed to access the CollisionDB API. Here, we present an overview of the technical developments, including data schemas, standards and user interface underlying the CollisionDB application, with particular emphasis on the API developed to support the integration of data into modeling and other codes.

Optimization of Yonsei Single-Photon Emission Computed Tomography (YSECT) Detector for Fast Inspection of Spent Nuclear Fuel in Water Storage

Background: The gamma emission tomography (GET) device has been reported a reliable technique to inspect partial defects within spent nuclear fuel (SNF) of pin-by-pin level. However, the existing GET devices have low accuracy owing to the high attenuation and scatter probability for SNF inspection condition. The purpose of this study is to design and optimize a Yonsei single-photon emission computed tomography version 2 (YSECT.v.2) for fast inspection of SNF in water storage by acquisition of high-quality tomographic images.Materials and Methods: Using Geant4 (Geant4 Collaboration) and DETECT-2000 (Glenn F. Knoll et al.) Monte Carlo simulation, the geometrical structure of the proposed device was determined and its performance was evaluated for the 137Cs source in water. In a Geant4-based assessment, proposed device was compared with the International Atomic Energy Agency (IAEA)-authenticated device for the quality of tomographic images obtained for 12 fuel sources in a 14 × 14 Westinghouse-type fuel assembly.Results and Discussion: According to the results, the length, slit width, and septal width of the collimator were determined to be 65, 2.1, and 1.5 mm, respectively, and the material and length of the trapezoidal-shaped scintillator were determined to be gadolinium aluminum gallium garnet and 45 mm, respectively. Based on the results of performance comparison between the YSECT.v.2 and IAEA’s device, the proposed device showed 200 times higher performance in gamma-detection sensitivity and similar source discrimination probability.Conclusion: In this study, we optimally designed the GET device for improving the SNF inspection accuracy and evaluated its performance. Our results show that the YSECT.v.2 device could be employed for SNF inspection.

Exploring the Zone of Possible Agreement on the Nuclear Issue of the Korean Peninsula

From 2003 to 2009, China, Japan, North Korea, Russia, South Korea, and the United States engaged in a series of multilateral negotiations to address North Korea’s nuclear program. On September 19, 2005, the six participants achieved a “gold standard” agreement on denuclearization. North Korea agreed to relinquish all nuclear weapons, abstain from deploying nuclear weapons, and rejoin the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), as well as adhere to International Atomic Energy Agency (IAEA) safeguards. The United States affirmed its lack of nuclear weapons on the Korean Peninsula and expressed no intention of attacking or invading the Democratic People’s Republic of Korea (DPRK) with nuclear or conventional weapons. China, Japan, Russia, South Korea, and the United States concurred to provide energy assistance to the DPRK. Furthermore, the agreement established the principle of “commitment for commitment, action for action,” which holds significance for the spirit of future engagement. The prevailing impasse in resolving the nuclear issue on the Korean Peninsula prompts the inquiry of a possible negotiation model. This paper uses the Harvard negotiation method to examine a zone of possible agreement (ZOPA) between China, North Korea, Russia, and the United States, which culminated in the September 19, 2005 Six Party Talks agreement addressing the nuclear issue on the Korean Peninsula. The first section of the article is devoted to scrutinizing the Zone of Possible Agreement (ZOPA), which facilitated the 2005 agreement. Based on the acquired insights, the second section assesses the prospects for implementing the 2005 Joint Statement in the current context. This section also concentrates on identifying a ZOPA under current conditions, taking into account past experiences and lessons learned from past negotiations.

The Contribution of Latin America and the Caribbean to Multilateral Nuclear Nonproliferation and Disarmament

This article addresses the developments and interconnections between regional and global-level negotiations to prohibit nuclear weapons. Ambassador Sergio Duarte, who has been one of the leading negotiators on nuclear weapons disarmament and nonproliferation since the 1960s and is the current president of the Pugwash movement, traces the history of Latin American and Caribbean efforts to forge stronger ties and foster regional cooperation. He goes back to the first quarter of the nineteenth century to show how those ties laid the ground for the conception of the Treaty of Tlatelolco, the first Nuclear-Weapons-Free Zone in a populated area, and facilitated the region’s active role in nuclear affairs. He also dives into other successful arrangements, such as the creation of a binational agency (ABACC) that ensures control of nuclear materials in cooperation with the International Atomic Energy Agency (IAEA) to build confidence and increase cooperation in the nuclear field, and he describes the region’s key role in enabling the Treaty on the Prohibition of Nuclear Weapons (TPNW).

The role of the UN in preventing the proliferation of nuclear weapons

According to the UN Charter (Article 26), the UN Security Council is the primary organ responsible for the maintenance of international peace and security. Nuclear states agreed to the adoption of a UN Security Council Resolution that provided positive security assurances. The adoption of UN Security Council Resolution №255 on June 19, 1968, was of particular significance. This resolution stipulated that instances of aggression involving the use of nuclear weapons or the threat of such aggression against a non-nuclear-weapon state would require immediate action by the UN Security Council and its permanent members, who are nuclear-armed states.
 The aim of the work is to determine the role of the UN Security Council in the system of preventing the proliferation of nuclear weapons. The methodological basis of the study will focus on the analysis and understanding of the impact of the UN Security Council on strategies and measures aimed at preventing the spread of nuclear weapons in the international context.
 The results of our research have shown that the role of the UN Security Council in the disarmament of Iraq’s nuclear program, which could have led to the development of nuclear weapons, proved to be significant. To achieve this, in accordance with UN Security Council Resolution №687 adopted on April 3, 1991, the Special Commission (UNSCOM) was established.
 During an extraordinary meeting of the UN Security Council at the highest level on September 24, 2009, Resolution UN Security Council Resolution № 1887 was adopted, aimed at supporting nuclear non-proliferation, criticizing Iran and North Korea. Resolution №1887 outlines measures to strengthen control and the rights of nuclear-weapon states to demand the return of nuclear materials and equipment in case of violations of the Non-Proliferation Treaty or withdrawal from it. It also involves enhancing security measures for the storage of nuclear materials and strict export controls.
 Conclusions. In our opinion, the powers of the UN Security Council in the field of non-proliferation of weapons of mass destruction should be utilized more promptly and effectively. The insufficient effectiveness of this international mechanism in preventing proliferation remains a cause for serious concern among UN members worldwide. To enhance the effectiveness of the UN Security Council, we propose the adoption of a comprehensive resolution that includes provisions on the procedure for a state’s withdrawal from the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and its violation of commitments to refrain from acquiring nuclear weapons. This resolution should stipulate the imposition of sanctions against such a state based on a special report from the International Atomic Energy Agency (IAEA). Such a mechanism can ensure an effective impact of the international community on states that withdraw from the NPT.

Application of uncertainty and sensitivity analysis in dose assessment during a postulated LBLOCA for VVER-1000 nuclear reactor

A key element in the process of accident analysis for the event of a severe nuclear emergency such as the large break loss of coolant accident (LBLOCA) is to properly quantify safety margins using reliable tools. Assessing the consequences of radioactive material release and the equivalant dose after the LBLOCA can provide clarity about the accident. Reliable safety analysis methods for nuclear power plants (NPPs) can be used to obtain relatively realistic outcomes considering the complex uncertainties of NPP events. In this study, an appropriate technique for sensitivity and uncertainty analysis is employed to develop a methodology for performing dose assessment within a postulated LBLOCA including uncertainties. Considering the approved reliability over the years and safety aspects, VVER reactor is among the most widely used nuclear reactors, which is selected as the case study in this article. The main problem that the study aims to solve is to illustrate whether the inordinate deviation of the input parameters from their reference values lead to violation of the allowed TEDE value by conducting uncertainty analysis. For performing calculations of total effective dose equivalent (TEDE), the environmental contamination with radioactive materials has been simulated using HotSpot code and the obtained results were compared with the solutions of JRODOS program. To obtain the most influential parameters on the obtained TEDE values in different distances from the NPP, an appropriate sensitivity analysis has been carried out, following which the Wilks’ statistical method is used to generate 59 data samples with uncertainty propagation and 95 % confidence. The resulting uncertainty bands demonstrate that the maximum TEDE values of calculated data lie within about 7 to 15 mSv in the postulated LBLOCA scenario, which are below the threshold limit of 50 mSv recommended by International Atomic Energy Agency.

Ensuring Nuclear Safety in Ukraine in Conditions of War

The ongoing war in Ukraine has significantly raised concerns about the safety of nuclear power plants (NPPs), especially in the context of the Zaporizhzhia NPP. This precarious situation has revealed substantial weaknesses in the existing global nuclear safety framework, emphasizing the need for sweeping reforms in international law. While the International Atomic Energy Agency (IAEA) has played a commendable role in advocating for nuclear safety through various resolutions, missions, and safety principles, the effectiveness of these efforts is compromised by Russia’s non-compliance and its ability to exercise veto power in the UN Security Council. Confronting these challenges requires a diverse and comprehensive approach from the international community. This includes revising international legal structures, conducting in-depth studies on nuclear safety in conflict zones, and considering diplomatic initiatives like establishing safety zones around nuclear facilities. Another possible strategy is the deployment of peacekeeping forces, though geopolitical factors currently limit its viability. Resolving the nuclear safety concerns intensified by the Russia-Ukrainian war demands robust legal and political actions, coupled with innovative solutions and global cooperation. Immediate and focused attention is crucial to avert any further escalation that risks a nuclear incident, posing dire threats not only to Ukraine but to the entire international community.

Nuclear Aspects of the Russia-Ukraine War and its Implications for Nepal

Nearly two years old Russia-Ukraine war seems to go on for a long period. The United States and European Union are supporting Ukraine’s offensive to regain their lost land. The Russian threat to use nuclear bombs at the outset has taken the world by great surprise. The use of a megaton nuclear bomb could lead to unimagined catastrophe killing a billion people, and a nuclear winter could set in leading to a worldwide famine that could kill millions more. The nuclear watchdog of the United Nations - the International Atomic Energy Agency, is keeping track of Europe’s largest nuclear power plant in Ukraine. Nuclear-related international treaties are fast becoming ineffective and World War III could be possible. This war is, however, coming to a stalemate. Peace initiatives taken are ineffective so far. This war must end soon and nuclear weapons should remain as deterrence and should not and never be used to save mankind.

Establishment and utilisation of national diagnostic reference level for adult computed tomography examinations in Ghana.

The International Atomic Energy Agency, as part of the new regional project (RAF/9/059), recommend the establishment of diagnostic reference levels (DRLs) in Africa. In response to this recommendation, this project was designed to establish and utilise national DRLs of routine computed tomography (CT) examinations. These were done by estimating CT dose index and dose length product (DLP) from a minimum of 20 patient dose report of the most frequently used procedures using 75th percentile distribution of the median values. In all, 22 centres that formed 54% of all CT equipment in the country took part in this study. Additionally, a total of 2156 adult patients dose report were randomly selected, with a percentage distribution of 60, 12, 21 and 7% for head, chest, abdomen-pelvis and lumber spine, respectively. The established DRL for volume CT dose index were 60.0, 15.7, 20.5 and 23.8mGy for head, chest, abdomen-pelvis and lumber spine, respectively. While the established DRL for DLP were 962.9, 1102.8, 1393.5 and 824.6mGy-cm for head, chest, abdomen-pelvis, and lumber spine, respectively. These preliminary results were comparable with data from 16 other African countries, European Commission and the International Commission on Radiological Protection. Hence, this study would serve as a baseline for the establishment of a more generalised regional and national adult DRLs for Africa and other developing countries.

Radionuclides distribution and radiation hazards assessment of black sand separation plant’s minerals: a case study

This study assessed the radioactivity levels and associated risks in the black sand-separated products obtained from the black sand separation plant in Delta, Egypt. A total of sixteen samples were taken from hot spots during and after the separation process. These include water samples and other samples that represent monazite, rutile, zircon, granite, ilmenite, and silica products. The hot spots included the area where the ore was stored. The activity concentrations of 232Th\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{232}Th$$\\end{document}, 226Ra\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{226}Ra$$\\end{document}, and 40K\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{40}K$$\\end{document} were determined in these samples using a p-type HPGe detector. Based on gamma spectrometric analysis, samples of rutile, zircon, and monazite had the highest amounts of radioactivity because they contained the highest NORM’s activity concentrations. In addition, it indicated that the radiological hazard indices of the collected samples were higher than the average world limits for sand texture. These findings suggest that the black sand separation process reveals potential risks to human health and the environment, and therefore, appropriate measures need to be taken to mitigate these risks, especially for the safety of the workers on-site. Reducing the risk associated with those sites should be controlled by implementing the recommendations declared for the series of International Basic Safety Standards of the International Atomic Energy Agency (GSR) Part 3, as affirmed in Document No. 103 of 2007 by the International Commission on Radiological Protection (ICRP) as will be presented in the paper body.

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.

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.

Six Country Vignettes: Strengthening Radiotherapy and Theranostics

BackgroundFor cancer patient populations worldwide, the synchronous scale-up of diagnostics and treatments yields meaningful gains in survival and quality of life. Among advanced cancer therapies, radiotherapy (RT) and theranostics are key to achieving practical, high-quality, and personalized precision medicine - targeting disease manifestations of individual patients and broad populations, alike. Aiming to learn from one another across different world regions, the six country vignettes presented here depict both challenges and victories in de novo establishment or improvement of RT and theranostics infrastructure. MethodsThe International Atomic Energy Agency (IAEA) convened global RT and theranostics experts from diverse world regions and contexts to identify relevant challenges and report progress in their own six countries: Belgium, Brazil, Costa Rica, Jordan, Mongolia, and South Africa. These accounts are collated, compared, and contrasted herein. ResultsCommon challenges persist which could be more strategically assessed and addressed. A quantifiable discrepancy entails personnel. The estimated radiation oncologists (ROs), nuclear medicine physicians (NMPs), and medical physicists (MPs for RT and nuclear medicine) per million inhabitants in the six collective countries respectively range between 2.69–38.00 ROs, 1.00–26.00 NMPs, and 0.30–3.45 MPs (Table 1), reflecting country-to-country inequities which largely match World Bank country-income stratifications. ConclusionEstablished goals for RT and nuclear medicine advancement worldwide have proven elusive. The pace of progress could be hastened by enhanced approaches such as more sustainably phased implementation; better multinational networking to share lessons learned; routine quality and safety audits; as well as capacity building employing innovative, resource-sparing, cutting-edge technologic approaches.Bodies such as ministries of health, professional societies, and the IAEA shall serve critical roles in convening and coordinating more innovative RT and theranostics translational research, including expanding nuanced global database metrics to inform, reach, and potentiate milestones most meaningfully. Policy SummaryAligned with WHO 25×25 NCDs target; WHA70.12 and WHA76.5 resolutions.