About the NTI Nuclear Security Index and Radioactive Source Security Assessment

The NTI Nuclear Security Index (NTI Index) is the only independent, transparent assessment of global nuclear security conditions. Developed by the Nuclear Threat Initiative (NTI) in partnership with Economist Enterprise (EE), the NTI Index uses a rigorous methodology and publicly available information to track nuclear and radiological security across 175 countries and Taiwan.¹ The NTI Index recommends actions for governments based on data-driven findings that emerge from three rankings:

• Theft: Secure Materials ranks the 22 countries with 1 kilogram or more of weapons-usable nuclear materials to assess actions to secure those materials against theft.
• Theft: Support Global Efforts ranks the 154 countries and areas with less than 1 kilogram of or no weapons-usable nuclear materials to assess actions to support global nuclear security efforts.
• Sabotage: Protect Facilities ranks the 48 countries and areas with nuclear facilities (e.g., nuclear power reactors and research reactors) that may or may not possess weapons-usable nuclear materials, to assess actions to protect those facilities against sabotage.

Since 2020, the NTI Index has also included a Radioactive Source Security Assessment that reviews national policies, commitments, and actions to secure radioactive sources and prevent radiological terrorism in 175 countries and Taiwan. This assessment does not score or rank countries and areas.

What the NTI Index Captures

A resilient global nuclear security system requires every government in the world to uphold international legal commitments, global norms, and domestic laws and regulations. The NTI Index paints a clear, data-grounded picture of where that system is healthy and where it requires urgent remedial action.

After a period of progress on nuclear security achieved through the Nuclear Security Summits (held from 2010 to 2016), the current era of nuclear security is defined by significant backsliding amid increased global uncertainty, geopolitical tensions, and dangers posed to nuclear facilities in active war zones. In this environment, the NTI Index’s centralized authoritative accounting of the global nuclear and radiological security landscape and prioritization of actions for governments to take is more essential than ever.

The Stakes of Theft and Sabotage

The quantity of weapons-usable nuclear material— plutonium or highly enriched uranium (HEU)—needed to build a nuclear bomb is relatively small. The International Atomic Energy Agency (IAEA) defines a “significant quantity” (the approximate amount of material needed for a nuclear explosive device) of plutonium as 8 kilograms and HEU as 25 kilograms. These weapons-usable nuclear materials are in 22 countries around the world, and if stolen, the results could be disastrous. Another 153 countries and Taiwan could serve as safe havens, staging grounds, or transit routes for illicit nuclear activities.

Civil nuclear facilities in 47 countries and Taiwan face mounting risks from disruptive technologies, like uncrewed aerial vehicles, climate change–related events (like wildfires and violent storms), and military attacks during war (like those on the Zaporizhzhia nuclear power plant in Ukraine and on the Barakah nuclear power plant in the United Arab Emirates). The terrorist threat also remains persistent. Groups and lone-wolf actors have demonstrated a clear intent to acquire nuclear materials for terrorist purposes and have repeatedly proved capable of sabotaging nuclear facilities. Protecting these facilities requires the constant vigilance of governments, nuclear operators, and international organizations.

The Theft and Sabotage Ranking Frameworks

The NTI Index’s three Theft and Sabotage rankings are each based on frameworks that assess key factors influencing nuclear security conditions. Each framework is different but draws from the same five categories of assessment factors.

1. Quantities and Sites

In the Theft: Secure Materials framework, the Quantities and Sites category captures the quantity of weapons-usable nuclear materials, the number and types of civil nuclear sites, and the frequency of transport of weapons-usable nuclear materials in a particular country—all factors related to the risk of theft of weapons-usable nuclear materials. It also measures whether a country is increasing or decreasing its stockpile of weapons-usable nuclear materials. In the Sabotage: Protect Facilities ranking, this category instead captures the number of civil nuclear sites in a country or area, and whether it is reprocessing spent nuclear fuel, using plutonium-based fuels in nuclear reactors, or exporting spent nuclear fuel for reprocessing abroad. This category is not included in the Theft: Support Global Efforts framework.

2. Security and Control Measures

In the Theft: Secure Materials and Sabotage: Protect Facilities frameworks, the Security and Control Measures category encompasses the core activities directly related to protection and accounting of nuclear materials. It includes indicators of physical protection, material control and accounting, insider threat prevention, response capabilities, cybersecurity, and security culture. In Theft: Secure Materials, it also measures security during transport. This category is not included in the framework for Theft: Support Global Efforts.

3. Global Norms

The Global Norms category measures actions that contribute to the strengthening of global norms for nuclear materials security and is included in all three ranking frameworks. It captures international legal commitments, voluntary participation in global initiatives, international assurances (excluded in Theft: Support Global Efforts), and IAEA information circulars (INFCIRCs) that highlight commitments made to improve nuclear security.

4. Domestic Commitments and Capacity

The Domestic Commitments and Capacity category indicates how well a country or area has implemented its international commitments and evaluates its capacity to do so. It appears in all three ranking frameworks and includes indicators on implementation of United Nations Security Council Resolution 1540, the status of legislation to implement the Amended Convention on the Physical Protection of Nuclear Material, and the presence of an independent regulatory body (excluded in Theft: Support Global Efforts).

5. Risk Environment

Across all three ranking frameworks, the Risk Environment category captures contextual factors, such as political stability, effective governance, corruption, armed conflict, and illicit activities by nonstate actors that are relevant to a country’s or area’s ability to implement effective security and regulatory oversight.

New Elements in 2026

NTI updates the ranking frameworks for each edition of the NTI Index to account for progress on nuclear security, incorporate new best practices, and acknowledge emerging challenges and risks. Previous editions of the NTI Index are then backscored to enable consistent comparison and tracking over time. Key changes this year include the following:

• New subindicators spanning multiple categories have been introduced to assess the nuclear security impact of national nuclear fuel cycles, including whether
  • Enrichment and reprocessing facilities are present
  • Spent nuclear fuel is reprocessed
  • Plutonium-based fuels are used in nuclear reactors
  • Spent nuclear fuel is exported for reprocessing abroad
  • Progress has been made on developing capacity for permanent disposition of spent nuclear fuel.
• Governments receive credit for establishing institutions that support regulatory capacity, including Nuclear Security Support Centers and cybersecurity research centers.
• Subindicators in the Security and Control Measures category have been revised to provide additional credit for regulatory requirements that mandate regular testing of security plans and systems in line with principles of continuous improvement and realistic threat assessment.
• A major revision of cybersecurity subindicators in the Security and Control Measures category has aligned them with modern practices in sensitive digital asset protection and supply chain cybersecurity risk management.
• New subindicators in the Global Norms category capture ratification of Additional Protocol I of the Geneva Conventions and support for the IAEA’s Seven Indispensable Pillars for Ensuring Nuclear Safety and Security During an Armed Conflict, reflecting lessons learned and new efforts to protect nuclear facilities from attack during war.
• Subindicators in the Risk Environment category have been revised to draw data from sources that allow higher-fidelity measurement of risk, such as the Heidelberg Institute for International Conflict Research’s Conflict Barometer and the Armed Conflict Location & Event Data conflict dataset. Armed conflict and violent demonstrations are now geo-mapped to enable scoring based on the proximity of those events to nuclear facilities.

The Radioactive Source Security Assessment Framework

The Radioactive Source Security Assessment does not score or rank the 176 countries and areas it includes. It is a qualitative overview of measures relevant to the security of radioactive sources in those countries and areas. The framework for the Radioactive Source Security Assessment comprises four categories.

A. National Measures

This category assesses a country’s or area’s domestic policies, commitments, and actions for managing and securing radioactive sources. It asks whether countries and areas have the following:

• An independent regulatory body to provide oversight over radioactive sources
• Domestic laws and regulations that explicitly require security (not just safety) measures to be in place to protect radioactive sources
• A maintained national registry of radioactive sources, a key step in tracking and accounting for sources at the national level
• Authority to inspect facilities with radioactive sources
• Licensing requirements for the export of IAEA Category 1 radioactive sources.

B. Global Norms

This category assesses a country’s or area’s international commitments and support for global norms around radioactive sources. It examines each country’s and area’s commitments in the context of the IAEA Code of Conduct on the Safety and Security of Radioactive Sources, including the Supplemental Guidance on the Import and Export of Radioactive Sources and Supplemental Guidance on the Management of Disused Radioactive Sources. It also asks whether a country or area participates in international organizations or conferences and is a party to key international legal agreements related to radiological security.

C. Commitment to Adopt Alternative Technologies

This category assesses a country’s or area’s commitment to supporting the development and implementation of alternative technology to high-activity radioactive sources through clear political commitments or national policies.

D. Risk Environment

The Radioactive Source Security Assessment uses the same risk environment measures as the Theft and Sabotage rankings of the NTI Index.

Expert Consultations

NTI and EE engage a wide array of experts throughout the development of each edition of the NTI Index. Participation in this process does not imply endorsement of the NTI Index by the individuals or the organizations with which they are affiliated.

International Panel of Experts

This panel of highly respected nuclear security experts played an advisory role in their personal capacities, ensuring that the NTI Index reflects a global perspective with accurate political and technical details of current nuclear security best practices.

• Nasser bin Nasser, Founder and CEO, Ambit Advisory
• Facundo Ciampagna Molina, Specialized Nuclear Security Advisor, Ministry of Security of the Republic of Argentina, National Cybercrime and Cyber Affairs Directorate
• Jae-Jun Han, Director, International Nuclear Nonproliferation and Security Academy, Korea Institute of Nuclear Nonproliferation and Control
• Kathleen Heppel-Masys, Vice President, Nuclear Operations Oversight, Atomic Energy Canada Limited
• Christopher Hobbs, Director, King’s Institute for Applied Security Studies, King’s College London
• Henrik Horne, Special Advisor, Nuclear Affairs, Advansia
• Margarita Kalinina-Pohl, Director, CBRN Security Program, James Martin Center for Nonproliferation Studies
• Yuki Kobayashi, Senior Research Fellow, Sasakawa Peace Foundation
• Dmitry Kovchegin, Independent Consultant
• Alfredo Labbé, Vice President, International Humanitarian Fact-Finding Commission
• Frans Mashilo, Chief Operations Officer, CAPRO Security Services
• Ruhee Neog, Director, Institute of Peace and Conflict Studies
• Sitara Noor, Research Fellow, Project on Managing the Atom, Harvard Belfer Center
• Pamela West, Nuclear Security Officer for the National Security Advisor of Nigeria

Risk Environment Experts

This group of practitioners, academics, nongovernmental researchers, and government officials advised on changes to the Risk Environment framework category.

• Muhammed Ali Alkiş, Research Affiliate, Odesa Center for Nonproliferation
• Seth Baum, Executive Director, Global Catastrophic Risk Institute
• Facundo Ciampagna Molina, Specialized Nuclear Security Advisor, Ministry of Security of the Republic of Argentina, National Cybercrime and Cyber Affairs Directorate
• Darya Dolzikova, Senior Research Fellow, Royal United Services Institute
• Sarah Laderman, Senior Analyst, Open Nuclear Network
• Frans Mashilo, Chief Operating Officer, CAPRO Security Services
• Ruhee Neog, Director, Institute of Peace and Conflict Studies
• Michiru Nishida, Professor, Nagasaki University Research Center for Nuclear Weapons Abolition
• Sitara Noor, Research Fellow, Project on Managing the Atom, Harvard Belfer Center
• Sonja Schmid, Professor, Department of Science, Technology, and Society, Virginia Tech
• Pamela West, Nuclear Security Officer for the National Security Advisor of Nigeria

Cybersecurity Technical Experts

These experts in the technical dimensions of cybersecurity and development of national and international security guidance helped inform the revision of cybersecurity measures in accordance with current best practice.

• William Gross, Chief Information Officer, Nuclear Energy Institute
• Michael Rowland, Principal Member of Technical Staff, Sandia National Laboratories