New Perspectives on Nuclear Verification

by MD Arifur Rahman (School of Politics and International Relations (SPIR), East China Normal University)

Tritium is a radioactive material with a half-life span of just 12.3 years, which is usually used as a boosting element in nuclear weapons, allowing relatively smaller bombs to release more than 10,000 tons of TNT energy without requiring a full thermonuclear weapon. Tritium quickly breaks down, so countries with nuclear arsenal sustain the production to maintain their arsenals. Meanwhile, tritium also uses in civilian fusion research, make it difficult to monitor due to the fact that it can serve both peaceful and military purpose, creating challenges for global disarmament effort.

In the nuclear disarmament context, irreversible means an arrangement that deters countries from easily rebuilding their nuclear arsenal, which help the long-term stability and trust among stakeholders. Layered verification, as proposed by Stephen Herzog, could include freeze, bands or international oversight, shut down the loopholes and prevent tritium from being used for weapon purpose. However, clandestine tritium production poses a risk as it can be done secretly in research reactors or accelerators, avoiding detection methods used for fissile materials. States can block the inspections, manipulate or hide the data, and exploit the treaty loopholes that let them rebuild later secret facilities and manipulated or hidden data weaken trust, particularly if the political promises fade away due to complex geopolitical calculation and increased tensions. These vulnerabilities show that without tritium-specific measures that integrate with fuel cycle transparency, disarmament is still reversible.

To address this concern, Robert E. Kelly propose Tritium Cut-off Treaty (TCOT), which doesn’t require immediate disarmament, instead it leverages tritium’s natural decay to produce automatic and irreversible reduction. This may invite nuclear-armed states to take a gradual approach. It would work as following: once a state stops producing tritium, half of its tritium supply should eliminate every 12.3 years, eventually disabling boosted weapons and cut the warhead stockpiles without intrusive dismantlement demands. Compared to the proposed Fissile Material Cut-off Treaty, that freeze capabilities at high levels, a TCOT would offer continuous decline. Verification, while difficult, is feasible, as Tritium released into the environment can be traced with adapted CTBTO-style sampling, production reactors have signatures distinct from commercial power reactors; and accountancy systems similar to IAEA safeguards could be expanded to tritium. As tritium can’t be stockpiled indefinitely, long-term covert storage is far less plausible than with fissile materials, providing an inherent advantage for verification.

Past initiative such as US-Soviet/Russian experiences in arms control, which include joint initiatives on warhead dismantlement transparency, past declaration of warhead numbers, and conversion of fissile materials could also inform a tritium cut-off treaty; however, these measures highly rely on the political will. Together with existing measures, such as implementing exports control measures, and universalizing the Additional Protocol to comprehensive safeguard agreements, a tritium freeze under international oversight would put extra layers of resilience to nonproliferation commitments and offer a relevant signal towards nuclear disarmament. Tritium is not a sole barrier to irreversible disarmament, but it is a very consequential. International cooperation led by the nuclear armed states and supported by the IAEA is key to make future disarmament commitments lasting and fair. By including tritium in the wider transparency framework, the international community can close the loopholes, establish trust and ensure nuclear disarmament is more secure and irreversible.

MD Arifur Rahman is currently a PhD candidate at the School of Politics and International Relations (SPIR), East China Normal University. His research focuses on nuclear verification, arms control and disarmament, and emerging technologies.

References:

• Kalinowski, M. B., & Colschen, L. C. (1995). International control of tritium to prevent horizontal proliferation and to foster nuclear disarmament. Science & Global Security, 5 (2), 131-203. Available at: https://scienceandglobalsecurity.org/archive/sgs05kalinowski.pdf (Accessed: 19/01/26)
• Woolf, A. F. (2024). Irreversibility in Nuclear Arms Control: Lessons from the US-Soviet/Russian Arms Control Process. Journal for Peace and Nuclear Disarmament, 7 (1), 27-40. https://doi.org/10.1080/25751654.2024.2359229
• Herzog, S. (2025). Layered verification: Irreversible nuclear disarmament and highly latent nuclear states. VERTIC Report, 1. Available at: https://www.vertic.org/2025/08/research-report-irreversible-nuclear-disarmament-and-highly-latent-states/ (Accessed: 19/01/26)
• Kelley, R. E. (2020, August 28). Starve nuclear weapons to death with a tritium freeze. SIPRI. Available at: https://www.sipri.org/commentary/topical-backgrounder/2020/starve-nuclear-weapons-death-tritium-freeze (Accessed: 19/01/26)