Iran Threatens Geiger Counter: Extreme Danger Escalates

Key Chapter Title List

1. Overview of the Iran Threat Geiger Counter
2. Methodology Overview
3. Detailed Analysis of Threat Drivers: Hostile Actions
4. Detailed Analysis of Threat Drivers: Hostile Rhetoric
5. Detailed Analysis of Threat Drivers: Lack of Transparency
6. Detailed Analysis of Threat Drivers: Nuclear Breakout
7. Detailed Analysis of Threat Drivers: Sensitive Nuclear Capabilities
8. Detailed Analysis of Threat Drivers: Beyond Breakout – Nuclear Weaponization
9. Iran's Pathways to a Nuclear Weapon and Relative Timeline
10. Crash Program: Building a Non-Missile-Deliverable Nuclear Weapon
11. Missile-Deliverable Nuclear Weapon

Document Introduction

This report, published by the Institute for Science and International Security (ISIS) in April 2025, aims to provide a periodic quantitative assessment of the threat posed by Iran's nuclear program. The report indicates that since the previous assessment in February 2024, the Iranian nuclear threat has significantly worsened. Core negative factors include the enhancement of Iran's nuclear weapon capabilities, the shortening of the time frame required to manufacture a nuclear weapon, and the increasing normalization of discussions within Iran supporting nuclear weapon development. Ongoing military conflicts in the Middle East have heightened the likelihood of Iran deciding to build a nuclear weapon, while Iran's refusal to fully cooperate with the International Atomic Energy Agency (IAEA) has increased uncertainty regarding the intent of its nuclear program.

The report employs a "Geiger Counter" assessment system, quantifying the threat level on a scale of 0 to 180 points, divided into six levels. The total score for this assessment has risen to 157 points (151 points in February 2024), marking the second consecutive time it falls within the "Extreme Danger" range. The scoring is based on six major categories: Hostile Actions (20 points), Hostile Rhetoric (29 points), Lack of Transparency (24 points), Nuclear Breakout Time (30 points), Progress in Sensitive Nuclear Capability Development (27 points), and Nuclear Weaponization Efforts Beyond Breakout (27 points).

In the detailed analysis, the report elaborates on each threat driver. Regarding hostile actions, despite significant setbacks suffered by Iran and its proxy forces (such as Hamas, Hezbollah) in recent conflicts, and the collapse of the Syrian Assad regime, Iran still maintains a considerable inventory of drones, ballistic missiles, and cruise missiles, and continues to transfer weapons technology to Russia. In terms of hostile rhetoric, senior Iranian military and political officials have repeatedly publicly threatened Israel and the United States, and internal discussions have emerged calling for a change in nuclear doctrine and the development of nuclear weapons.

Lack of transparency is a primary concern. Iran continues to violate its Comprehensive Safeguards Agreement, refuses to implement the Additional Protocol, obstructs IAEA investigations into four undeclared sites, and has reduced monitoring access under the Joint Comprehensive Plan of Action framework, preventing the IAEA from obtaining a complete picture of its centrifuge and key component production and storage. Nuclear breakout capability has reached an extreme level; Iran possesses sufficient 60% highly enriched uranium to break out to weapons-grade enriched uranium within days, and its Fordow underground fuel enrichment plant already has the capability to rapidly produce weapons-grade uranium in large quantities.

Sensitive nuclear capabilities continue to be upgraded. Iran has increased the number of advanced centrifuges, boosted the production and stockpile of 60% highly enriched uranium, and retains the capability at Isfahan to convert enriched uranium hexafluoride into metal. Regarding nuclear weaponization, there are indications that Iran is accelerating nuclear weapons research and development, including conducting computer simulations related to nuclear explosions and resuming sensitive high-explosive work at former "Amad Plan" sites, potentially shortening the time to build its first nuclear weapon to a matter of months.

Finally, the report explores various pathways and timelines for Iran to acquire its first nuclear weapon, including an approximately six-month "crash program," a roughly two-year pathway to reconstitute the "Amad Plan," and a pathway involving the slow production of weapons-grade uranium under safeguards. The report emphasizes that the current regional tensions, Iran's growing capabilities, and the risk of an internal decision to develop nuclear weapons collectively constitute an extremely dangerous situation.