How Los Alamos Scientists Trace Illicit Nuclear Material
In a world where nuclear security threats loom, scientists at Los Alamos National Laboratory stand ready to analyze nuclear evidence and unmask its origins.
Explore the ScienceImagine a smoking gun that could trigger a global crisis—a intercepted nuclear device or smuggled radioactive material. Unlike conventional evidence, this "smoking gun" is radioactive, incredibly dangerous, and its origins are intentionally obscured.
Nuclear forensics, the scientific discipline of analyzing nuclear materials to trace their source and history, is our best defense against such threats. At Los Alamos National Laboratory (LANL), a team of dedicated scientists has spent decades honing the techniques to act as nuclear detectives, ensuring that even the smallest trace of nuclear material can tell a story that helps keep the world safe.
At its core, nuclear forensics is "the examination of nuclear and other radioactive materials using analytical techniques to determine the origin and history of this material" 5 .
Just as a traditional detective looks for fingerprints or DNA at a crime scene, a nuclear forensic scientist searches for the unique chemical and isotopic characteristics of nuclear material that reveal its past.
These signatures can answer critical questions: Was this plutonium produced in a power reactor or a dedicated production reactor? How long has it been since it was purified? What geological source did its uranium precursor come from?
The end of the Cold War and the subsequent collapse of the Soviet Union brought new fears of nuclear material trafficking into the West.
"The world saw that terrorists have no limits," explains Warren Oldham of the Nuclear and Radiochemistry group at Los Alamos. "An improvised nuclear device went from a low‑probability concern to suddenly a very real, immediate threat" 5 .
"We have expertise in handling materials, providing chemical and isotopic analysis, and assessing the data. Our weapons designers can take their known data and apply it to unknown—potentially dangerous—situations."
How does a country prepare for a nuclear emergency? The answer lies in relentless practice. In 2024, the National Nuclear Security Administration (NNSA) conducted a multi-laboratory nuclear forensics exercise called Epic Shadow to demonstrate its readiness 6 .
The exercise scenario began with local law enforcement intercepting nuclear material that a fictitious perpetrator intended to use in a nuclear device.
The Epic Shadow exercise successfully demonstrated that the U.S. nuclear forensics infrastructure can rapidly and effectively analyze illicit nuclear material.
The results from these laboratories are admissible in legal proceedings and could underpin both national and international responses to a nuclear security event 6 .
"NF-MAP is a vital element of U.S. national security. When it comes to nuclear materials, our nuclear forensics analysis capability provides a sound scientific foundation for us to figure out who did it and hold them accountable."
Los Alamos National Laboratory
Lawrence Livermore National Laboratory
Oak Ridge National Laboratory
Pacific Northwest National Laboratory
The power of nuclear forensics lies in the sophisticated tools and methods scientists use to extract information from nuclear materials.
| Technique | Brief Description | Primary Function in Nuclear Forensics |
|---|---|---|
| Mass Spectrometry | Measures the masses of atoms and molecules to determine isotopic ratios. | Considered a key "nuclear forensic signature" for identifying the origin and production history of nuclear material . |
| Gamma Spectroscopy | A non-destructive technique that measures the energy of gamma rays emitted by a material. | Used to identify radioactive isotopes present, providing clues about the material's age and intended use 5 . |
| Electron Microscopy | Uses a beam of electrons to create a high-resolution image of a sample. | Reveals the physical structure and microstructure of the material, which can be tied to a specific manufacturing process 1 . |
| Computational Modeling | Uses advanced computer simulations to model reactor operations and material production. | Generates theoretical nuclear forensic signatures for comparison, especially when access to actual facilities is limited . |
| Material/Reagent | Critical Function |
|---|---|
| Plutonium & Uranium Matrices | The primary subjects of analysis; their isotopic and chemical composition provides the most critical attribution signatures 1 . |
| Actinide Analytical Chemistry Labs | Specialized facilities that allow for the safe handling, preparation, and analysis of highly radioactive samples 1 . |
| Reference Materials | Certified standard materials with known compositions, essential for calibrating instruments and validating measurement accuracy. |
| Sample Preparation Reagents | High-purity acids and chemicals used to dissolve and prepare solid nuclear samples for analysis in mass spectrometers and other instruments. |
Los Alamos's facilities support analysis of samples containing nearly any mass of an actinide, from attogram (a quintillionth of a gram) to kilogram levels 1 .
The laboratory uses numerous means to validate and independently verify that measurement data quality objectives are met, ensuring that every result is reliable and defensible 1 .
Los Alamos is the only laboratory in the complex that can contribute technical expertise to all phases of a nuclear forensics investigation, from initial detection to final analysis 5 .
The work of Los Alamos's nuclear detectives extends far beyond the laboratory walls, with global initiatives to strengthen nuclear security worldwide.
They lead the Offsite Source Recovery Program, which has recovered disused and vulnerable radioactive sources from domestic and international sites since 1997, preventing them from falling into the wrong hands 3 .
LANL experts support the IAEA in conducting national inventories in other countries and developing strategies for managing disused sources 3 . This global cooperation is vital for strengthening international nuclear security infrastructure.
IAEA
GICNT
INTERPOL
NNSA
DOE
DOD
The future of nuclear forensics depends on maintaining momentum. As one Los Alamos report aptly put it, "Keeping the Momentum" is essential 1 2 4 . This involves continuous research and development into new signatures, ongoing training of the next generation of scientists, and regular exercises like Epic Shadow to ensure readiness.
"We must be prepared for a low-probability, high-impact event. We're always weighing immediate threats versus long-term risks, hoping to maintain global security."
In the high-stakes world of nuclear security, the silent, meticulous work of the nuclear detectives at Los Alamos provides a powerful deterrent. Their ability to trace a material back to its source ensures that any would-be proliferator or terrorist can be identified and held accountable, making the world a safer place for everyone.