It was a blisteringly hot morning when I reported to Los Alamos National Laboratory (LANL) for nuclear inspector school. The lab is the old home of the Manhattan Project, the secret effort to develop the first nuclear weapons. It sits atop a mesa north of Santa Fe, New Mexico, isolated by geography and security checkpoints.
Credentials checked, I was driven down 鈥淧lutonium Corridor,鈥� a main road that passes a building encased in five layers of barbed fencing. It is where they design and maintain nuclear bombs. Elsewhere, LANL trains nuclear inspectors detect plutonium and enriched uranium 鈥� the hallmarks of nuclear weapon-building programmes.
The increasing fears over North Korea and Iran developing the bomb show why such lessons are needed. One goal is to build partnerships with countries as they start to use nuclear power, instead of policing a nuclear programme run unchecked for years, says Danielle Watts at the US National Nuclear Security Administration.
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I had been invited to join the training session for two days, provided I stick to a few strict rules: no phones, no computers, and no touching the plutonium.
Given the secure nature of the work, I am not allowed to name my fellow trainees, or their home nations, though I can say they came from 11 countries across Africa and Asia. 聽One of them told me he works as an internal inspector, checking for nuclear material at the border. Another was setting up his country鈥檚 first ever system for nuclear regulations.
Our host, Bill Geist, started by handing out dosimeters to track any radiation we received. Some of the students immediately seemed concerned 鈥� we were going to be working with plutonium, after all. Geist reassured us. 鈥淚鈥檝e been working in these labs for years, and I鈥檝e never had a reading that went above safe levels,鈥� he said.
Nuclear fingerprinting
After a morning of lectures, we went into the lab. First up was detecting gamma rays. 鈥淕amma rays are like a fingerprint. They can uniquely identify a material,鈥� said Ram Venkataraman, one of the instructors from Oak Ridge National Laboratory, Tennessee.
I saw what he meant when we placed a sample of cobalt-60 in front of a sodium-iodide detector. Mountains of red bars took over the computer screen. The peaks and valleys were energy levels of x-rays and gamma rays emanating from the sample. Like the whorls of a fingerprint, each element has a distinct readout.
The samples we used were contained in nested boxes. The biggest was a small聽plastic box聽with a blue lid, the kind of thing you might use to store salad dressing. Within that was a smaller plastic box and inside that was a coin of metal. At its centre, a dot of cobalt was barely visible.
Then things got serious. Our instructor, Robert Weinmann-Smith, went to a secured-off area and came back with a metal cannister about the size of a paint can. It had a makeshift handle of yellow duct tape. 鈥淣ow let鈥檚 measure plutonium,鈥� he said, setting it on the table with a loud clank. The sample emitted so many x-rays that it overloaded the detector, so we had to add shielding to see anything useful.
Finally, we had the last, mystery sample. The only clue we had was the large red tape on its side that read 鈥淣UCLEAR MATERIAL.鈥� Studying the pattern of gamma radiation, we cracked it: uranium.
The next day we went hunting with handheld detectors, which show a red bar that grows as you get closer to a radioactive source. We pointed them under chairs and behind computers. Soon, three people clustered in a corner. They had found a container of something radioactive in a desk drawer. Next, they had to figure out what was inside.
Difficult search
This proved difficult because it was a mixture of several materials. The radiation given off by a combination of two fairly innocuous materials can look like plutonium or uranium to the untrained eye. On the other hand, a bit of caesium can mask the signature usually seen from plutonium.
We also learned to determine how enriched a sample of uranium. Three to five per cent is normal for nuclear power plants, while anything above could be used in a weapon. Finally, they were taught how to calculate the mass of nuclear material inside a sealed container. That鈥檚 important, because people attempting to make a bomb could skim off a small amount from each canister at a nuclear fuel plant, and then enrich it.
At times, piecing all this together felt like a game of Cluedo: which isotope, how much of it, and how enriched is it? But then I鈥檇 remember what Weinmann-Smith told me 鈥� that there鈥檚 at least enough nuclear material in the world to make 200,000 bombs, and the IAEA speculates that 30 countries have the capability to do so. Given the current climate, this work is deadly serious.
