After a few more minutes of small talk, Salehi led them downstairs for a tour of the center. They were joined by the chief engineer, a tall man with a huge nose who also spoke English. He led them past a big concrete-and-metal sculpture of a crescent with a sun in the middle. Beyond it rose a tall red-and-white ventilator stack.
Salehi explained that all the facility’s structures were designed to withstand the specific seismic conditions of the region. The building housing the reactor complex and radiochemical lab were built to nine-point seismicity. These precautions almost completely eliminated the possibility of a core meltdown caused by an earthquake.
Crocker asked, “When was the last time you used your centrifuges to enrich uranium?”
Salehi raised one of his black eyebrows. “We have had no need to enrich uranium since 2003.”
Crocker, who was exhausted and had no more patience, cut straight to the point. “I’m sorry, but that’s not what I asked.”
“Perhaps I didn’t understand the question.”
“I didn’t ask if you needed to enrich uranium. I asked if you’ve done it since 2003.”
“No, of course not,” the director general answered curtly. He seemed offended.
Crocker didn’t care. “But you continue to store low-enriched uranium fuel to run the reactor?”
“That’s correct.”
As difficult as it was for Crocker to focus, he understood that there was a big difference between reactor-grade uranium and weapons-grade uranium. But even low-enriched uranium could be used to fuel a dirty bomb. He was one of a handful of people who were aware that something like that had almost happened when Iraq’s Tuwaitha Nuclear Research Center was looted in April 2003, following the fall of Saddam Hussein, and a quantity of low-enriched uranium was seized by al-Qaeda terrorists. Crocker had led a team into Iraq to recover the uranium in that highly dangerous environment. They succeeded, but Crocker still regretted that he had lost two men.
Even though Tajoura’s security hadn’t been compromised during the fighting in Libya, in his mind the situation here was even more troubling. Because while the IAEA had removed all existing weapons-grade uranium from Tajoura in 2004, it hadn’t disassembled the facility’s centrifuge plant. As ST-6’s WMD officer, he knew the technology. One needed an elaborate centrifuge plant like that at Tajoura—which featured over ten thousand P2 gas centrifuges—to separate weapons-grade uranium (U-235) from the heavier metal. Uranium ore contained roughly 0.7 percent of U-235.
The process was complicated and time consuming. First, a cylindrical rotor housed in a glass casing was evacuated of all air to produce frictionless rotation. A motor was used to spin the rotor, creating centrifugal force. Heavier molecules separated to the bottom of the centrifuge, while the light molecules moved to the top. Output lines at the top of the centrifuge carried the lighter molecules to other centrifuges that kept refining them.
After separating the gaseous U-235 through many centrifuge steps, engineers then used another chemical reaction to turn the uranium gas back into a solid metal that could then be shaped for use as bombs.
As they continued to tour the facility, Crocker asked himself, If they weren’t enriching weapons-grade uranium, why were they storing UF6?
It was a question that wasn’t answered during their visit and that continued to bug him as they drove away.
“What’d you think?” Mancini asked from behind the wheel.
Crocker was trying to separate his anxiety about Holly from the questions he had about the center. He said, “Something about the whole thing leaves a bad taste in my mouth.”
“I wonder why they let us tour the reactor complex but didn’t show us the radiochemical lab, which is the probable location of the centrifuge plant.”
“I’ve been asking myself the same thing.” In fact, Crocker had specifically asked to see it. He was told the lab was closed and unsafe to visit because of high levels of radiation.
Now what?
They called Ritchie and Davis again, but they had no news. Then he called Leo Debray at the embassy; he was out of the office. Crocker didn’t feel like sitting around the guesthouse or driving around aimlessly. He also didn’t see the point of going back to the embassy and trying to explain his suspicions about Tajoura to Remington. He preferred that Remington and his staff focus on locating—or better yet, rescuing—Holly and Brian.
Troubled about the UF6 and Salehi’s evasions, and not knowing what to do next, he said, “Let’s stop here and wait near the gate.”
“Why?” Akil asked.
“I need to think.”