"The hardest part of making a bomb is to get the material," he said. "That's why it's so imperative that we get that material locked up tightly in a way that essentially like a super Fort Knox, where terrorists simply cannot get at. It would be devastating if terrorists got their hands on this material, set it off in a major metropolitan area anywhere in the world."
The top-secret mission in Chile unfolded as heads of state from 47 countries prepared to come to Washington, D.C., for the first-ever nuclear security summit, beginning April 12.
Securing vulnerable nuclear material from civilian sites around the world has been a priority for the Obama administration.
At the start of his term, President Obama pledged to reduce nuclear arsenals around the world and this week, the administration announced changes to U.S. nuclear policy, which will restrict the use of nuclear weapons. The new policy includes a controversial pledge to refrain from using nuclear weapons to attack any country that is in compliance with the Nuclear Non-Proliferation Treaty, even if that country has attacked the United States with chemical or biological weapons.
In Prague last April, the Obama administration announced a new international effort to secure all vulnerable nuclear material around the world within four years.
The NNSA has been working behind the scenes to reach that formidable goal. It has upgraded security at hundreds of sites, converted 60 reactors to non-weapons-grade fuel, and helped retrieve more than 150 bombs-worth of nuclear material from sites in dozens of countries. The mission in Chile is one part of that effort.
It's all part of Obama's larger agenda to "prevent the spread of nuclear weapons" and enhance global security.
As part of their mission in Chile, the NNSA team -- working closely with the Chileans -- removed fresh uranium as well as the highly-radioactive spent uranium from the heart of the reactor.
"As long as there is highly enriched uranium, there is always a concern that something that could happen to a facility," said Bieniawski.
Armed guards secured the perimeter as every bit of the material was weighed so each microgram could be accounted for on every step of the journey. After 10 days, the material was packed and ready to go.
The next day, the earthquake struck. No one on the team was hurt, but suddenly the mission had become infinitely more complex.
"There is no power in this facility here," Bieniawski said. "The toilets aren't really working very well. ... We are walking down the halls with flashlights. People are basically tripping down the stairs because there is no emergency backup lighting."
The port the team intended to ship the nuclear material from suffered major damage from the quake, forcing them to chart a whole new route.
"We have never been in a situation where we have had an earthquake and had to adapt to a situation like this," Bieniawski said.
At dusk, armed guards stood watch as the cargo was loaded on to trucks for the overnight journey to the port.
"The truck over here to my right has the most attractive material from a terrorist perspective," Bieniawski said. "It is fresh highly enriched uranium, which means you can just hold it in your bare hands, so our biggest concern is to make sure this container is protected."