WASHINGTON — As President Obama gathers world leaders in Washington this week for his last Nuclear Security Summit, tons of materials that terrorists could use to make small nuclear devices or dirty bombs remain deeply vulnerable to theft. Still, Mr. Obama’s six-year effort to rid the world of loose nuclear material has succeeded in pulling bomb-grade fuel out of countries from Ukraine to Chile, and has firmly put nuclear security on the global agenda.
But despite the progress, several countries are balking at safeguards promoted by the United States or are building new stockpiles.
President Vladimir V. Putin of Russia, where some of the largest stockpiles of civilian nuclear material remain, has decided to boycott the summit meeting, which begins Thursday night. Mr. Putin has made it clear he will not engage in nuclear cleanup efforts dominated by the United States.
In addition, Pakistan’s embrace of a new generation of small, tactical nuclear weapons, which the Obama administration considers highly vulnerable to theft or misuse, has changed the way the administration talks about Pakistani nuclear security. While Mr. Obama declared early in his presidency that the United States believed Pakistan’s nuclear assets were secure, administration officials will no longer repeat that line. Instead, when the subject comes up, they note the modest progress Pakistan has made in training its guards and investing in sensors to detect break-ins. They refuse to discuss secret talks to persuade the Pakistanis not to deploy their new weapons.
Pakistan, China, India and Japan are all planning new factories to obtain plutonium that will add to the world’s stockpiles of bomb fuel.
And Belgium, where a nuclear facility was sabotaged in 2014 and where nuclear plant workers with inside access went off to fight for the Islamic State militant group, has emerged as a central worry. The country is so divided and disorganized that many fear it is vulnerable to an attack far more sophisticated than the bombings in the Brussels airport and subway system last week.
Near Beijing, one of the largest training centers opened this month. “It’s in our national interest” to help foreigners secure their atomic materials, said Nick Winowich, an engineer at Sandia National Laboratories, one of the American nuclear labs that helped in the center’s development.
The biggest wins have been the removal of all highly enriched uranium from 12 countries, including Austria, Chile, Hungary, Libya, Mexico, Turkey and Vietnam. The material was mostly reactor fuel. But officials said terrorists could have turned it into least 130 nuclear weapons.
Read more at Nuclear Materials Remain Vulnerable to Theft, Despite U.S.-Led Effort