WASHINGTON – A computer designed to run virtual tests of U.S. nuclear weapons will be the world's fastest, making 1,000 trillion calculations per second, the U.S. Department of Energy said Monday.

The IBM Roadrunner supercomputer at Los Alamos National Laboratory in New Mexico is the first to achieve a what is known as a petaflop of sustained performance, the department and IBM said.

“Flop” is an acronym meaning floating-point operations per second. One petaflop is 1,000 trillion computer calculations per second.

“Roadrunner will be used by the Department of Energy's National Nuclear Security Administration to perform calculations that vastly improve the ability to certify that the U.S. nuclear weapons stockpile is reliable without conducting underground nuclear tests,” the department said in a statement.

“Roadrunner will not only play a key role in maintaining the U.S. nuclear deterrent, it will also contribute to solving our global energy challenges, and open new windows of knowledge in the basic scientific research fields,” it added.

“To put this into perspective, if each of the 6 billion people on earth had a hand calculator and worked together on a calculation 24 hours per day, 365 days a year, it would take 46 years to do what Roadrunner would do in one day,” the department said.

(Reporting by Maggie Fox, Editing by Eric Auchard)