Clocking in at 16.32 sustained petaflops, a supercomputer at Lawrence Livermore National Laboratory has been named the world’s fastest computing system.

A petaflop is computer-speak for a quadrillion calculations per second.

To put the speed into perspective, if each of the 7 billion people on Earth had a hand calculator and worked together on a calculation 24 hours a day, 365 days a year, it would take about 300 years to do what this computer can do in one hour.

The speedy IBM-built computer named Sequoia earned the No. 1 ranking on the industry standard “Top 500” list released Monday at the International Supercomputing Conference in Hamburg, Germany. It was the first time since 2009 that a U.S. computer has topped the list. The former leader, a Japanese supercomputer called K, now ranks second.

Sequoia is used by the Department of Energy’s National Nuclear Security Administration for nuclear weapons simulation, essential since underground testing ended in 2009. Its quick calculations aid more complete understanding of weapons performance, such as hydrodynamics and how materials perform under extreme pressure and temperature. The simulations also are used to assess the viability of stockpiled weapons.

Sequoia will also be available for research in astronomy, energy, studying of the human genome and climate change.

By the end of the summer, it will calculate even faster — reaching a peak speed of 20 petaflop, according to Livermore lab spokesman Don Johnston.

The national laboratory in Livermore is managed by Lawrence Livermore National Security for the U.S. Department of Energy’s National Nuclear Security Administration.

Contact Lisa M. Krieger at 650-492-4098.