WASHINGTON, D.C. – The National Nuclear Security Administration (NNSA) has announced that two of its supercomputers are ranked in the top ten of the TOP500 List of the world’s most powerful supercomputers.
Both NNSA computers are located at Los Alamos National Laboratory (LANL) -- Cielo is ranked number six on the list and Roadrunner is ranked number 10. Five other supercomputers housed at NNSA sites are ranked in top 26 of the TOP500 list.
“The exceptional computing power of Cielo and Roadrunner supercomputers is critical to ensure the safety, security, and effectiveness of the nuclear stockpile while maintaining the moratorium on underground nuclear explosive testing,” said Don Cook, NNSA’s Deputy Administrator for Defense Programs. “The work done on all NNSA supercomputers is a vital part of NNSA’s efforts to implement President Obama’s nuclear security agenda.”
As part of NNSA’s mission to extend the lifetime of nuclear weapons in the stockpile, the Advanced Simulation and Computing (ASC) Campaign provides NNSA with leading edge, high-end simulation capabilities. The ASC program helps NNSA to meet nuclear weapons assessment and certification requirements, including: weapon codes, weapon science, computing platforms, and supporting infrastructure.
Cielo , a petascale resource for conducting NNSA weapons simulations in the 2011-2015 timeframe, can achieve more than one quadrillion floating point operations per second. Earlier this year, the Cielo system was upgraded from 1.03 petaflops (72 cabinets) to 1.37 petaflops (96 cabinets). Cielo is operated by the New Mexico Alliance for Computing at Extreme Scale (ACES), a collaboration between LANL and Sandia National Laboratories.
Roadrunner  has a peak performance of 1.38 petaflops and was the first supercomputer in the world to perform at a sustained petaflops rate on a scientific calculation. Roadrunner has a unique architecture that was designed to explore new computing technology, and is an important stepping stone to even larger systems in the future.
The top 26 include number 15: The Appro Xtreme-X, Lawrence Livermore National Laboratory (LLNL); number 17: BlueGene/Q, LLNL; number 22: BlueGene/L, LLNL; number 24: Red Sky, Sandia/National Energy Laboratory; number 26: Dawn – Blue Gene/P, LLNL.
The TOP500 list is compiled by Hans Meuer of the University of Mannheim, Germany; Erich Strohmaier and Horst Simon of NERSC/Lawrence Berkeley National Laboratory; and Jack Dongarra of the University of Tennessee, Knoxville. To see the entire list, see: http://www.top500.org/lists/2011/11 
To learn more about NNSA’s ASC Program, visit: http://nnsa.energy.gov/asc 
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Established by Congress in 2000, NNSA is a semi-autonomous agency within the U.S. Department of Energy responsible for enhancing national security through the military application of nuclear science. NNSA maintains and enhances the safety, security, reliability and performance of the U.S. nuclear weapons stockpile without nuclear testing; works to reduce global danger from weapons of mass destruction; provides the U.S. Navy with safe and effective nuclear propulsion; and responds to nuclear and radiological emergencies in the U.S. and abroad.