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The Laboratory
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Sequoia Ranks Number 1 in Top500
The Laboratory’s Sequoia ranked as the world’s most powerful supercomputer on the Top500 list released in June 2012. Sequoia, a 96-rack IBM BlueGene/Q system developed in partnership with the National Nuclear Security Administration (NNSA), demonstrated a sustained performance of 16.32-quadrillion floating-point operations per second (petaflops) on the industry standard LINPACK benchmark. Sequoia will enable simulations that explore phenomena at a level of detail never before possible. The computer is dedicated to NNSA’s Advanced Simulation and Computing (ASC) Program for stewardship of the nation’s nuclear weapons stockpile, a joint effort of Lawrence Livermore, Los Alamos, and Sandia national laboratories.

“Computing platforms such as Sequoia help the United States keep its nuclear stockpile safe, secure, and effective without the need for underground testing,” says NNSA Administrator Thomas D’Agostino. “While Sequoia may be the fastest, the underlying computing capabilities it provides give us increased confidence in the nation’s nuclear deterrent as the weapons stockpile changes under treaty agreements, a critical part of President Obama’s nuclear security agenda. Sequoia also represents continued American leadership in high-performance computing, key to the technology innovation that drives high-quality jobs and economic prosperity.”

“Sequoia will provide a more complete understanding of weapons performance, notably hydrodynamics and properties of materials at extreme pressures and temperatures,” says Bob Meisner, NNSA director of the ASC Program. “In particular, the system will enable suites of highly resolved uncertainty quantification calculations to support the effort to extend the life of aging weapons systems; what we call a life-extension program.”
Contact: Dona Crawford (925) 422-1985 (crawford13@llnl.gov).

A Faster, Lower-Cost Desalination Technique
A team of Laboratory researchers led by Michael Stadermann has developed a capacitive desalination technique that could ultimately lower the cost and time of desalinating seawater. In capacitive desalination (CD), a voltage is applied between two porous electrodes to adsorb ions onto the electrode surface and thus remove them from the feed stream. Traditionally, due to the small pore sizes of the electrodes, the feed stream flows between the electrodes and through a dielectric porous separator. The new technique, called flow-through electrode CD, uses porous carbon materials with a hierarchical pore structure, which allows the saltwater to easily flow through the electrodes themselves.

The Livermore approach offers several advantages relative to traditional flow-between systems, including faster and more energy efficient desalination with more salt removed for each charge of the capacitor. Finally, flow-through can be used with a thinner separator because the separator is no longer a flow channel, thereby reducing the overall and electrical resistance of the device, which further decreases costs.

“By leveraging innovative porous carbon materials recently developed at Livermore, our method removes the diffusion limitations afflicting traditional CD cells. The desalination process now only takes as long as it takes to charge the electrodes, on the order of minutes or less,” says Matthew Suss, a Lawrence scholar and first author of a paper that appeared online June 26, 2012, in Energy & Environmental Science. “The new method currently removes salt five to ten times faster than previous CD systems and can be further optimized for increased speed. It also reduces the concentration of the feed up to three times as much per charge.” Other Livermore researchers on this project include Theodore Baumann, William Bourcier, and Christopher Spadaccini.
Contact: Michael Stadermann (925) 423-9128 (stadermann2@llnl.gov).

New Accelerator Ready to Go
The Department of Energy’s Heavy-Ion Fusion Science Virtual National Laboratory (HIFS-VNL), whose member institutions include Lawrence Livermore and Lawrence Berkeley national laboratories and the Princeton Plasma Physics Laboratory, has recently completed a new accelerator designed to study an alternate approach to inertial fusion energy. Housed at Lawrence Berkeley, NDCX-II is a compact machine designed to produce a high-quality, dense beam that can rapidly deliver a powerful punch to a solid target.

Research with NDCX-II will introduce advances in the acceleration, compression, and focusing of intense ion beams that can inform and guide the design of major components for heavy-ion fusion energy production. Livermore developed most of the physics design for NDCX-II under a subcontract to Lawrence Berkeley. The Laboratory also provided the accelerating cells, which were previously used for its Advanced Test Accelerator, and the Blumleins, which are 250,000-volt, pulsed-power sources that provide the rapid final acceleration.

“NDCX-II represents the first conversion of electron induction accelerator components into a pulse-compressing ion accelerator,” says Livermore’s Alex Friedman, the project’s beam acceleration task area leader. “With NDCX-II, we will be able to study fusion-relevant intense-beam physics, properties of ion-heated matter, and elements of target physics for ion-beam-driven inertial fusion energy.”
Contact: Alex Friedman (510) 486-5592 (friedman1@llnl.gov).



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Privacy & Legal Notice | UCRL-TR-52000-12-10/11 | October 1, 2012