NNSA, LANL Complete DARHT Improvements With Successful Multi-frame Hydrodynamic Test

Press Release
Aug 10, 2010

WASHINGTON, D.C. – The National Nuclear Security Administration (NNSA) announced today that Los Alamos National Laboratory’s (LANL) Dual Axis Radiographic Hydrodynamic Test (DARHT) facility has completed another successful two axis, multi-frame hydrodynamic test following a period of facility maintenance and several key facility and technical improvements.

The successful hydrodynamic test, number 3648, resulted in five superior-quality radiographs — essentially high-powered X-ray images — of a surrogate-material implosion system in support of baseline activities that allow the NNSA to ensure the safety, security and effectiveness of the U.S. nuclear deterrent.

“The results of this successful DARHT test demonstrate NNSA’s commitment to ensuring we have top-quality tools and first-rate people required to ensure the safety, security and effectiveness of nuclear weapons stockpile without testing,” said Don Cook, Deputy Administrator for Defense Programs. “The recent technical upgrades and facility maintenance at DARHT were important investments to NNSA’s infrastructure to help solve tough national challenges. We congratulate the Los Alamos lab for a job well done.”

Data sets from DARHT experiments are used to verify nuclear weapons-related computer codes by providing multiple X-ray pictures of imploding weapon component mockups from two viewpoints at a 90-degree angle. These images are used to evaluate the hydrodynamics of nuclear weapons components. This area of hydrodynamics is the study of how solid materials behave like liquids under extreme pressures and temperatures.

“Once again the people supporting DARHT have demonstrated their exceptional professionalism in facility operations,” said Charles McMillan, Principal Associate Director for Nuclear Weapons at Los Alamos. “Their focus continues to be the delivery of high quality data, effectively dealing with complex technical questions as they arise, and consistently seeking ways to advance the scientific and technical capability at DARHT.

DARHT consists of two linear-induction accelerators oriented at right angles to one another. A linear-induction accelerator uses magnetic cores to allow better coupling of electrostatic fields to accelerate electrons or other particles to extremely high energies. At DARHT those electron beams are focused on a metal target. As the high-energy electrons hit the target, the electrons are slowed, converting the beam’s kinetic energy into powerful X-rays. The X-rays produce radiographic images of full-scale mockups of certain nuclear weapon components as they are driven to implode by high explosives. In the case of DARHT, the experiment has to make an x-ray through thick metal in less than a millionth of a second.

The DARHT program has two more hydrodynamic tests scheduled in fiscal year 2010, with future plans to improve its multi-image capability – potentially increasing the number of radiographs possible with each test.

Prior to this latest test the DARHT facility completed a months-long maintenance and upgrade project. The second axis went through a refurbishment of the 88-stage Marx bank — essentially a series of 88 large capacitors that can be charged together but discharged in a series, resulting in extremely high voltage pulses — and the facility’s accelerator and execution control rooms underwent extensive upgrades that included building an all fiber-optic timing, firing, and communications system — greatly improving reliability — and adding energy-efficient, high-definition video monitors.

About LANL (www.lanl.gov/ offsite link): Los Alamos National Laboratory, a multidisciplinary research institution engaged in strategic science on behalf of national security, is operated by Los Alamos National Security, LLC, a team composed of Bechtel National, the University of California, The Babcock & Wilcox Company, and URS for the Department of Energy’s National Nuclear Security Administration. Los Alamos enhances national security by ensuring the safety and reliability of the U.S. nuclear stockpile, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to energy, environment, infrastructure, health, and global security concerns.

Follow NNSA News on Facebook, Twitter, YouTube, and Flickr.

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 in the nation’s national security enterprise. NNSA maintains and enhances the safety, security, reliability, and performance of the U.S. nuclear weapons stockpile without nuclear testing; reduces the 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.