April 7, 2005

Lab Uses X-Ray to Study Nuclear Explosions

ALBUQUERQUE (AP) -- Scientists at Los Alamos National Laboratory are using an enormous X-ray machine to see what happens inside an exploding nuclear weapon without actually setting one off.

The machine examines an explosion of the non-nuclear parts of a warhead commonly used in submarine-launched ballistic missiles.

In the latest of about a dozen large-scale nuclear weapons tests, scientists gathered data on the components' behavior during an explosion.

The lab said the data collected during the April 1 test will be used to improve computer models of weapons explosions, which took the place of underground nuclear tests after they were banned in 1992.

The Dual Axis Radiographic Hydrodynamic Test Facility's flash X-ray machine is the most powerful in the world and creates a snapshot of material moving over 2,000 miles per hour, according to the lab.

"It is an enormous version of a dentist's X-ray," said lab spokesman Jim Danneskiold.

Los Alamos has said DARHT will be the primary experimental facility for certifying the nuclear stockpile in the next decade.

The most recent test is part of an effort to ensure 100-kiloton W76 warheads for Trident missiles and other weapons remain safe and reliable as they age. There are about 2,700 W76s in the U.S. nuclear arsenal - more than any other nuclear weapon.

As the arsenal ages, the Energy Department started programs at LANL and other labs to determine the effects of time and changing maintenance technology on different models of weapons.

Construction of DARHT began in 1988 with a $30 million plan for an L-shaped building housing two X-ray machines that would produce nearly three-dimensional images of imploding weapons parts.

In 1998, the project expanded to increase the capability of the second axis, which bumped the price up to $270 million.

The first axis went into operation in 2000 and has been used in numerous tests. The second axis won't be ready until 2008, Danneskiold said. Construction was delayed by technical problems.

In 2003, the DOE's inspector general issued a report critical of the program for being behind schedule and moving research within lab departments to keep DARHT on budget.

Lab officials disagreed with the report, saying the project adhered to DOE management requirements.

The next large-scale experiment using DARHT is scheduled for this summer.


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