Testing at DARHT Results in Contamination of the Facility
August 8, 2008
Recent routine testing at the Dual Axis Radiographic Hydrodynamic Test Facility (DARHT) at Los Alamos National Laboratory (LANL) resulted in contamination of the large X-ray machine. During a test of the X-ray beam on July 31, a piece of graphite was vaporized and contaminated over 20 percent of the vacuum chambers. It will take about three months to clean up, resulting in delays of the first full-scale test using both of the DARHT axes.
DARHT is designed to digitally capture the images created by mock nuclear weapon devices as they implode. The experiments are called "hydrotests." During the experiments, DARHT generates a 17-million-volt beam of electrons that are slammed at right angles into a high explosive target. The two X-ray beams digitally photograph the interior of the materials being compressed to simulate a nuclear warhead explosion.
Electron accelerators create magnetic fields in a long row of large, circular aluminum vacuum chamber structures within the DARHT Facility. The magnetic fields steer the electrons in a beam to a target. During routine testing, graphite is used to block the X-rays from the target. During the recent test, a piece of the graphite broke off, was vaporized and sent carbon contamination through 17 of the 74 aluminum structures.
Many have criticized DARHT as being too expensive and behind schedule. In 2003, scientists found voltage breakdown problems in the second axis. As a result, DARHT underwent several years of reconstruction.
In May, the Department of Energy (DOE) announced the successful completion of the reconstruction and stated that it planned to conduct its first full-scale test by September or October 2008. That test is now delayed until early 2009.
The rebuilding effort cost $90 million and took five years to complete. Current cost estimates indicate that DARHT is a $350 million facility, which began construction in 1988. Construction was halted in 1995 when CCNS and the Los Alamos Study Group sued DOE because the required environmental studies had not been done. The groups were successful and DOE was required to complete an environmental impact statement for the facility.
LANL spokesman Kevin Roark said of the recent incident that, "It's an unwelcome thing, but when you're doing something for the first time and you're putting together a highly complex machine, you do expect things like this to happen. You'd like it better if they didn't happen, but it's a setback, not a disaster."
Sheri Kotowski, of the Embudo Valley Environmental Monitoring Group, based in the downwind community of Dixon, New Mexico, responded by saying, "Some call it an 'unwelcome thing,' and this unwelcome thing comes with an enormous price tag. LANL has continuous funding shortfalls when it comes to environmental clean up that impacts surrounding communities. Pressure needs to be put on regulators and elected officials to deal with the environmental contamination from the numerous 'uncontained' experiments conducted in previous years. That does not mean continued burial of wastes in unlined pits and trenches that threaten our ground water or wastes left on the ground to be dispersed through the air."