July 27, 1998

Chris Kielich, DOE/HQ, 202/586-5806
Staci West, PNNL, 509/372-6313

Breakthrough Systems to Detect Nuclear Explosions Worldwide

Scientists at the Department of Energy's Pacific Northwest National Laboratory in Richland, WA, have developed two breakthrough devices that can detect nuclear detonations by analyzing the atmosphere for traces of radioactive material. These systems, once activated, will be located around the globe and used to monitor the Comprehensive Nuclear-Test-Ban Treaty (CTBT) by detecting nuclear explosions.

President Clinton has determined that nonproliferation of nuclear weapons is one of the nation's highest priorities. The Department of Energy is responsible for the United States' research and development to monitor nuclear explosions in the context of a test ban treaty. The Energy Department provides technological and analytical support to guard against the spread of nuclear weapons and weapons-usable materials and has long been actively involved in preventing proliferation of nuclear weapons technology and protecting nuclear material and facilities.

"These new technologies enhance the ability of the United States and the international community to detect and confirm nuclear explosions," said Under Secretary of Energy Ernest Moniz. "This advancement in our ability to verify nuclear tests creates more impetus for Senate debate and vote to ratify the Comprehensive Nuclear-Test-Ban Treaty."

The two new detonation identification devices represent a quantum leap beyond existing monitoring devices, with greater sensitivity, full automation, near real-time reporting, and novel nuclear radiation detectors.

ARSA, the Automated Radioxenon Sampler/Analyzer, and RASA, the Radionuclide Aerosol Sampler/Analyzer, were created to verify the Comprehensive Nuclear-Test-Ban-Treaty. An international monitoring system is being set up to use the latest technology to watch for evidence that nuclear weapons are being tested. ARSA and RASA will comprise a large part of the technology employed in an 80-station radionuclide network.

"ARSA is the most valuable radionuclide detection method available to the CTBT," said Ted Bowyer, Pacific Northwest principal investigator for ARSA. "These two systems allow us to capture a tiny part of the weapon. Radionuclides are a smoking gun. They are positive confirmation of recent nuclear fission."

ARSA analyzes air samples for radioactive xenon, or radioxenon, that seeps from underground nuclear explosions – the most common testing method today but the most difficult to detect. ARSA has a detection sensitivity 10 to 100 times greater than other systems being used. In addition, it is the only completely automated radioactive xenon monitor.

ARSA collects air samples, then processes them to trap the radioactive xenon on cold charcoal. The system purifies the radioactive xenon, then transfers it to a nuclear counting system. The different isotopes of xenon are automatically measured, then the results are automatically passed to a data center by communication link. ARSA can be accessed by modem and programmed remotely.

RASA detects fission products from atmospheric nuclear explosions. This basic technique has been available for 30 years, but Pacific Northwest researchers have created the most sensitive automated system ever – more than 100 times as sensitive as the best previous technology.

RASA filters a huge volume of air each day to check for evidence of fission products from a nuclear explosion that attach to dust particles. The automated system draws air through a series of filters, which remove practically all of the atmospheric particles. The filters are sealed, bar coded, then passed to a radiation detection system. Radiation from weapons debris is then registered and translated to prove a violation of the treaty.

Information collected by ARSA, RASA and other monitoring systems at the global stations will be passed on to an international data center – a prototype is currently located in Arlington, VA, and planned for permanent housing in Vienna, Austria as part of the Comprehensive Nuclear-Test-Ban Treaty's international monitoring system. The other systems under development or in use include seismic, infrasound and hydroacoustic monitors.

Development of both RASA and ARSA is sponsored by the Energy Department's Office of Nonproliferation and National Security with the goal of transferring the technology to commercial vendors so that any country can acquire the systems to meet its obligations under the CTBT.

Pacific Northwest is one of the Department of Energy's nine multiprogram national laboratories and conducts research in the fields of environment, energy, health sciences and national security. Battelle, based in Columbus, OH, has operated Pacific Northwest for DOE since 1965.

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