Atmospheric Release Advisory Capability (ARAC)

Atmospheric Release Advisory Capability (ARAC)

The Atmospheric Release Advisory Capability (ARAC) is an effort through which the United States Department of Energy (DOE) monitors and predicts the release of hazardous materials into the atmosphere. The bulk of its activities takes place at the National Atmospheric Release Advisory Center (NARAC), located at the University of California's Lawrence Livermore National Laboratory. ARAC and NARAC have provided assessment on more than 100 incidents of hazardous-material release, whether accidental or intentional, involving nuclear, chemical, biological, and natural materials.

In 1973, Rudy J. Engelmann of the DOE consulted scientists at Livermore to learn if it were possible to create an integrated system for providing data on potential and ongoing atmospheric hazards. The laboratory undertook a feasibility study, and the result was the creation of ARAC a year later. ARAC and its national center, NARAC, got their first major test on March 28, 1979, after a malfunction in the nuclear power plant at Three Mile Island near Harrisburg, Pennsylvania, threatened to release radioactive materials into the atmosphere. NARAC analysis helped provide DOE with an accurate picture of radioactivity in and around the plant, and helped prevent an environmental disaster.

Seven years later, a far worse nuclear incident occurred in what is now Ukraine, then a part of the Soviet Union. On April 26, 1986, an accident at the Chernobyl nuclear reactor killed 31 workers immediately, and ultimately led to the deaths of some 10,000 people. With the Soviet government withholding information, even from its own citizens in the threatened area, the U.S. government turned to ARAC. Over the weeks that followed, the team at NARAC assisted western European U.S. allies in assessing the threat, and accurately predicted the subsequent spread of radioactive material across the northern hemisphere.

Accidental nuclear hazards are only one type of event among many for which ARAC has provided data. Other examples include the oil fires set by a retreating Iraqi army during the final days of the Persian Gulf War in February 1991; the volcanic eruption of Mount Pinatubo in the Philippines in June of that year; a sulfuric-acid spill in Richmond, California, in 1993; the reentry of a nuclear-powered Russian spacecraft over Chile in 1996; and the Hanford wildfire in Richland, Washington, in 2000.

Though ARAC and NARAC might seem to be virtually identical, the former is an agency of DOE, while the latter supports both DOE, the Department of Defense, and other governmental organizations. Nor are its DOE responsibilities confined to the consequence-management mission of ARAC, though this is certainly a primary activity for NARAC. NARAC also supports other federal, state, and even local agencies in accordance with the Federal Radiological Emergency Response Plan and the Federal Response Plan.



Cassaro, Edward, and Linda Lomonaco. Operators Guide: Atmospheric Release Advisory Capability (ARAC) Site Facility. Springfield, VA: Department of Energy, 1979.

Orphan, R. C. A Study of Applying the Atmospheric Release Advisory Capability to Nuclear Power Plants. Springfield, VA: Department of Energy, 1978.


National Atmospheric Release Advisory Center. < > (January 14, 2003).


Chernobyl Nuclear Power Plant Accident, Detection and Monitoring
DOE (United States Department of Energy)
Lawrence Livermore National Laboratory (LLNL)
Nuclear Detection Devices

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