Sandia National Laboratory Shortcuts Hazard Analysis

June 11, 2010

Sandia National Laboratory took shortcuts when determining the amount of protection that is needed for operations at the "Z" machine, which vaporizes plutonium in nuclear weapons experiments. Sandia did not conduct a full analysis as required by the Department of Energy (DOE) standards, resulting in a possible under estimation of the hazard by 100 to 1,000 times.

In a recent report, the Defense Nuclear Facility Safety Board said that Sandia did not comply with the DOE standard that sets out a two-part test for categorizing hazards. Depending upon the level of hazard, more protective measures must be taken in order to ensure the safety of workers, the public, and the environment. [Click on the enclosure.]

In 1988, Congress established the Board as an independent federal agency charged with safety oversight of the nuclear weapons complex.

Sandia nuclear weapons scientists conduct thermodynamic experiments in the Z machine in which plutonium is compressed by magnetic pressure. The Z machine was recently refurbished and preparations are being made for restarting the experiments.

The first step of the DOE hazard test requires determination of the amount of material used. Sandia categorized the Z machine as less than a Hazard Category 3, which means that less than 8.4 grams of plutonium will be located in the facility.

The second part of the test requires computer analysis of a potential release from the facility in which no equipment is in place to contain it. The experiments are primarily contained by a set of valves that are activated by a compression signal. A second engineered containment is provided in the emissions stack.

Sandia did only the first part of the analysis, but it did not take the second step.

Sandia's initial analysis was based on experiments conducted in 2005, which gave credit for the secondary containment found in the emissions stack. In 2007, another analysis was done, again determining that the Hazard Category 3 applied.

But the Board questioned whether the containment system noted in the 2005 report was included in the 2007 report. It stated that because plutonium is vaporized in the experiments, the second requirement applied for calculating the release. The Board lists possible failures of the containment system, such as that one or more of the 36 modules could pre-fire, or that the engineered emission stack could fail, or failure of the plutonium target.

Dave McCoy, Director of Citizen Action New Mexico, said, "Sandia's failed safety valve for the Z Machine poses danger to workers and the public from cancer causing amounts of airborne plutonium that are up to a thousand times higher than Sandia's estimates. British Petroleum's design for prevention of an oil rig blow-out similarly relied on a flawed safety valve."

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