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High Hazard 618-7 Burial Ground Finished On Schedule

01.13.2009

RICHLAND, Wash. — The Department of Energy and its River Corridor cleanup contractor, Washington Closure Hanford, have met a Tri-Party Agreement milestone by safely completing one of the most hazardous burial grounds along the Columbia River.

The 618-7 Burial Ground is located about a mile north of Richland. It is composed of three trenches that, from 1960 to 1973, received waste from a nearby nuclear fuel fabrication facility. The smallest of the trenches is 460 feet long by 30 feet wide; the two larger trenches are 650 feet long by 100 feet wide.

Among the dangerous contents of the trenches was thorium, which was used to produce uranium-233 fuel elements. The trenches also contained chips of zircaloy, which can spontaneously ignite. The site also contained less volatile but still hazardous substances such as lead, beryllium and cadmium.

During the time of 618-7’s operation, the common practice was to bury contaminants as either loose debris or in drums. Project staff had limited records on which to base their assumptions about what the burial ground might contain.

Careful planning and detailed safety procedures enabled Washington Closure to safely handle a number of unique hazards during excavation. In August 2008, a small flash of fire occurred in one of the trenches but was addressed quickly without injuries or spread of contamination. Then in October 2008, two compressed gas cylinders suspected of containing dangerous chemical agents were found. A special contractor was hired to open, sample and neutralize the contents. In the end the cylinders were found to have been safely configured, and work proceeded without further delay.

In the year-long project, Washington Closure removed a range of materials from the 618- 7 Burial Ground including:

• More than 800 barrels containing, among other things, zircaloy chips, thorium, uranium, and oils
• 180,000 tons of soil and contaminated material
• Twenty large stainless steel tanks (some of which contained thorium powder)
• More than 100 drums of zircaloy chips contaminated with beryllium
• Extensive amounts of lead-contaminated soil and debris

Background Information