Projects | ARRA

The Environmental Restoration Disposal Facility is being expanded and upgraded for the fourth time since it began operation in 1996. ERDF accommodates low-level radioactive, hazardous and mixed waste generated during cleanup activities from the River Corridor Cleanup Project and other Hanford contractors. As of February 2010, ERDF had received nine million tons of waste for disposal.

The facility consists of a series of disposal areas called cells. A pair of adjoining cells is 70 feet deep, and 500 feet by 1,000 feet at the base. Each cell is constructed with a bottom liner consisting of multiple layers of plastic, other impermeable materials and a system to collect and remove liquids as they drain through the waste materials.

In the past, the facility has expanded two cells at a time. But recent design upgrades have led to the combination of two cells into one “super cell.” Two new super cells – Nos. 9 and 10 – are under construction. The expansion, which will increase total disposal capacity to more than 16 million tons, is necessary to accommodate cleanup waste disposed by Washington Closure and other Hanford contractors.

TradeWind Services, a service-disabled, veteran-owned small business, recently began work to add two new “super” cells – or waste disposal areas – to the facility. Super cells are twice the size of existing cells, or disposal areas. TradeWind, along with prime subcontractor DelHur Industries, will excavate super cell 10 and construct the liner and leachate collection system of super cells 9 and 10. DelHur completed the excavation of super cell 9 earlier this year.     

The 618-10 Burial Ground is considered the most complex Washington Closure has addressed to date. From 1954 to 1963, Hanford workers dumped highly radioactive waste into 94 vertical pipes and 23 waste trenches. Vertical pipe units, or VPUs, are five bottomless 55-gallon drums welded together end to end and buried vertically.

An extensive search of Hanford records yielded valuable information about burial ground contents. However, more information is needed before workers can safely clean up the site. Because of the potential risks and challenges, Washington Closure is taking an extremely cautious approach to clean up the 618-10 Burial Ground.

In late 2009, Washington Closure began nonintrusive characterization activities. Washington Closure subcontractor North Wind Inc. installed four narrow steel cylinders called cone penetrometers around each VPU and 100 cone penetrometers in selected trenches. A multi-detector probe is then inserted into the cone penetrometers to measure radiation sources. 

An area designated as the IU 2 & 6 Segment 1 encompasses about 23 square miles of the northeastern portion of the Hanford Site, away from the nine surplus plutonium production reactor areas. Six waste sites located in IU 2 & 6 segment 1 were discovered during a 2008 orphan site evaluation and required remediation. The sites were relatively small and contained mostly surface debris that were removed and transported to an approved disposal facility.

Remediation was completed at three of the six waste sites – 600-343, 600-345, and 600-346.
Some remediation work also was completed at site 600-341, which consists of four areas. Remediation of site 344 will proceed after a historical and cultural review. Last month, a global positioning environmental radiological survey indicated that site 600342 did not require additional remediation.

Site 600-343 consisted of residual ash from burned material and dumped asphalt in an excavated trench, site 600-345 was a stained area with oil filters, site 600-346 consisted of four small fly ash dump areas with metal debris, and site 600-341 consists of four areas that contain dry cell battery remnants and/or battery debris. 

F Area is the home of F Reactor, one of Hanford’s nine surplus plutonium production reactors. During reactor construction and operations, all site refuse, ranging from office trash to radioactive equipment and debris, was disposed in unlined pits and trenches throughout the100F Area.

Most of the cleanup work at F Area has been completed. However, during the course of cleanup, 13 other waste sites were discovered. A visual inspection of some sites confirmed remediation was necessary. They include sites that contain asbestos and a pipeline that contains chromium. Other sites required sampling, called confirmatory sampling, to determine if cleanup was necessary. Those sites failed the confirmatory sampling process and require cleanup to meet regulatory standards.

Later this spring, a request for proposals will be issued soliciting bids from companies to clean up the 12 sites. The selected subcontractor should be ready to begin site cleanup by fall 2010.

The remediation sites are: 100-F-26:4 pipeline, 100-F-26:7 pipeline, 100-F-44:8 pipeline, 100-F-44:9 pipeline, 100-F-45 riverbank pipeline, 100-F-47 substation, 100-F-48 coal pit debris, 100-F-49 maintenance garage, 100-F-51 fish lab, 100-F-55 ash layer, 100-F-56 scattered surface debris, 100-F-57 pump house pipe cradle debris, and 100-F-58 scattered ACM sites. 

In the 1980s and 1990s, an extensive effort was conducted to catalog all of Hanford’s known wastes sites and burial grounds. Those sites were included in cleanup agreements between the U.S. Department of Energy and its regulators, as well as in the scope of work for Hanford’s cleanup contractors.

However, as cleanup progressed across the 586-square-mile Hanford Site, other suspicious areas were discovered that, at a minimum, required further investigation to determine if the site met cleanup standards. The process of making that determination is called confirmatory sampling.

Sixty-six sites scattered about the northern portion of the Hanford Site near the Columbia River were recently added to the list of those requiring confirmatory sampling. Some sites were used as burn pits and tar dumps, while others were used to store batteries or are suspected of housing dichromate facilities. Still there are others that are not clear what they might contain, which is why sampling is required.

Later this spring, WCH will issue a request for proposals for a company to provide excavation and sampling support for the 66 sites. Those sites that pass the confirmatory sampling process will be closed out and no further action will be required under the existing interim record of decision. Those that fail will be recommended for cleanup to meet regulatory standards.

Sampling of the sites is expected to begin in summer 2010.