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Title: PROGRESS & CHALLENGES IN CLEANUP OF HANFORDS TANK WASTES

Conference ·
OSTI ID:875790

The River Protection Project (RPP), which is managed by the Department of Energy (DOE) Office of River Protection (ORP), is highly complex from technical, regulatory, legal, political, and logistical perspectives and is the largest ongoing environmental cleanup project in the world. Over the past three years, ORP has made significant advances in its planning and execution of the cleanup of the Hartford tank wastes. The 149 single-shell tanks (SSTs), 28 double-shell tanks (DSTs), and 60 miscellaneous underground storage tanks (MUSTs) at Hanford contain approximately 200,000 m{sup 3} (53 million gallons) of mixed radioactive wastes, some of which dates back to the first days of the Manhattan Project. The plan for treating and disposing of the waste stored in large underground tanks is to: (1) retrieve the waste, (2) treat the waste to separate it into high-level (sludge) and low-activity (supernatant) fractions, (3) remove key radionuclides (e.g., Cs-137, Sr-90, actinides) from the low-activity fraction to the maximum extent technically and economically practical, (4) immobilize both the high-level and low-activity waste fractions by vitrification, (5) interim store the high-level waste fraction for ultimate disposal off-site at the federal HLW repository, (6) dispose the low-activity fraction on-site in the Integrated Disposal Facility (IDF), and (7) close the waste management areas consisting of tanks, ancillary equipment, soils, and facilities. Design and construction of the Waste Treatment and Immobilization Plant (WTP), the cornerstone of the RPP, has progressed substantially despite challenges arising from new seismic information for the WTP site. We have looked closely at the waste and aligned our treatment and disposal approaches with the waste characteristics. For example, approximately 11,000 m{sup 3} (2-3 million gallons) of metal sludges in twenty tanks were not created during spent nuclear fuel reprocessing and have low fission product concentrations. We plan to treat these wastes as transuranic waste (TRU) for disposal at the Waste Isolation Pilot Plant (WIPP), which will reduce the WTP system processing time by three years. We are also developing and testing bulk vitrification as a technology to supplement the WTP LAW vitrification facility for immobilizing the massive volume of LAW. We will conduct a full-scale demonstration of the Demonstration Bulk Vitrification System by immobilizing up to 1,100 m{sup 3} (300,000 gallons) of tank S-109 low-curie soluble waste from which Cs-137 had previously been removed. This past year has been marked by both progress and new challenges. The focus of our tank farm work has been retrieving waste from the old single-shell tanks (SSTs). We have completed waste retrieval from three SSTs and are conducting retrieval operations on an additional three SSTs. While most waste retrievals have gone about as expected, we have faced challenges with some recalcitrant tank heel wastes that required enhanced approaches. Those enhanced approaches ranged from oxalic acid additions to deploying a remote high-pressure water lance. As with all large, long-term projects that employ first of a kind technologies, we continue to be challenged to control costs and maintain schedule. However, it is most important to work safely and to provide facilities that will do the job they are intended to do.

Research Organization:
Hanford Site (HNF), Richland, WA (United States)
Sponsoring Organization:
USDOE
DOE Contract Number:
DE-AC27-99RL14047
OSTI ID:
875790
Report Number(s):
ORP-28556-FP Rev 0; TRN: US0600776
Resource Relation:
Conference: WM'06 CONFERENCE 02/26/2006 THRU 03/02/2006 TUCSON, AZ
Country of Publication:
United States
Language:
English