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Title: HIGH LEVEL WASTE TANK CLOSURE PROJECT AT THE IDAHO NATIONAL ENGINEERING AND ENVIRONMENTAL LABORATORY

Conference ·
OSTI ID:827463

The Department of Energy, Idaho Operations Office (DOE-ID) is in the process of closing two underground high-level waste (HLW) storage tanks at the Idaho National Engineering and Environmental Laboratory (INEEL) to meet Resource Conservation and Recovery Act (RCRA) regulations and Department of Energy orders. Closure of these two tanks is scheduled for 2004 as the first phase in closure of the eleven 1.14 million liter (300,000 gallon) tanks currently in service at the Idaho Nuclear Technology and Engineering Center (INTEC). The INTEC Tank Farm Facility (TFF) Closure sequence consists of multiple steps to be accomplished through the existing tank riser access points. Currently, the tank risers contain steam and process waste lines associated with the steam jets, corrosion coupons, and liquid level indicators. As necessary, this equipment will be removed from the risers to allow adequate space for closure equipment and activities. The basic tank closure sequence is as follows: Empty the tank to the residual heel using the existing jets; Video and sample the heel; Replace steam jets with new jet at a lower position in the tank, and remove additional material; Flush tank, piping and secondary containment with demineralized water; Video and sample the heel; Evaluate decontamination effectiveness; Displace the residual heel with multiple placements of grout; and Grout piping, vaults and remaining tank volume. Design, development, and deployment of a remotely operated tank cleaning system were completed in June 2002. The system incorporates many commercially available components, which have been adapted for application in cleaning high-level waste tanks. The system is cost-effective since it also utilizes existing waste transfer technology (steam jets), to remove tank heel solids from the tank bottoms during the cleaning operations. Remotely operated directional spray nozzles, automatic rotating wash balls, video monitoring equipment, decontamination spray-rings, and tank -specific access interface devices have been integrated to provide a system that efficiently cleans tank walls and heel solids in an acidic, radioactive environment. Through the deployment of the tank cleaning system, the INEEL High Level Waste Program has cleaned tanks to meet RCRA clean closure standards and DOE closure performance measures. Design, development, and testing of tank grouting delivery equipment were completed in October 2002. The system incorporates lessons learned from closures at other DOE facilities. The grout will be used to displace the tank residuals remaining after the cleaning is complete. To maximize heel displacement to the discharge pump, grout was placed in a sequence of five positions utilizing two riser locations. The project is evaluating the use of six positions to optimize the residuals removed. After the heel has been removed and the residuals stabilized, the tank, piping, and secondary containment will be grouted.

Research Organization:
Bechtel BWXT Idaho, Idaho National Engineering and Environmental Laboratory, P.O. Box 1625, MS 3670, Idaho Falls, Idaho 83415; DOE-ID, U. S. Department of Energy Idaho Operations Office, 850 Energy Drive Idaho Falls, Idaho 83401-1563 (US)
Sponsoring Organization:
US Department of Energy (US)
OSTI ID:
827463
Resource Relation:
Conference: Waste Management 2003 Symposium, Tucson, AZ (US), 02/23/2003--02/27/2003; Other Information: PBD: 27 Feb 2003
Country of Publication:
United States
Language:
English