SMART 3D SUBSURFACE CONTAMINANT CHARACTERIZATION AT THE BGRR DEC OMMISSIONING PROJECT.
The Brookhaven Graphite Research Reactor is currently on an accelerated decommissioning schedule with a completion date projected for 2005. The accelerated schedule combines characterization with removal actions for the various systems and structures. A major project issue involves characterization of the soils beneath contaminated Below Grade Ducts (BGD), the main air ducts connecting the exhaust plenums with the Fan House. The air plenums experienced water intrusion during BGRR operations and after shutdown. The water intrusions were attributed to rainwater leaks into degraded parts of the system, and to internal cooling water system leaks. If the characterization could provide enough information to show that soil contamination surrounding the BGD is either below cleanup guidelines or is very localized and can be ''surgically removed'' at a reasonable cost, the ducts may be decontaminated and left in place. This will provide significant savings compared to breaking up the 170-ft. long concrete duct, shipping the projected 9,000 m{sup 3} of waste off-site and disposing of it in an approved site. The focus of this Department of Energy Accelerated Site Technology Deployment (DOE ASTD) project was to determine the extent (location, type, and level) of soil contamination surrounding the BGD. A suite of innovative characterization tools was used to complete the characterization of the soil surrounding the BGD in a cost-effective and timely fashion and in a manner acceptable to the stakeholders. A state-of-the-art perfluorocarbon tracer (PFT) technology was used to screen the BGD for existing leak pathways and thus focus the characterization on potential contamination ''hot spots.'' Once pathways were identified, the sampling and analysis plan was designed to emphasize the leaking areas of the duct and perform only confirmatory checks in areas shown to be leak-free. A small-footprint Geoprobe{reg_sign} was used obtain core samples and allowed sampling in areas surrounding the BGD that were difficult to access. Two novel, field-deployed, radiological analysis systems (ISOCS and BetaScint{trademark}) were used to analyze the core samples and a three-dimensional (3-D) visualization system facilitated data analysis/interpretation for the stakeholders. All of the technologies performed as well or better than expected and the characterization could not have been completed in the same time or at the same cost without using this approach. A total of 904 BGD soil samples were taken, evaluated, and modeled. Results indicated that contamination was primarily located in discrete areas near several expansion joints and underground structures (bustles), but that much of the soil beneath and surrounding the BGD was clean of any radiological contamination. One-year project cost savings are calculated to be $1,254K. Life cycle cost savings, resulting from reduction in the number of samples and the cost of sample analysis, are estimated to be $2,162K. When added to potential cost savings associated with decontaminating and leaving the BGD in place ($7.1 to 8.1M), far greater overall savings may be realized.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- DOE/ER/WM (US)
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 797988
- Report Number(s):
- BNL-69294; R&D Project: 07556; EW4010000; TRN: US0202985
- Resource Relation:
- Conference: SPECTRUM 2002, RENO, NV (US), 08/04/2002--08/08/2002; Other Information: PBD: 4 Aug 2002
- Country of Publication:
- United States
- Language:
- English
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