Technology:
Segmented Gate System (SGS)
- SGS is a combination of conveyer systems, radiation detectors (primarily gamma radiation), and computer control
- Contaminated soil on conveyer belt was diverted by segmented gates into stockpiles
- Detectors monitored radioactivity content of soil traveling on belt and computer opened specified gates to separate portions of soil based on radioactivity criteria
- Operating parameters included a belt speed of 30 ft/min, belt length of 16 -18 ft, soil layer thickness of 2 inches by width of 30.75 inches, and soil density of 1.29 g/cm3
- Average daily processing time was 2.06 hours, with a total of 22.7 hours over 11 days
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Cleanup Authority:
RCRA Corrective Measure
Site Contact:
James Brower
Brookhaven National Laboratory
(631) 344-7513 | Technical Contact:
Ray Patteson
Sandia National Laboratories
(505) 844-1904 |
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Contaminants:
Radionuclides
- Cesium 137 levels ranged from background to 348 pCi/g |
Waste Source:
Spills of fission products |
Type/Quantity of Media Treated:
Soil
- 625 yds3 of soil were processed
- Moisture content relatively high; soil contained clumps of grass with root systems and grass stems |
Purpose/Significance of Application:
Use of a gate system to reduce volume of radioactive-contaminated soil requiring off-site disposal |
Regulatory Requirements/Cleanup Goals:
- Reduce the volume of contaminated soil that was above the specified criteria and that would require storage and disposal, from soil that was below the criteria
- The sorting criterion was 23 pCi/g |
Results:
- Reduce the volume of contaminated soil that was above the specified criteria and that would require storage and disposal, from soil that was below the criteria
- The sorting criterion was 23 pCi/g |
Cost Factors:
- The vendor's cost was $373,509, including $52,410 for pre-deployment site characterization, $25,700 for other pre-deployment activities, $73,300 for mobilization, $147,459 for operations and delays, $49,000 for demobilization, $18,640 for post-excavation mower survey and $7,000 for the final report and documentation; BNL's costs were $321,000, including $136,662 for supporting the use of SGS
- Overall unit cost was $78/yd3, based only on costs for processing activities |
Description:
Brookhaven National Laboratory (BNL), located in Suffolk County, New York, approximately 60 miles east of New York City, encompasses an area of 5,265 acres (approximately 8.21 square miles). The site was formerly occupied by the U.S. Army as Camp Upton during World Wars I and II, and was transferred to DOE in 1977. In 1980 and 1983, aerial radiation surveys were conducted at the BNL site and 23 areas of man-made radioactivity were identified. The source of the radioactive material was believed to be from spills of fission products removed from the hazardous waste management facility. The material at Area of Concern 16 was 137Cs radionuclide-contaminated landscape surface soil.
A Segmented Gate System (SGS) was used to reduce the volume of contaminated soil that required off-site disposal. SGS is a combination of conveyer systems, radiation detectors, and computer control, where contaminated soil on a conveyer belt is diverted by segmented gates into stockpiles. Detectors monitor the radioactivity content of the soil traveling on the belt and a computer opens specified gates to separate portions of soil based on radioactivity criteria. At this site, the overall volume reduction was measured as 16%. This relatively low percentage was attributed to differences between requirements specified in the work plan and actual field conditions. The vendor's cost for the project was $373,509, and BNL's cost was $321,000. The overall unit cost was $78/yd3, based only on costs for processing activities |
