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A U.S. Department of Energy Office of Science Laboratory Operated by The University of Chicago Office of Science U.S. Department of Energy Streamlined.

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Presentation on theme: "A U.S. Department of Energy Office of Science Laboratory Operated by The University of Chicago Office of Science U.S. Department of Energy Streamlined."— Presentation transcript:

1 A U.S. Department of Energy Office of Science Laboratory Operated by The University of Chicago Office of Science U.S. Department of Energy Streamlined Approaches to Characterizing NORM-Contaminated Sites Can Translate into Significant Cost Savings K.P. Smith, R.L. Johnson, and J. Quinn Environmental Assessment Division Argonne National Laboratory

2 Pioneering Science and Technology Office of Science U.S. Department of Energy 2 Sampling Programs Are Key Components of All Environmental Restoration Processes Preliminary site assessment Extended site investigation Corrective action study Remedial action Closure Multiple steps in a restoration project involve environmental sampling and analysis: Traditional sampling and analysis programs are expensive and time-consuming.

3 Pioneering Science and Technology Office of Science U.S. Department of Energy 3 Adaptive Sampling and Analysis Programs (ASAP) Can Cut Costs Significantly Approach Real-time sample analysis Rapid on-site decision making Requirements Field analytical method Decision support on site Advantages Reduce cost/sample Reduce # of samples Reduce # of events Better characterization Allows in situ soil segregation

4 Pioneering Science and Technology Office of Science U.S. Department of Energy 4 ASAP Decision Support Has Three Distinct Phases Assemble Baseline Information Base maps Geological information Existing sampling data Make Quantitative Decisions On Site Extent of contamination Where to stop When to stop Make Qualitative Decisions about Data Management Data integration Data visualization Data dissemination

5 Pioneering Science and Technology Office of Science U.S. Department of Energy 5 Can ASAP Efficiencies Be Realized at a NORM Site? Oil and gas production and processing activities can cause NORM to accumulate above natural background levels. Radionuclides: Ra-226, Ra-228, and their decay products Waste streams: produced water, scale, sludge, equipment, surface soils

6 Pioneering Science and Technology Office of Science U.S. Department of Energy 6 NORM Cleanup Requirements in the U.S. Typical NORM cleanup criteria: Averaged over 100 m 2 Ranges from 5 to 30 pCi/g (0.185 to 1.1 Bq/g) Ra-226 or Ra-228 above background Sometimes two different limits based on radon emanation rate

7 Pioneering Science and Technology Office of Science U.S. Department of Energy 7 NORM Case Study: Michigan Site 1.4-hectare pipe handling facility NORM contamination in surficial soils: Ra-226 activity levels into the tens of thousands of pCi/g State guidelines require remediation to 5 pCi/g (0.185 Bq/g) averaged over 100 m 2 About 27 m 3 of soil previously excavated and drummed based on gross activity screens

8 Pioneering Science and Technology Office of Science U.S. Department of Energy 8 The ASAP Approach Is Ideal for NORM- Contaminated Soils Large number of field screening, direct measurement, and field analytical methods: Combined walkover/GPS systems for gross activity Stationary in situ NaI instruments Stationary in situ HPGe measurements Mobile laboratories with gamma spectroscopy capabilities

9 Pioneering Science and Technology Office of Science U.S. Department of Energy 9 Gamma Walkover Surveys Provide Inexpensive, Comprehensive, Qualitative Information Sodium Iodide (Na I) sensor  measures total activity High detection efficiency, low energy resolution Collects data at 2 second intervals, generating hundreds to thousands of data points per acre Inexpensive: pennies per data point Combined with differential GPS systems to visualize walkover results

10 Pioneering Science and Technology Office of Science U.S. Department of Energy 10 Direct NaI Measurements Can Provide Estimates of Ra-226 Concentrations RadInSoil TM provides Ra-226 concentrations (pCi/g) for surface soils based on 5–10 min. readings Instrument needs to be calibrated to background at the site and assumes no other decay chain exists above background Per measurement costs on the order of $10–20 per data point Requires little training to operate

11 Pioneering Science and Technology Office of Science U.S. Department of Energy 11 In Situ HPGe Measurements Provide Accurate, Isotope-Specific Concentrations In situ High Purity Germanium (HPGe) gamma spectroscopy provides accurate, isotope- specific concentrations for surface soils Concentrations hold for the “field of view” of the instrument Costs are on the order of $100 per measurement Requires trained operator Low detection efficiency, high energy resolution

12 Pioneering Science and Technology Office of Science U.S. Department of Energy 12 Relationships between Gross Activity and Cleanup Criteria Are Key Decisions are binary — either cleanup soil or leave behind Want to identify “trigger” levels that can be used to carve up the site based on gross activity information Makes use of nonparametric approach with no assumptions about linear correlation Use paired information to do the analysis

13 Pioneering Science and Technology Office of Science U.S. Department of Energy 13 ASAP Process for Michigan Site Step 1: Complete Gamma Walkover Step 2: Develop Relationship between Gamma Walkover Data and Cleanup Criteria Paired gross activity to RadInSoil measurements collected at 49 sites Established trigger levels for 5-pCi/g cleanup criterion: 1,800–2,500 cpm

14 Pioneering Science and Technology Office of Science U.S. Department of Energy 14 ASAP Process for Michigan Site Three areas: likely clean, likely contaminated, and uncertain based on available data Step 3: Divide Site on Basis of Trigger Levels Average data over 100 m 2 using moving window averages on gamma walkover data

15 Pioneering Science and Technology Office of Science U.S. Department of Energy 15 ASAP Process for Michigan Site Step 4: Remediate and Rewalk Verification of “uncertain” areas with in situ HPGe Selective removal of “hot” spots across site Rewalk with gamma walkover surveys and reshoot with HPGe to confirm clean Note: The site was not cleaned up to background but was brought into compliance with state guidelines: 5 pCi/g Ra-226 averaged over 100 m 2.

16 Pioneering Science and Technology Office of Science U.S. Department of Energy 16 The Michigan Case Had Positive Results Excellent agreement between off-site confirmatory sample results and on-site analytics Reduced disposal costs  possibly as much as $36,000 less Significant analytical cost savings  about a 90% savings using in situ analytical capabilities Compressed time line because remediation was integrated with characterization

17 Pioneering Science and Technology Office of Science U.S. Department of Energy 17 For more information: Final report available from: Download in PDF format from “www.ead.anl.gov” More information available from: Bob Johnson Karen P. Smith , ext. 267 Consistent with Triad approach being recommended by the USEPA:


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