Methodologies and tools developed by CEA/SAS

Transcription

1 Characterization and Visualization Technologies in DD&R December 8 th 2011, France Methodologies and tools developed by CEA/SAS Julien ATTIOGBE attiogbe@geovariances.com CEA-FAR/SAS 1

2 Software Development Radiological characterization for contaminated sites through data processing (Krigéo) associated to a GIS (Kartotrak) Optimization & decision makind aid module (STRATEGE) CEA-FAR/Clean-up Section 2

3 Softwares dedicated to the geographic representation of the measures in the different stages of the clean-up process Real-time data acquisition Data processing through Geostatistics Calculation of the projected impact Preparing the sampling plan Validating the cleanup objective Establishing the theoretical mesh Observing the extension of the pollution Developments since 2003 CEA-FAR/Clean-up Section 3

4 Kartotrak : Geographic Information System GIS component Use of vectorial maps No pixeling effect when zooming in Different layers: vectorial + raster Georeferenced maps Used with a differential GPS Data management Path of the vehicle CEA prototype Sampling Plan Editing CEA-FAR/Clean-up Section 4

5 Kartotrak : Geographic Information System Different working processes: - Manual acquisition along the measuring campaign - Following a defined sampling plan Data acquisition : - Automatic geographic location - Entering manually the in situ measure Save/ Load a data file CEA-FAR/Clean-up Section 5

6 Kartotrak : Geographic Information System Different working processes: systematic mesh Specify areas to be/not to be measured Specify areas with an historical interest (known location of contamination) Area to be measured 8400 m² Area of interest m² Excluded area (building) 2150 m² 245 georeferenced data CEA-FAR/Clean-up Section 6

7 GEOSTATISTICS A brief introduction CEA-FAR/Clean-up Section 7

8 Geostatistics : basics Data analysis Known Data Histogram Kriging 3D Experimental variogram and model 2D Interpolation (initial cartography) 3D Interpolation (with drillings) CEA-FAR/Clean-up Section 8

9 Geostatistics: Kriging Method Kriging is a geostatistical method for measurement interpolation. It proceeds in different steps : - Understand and quantify the spatial variability - Estimate the value where it remains unknown - Draw the uncertainty map - Analyse the risk Experimental variogram Variogram fitting The variographic study is the key element of Geostatistics in order to analyse and understand the phenomenon CEA-FAR/Clean-up Section 9

10 Geostatistics: First results Interpolation Map Uncertainty Map The Interpolation Map highlights areas of various activities according to the available data The Uncertainty Map points out areas that lack measures. Update the sampling-plan CEA-FAR/Clean-up Section 10

11 STRATEGE CEA-FAR/Clean-up Section 11

12 Evaluation objectives and sampling Different sampling plans for different evaluations BRGM data Random sampling Regular sampling Circular grid sampling Profile sampling Appraisal sampling Artistic sampling? CEA-FAR/Clean-up Section 12

13 Decision making aid module : STRATEGE STRATEGies d Echantillonnage Module developed in 2007 which covers each step of a sampling campaign Evaluation objective Removal of doubt / Initial cartography Environmental diagnosis Radiological characterization End of remediation controls Determine and optimize the sampling plan Optimized grid Circular grids Drillings distribution PESCAR, Wilks method Forecast measures performances Estimating the projected budget 32% Editing a report of the evaluation preparation 68% CEA-FAR/Clean-up Section 13

14 STRATEGE : Sampling optimization Too much? Not enough? 5000 m² 400 measures m² 270 measures Variability Variability Adjustment Experimental variogram Distance (m) Distance (m) CEA-FAR/Clean-up Section 14

15 STRATEGE : Sampling optimization Analysing the experience feedback 1,2 Optimizing the systematic grid in order to use geostatistics (highlight the spatial structure of the data) Variogramme (h) 1 0,8 0,6 0,4 0, Distance h Considering the informations of the area ( historical, geology, topography) and the evaluation constraints (budget, performances ) Graphic indicators: Probability of hitting a target Impact/relevance of extra measures Probability of hitting (%) Probabilité de toucher (%) Normal Intérêt Size Dimension of the de target la cible (m) CEA-FAR/Clean-up Section 15

16 GEOSTATISTICS Complementary facts CEA-FAR/Clean-up Section 16

17 Example of initial cartography - Kriging Interpolation Map Uncertainty Map The Interpolation Map highlights areas of various activities according to the available data The Uncertainty Map points out areas that lack measures. Update the sampling-plan CEA-FAR/Clean-up Section 17

18 Risk analysis Probability maps Allows to estimate the local probability of exceeding a given value. High probability, very likely Intermediary probability, uncertainty Low probability, very likely Complementary to the contaminated surface estimation (through simulation) Helps to establish a relevant drilling positioning CEA-FAR/Clean-up Section 18

19 REAL TIME ACQUISITION CEA-FAR/Clean-up Section 19

20 VEgAS: Expertise and Investigation Vehicle Vehicle dedicated to investigate radiologically contaminated sites for a quick identification of areas of interest or radionuclides. It can be used for post-accidental assessment or in a standard clean-up campaign. Characterizing m² per hour. 4 W-D vehicle (< 3.5 t) Speed control system 2.5 ; 5 and 10km/h Air filtration system Differential GPS with submetric accuracy CEA-FAR/Clean-up Section 20

21 VEgAS Measurement instruments GPS NaI Spectro Gamma DSP Protection hood Instruments Two plastic scintillation detectors (25 L) NaI detector (crystal 2.4 L) High-Purity Germanium detector, 30% effectiveness Centralization and monitoring of the measures in the vehicle Laptop CEA-FAR/Clean-up Section 21

22 DSP: Plastic scintillator with a photomultiplier DSP detection performances Performances for a punctual source at 2.5 km/h Punctual source Nuclide Punctual Source Activity 2.5 km/h 5 km/h 241 Am E=60 kev 37 kbq 58 kbq 137 Cs E=662 kev 1,8 kbq 2,8 kbq 57 Co E=124 kev 2,9 kbq 4,4 kbq 226 Ra eq=60% Multi γ 0,30 kbq 0,47 kbq Performances for 1 m² ground/tar pollutions Radionuclide TAR ROAD (1 m² pollution) Detection limit (kbq/m²) GROUND (1 m² pollution, 5 cm thick) Detection limit (Bq/kg) 2.5 km/h 5 km/h 2.5 km/h 5 km/h 137 Cs Co CEA-FAR/SAS 22

23 Acquiring the measures in real time : Kartotrak RT Intesity of the signal per second DSP 2 DSP 1 Number of the acquisition Intesity of the signal per second NaI Total Average DSP Spectro Gamma Total Number of the acquisition Finding a area of interest Confirmed by all the instruments CEA-FAR/Clean-up Section 23

24 Analysing the data Different natures of soils VECTORIAL MAP AERIAL VIEW Counting rate (cps) : Grass 2 : Road 3 : Gravels Acquisiton number The signal may vary according to the nature of the soil. Important information to consider Soon to be integrated in the software CEA-FAR/Clean-up Section 24

25 From RT data to areas of interest Highlighting 2800 m² of interest out of a 7050 m² zone Historical Knowledge RealTime Measuring Identifying the areas of interest Sound characterization of the areas of interest CEA-FAR/Clean-up Section 25

26 Optimizing example Area : 7050 m² Total surface area : 2800 m² Additional measures 105 measures (5-meter mesh) Characterization 178 measures (6-m mesh) CEA-FAR/Clean-up Section 26

27 Real-Time Acquisition Surface to characterize: m² Positioning equipment 1 spot = 1-second acquisition data 10 cm accuracy Each data can be easily localised on a map. Counting rate (cps) Acquisiton number CEA-FAR/Clean-up Section 27

28 Data Processing Geostatistics Approach Collected data Histogram Variograms Real time acquisition Interpolation map Data Processing (geostatistics) Highlighting the areas of interest CEA-FAR/Clean-up Section 28

29 Data Processing Further actions Uncertainty map Combined to uncertainty and probability maps, the kriging result helps decide further actions: - more measurements to reduce uncertainty - gamma spectrometry for nuclide identification - samplings - drillings gravel granit Probability map gravel gravel concrete CEA-FAR/Clean-up Section 29

30 Gamma Spectrometry Measured area with/without a collimator HP Germanium Detector 226 Ra 137 Cs 40 K 40 K 137 Cs 40 K Natural radioactivity Artificial radioactivity In situ gamma spectrometry activity results are compared with laboratory results from samples. CEA-FAR/Clean-up Section 30

31 Complementary Way When the VEgAS vehicle cannot access rugged areas (forest, confined or steep places ) Simple equipment: GPS + NaI 3" connected to a laptop Detection limit when walking: 1Bq/g eq. 137 Cs CEA-FAR/SAS 31

32 Example: Back on cleaned area Mapping after 2-week campaign Mapping after 1-day campaign with VEgAS Controled area: 9300 m² In situ gamma spectrometry (42) In-depth samples Controled area: 3400 m² Real-time acquisition In situ gamma spectrometry (3) 137 Cs 52 Bq/kg 137 Cs 600 Bq/kg 137 Cs 100 Bq/kg Cs 255 Bq/kg 137 Cs < 2,5 Bq/kg Depth (cm) Profile of a drilling 137 Cs Activity (Bq/kg) Quick identification of cleaned areas, or contaminated areas CEA-FAR/Clean-up Section 32

33 3D ANALYSIS CEA-FAR/Clean-up Section 33

34 GEOPHYSICS INVESTIGATIONS SAMPLING TECHNIQUE Confirm the position of drill holes by checking the absence of metallic parts or underground network near the drill holes. Contact : Jean-Christophe SPARFEL anomaly Contact : Stéphane BELBEZE ANTEA Ingénierie 3 Av. Claude Guillemin BP Orléans cedex 2 s.belbeze@anteaingenierie.fr Drillings with auger or Geoprobe Depends on the field, maximal depth: 2m Simple and relatively cheap Unsuitable for chemical measures Unsuitable for containment Drillings with ultrasonic device Every type of soils Maximal depth 50 to 100m Suitable for containment Expensive technique CEA-FAR/Clean-up Section 34

35 From the 2D to the 3D viewing The preliminary 2D mapping leads to a drillhole campaign processed in 3D. Drillholes View from below Isatis 3D Viewer (Geovariances) CEA-FAR/Clean-up Section 35

36 3D Analysis Roads monitoring Underground evaluation Radiological evaluation of walls and floors CEA-FAR/Clean-up Section 36

37 Thank you CEA-FAR/Clean-up Section 37