Cleanup Associated with Fukushima Incident Radiological Survey & Soil Sorting for Waste Minimization

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1 Cleanup Associated with Fukushima Incident Radiological Survey & Soil Sorting for Waste Minimization Steve Rima, CHP, CSP Vice President, AMEC Environment & Infrastructure

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3 Cesium Surface Deposition Map 3

4 Dose Rate 1m from Ground Surface 4

5 Restricted and Evacuated Areas 5

6 Problem Approximately 1,300 square kilometers are evacuated and must be cleaned prior to return of residents Includes towns, agricultural land, forests, rivers, etc. Very large volume of low level l radioactive waste will be generated No permanent disposal for radioactive waste exists in Japan Some types of land, e.g. forests, mountains, cannot be cleaned without destroying them Cost effective waste minimization techniques are badly needed 6

7 Technology Demonstration Projects Objective: Demonstration of remediation technologies toward full remediation of evacuation areas Overseen by Japanese Atomic Energy Agency (JAEA) AMEC on team led by Obayashi JV Included 114 ha (1,140,000 m 2 ) Demonstration of characterization, decontamination and remediation of towns, buildings and land Included towns of Hirono, Naraha, Okuma and Kawauchi AMEC deployed its proprietary Orion ScanPlot SM and ScanSort SM technologies Both use real-time, laboratory-quality, gamma spectroscopy in the field 7

8 Technology Demonstration Projects Definition iti of clean not yet defined. d Soil concentration limit v. dose rate above ground surface 2,000 4,000 Bq/kg used as sorting criteria during Demonstration Project Concentration limit can be applied in situ or ex situ Dose rate can only be applied in situ One interesting ti discovery was that t some (many) property owners (outside of evacuated areas) have already undertaken remediation of their property Scrape ground surface Bury removed contaminated soil temporarily on site 8

9 Survey of School Yard after Remediation by Owner 9

10 Characterization with AMEC s Orion ScanPlot SM Systems AMEC deployed its proprietary Orion ScanPlot SM system in various configurations to survey properties and areas. 10

11 AMEC s Orion ScanPlot SM Radiological Scanning Survey System uses: Large volume spectroscopy grade NaI detectors, AMEC s advanced scanning spectrometer software, High-accuracy spatial position sensing equipment. Detects and isotopically speciates gamma-emitting radionuclides in the near surface soil as the system moves over the ground surface (real-time, scanning, field, laboratory-quality quality, gamma spectroscopy) Automatically logs the radiological spectra and associated geographic position 11

12 Characterization Pre- and Post-Remediation Surveys of School Yards outside evacuation zone 12

13 Pre- Remediation Survey of Rice Paddy 13

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15 AMEC s ORION ScanSort SM Radiological Soil Sorting Survey System uses: Large volume spectroscopy grade NaI detectors AMEC s scanning spectrometer software, Advanced, computer-controlled, electro-mechanical material handling and sorting equipment. Detects gamma-emitting isotopes as the soil on the belt moves past the active area of the detector Other specialized detectors can also be fitted to the system to detect isotopes that are not amenable to detection by NaI spectroscopy 15

16 Naraha N h Town T 16

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18 Typical Post-Remediation Radioactive Waste Storage 18

19 Rice Paddy Post-Excavation 19

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21 Typical PPE in Exclusion Zone 21

22 ScanSort at Naraha Town Test cases Case Layer Number of Use of DCS (mm) excavation transportation (Bq/kg) for layer vehicle on a rough terrain RP2-1 0~100 one No 2,000 RP2-2 0~100 one Yes 4,000 RP2-3 0~50 one Yes 4,000 truck Transportation vehicle on a rough terrain RP2-4 50~100 one Yes 4,000 RP3-1 0~100 three No 4,000 RP3-2 0~100 one Yes 4,000 Excavated soils Soils above criteria Soils below criteria ScanSort 22

23 Cs137 Concentration by Depth in Rice Paddy 0~30mm 30~60mm 0~100mm (mixed) Soil Layer [mm] Range Temporal Observation Numbers Average Concentration [Bq/kg] 0 to to to to to to to 100 (mixed*) 386 to

24 Cs137 Concentration by Depth in Rice Paddy 0~50mm 50~100mm 24

25 Contamination Profile Majority of contamination now is Cs137 Even after a year, most of the Cs is in the top 1-2 cm of soil Contamination in soil seems to be relatively immobile Non-soil (roads, etc.) contamination is concentrated where expected Runoff areas, ditches, etc. 25

26 Summary Cs 137 is widespread over approximately 1,300 sq. km at levels from very low to over 300,000 Bq/m 2 Dose rates at 1m above the ground vary from very low to >20 µsv/h Remediation will take many years at a very high cost (Japanese Government estimates $14B USD for off site cleanup) Waste minimization techniques are needed due to lack of disposal space for radioactive waste AMEC s OrionScanSort SM reduced volume of radioactive waste from rice paddy remediation by approximately 50% 26

27 With sincere gratitude to Shoko Yashio and the many other excellent employees of Obayashi Special thanks to the people of Japan! 27