Cleanup Associated with Fukushima Incident – Radiological Survey & Soil g ySorting for Waste Minimization

Steve Rima, CHP, CSPVice President, AMEC Environment & Infrastructure

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Cesium Surface Deposition Map

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Dose Rate 1m from Ground SurfaceSurface

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RestrictedRestricted and Evacuated Areas

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Problem

Approximately 1,300 square kilometers are evacuated and must be cleaned prior to return of residents

Includes towns, agricultural land, forests, rivers, etc.

V l l f l l l di ti t ill bVery large volume of low level radioactive waste will be generatedNo permanent disposal for radioactive waste exists inNo permanent disposal for radioactive waste exists in JapanSome types of land e g forests mountains cannot beSome types of land, e.g. forests, mountains, cannot be cleaned without destroying themCost effective waste minimization techniques are badlyCost effective waste minimization techniques are badly needed

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Technology Demonstration Projects

Objective: Demonstration of remediation technologiesObjective: Demonstration of remediation technologies toward full remediation of evacuation areasOverseen by Japanese Atomic Energy Agency (JAEA)Overseen by Japanese Atomic Energy Agency (JAEA)AMEC on team led by Obayashi JV

Included 114 ha (1,140,000 m2)Included 114 ha (1,140,000 m )Demonstration of characterization, decontamination and remediation of towns, buildings and landIncluded towns of Hirono, Naraha, Okuma and Kawauchi

AMEC deployed its proprietary Orion ScanPlotSM and ScanSortSM technologiesScanSortSM technologies

Both use real-time, laboratory-quality, gamma spectroscopy in the field

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Technology Demonstration Projects

D fi iti f “ l ” t t d fi dDefinition of “clean” not yet defined. Soil concentration limit v. dose rate above ground surface2 000 – 4 000 Bq/kg used as sorting criteria during Demonstration2,000 – 4,000 Bq/kg used as sorting criteria during Demonstration ProjectConcentration limit can be applied in situ or ex situDose rate can only be applied in situ

O i t ti di th t ( ) tOne interesting discovery was that some (many) property owners (outside of evacuated areas) have already undertaken remediation of their propertyundertaken remediation of their property

Scrape ground surfaceBury removed contaminated soil temporarily on site

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Survey of School Yard after Remediation by Ownerby Owner

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Characterization with AMEC’s Orion ScanPlotSM SystemsScanPlotSM Systems

AMEC deployed its proprietary Orion S SMScanPlotSM system in various configurations to survey properties and areas.

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AMEC’s Orion ScanPlotSM Radiological Scanning Survey System uses:

Large volume spectroscopy grade NaI detectors,AMEC’s advanced scanning spectrometer software,High accuracy spatial position sensing equipmentHigh-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 gamma spectroscopy)laboratory quality, gamma spectroscopy)Automatically logs the radiological spectra and associated geographic position

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Characterization

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

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Pre-Pre-Remediation Survey of Rice PaddyRice Paddy

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AMEC’s ORION ScanSortSM Radiological Soil Sorting g gSurvey System uses:

Large volume spectroscopy grade NaI detectorsAMEC’s scanning spectrometer software, Advanced, computer-controlled, electro-mechanical material handling and sorting equipmenthandling and sorting equipment.

Detects gamma-emitting isotopes as the soil on the belt moves past the active area of the detectorpOther specialized detectors can also be fitted to the system to detect isotopes that are not amenable to detection by N I tNaI spectroscopy

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N h TNaraha Town

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Typical Post-Remediation Radioactive Waste StorageWaste Storage

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Rice Paddy Post-Excavation

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Typical PPE in Exclusion Zone

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ScanSort at Naraha Town

Case Layer Number of Use of DCSTest cases

truck

(mm) excavationfor layer

transportation vehicle on a rough terrain

(Bq/kg)

RP2-1 0~100 one No 2,000

Transportation vehicle on a rough

terrain

RP2-2 0~100 one Yes 4,000

RP2-3 0~50 one Yes 4,000

RP2-4 50~100 one Yes 4,000

RP3-1 0~100 three No 4,000

RP3 2 0 100 one Yes 4 000

Soils above criteria

Excavated soils

Soils below criteria

RP3-2 0~100 one Yes 4,000

Soils below criteria

ScanSort

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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]y [ ] g p g [ q g]

0 to 30 165 to 202 1091830 to 60 247 to 283 5041

60 t 100 206 t 244 512

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60 to 100 206 to 244 5120 to 100 (mixed*) 386 to 448 2692

Cs137 Concentration by Depth in Rice Paddy

0 1000~50mm

50~100mm

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Contamination Profile

Majority of contamination now is Cs137Even 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 etcRunoff areas, ditches, etc.

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Summary

Cs 137 is widespread over approximately 1,300 sq. km at levels from very low to over 300,000 Bq/m2

Dose rates at 1m above the ground vary from very low to 20 S /h>20 µSv/h

Remediation will take many years at a very high cost (Japanese Government estimates $14B USD for off site(Japanese Government estimates $14B USD for off site cleanup)Waste minimization techniques are needed due to lack ofWaste minimization techniques are needed due to lack of disposal space for radioactive wasteAMEC’s Orion ScanSortSM reduced volume of radioactiveAMEC s Orion ScanSort reduced volume of radioactive waste from rice paddy remediation by approximately 50%

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With sincere gratitude to Shoko Yashio and the many other excellent and the many other excellent 

employees of Obayashi

fSpecial thanks to the people of Japan!

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