Cleaning up the Legacy of the Cold War: Plutonium Oxides and the Role of Synchrotron Radiation Research

Conference · Wed Jan 21 00:00:00 EST 2015

OSTI ID:1168715

Clark, David Lewis ^[1]

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

The deceptively simple binary formula of AnO₂ belies an incredibly complex structural nature, and propensity to form mixed-valent, nonstoichiometric phases of composition AnO_2±x. For plutonium, the very formation of PuO_2+x has challenged a long-established dogma, and raised fundamental questions for long-term storage and environmental migration. This presentation covers two aspects of Los Alamos synchrotron radiation studies of plutonium oxides: (1) the structural chemistry of laboratory-prepared AnO_2+x systems (An = U, Pu; 0 ≤ x ≤ 0.25) determined through a combination of x-ray absorption fine structure spectroscopy (XAFS) and x-ray scattering of laboratory prepared samples; and (2) the application of synchrotron radiation towards the decontamination and decommissioning of the Rocky Flats Environmental Technology Site. Making the case for particle transport mechanisms as the basis of plutonium and americium mobility, rather than aqueous sorption-desorption processes, established a successful scientific basis for the dominance of physical transport processes by wind and water. The scientific basis was successful because it was in agreement with general theory on insolubility of PuO₂ in oxidation state IV, results of ultrafiltration analyses of field water/sediment samples, XAFS analyses of soil, sediment, and concrete samples, and was also in general agreement with on-site monitoring data. This understanding allowed Site contractors to rapidly move to application of soil erosion and sediment transport models as the means of predicting plutonium and americium transport, which led to design and application of site-wide soil erosion control technology to help control downstream concentrations of plutonium and americium in streamflow.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC52-06NA25396
• OSTI ID: 1168715
• Report Number(s): LA-UR-15-20329; TRN: US1600039
• Resource Relation: Conference: 12. Symposium on Nuclear and Radiochemistry (NUCAR 2015), 9-13 Feb 2015, Mumbai (India)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
54 ENVIRONMENTAL SCIENCES
PLUTONIUM OXIDES
SYNCHROTRON RADIATION
PLUTONIUM
AMERICIUM
DECONTAMINATION
EROSION CONTROL
ENVIRONMENTAL TRANSPORT
ABSORPTION SPECTROSCOPY
X-RAY SPECTROSCOPY
X-RAY DIFFRACTION
WATER
CONCRETES
SEDIMENTS
SOILS
ULTRAFILTRATION
CHEMISTRY
DECOMMISSIONING
EROSION
MONITORING
PARTICLES
VALENCE
WIND
REMEDIAL ACTION
URANIUM OXIDES
ROCKY FLATS PLANT