CHARACTERIZATION OF ACTINIDES IN SIMULATED ALKALINE TANK WASTE SLUDGES AND LEACHATES

Technical Report · Thu Nov 20 00:00:00 EST 2008

DOI:https://doi.org/10.2172/941420· OSTI ID:941420

Nash, Kenneth L

In this project, both the fundamental chemistry of actinides in alkaline solutions (relevant to those present in Hanford-style waste storage tanks), and their dissolution from sludge simulants (and interactions with supernatants) have been investigated under representative sludge leaching procedures. The leaching protocols were designed to go beyond conventional alkaline sludge leaching limits, including the application of acidic leachants, oxidants and complexing agents. The simulant leaching studies confirm in most cases the basic premise that actinides will remain in the sludge during leaching with 2-3 M NaOH caustic leach solutions. However, they also confirm significant chances for increased mobility of actinides under oxidative leaching conditions. Thermodynamic data generated improves the general level of experiemental information available to predict actinide speciation in leach solutions. Additional information indicates that improved Al removal can be achieved with even dilute acid leaching and that acidic Al(NO3)3 solutions can be decontaminated of co-mobilized actinides using conventional separations methods. Both complexing agents and acidic leaching solutions have significant potential to improve the effectiveness of conventional alkaline leaching protocols. The prime objective of this program was to provide adequate insight into actinide behavior under these conditions to enable prudent decision making as tank waste treatment protocols develop.

• Research Organization: Washington State University, Pullman, WA
• Sponsoring Organization: USDOE Office of Science (SC); USDOE Assistant Secretary for Environmental Management (EM); USDOE Office of Worker and Community Transition (WT)
• DOE Contract Number: FG02-04ER63757
• OSTI ID: 941420
• Report Number(s): DOE/FG/63757-final; EMSP Project ID number 81940; TRN: US1001446
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
ACTINIDES
CHELATING AGENTS
CHEMISTRY
DECISION MAKING
DISSOLUTION
LEACHATES
LEACHING
OXIDIZERS
REMOVAL
SLUDGES
TANKS
THERMODYNAMICS
WASTE PROCESSING
WASTE STORAGE
WASTES
alkaline sludge washing
americium
neptunium
plutonium
chromium
aluminum
oxidation
cleanup