Leaching study of PNL 76-68 glass beads using the LLNL continuous-flow method and the PNL modified IAEA method. Final report

Technical Report · Mon Oct 04 04:00:00 EDT 1982

DOI:https://doi.org/10.2172/6764690· OSTI ID:6764690

Coles, D G; Mensing, R W; Rego, J; Weed, H C; Buddemeier, R W

A long-term single-pass continuous-flow (SPCF) leaching test was conducted on the glass waste form PNL 76-68. Leaching rates of Np, Pu and various stable elements were measured at 25 and 75/sup 0/C with three different solutions and three different flow rates. The SPCF leaching results were compared with results of a modified IAEA leach test performed by Pacific Northwest Laboratories (PNL). Elemental leach rates and their variation with temperature, flow rate and solution composition were established. The LLNL and PNL leach test results appear to agree within experimental uncertainties. The magnitude of the leach rates determined for Np and the glass matrix elements is 10/sup -5/ grams of glass/cm/sup 2/ geometric solid surface area/day. The rates increase with temperature and with solution flow rate, and are similar in brine and distilled water but higher in a bicarbonate solution. Other cations exhibit somewhat different behavior, and Pu in particular yields a much lower apparent leach rate, probably because of sorption or precipitation effects after release from the glass matrix. After the initial few days, most elements are leached at a constant rate. Matrix dissolution appears to be the most probable rate controlling step for the leaching of most elements. 23 figures, 12 tables.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6764690
• Report Number(s): UCID-19492-Rev.1; ON: DE83001875
• Country of Publication: United States
• Language: English

Related Subjects

052000* -- Nuclear Fuels-- Waste Management
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
ACID CARBONATES
ACTINIDES
BRINES
COMPARATIVE EVALUATIONS
DATA
DISSOLUTION
ELEMENTS
EXPERIMENTAL DATA
FLOW RATE
GLASS
HYDROGEN COMPOUNDS
INFORMATION
KINETICS
LEACHING
MATERIALS
MATRIX MATERIALS
MEASURING METHODS
METALS
NEPTUNIUM
NUMERICAL DATA
OXYGEN COMPOUNDS
PLUTONIUM
RADIOACTIVE MATERIALS
RADIOACTIVE WASTES
SEPARATION PROCESSES
TEMPERATURE DEPENDENCE
TRANSURANIUM ELEMENTS
WASTES
WATER