Neptunium retardation with tuffs and groundwaters from Yucca Mountain

Conference · Mon Feb 01 04:00:00 EST 1993

OSTI ID:138815

Triay, I R; Robinson, B A; Lopez, R M; Mitchell, A J; Overly, C M

The retardation of neptunium was studied using batch sorption and column techniques. Pure mineral separates, tuffs and groundwaters from Yucca Mountain were used for these experiments. Our results indicate that Np sorption increases rapidly as the pH of the water increases in cases where surface complexation is thought w be the dominant sorption mechanism. Oxide minerals (such as hematite) sorb Np strongly; therefore, these minerals even at trace levels in Yucca Mountain tuffs can result in significant Np retardation. Neptunium in groundwaters from Yucca Mountain exhibited a significant amount of sorption onto quartz. Neptunium sorption onto quartz is important because of the large quantity of silica in the tuffs. Elution of neptunium solutions in groundwater through columns made of crushed tuff yielded sorption coefficients that agree with the sorption results obtained using batch sorption techniques. Agreement between batch and column experiments indicates a neptunium sorption mechanism that is linear, reversible, and instantaneous.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 138815
• Report Number(s): LA-UR--93-436; CONF-930408--20; ON: DE93007324
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
GROUND WATER
HIGH-LEVEL RADIOACTIVE WASTES
NEPTUNIUM
QUARTZ
RADIONUCLIDE MIGRATION
SORPTION
SORPTIVE PROPERTIES
TUFF
UNDERGROUND DISPOSAL
YUCCA MOUNTAIN
Yucca Mountain Project