Equilibrium modeling of the formation of zeolites in fractures at Yucca Mountain, Nevada

Conference · Sun Aug 01 00:00:00 EDT 1993

OSTI ID:139250

Chipera, S J; Bish, D L; Carlos, B A

Yucca Mountain, in southern Nevada, is currently being investigated to determine its suitability to host the first US high-level nuclear waste repository. One of the reasons that Yucca Mountain was chosen for study is the presence of thick sequences of zeolite-rich horizons. In as much as fractures may serve as potential pathways for aqueous transport, the minerals that line fractures are of particular interest. Zeolites are common in fractures at Yucca Mountain and consist mainly of clinoptilolite/heulandite and mordenite although sporadic occurrences of chabazite, erionite, phillipsite, and stellrite have been identified using X-ray powder diffraction. To understand better the conditions under which the observed zeolite species were formed, thermodynamic data were estimated and calculations of log a((K{sup +}){sup 2}/Ca{sup ++}) versus log a((Na{sup +}){sup 2}/Ca{sup ++}) were conducted at various temperatures and silica activities. Using present-day Yucca Mountain water chemistries as a lower constraint on silica activity, clinoptilolite/heulandite and mordenite are still the zeolite species that would form under present conditions.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 139250
• Report Number(s): LA-UR-93-2761; CONF-9306100-4; ON: DE93018290; TRN: 93:018932
• Resource Relation: Conference: Zeolite 93: 4th international conference on the occurrence, properties, and utilization of natural zeolites, Boise, ID (United States), 20-28 Jun 1993; Other Information: PBD: [1993]
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
58 GEOSCIENCES
ZEOLITES
MINERALOGY
HIGH-LEVEL RADIOACTIVE WASTES
UNDERGROUND DISPOSAL
YUCCA MOUNTAIN
RADIOACTIVE WASTE FACILITIES
SILICA
PETROCHEMISTRY
GEOLOGIC FRACTURES
RADIONUCLIDE MIGRATION
TUFF
THERMODYNAMICS
MORDENITE
CLINOPTILOLITE
HEULANDITE
WATER CHEMISTRY
CALCIUM
Yucca Mountain Project