Status of LANL investigations of temperature constraints on clay in repository environments

Caporuscio, Florie A¹  Cheshire, Michael C¹  Newell, Dennis L¹  McCarney, Mary Kate¹ 

[1]Los Alamos National Laboratory

关键词: BOREHOLES;    CAPACITY;    CLAYS;    CONTAINERS;    HEATING;    HYDRAULICS;    ILLITE;    LANL;    MECHANICAL PROPERTIES;    PRECIPITATION;    SILICA;    SMECTITE;    WASTES;    WATER;   

DOI  :  10.2172/1049356
RP-ID  :  LA-UR-12-24272
PID  :  OSTI ID: 1049356
Others  :  TRN: US1204494

美国|英语

来源: SciTech Connect

【 摘 要 】

The Used Fuel Disposition (UFD) Campaign is presently evaluating various generic options for disposal of used fuel. The focus of this experimental work is to characterize and bound Engineered Barrier Systems (EBS) conditions in high heat load repositories. The UFD now has the ability to evaluate multiple EBS materials, waste containers, and rock types at higher heat loads and pressures (including deep boreholes). The geologic conditions now available to the U.S.A. and the international community for repositories include saturated and reduced water conditions, along with higher pressure and temperature (P, T) regimes. Chemical and structural changes to the clays, in either backfill/buffer or clay-rich host rock, may have significant effects on repository evolution. Reduction of smectite expansion capacity and rehydration potential due to heating could affect the isolation provided by EBS. Processes such as cementation by silica precipitation and authigenic illite could change the hydraulic and mechanical properties of clay-rich materials. Experimental studies of these repository conditions at high P,T have not been performed in the U.S. for decades and little has been done by the international community at high P,T. The experiments to be performed by LANL will focus on the importance of repository chemical and mineralogical conditions at elevated P,T conditions. This will provide input to the assessment of scientific basis for elevating the temperature limits in clay barriers.