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Title: Drift-scale thermomechanical analysis for the retrievability systems study

A numerical method was used to estimate the stability of potential emplacement drifts without considering a ground support system as a part of the Thermal Loading Systems Study for the Yucca Mountain Site Characterization Project. The stability of the drift is evaluated with two variables: the level of thermal loading and the diameter of the emplacement drift. The analyses include the thermomechanical effects generated by the excavation of the drift, subsequently by the thermal loads from heat-emitting waste packages, and finally by the thermal reduction resulting from rapid cooling ventilation required for the waste retrieval if required. The Discontinuous Deformation Analysis (DDA) code was used to analyze the thermomechanical response of the rock mass of multiple blocks separated by joints. The result of this stability analysis is used to discuss the geomechanical considerations for the advanced conceptual design (ACD) with respect to retrievability. In particular, based on the rock mass strength of the host rock described in the current version of the Reference Information Base, the computed thermal stresses, generated by 111 MTU/acre thermal loads in the near field at 100 years after waste emplacement, is beyond the criterion for the rock mass strength used to predict the stability ofmore » the rock mass surrounding the emplacement drift.« less
Authors:
 [1]
  1. M&O/Woodward Clyde Federal Services, Las Vegas, NV (United States)
Publication Date:
OSTI Identifier:
433009
Report Number(s):
NUREG/CP--0150; CONF-9409238--
ON: TI96011022; TRN: 96:006559-0005
Resource Type:
Conference
Resource Relation:
Conference: Workshop on rock mechanics issues in repository design and performance assessment, Rockville, MD (United States), 19-20 Sep 1994; Other Information: PBD: Apr 1996; Related Information: Is Part Of Workshop on rock mechanics issues in repository design and performance assessment; PB: 265 p.
Research Org:
Nuclear Regulatory Commission, Washington, DC (United States). Div. of Regulatory Applications; Southwest Research Inst., San Antonio, TX (United States). Center for Nuclear Waste Regulatory Analyses
Country of Publication:
United States
Language:
English
Subject:
05 NUCLEAR FUELS; 36 MATERIALS SCIENCE; YUCCA MOUNTAIN; UNDERGROUND FACILITIES; SITE CHARACTERIZATION; ROCK MECHANICS; HIGH-LEVEL RADIOACTIVE WASTES; UNDERGROUND DISPOSAL; SPENT FUELS; TUFF; THERMOMECHANICAL TREATMENTS; STABILITY