The fraction of intended emplacement hole positions along a KBS3-type
nuclear waste deposition tunnel that can actually be used for depositi
on of waste canisters will be an important issue during different stag
es of decision-making within the repository site selection, design and
construction phases. Some criteria for rejecting positions will deal
with long-time performance aspects, e.g. expected post-closure groundw
ater flow in fractures that intersect the deposition hole and connect
to the tunnel or to nearby major fracture zones. Other criteria will b
e concerned with construction aspects, e.g. inflow into the open depos
ition hole during construction and emplacement, or the mechanical stab
ility of the deposition hole walls. Acceptance or rejection of individ
ual deposition hole positions will depend on the expected consequences
of a number of processes: excavation of tunnel and emplacement hole,
interaction with the swelling bentonite buffer, heating and subsequent
cooling. Additional, hypothetical processes include effects of glacia
tion and seismic events. The consequences of these processes will depe
nd on the arrangement of fractures in the nearfield, on the mechanical
properties of the nearfield- and farfield rock, and on the initial st
ress field. This paper deals with the first stage of an ongoing numeri
cal thermomechanical study, aimed at providing consequence description
s that are relevant on the tunnel- and deposition hole scale. The resu
lts regard results from continuum analyses. Comparisons are made with
recently developed analytical solutions for the temperature field and
the thermoelastic stress- and strain fields around and within the volu
me occupied by the repository. The discussion focuses on the relevance
of the results and the applicability of the numerical method. (C) 199
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