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Draft 3.1.9<br />

Issue<br />

225<br />

GEOLOGIC CONSIDERATIONS<br />

One commenter indicated that the statement "Joint can be ..." is too vague. Are joints<br />

usually, <strong>of</strong>ten, or seldom anhydrite-filled, near vertical, unopen, moderately spaced, and<br />

generally extensive? (208-NRC)<br />

Response<br />

Salt, as a generic rock and mineral type can contain joints with properties as identi-<br />

fied in the statement. To characterize the joints more specifically would require specific<br />

data at a specific location.<br />

Draft pp. 3.1.9, 3.1.13, 3.1.14<br />

Issue<br />

Permeabilities <strong>of</strong> granite and basalt, while low, are not nil. If they were, the repos-<br />

itories in granite and basalt could be located a few meters beneath the weathered layer.<br />

There seems to be no appreciation that values <strong>of</strong> permeability determined in the laboratory<br />

differ quite frequently from effective (rock mass) permeability by several orders <strong>of</strong><br />

magnitude. (208-NRC)<br />

Response<br />

"Joints, fracutres and faults are generally not faborable from a geologic site selec-<br />

tion..." See draft p. 3.1.48. These types <strong>of</strong> settings will be avoided, as possible.<br />

"Methods <strong>of</strong> evaluating free water and its movement...(for example, laboratory determinations<br />

<strong>of</strong> porosity and permeability...) but zones <strong>of</strong> fracture or joint flow are difficulat to eval-<br />

uate and describe in laboratory tests." See draft p. 3.1.49. "Joints and fractures (and<br />

possibly faults) that act or could act as preferrential flow paths for water can be diffi-<br />

cult to locate and describe in terms <strong>of</strong> distribution and flow properties..." See draft,<br />

pp. 3.1.49, 50. These comments are in contrast to those made for flow in a porous medium.<br />

See fourth paragraph, draft p. 3.1.26.<br />

Draft p. 3.1.10<br />

Issue<br />

One commenter pointed out that in the last paragraph it is indicated that igneous rocks<br />

closely related to granite might not be suitable because <strong>of</strong> trace element and mineralogic

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