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Management of Commercially Generated Radioactive Waste - U.S. ...

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K.25<br />

K.2.2 Recoverable Emplacement<br />

At the end <strong>of</strong> the period <strong>of</strong> readily retrievable emplacement (assumed to last 5 years<br />

for this conceptual repository), holes are no longer lined with sleeves or sealed with con-<br />

crete plugs, and rooms are backfilled after being filled with waste. For the remainder <strong>of</strong><br />

repository emplacement operations the wastes are considered to be recoverable with consider-<br />

ably greater effort than required for removal <strong>of</strong> readily retrievable wastes. Although sufficient<br />

confidence in repository performance existed to justify termination <strong>of</strong> ready<br />

retrievable emplacement, observations and measurements will likely continue.<br />

Recovery operations are more complex after the phase <strong>of</strong> readily retrievable emplacement<br />

ends. Before removal operations could begin, backfilled rooms first have to be reexcavated.<br />

This is done using standard earth-moving equipment with care taken to avoid excessive damage<br />

to emplacement holes. Backfill is removed from emplacement holes using shielded boring<br />

equipment; again, care is taken to avoid damage to the hole or canister. At this point the<br />

waste canister is removed to the surface as described for the readily retrievable case.<br />

In the event that a canister has become damaged and is not able to be extracted<br />

directly from the hole special steps need to be-taken. This may include core drilling<br />

around the damaged canister through the surrounding rock. The rock and waste are then<br />

transported to the surface and repackaged for temporary storge and disposal elsewhere.

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