Can the waste be retrieved?

Yes. The Nuclear Regulatory Commission (NRC) requires waste to be retrievable for a period of time. The drilling industry regularly retrieves objects and monitoring instruments from drillholes, and the process is standard. For a Deep Isolation sealed drillhole, an expert crew could still retrieve the waste, but it would take a week or possibly longer. Doing so is sufficiently complex to offer substantial security from a terrorist attempt to retrieve the waste. We have already demonstrated the canisters can be retrieved.