It is a proven technique.
In-situ disposal has been used successfully at a number of nuclear sites worldwide since the 1960’s. It is a technique that was used to effectively remediate sites contaminated with toxic and hazardous wastes. In-situ disposal of NPD will meet the requirements of all current legislation and will do so by reaching or exceeding the requirements of all Canadian safety standards.
Internationally, the nuclear industry has successfully used in-situ disposal to safely decommission power and research reactors such as, Hallam in Nebraska, Savannah River Site P and R, the Experimental Breeder Reactor (EBR) II, Boiling Nuclear Superheater (BONUS) Reactor Facility and Piqua. Two of these examples were decommissioned in the 1960’s and the 60 year performance of these facilities demonstrates the strength of this approach at protecting people and the environment.
Furthermore, the radioactive inventory that the NPD Closure Project proposes to dispose of at the NPD site is much lower in comparison to the radioactive inventory disposed of at other facilities.
In the long-term, there are natural analogues to give insight into how materials behave over the course of thousands of years.
Natural analogues, which are natural or anthropogenic (man-made) features, are used to better understand how safety features can last over thousands of years, which increases the confidence in the how the disposed facility will behave. Natural features similar to NPD’s containment and isolation safety features provide supporting evidence, for instance:
Knowledge of how archaeological artefacts (e.g., iron nails from the first century) corrode under a wide range of environmental conditions, supports our understanding of how NPD’s reactor system will survive over long periods of time.
Early cements, such as those used by the ancient Romans, have proven to be extremely durable, even in harsh environments, and have lasted thousands of years. This gives a solid understanding of the longevity of NPD’s concrete structure and grout backfill.
Anthropogenic or man-made barrier systems, such as ancient tombs, support the appropriateness of using a cover structure to keep below-grade systems dry for a long period of time.