How much radioactivity will be emitted by the spent fuel before the repository is sealed? How much after the drillhole is sealed?

Nuclear radiation is emitted by the canisters whether above or below ground. Virtually all of this consists of “gamma rays,” which are like high-energy X-rays. To assure safety, there will be shielding between the canisters and any workers. Once underground, the rock will provide shielding and safety for the environment and human health.

At all times, the drillhole will be in compliance with regulations for the release of radioactive isotopes and radioactive dose to the public. The release of radioactive isotopes has been specified by law and regulation. These laws and regulations are written in highly technical language, but generally speaking, they assure that no human-harmful levels of radioactivity will reach the surface for tens of thousands to millions of years. The geologic formations chosen for the Deep Isolation drillholes will have been stable for tens to hundreds of millions of years. Ultimately, it is the geology that provides long-term confinement.