The waste repository will be the final reservoir for all radioactivity generated by nuclear power. It will remain radioactive for a very long time, with some radioactivity even remaining for millions of years. As yet, complete safety analyses of waste repositories are not available. However, several attempts to approach the problem are known, and a number of systematic programs are on their way in various countries.

Proceeding from the assumption that water will be the only vehicle that possibly can carry radioactive material from the repository to people, the following processes must take place to create an actual risk:

1. The geologic containment fails and water is allowed to enter the repository and to find its way to the solidified waste, or brine present in the repository may contact the waste.

2. Radioactivity is released from the repository through contaminated water or brine entering an aquifier which is connected to circulating groundwater.

The magnitude of the consequences will obviously be a function of the radioactive inventory of the waste repository at the time when the sequence starts. As this inventory decreases by natural decay, the consequences will also decrease and will eventually drop below the level of significance.