A structured decision process is an essential part of Adaptive Staging. The purpose of a Decision Point is to assimilate new information, generate options (both anticipated and unanticipated), and make choices for subsequent actions based on acquired data. At Decision Points the implementer, following stakeholder consultation, determines whether the program will proceed or reiterate a previous stage. Decision Points should be planned at the end of all stages to assess the lessons learned. They can also be introduced in a stage whenever necessary (i.e., if new information warrant reconsideration of program direction). The decision to apply for a license (construct, operate, close the repository, or terminate activities) is an example of a planned Decision Point. The decision in the U.S. program to add the titanium drip shield to the engineered barrier system at Yucca Mountain would have been an example of an unplanned Decision Point if it had been carried out as described in this section. The implementer, DOE, judged that the drip shield was required to meet repository performance goals. In contrast with Adaptive Staging, Linear Staging attempts to anticipate all options initially, chooses a path, and does not allow for generating additional options during the process unless an unexpected event forces it. Decision Points in Adaptive Staging add flexibility and opportunities for program improvement with respect to safety, costs, and schedule.
A Decision Point is not just a “point” in time but a process involving analyses, review, and evaluations, as well as the consequent decisions for future actions. Thus, at a Decision Point the program implementer initiates a process that:
systematically gathers, synthesizes, evaluates, and applies the information acquired to date;
develops options for the next stage, including explicit consideration of reverting to an earlier stage;7
evaluates and updates the assessment of the safety of the repository system, in light of the options;
makes the findings publicly transparent and available;
engages in dialogue with stakeholders;
decides on the next stage based on all of the above; and
disseminates decisions and their rationales.
Figures 2.1a, b, and c illustrate schematically the committee’s view of the overall Adaptive Staging process, stages, and Decision Points. The more important or far-reaching the decision, the more it resembles the Decision Point-process above. Of course, the program implementer makes many more decisions than those at the formal Decision Points.