an exemption is applied for and approved by the U.S. EPA. The result is a highly inflexible system, as described in Chapter 2. Logically, one could create flexibility in one or both of two places: the classification decision or the disposal decision. The committee has chosen to consider flexibility in the classification decision only, for four reasons:

1. It more readily accommodates the kind of exemption that the committee recommends.

2. Classification has been for some time the focus of concern with the disposal provisions for HLW and TRU waste.

3. Such an approach requires the least change in the fundamental structure of the existing HLW and TRU waste disposal requirements.

4. Most importantly, it poses a familiar regulatory problem of over-inclusive categories, which has familiar solutions.

Additionally, if the focus is the disposal decision, the inevitable result of an approved exemption would be the existence of at least two types of HLW—for example, “near-surface” HLW and “deep-geologic” HLW—which is sure to result in confusion. It would be a mistake, however, to see the two areas of flexibility as entirely separate. As is plain in the discussions of the exemption process in Section 3.2 of this chapter and of a risk-informed process in Chapter 4, flexibility in classification will require careful consideration of the characteristics, especially as they relate to risk, of alternative disposal options.

The existing system for managing HLW and TRU waste is inflexible because it is based on a system of categories with predetermined consequences. It is a common, if not universal, characteristic of regulatory systems that they establish certain categories at the outset and then specify the different consequences that flow from being placed in one category or another. This is a conceptually simple and administratively manageable way to apply general rules to variegated reality. Moreover, since regulators are not omniscient, it is a way to limit the universe of considerations to those for which the information is obtainable at a reasonable cost (Karkkainen, 2001). It is also common, if not universal, that categories are over- and underinclusive in the sense that they cover either more or fewer—or, often, both—instances than their rationale would indicate should be covered.