various aspects of the WIPP project. The U.S. government also requested a peer review of the WIPP performance assessment from an expert committee under the auspices of the Nuclear Energy Agency and International Atomic Energy Agency. These reviews have improved the WIPP program and increased its credibility. The compliance certification process was carried out transparently according to rules agreed on in advance by all participants.
Defense transuranic waste has a relatively low radionuclide content and produces relatively little heat.Consequently, there is expected to be little thermal energy generated in the repository to promote processes that could lead to the loss of containment.
The engineered barrier system was modified to respond to technical concerns identified during the performance assessment studies (e.g., backfilling materials were introduced).
Although some of these factors are site or waste specific, there are lessons from the WIPP program that can be applied to other repository siting efforts—most notably, the importance of choosing a suitable site; allowing sufficient time to undertake the scientific and technical investigations necessary to demonstrate its suitability; and obtaining external, independent scientific and technical reviews of these investigatory efforts. These factors are discussed in more detail in Chapter 6 and Chapter 8 .
ered waste. Nevertheless, national programs have made measurable progress. The reasons this progress has been slower than foreseen in most countries include the following:
The development and acceptance of disposal technology has proved less straightforward than expected.
The technical issues associated with site selection and, more particularly, site characterization are more complex than assumed earlier.
The sociological and political problems raised by disposal projects were greatly underestimated.
The siting of centralized interim waste storage facilities has also encountered opposition, even though storage is a well-established technology that maintains options for monitoring and retrieval. Several countries, including Finland, Germany, Japan, Sweden, and Switzerland, have succeeded in siting centralized facilities while the United States, for example, has not.
Despite the lack of successes in siting geological repositories, there remains within national programs the general consensus that geological disposal is the only feasible, permanent solution to the HLW problem. There is also a general recognition, however, that technical answers alone are inadequate for deciding societal issues.