Safety in the final disposal of radioactive waste. Final report of the Nordic Nuclear Safety Research Project AFA-1

During 1994-1997 a project on the disposal of radioactive waste was carried out as part of the NKS program. The objective of the project was to give authorities and waste producers in the Nordic countries background material for determinations about the management and disposal of radioactive waste. The project NKS/AFA-1 was divided into three sub-projects: AFA-1.1, AFA-1.2 and AFA-1.3.

AFA-1.1 dealt with waste characterisation, AFA-1.2 dealt with performance assessment for repositories and AFA-1.3 dealt with Environmental Impact Assessment (EIA). The studies mainly focused on the management of long-lived low- and intermediate-level radioactive waste from research, hospitals and industry.

The AFA-1.1 study included an overview on waste categories in the Nordic countries and methods to determine or estimate the waste content. The results from the AFA-1.2 study include a short overview of different waste management systems existing and planned in the Nordic countries. However, the main emphasis of the study was a general discussion of methodologies developed and employed for performance assessments of waste repositories.

Some of the phenomena and interactions relevant for generic types of repository were discussed as well. Among the different approaches for the development of scenarios for safety and performance assessments one particular method, the Rock Engineering System (RES), was chosen to be tested by demonstration.

The possible interactions and their safety significance were discussed, employing a simplified and generic Nordic repository system as the reference system. New regulations for the inventory of a repository may demand new assessments of old radioactive waste packages. The existing documentation of a waste package is then the primary information source although additional measurements may be necessary. (EG).