The operational safety assessment is an important part of a safety case for the deep geological repository of spent fuels. It consists of different stages such as the identification of initiating events, event tree analysis, fault tree analysis, and evaluation of exposure doses to the public and radiation workers. This study develops a probabilistic safety assessment method for the operational safety assessment and establishes an assessment framework. For the event and fault tree analyses, we propose the advanced information management system for probabilistic safety assessment (AIMS-PSA Manager). In addition, we propose the Radiological Safety Analysis Computer (RSAC) program to evaluate exposure doses to the public and radiation workers. Furthermore, we check the applicability of the assessment framework with respect to drop accidents of a spent fuel assembly arising out of crane failure, at the surface facility of the KRS+ (KAERI Reference disposal System for SNFs). The methods and tools established through this study can be used for the development of a safety case for the KRS+ system as well as for the design modification and the operational safety assessment of the KRS+ system.

1. Introduction
2. Method for the operational safety assessment
3. Operational Safety Assessment Framework
    3.1 Selection of initiating events
    3.2 Event tree analysis tool
    3.3 Fault tree analysis tool
    3.4 Exposure dose assessment tool
4. Example analysis
5. Summary and Conclusion
REFERENCES

• Jongtae Jeong(Korea Atomic Energy Research Institute) Corresponding Author
• Dong-Keun Cho(Korea Atomic Energy Research Institute)