Technology for high-level-waste disposal employing a multibarrier concept using engineered and natural barrier in stable bedrock at 300–1,000 m depth is being commercialized as a safe, long-term isolation method for high-level waste, including spent nuclear fuel. Managing heat generated from waste is important for improving disposal efficiency; thus, research on efficient heat management is required. In this study, thermal management methods to maximize disposal efficiency in terms of the disposal area required were developed. They efficiently use the land in an environment, such as Korea, where the land area is small and the amount of waste is large. The thermal effects of engineered barriers and natural barriers in a high-level waste disposal repository were analyzed. The research status of thermal management for the main bedrocks of the repository, such as crystalline, clay, salt, and other rocks, were reviewed. Based on a characteristics analysis of various heat management approaches, the spent nuclear fuel cooling time, buffer bentonite thermal conductivity, and disposal container size were chosen as efficient heat management methods applicable in Korea. For each method, thermal analyses of the disposal repository were performed. Based on the results, the disposal efficiency was evaluated preliminarily. Necessary future research is suggested.

1. Introduction
2. Review of Current Status of ThermalManagement
    2.1 Crystalline Rocks
    2.2 Sedimentary Rocks
    2.3 Other Host Rocks
    2.4 Summary of Repository ThermalManagement Concepts
3. Thermal Management Methods forDeep Geological Repository
    3.1 Extension of the Spent Nuclear FuelCooling Time
    3.2 Changes in the Characteristics ofDisposal Containers
    3.3 Changes in the Structure or MaterialProperties of Engineered Barriers
    3.4 Change in Design Limit of Temperature
    3.5 Changes in the Disposal Methods ofSpent Nuclear Fuel
4. Analyses of the Efficiency of theThermal Management Methods
    4.1 Cooling Time of Spent Nuclear Fuel
    4.2 Buffer Thermal Conductivity
    4.3 Disposal Container Size
    4.4 Results of Disposal Efficiency AnalysesWith Thermal Management Methods
5. Conclusions and Future Plans
Acknowledgements
REFERENCES

• Jongyoul Lee(Korea Atomic Energy Research Institute) Corresponding Author
• Heuijoo Choi(Korea Atomic Energy Research Institute)
• Dongkeun Cho(Korea Atomic Energy Research Institute)