The Status and Outlook of High-Level Radioactive Waste Disposal in Deep Borehole Focusing on Behavior of Large-Diameter Deep Borehole

Abstract

This technical note describes the status and outlook of high-level radioactive waste disposal in a deep borehole, which is considered as an alternative way to isolate spent fuel and/or high-level radioactive waste permanently. The deep borehole disposal (DBD) concept consists of drilling into deep crystalline basement rock, emplacing waste canisters in the lower disposal zone of the borehole, and sealing and plugging the upper portion of the borehole through backfill. To make this concept viable, we should develop a new drilling technology that can achieve relatively larger bottom hole diameter drilling. It is expected that the large diameter drilling contributes to unpredictable borehole instability, e.g., severe borehole breakout or lost circulation, which takes up the additional cost. Furthermore, lack of scientific drilling experience in Korea, compared with other countries with rich experience and obstacle to find an appropriate site still remains as a challenge to overcome.