Borehole Construction and Operation for Disposal in Crystalline Rocks

摘要

While DBD offers new challenges for the deep drilling industry and the need for the development of some new technology, it is considered that a deep borehole system can be designed and constructed to fulfill the requirements of radioactive waste disposal, ensuring that the waste is isolated from the biosphere to a degree that a robust safety case can be demonstrated. There is a strong case for a slim investigation borehole to characterize the geology and hydrogeology and to allow relevant evaluation and testing at a potential location. If such a borehole is located close to an eventual waste disposal borehole(s), however, the plug and abandonment (sealing) must be to the same standards as in the larger-diameter disposal borehole to eliminate any additional direct pathways for radionuclides to reach the biosphere. Therefore, the sealing and isolation of the investigation borehole must adopt the same systematic approach as for the waste disposal borehole. In any demonstration or early disposal, time and cost should not be a priority. An environment for innovation and engineering is important and must be encouraged. Value engineering comes later after the concept is proven by a full-scale demonstration and successful early disposal of actual waste.