Evaluation of Approaches for Well Abandonment and Temporary Shutdown at the "Yeniseiskiy" Site (Krasnoyarsk Territory, Nizhnekanskiy Massif)

Abstract

Rock mass is considered as a natural barrier impeding the release of radioactive waste into the environment, being part of a multi-barrier system designed to ensure the safety of deep disposal facilities for radioactive waste (DDF RW). A number of regulatory documents [1] and recommendations [2, 3] states the importance of the geological medium, namely, its characteristics for the long-term safety of RW disposal. Current stage of URL development project is specifically focused on providing the opportunities for geological research covering target RW disposal horizons solely via borehole methods before the entire complex of underground excavations is formed. Due to long-term operation of wells and their initial design features, the state of some of these wells has appeared to be unsatisfactory requiring reconstruction. In addition, in accordance with certain legislative requirements, all wells shall be abandoned after relevant operations have been completed. The article discusses the reconstruction and abandonment of wells drilled at the Yeniseiskiy site. It demonstrates the feasibility of proposed designs providing the opportunities for further expansion of studies to investigate the state of rocks under natural conditions and to arrange for monitoring. The paper provides an evaluation and comparative analysis of plugging materials proposed to be applied under well abandonment operations.