3D instability analysis of an underground geological repository—an Indian case study

Abstract

Conceptual geological repositories are generally used for disposing spent nuclear wastes containing both high and low level of nuclear radiation and heat. Due to its long-lasting effect, it is imperative to analyze its long-term effect on the surrounding rock. Before analyzing radiation and thermal effect, it is important to have structurally stable cavern because designing an opening in rock is a more difficult problem than designing the structure made of steel. Underground rocks are under stress because of the weight of the overlying rock, and in addition, an underground opening will produce a stress concentration and stress relaxation in the surrounding rock. If the induced stress in the surrounding rock exceeds its strength, the opening will fail either by fracturing or by deforming more than the tolerable limit. In this paper, the stability of four different shapes of excavation has been examined for conceptual geological repositories in Indian context. This has been done using equivalent continuum numerical model which has been incorporated in the commercial finite difference code-FLAC-3D. Effects of opening shapes on stress distribution, subsidence of crown and side wall, and their stability have been analyzed and discussed. The validation of FLAC 3D software for its applicability in conceptual underground geological repositories has been done with a published literature.

Discrete element modelling of conceptual deep geological repository for high-level nuclear waste disposal

“…Radioactive waste is generated by a wide range of industrial, medical and military activities, each having its own specific inventory of radio nuclides. There are various possible methods adopted for management of nuclear waste like recycling, transmutation (Chwaszczewski 2003;Vladimir et al 2005), space disposal (Ehricke 1983), ocean disposal although comparatively unsafe, and ground burial (Kwon 2005;Verma et al 2011Verma et al , 2013Verma and Singh 2010;Laredj et al 2011;Sengun 2013;Mohammed and Sharaf 2011;Bo et al (2014);Jonny et al 2014). Whatever is the method of disposal, measurement and understanding of radiation effect on surrounding environment is of utter importance.…”