Why is clay a good material for storing radioactive waste?

Clay is an effective material for storing radioactive waste due to its low permeability, which prevents the migration of contaminants into the surrounding environment. Its stable structure and ability to absorb moisture help inhibit the corrosion of waste containers. Additionally, clay has a high capacity for ion exchange, which can further immobilize radionuclides and reduce their mobility. These properties make clay a suitable barrier in deep geological repositories for long-term waste containment.