Decommissioning of nuclear facilities requires management of bulk materials on a large scale. Clearance (also called “free release”) is an essential part of material management and is necessary to reduce the amount of radioactive waste generated. Cleared materials can either be recycled for other use or disposed of as conventional waste. While guidance for decommissioning of reactors in the United States is well established by the Nuclear Regulatory Commission (NRC) and License Termination criteria as codified in 10 CFR 20 Subpart E are applied, there is no specific criteria or detailed guidance for the clearance of solid materials. The issue has been around for over three decades. The approach taken by the NRC is still on a case by case basis.
In contrast, the guidance at the international scene is more detailed and clearance of solid materials (for recycling or disposition) from the decommissioning of nuclear facilities is regularly practiced in European countries (such as, Sweden, Belgium and Germany). The cost of disposal of bulk materials from decommissioning, such as demolition debris that may or may not be contaminated, as radioactive waste is prohibitive. A path to free release under some criteria is necessary. It is not a question of radiological safety since there is consensus on extremely low dose criteria and these are accepted at the international level. It is rather, an issue of regulatory void in the United States where clarity and explicit guidance at the national level is pending.
This paper provides an overview of national and international guidance and regulatory developments for the clearance of solid materials from nuclear decommissioning projects including dose risk based methodologies. It will summarize the cost dimension of the issue and the field experience gained from the Big Rock Point decommissioning project.