A New Approach to Derive Clearance Levels for Wastes Containing Naturally Occurring Radioactive Materials (NORM) (Case Study: Lavan Island, Iran)

Naturally Occurring Radioactive Materials (NORM) are present in earth's crust with different concentrations. Human activities such as oil and gas production and mineral extraction and processing could enhance the natural level of NORM in by-products and waste streams. To protect public and workers from these enhanced NORM sources, clearance levels should be established. Clearance levels are regulatory limits which are defined in order to protect the environment and human from radiation sources. This study proposes a new approach to derive both generic and specific clearance levels. This approach consists of two scenario systems; Generic Scenario System (GSS) and Specific Scenario System (SSS). GSS is a comprehensive assessment tool which can be applied for any country. GSS is assembled by extensive research and actual NORM management methods. GSS investigates the radiological impacts of NORM from generation through final disposal. SSS is acquired through combination of GSS with field data and observation. This approach simultaneously considers both human health and economic aspects. To examine the implication of this method, Lavan Island in Persian Gulf is chosen for case study. The comparison between the generic and specific approaches for Lavan Island indicates that most exposure scenarios in generic approach which could result in extremely conservative values do not exist in specific scenarios regarding Lavan Island. Exposure groups, waste management options and enclosed circumstances of Islands, make them a preferable location to distinguish between SSS and GSS and understand the approach of this paper.