Determination of Baseline Value of Radionuclides in Iranian Near-Surface Disposal Facility

Abstract

According to the radioactivity criteria, about 97% of radioactive waste is categorized as Low and Intermediate Level Waste (LLW or ILW). Such waste has been disposed of in near-surface repositories for many years all over the world. Surveillance programs, such as monitoring, are important elements in ensuring the safety of operation and closure of near-surface waste disposal facilities. During construction, operation, and closure, these safety parameters are assured by active control measures exercised at the repository and the quality management process. This paper primarily aims to examine the pre-operational radiomonitoring program for Iran's near-surface disposal site in Anarak. The goal is to measure baseline values of natural radioactive materials resulting from atmospheric deposition in the repository's surrounding environment. as well as to track their seasonal variations in water, plants, and the atmosphere. The analysis of soil and sediment radiomonitoring will be covered in the next study. In such a manner, after the site selection process, a comprehensive plan is designed for the Anarak waste repository, including sampling methods, sampling frequency, sampling stations, and key radionuclides. After the nuclear facility construction, the baseline radiation values are recorded to assess any changes in the zone's radioactive levels for the long-term operational and post-closure safety assessment programs, which is crucial to determine when and where radioactive contamination becomes hazardous for industrial workers and the public. The results showed, the beta particle radioactivity concentration in nine samples of water is measured from 0.12 to 0.94, and this range varies from 0.14 to 0.90 for alpha particles in the same samples. Moreover, the 40K ،137Cs, and 232Th concentrations in nine samples are less than the Minimum Detectable Activity (MDA). Finally, all measured values were compared and analyzed with national and international guidelines to record as a baseline value for the Anarak disposal facility and the surrounding environment.