Radiological characterization of the irt-5000(14-Tammuz) research nuclear reactor at Al-Tuwaitha nuclear center in Iraq

Abstract

Measurements were made at the destroyed nuclear reactor IRT-5000 (14-Tammuz research nuclear reactor at AL-Tuwaitha Nuclear Center in Iraq) to provide a basic comprehensive radiological characterization and to assess risk and dose for the workers in the workplace. Samples were collected from the site and analyzed, as well as using a portable survey meter to determine the external exposure dose rates. The quantity and quality of radionuclides were determined using gamma spectrometry techniques. The dose rate measured within the reactor core body ranged from 55 to 1250 mSv/h. The maximum dose was recorded in the middle of the corner near the horizontal experimental channel number seven, with activity concentration of 19.97 GBq estimated from Co-60 isotope. Most samples were contaminated with Cs-137, Co-60, and Eu-152 isotopes. The highest activity concentration of Cs-137 is 14772.41 ± 99.91 Bq/L and Co-60 is 7642.22 ± 40.02 Bq/kg, were found in slag from reactor tank. Two scenarios were developed based on the water level of the reactor tank. Assuming there are three locations for workers on the reactor surface. The annual dose of workers on the surface of the reactor (when the reactor tank is empty) ranges from 116 to 153 mSv, which is higher than the annual dose limit for workers. Therefore, workers will be subjected to the principle of As Low As Reasonable Achievable (ALARA) during all phases of dismantling nuclear reactor IRT-5000 (14-Tammuz) as recommended by International Atomic Energy Agency (IAEA).