Evaluation of aerosol retention inside a steam generator under steam generator tube rupture accident conditions

Abstract

The necessity has arisen to conduct risk evaluations of the steam generator tube rupture (SGTR) accident for domestic operating nuclear power plants in the Republic of Korea in accordance with a recent amendment to the Nuclear Safety Act. To evaluate the aerosol-type radionuclides released to the environment during the accident and to prepare mitigation strategies, tests conducted in experimental facilities that faithfully reflect the properties of domestic plants are essential. In this work, one such experimental facility was installed at the Korea Atomic Energy Research Institute with scaling work considering the geometrical shapes of a domestic Korean plant and the major aerosol removal mechanisms inside the steam generators. A preliminary test was first conducted to understand the amount of aerosol removal inside the pipes of the facility with analytical methods. Then, aerosol retention tests were performed in both dry and flooded conditions. Decontamination factors were evaluated in each test, and the results were analyzed using filter measurements, an electrical low-pressure impactor, and deposition mass in the tubes. The test results are believed to provide a good starting point to improve the related accident management strategies to increase the safety of domestic Korean nuclear power plants.