Abstract
The 4th generation storage ring (4GSR) facility is under construction in Korea. The facility includes a 200-MeV Linac, a booster ring operating from 200 MeV to 4 GeV, and a storage ring. Storage ring circumference is 799.297 m, stored electron energy and current are 4 GeV and 400 mA, respectively. Both storage ring and booster ring are located in the same tunnel. Shielding assessment was performed using the FLUKA 4-4.0 Monte Carlo code to determine the required thickness and shielding structure of the Linac and storage ring tunnels. Various beam loss scenarios under normal and abnormal operations were considered for the shielding analysis. The injection efficiency from booster ring into storage ring was assumed as 90%. For the shielding calculations, it was assumed that 4 mA beam current is injected into the storage ring every 2 min. The electron beam injection from Linac to booster ring, beam extraction from booster ring, and injection from booster ring to storage ring are all located near each other. Thus, the shielding calculations were categorized for the injection area and non-injection area so that for each area different tunnel wall thicknesses were considered. The shielding criteria were based on the Nuclear Safety Act in Korea and the As Low As Reasonably Achievable (ALARA) principle. These simulations will provide an overall radiological framework for shielding the 4GSR in Korea based on the present design conditions.