Application of shielding factors for protection against gamma radiations during a nuclear accident

The derivation of derived intervention level (DIL) for sheltering in the event of nuclear accident relies heavily on the effectiveness of shielding provided by the shelters. Shielding factors for concrete and glass based on the equivalent dose buildup factors in the materials have been calculated, and these factors are applicable for estimating the protection against a radioactive plume. The γ emitters normally present in the plume are divided into three groups for the convenient selection of appropriate shielding factors. A case study on the application of shielding factors for protection against a design based accident occurring at the Guangdong Daya Bay nuclear power plant is also described. The discussion focuses on the practical application and meaning of the DIL