Abstract
The paper provides an overview of the radiation protection challenges and the advanced simulation techniques used to study and plan complex interventions in radiation areas at CERN, particularly with regard to the Large Hadron Collider. The operational radiation protection aspects are supported by state of the art simulations by means of the FLUKA Monte Carlo code and estimates obtained via several tools, used within the CERN Radiation Protection group, such as ActiWiz, SESAME, and the Fluence Conversion Coefficients (FCC) method which extend the built-in FLUKA capabilities. The paper covers the general Radiation Protection principles and rules in force at CERN, the simulation tools/techniques used to fulfill operational tasks and predictive studies, and a set of case studies covering relevant applications at the Large Hadron Collider machine and experiments.