Validation of shutdown dose rate Monte Carlo calculations through a benchmark experiment at JET

A benchmark experiment has been performed during the 2005–2007 campaigns of JET in order to validate the rigorous two-step (R2S) and direct one-step (D1S) methods for the prediction of shutdown dose rates in full 3D geometry. Dose rate levels calculated using D1S and R2S methods have been compared with experimental data collected before and during off-operational periods and at the end of the last JET campaigns. Measurements have been carried out in two irradiation positions: in-vessel with high sensitivity thermoluminescent detectors and ex-vessel with an active detector of Geiger–Mueller type. Satisfying agreement between calculations and measurements has been obtained in in-vessel position, whereas both methods underestimate the experimental quantity in the external one.