Dose Rates Comparative Study for Workers Involved in the Hot-Cells Clean-Up Activities of the VVR-S Nuclear Research Reactor under Decommissioning

Abstract

The present study consists in the assessment of the dose rates potentially received by the workers involved in Hot Cells decontamination from a VVR-S type Nuclear Research Reactor under decommissioning. Two exposure scenarios were considered: the dosimetrist performing contamination scanning measurements (H*(10) inside of the Hot Cell prior decontamination and the mechanical worker performing floor decontamination. The dose rates were calculated based on the floor hot spots activity concentration using a standard and a numerical method (RESRAD Build code) assuming that the highest radiological risks are from these surfaces. It was noticed that the external dose rate is relatively high both for the floor scanning and decontamination and the internal committed effective dose is relatively low for floor decontamination due to fact that the worker is equipped with a high filter efficiency mask. By comparing the two methods results it is noticed that the dose rate obtained using the numerical method is 32% lower than the dose rate evaluated with the standard method, due to model complexity.