Architecture and management of a geological repository - Andra

11 – Operational SafetyExternal exposureThe exposure of personnel to ionising radiation is a function of the nature and annual flow of the wastepackages received as well as the operating process. The latter is defined by the mode of operation ofthe installations and equipment (local or remote operation or operation from a control room) as well asby the time required to carry out different operations related to the running of the facilities(cf. Chapter 9).Based on this data, the dosimetric evaluation is carried out as follows:- The annual dose is evaluated for each production-related activity, taking into account the numberof times this operation is repeated throughout the year. The average dose received by an operatoris calculated based on the estimated total number of operators planned for each of theseoperations;- With respect to activities that are not directly related to production (control room, monitoring,etc.), the dosimetric evaluation is calculated directly for the station in question.Internal exposureExposure through the ingestion of radioactive materials has been considered negligible on account ofthe preventive measures taken.There are two component factors to exposure through the inhalation of radioactive gases:- For B waste packages which emit radioactive gases, the scenario used is that of the transfer of aB5-1 waste disposal package in a transfer cask to a poorly ventilated drift. The exposure ofpersonnel estimated on the basis of activity concentrations and dose coefficients related toinhalation for tritium and carbon 14 are negligible (of the order of 10 -3 mSv per year);- As far as doses related to radon emitted by the geological environment is concerned, the annualvalue used is 0.5 mSv for all operators working in the underground installations, both the nuclearzone and the construction zone.DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM440/495