Architecture and management of a geological repository - Andra

11 – Operational SafetyTable 11.1.1 Equivalent dose rate in contact with primary packages [3]Type of packageNature of contentsMaximum EDR 152 incontact with the primarypackage (Sv.h -1 )B1, B7.2 Compacted activation products 25B2 Bituminised waste 2B3, B7.1,B7.3, B8Compacted or cemented technological waste 0.5B B4 Cemented cladding waste 0.5B5Compacted cladding waste with or withouttechnological waste15B6Cladding waste and technological waste indrums2C0C0 Vitrified waste 150Other C Vitrified waste 250CU1 (UOx) Spent fuel assembly 25SF CU2 (MOx) Spent fuel assembly 15CU3 Spent fuel 150• Internal exposureExposure through inhalation is associated, on the one hand, with radioactive gases and aerosolsemitted by some B waste packages between their reception at surface installations and subsequentemplacement in the disposal cell, and on the other, with radon gas emitted naturally by the geologicalenvironment into the drifts of the underground installations.Radioactive gases emitted by the packagesSome packages contain traces of radioactive gases. Measures to reduce the release of these gases werepresented in Chapter 4. However, these measures do not apply to packages that also generate hydrogendue to radiolysis (B2 and B5.1 waste packages). For B5.1 reference packages, the most pessimisticcase, the adopted release rates (in becquerels per hour and by primary package) are roughly 400 fortritium, 14 for carbon and 7,000 for krypton 85.Radon gas emitted by the rock in the underground installationsThe radon exhalation rate from the rock varies according to various factors such as : ventilation andnature of drift lining. At this stage, the value used corresponds to the average value observed inFrance.11.1.2.2 Dosimetric evaluationThe dosimetric evaluation [107] is carried out for each type of work station identified on the disposalsite and for the public around the periphery of the site.• Dosimetric evaluation for personnel operating in nuclear installationsThe results are presented by distinguishing between the different work stations in the surface andunderground installations (cf. Table 11.1.2).152 In the case of slightly or highly exothermic packages, the values given here correspond to a packages with an age of 5 years in the caseof B1 packages, 10 years for B5 and SF3 packages, 20 years for C0, 60 to 70 years for SF1 (UOx) and 90 years for SF2 (MOx).DOSSIER 2005 ARGILE -ARCHITECTURE AND MANAGEMENT OF A GEOLOGICAL DISPOSAL SYSTEM439/495