The manufacture, possession or use of ionising radiation sources is subject to declaration when the activity meets one of the following two conditions:
1° The weighted sum of the radionuclide activity mass concentrations divided by the declaration limit value set in the fourth column of table 2 ofappendix 13-8 for each of these radionuclides is less than 1 and the activity is not exempt pursuant to article R. 1333-106. This weighted sum of mass activities is achieved by taking into account all the radionuclides present at any one time on each homogeneous or related assembly present on the site where the nuclear activity is carried out;
2° The ionising radiation source is manufactured, held or used as part of a nuclear activity included on a list drawn up by decision of the Nuclear Safety Authority and approved by the Minister responsible for radiation protection. This list of nuclear activities takes into account, in particular, the justification for the nuclear activity, the characteristics of the ionising radiation sources and the devices containing them, their design, their conditions of use and the devices provided to ensure effective protection of people and the environment.