ASN Report 2018

As a result of the activity of the sources and the movement of the sources outside the storage container when the device is being used, gamma radiography can entail significant risks for the operators in the event of incorrect use, failure to comply with radiation protection rules, or operating incidents. Furthermore, these gamma radiography activities are often carried out on work sites under difficult conditions (working at night, in places that are exposed to the elements, or in cramped spaces). This is therefore an activity with serious radiation protection implications that figures among ASN’s inspection priorities. • Industrial X-ray radiography Industrial X-ray adiography is used for checking the quality of weld beads or for the fatigue inspection of materials. It is carried out using fixed devices or worksite devices employing directional or panoramic beams which replace gamma radiography devices if the utilisation conditions so permit. These devices can also be used for more specific and therefore rarer purposes, such as radiography for the restoration of musical instruments or paintings, archaeological study of mummies or the analysis of fossils. 3.1.2  –  Assessment of radiation protection in industrial radiography activities Industrial radiology activities are high-risk activities which have been an inspection priority for ASN for several years now, with 100 inspections per year in this area on average (excluding inspections in BNIs). The ASN inspectors perform their inspections by observing the practices in the field; half the inspections in this area are unannounced inspections on worksites which generally take place at night (in 2018, 54 inspections took place in agencies and 52 on worksites). The system of on-line notification of worksite schedules for industrial radiography contractors put in place by ASN in 2014 facilitates the organisation of these inspections. ASN notes that virtually all the licensees concerned generally use this system for the worksite notifications. This being said, the reliability of the transmitted information is still variable. The points to improve concern in particular: ∙ ∙ the updating of schedules when changes are made; ∙ ∙ the accuracy of the worksite location information (not to be confused with the address of the ordering company); ∙ ∙ the completeness of the worksite notification. From its inspection findings, ASN considers that the way risks are taken into account varies between companies. The risks of incidents and the doses received by the workers are generally well controlled by the licensees when this activity is conducted in a bunker in conformity with the applicable regulations. Selenium-75 gamma radiography  The use of selenium-75 in gamma radiography has been authorised in France since 2006. Implemented in the same devices as those functioning with iridium-192, selenium-75 offers significant radiation protection advantages in gamma radiography. The reason for this is that equivalent dose rates are about 55 millisieverts (mSv) per hour and per TBq one metre from the source, as opposed to 130 mSv/h/TBq for iridium-192. In France, about 19% of portable devices are equipped with selenium-75 sources. Although the use of selenium has been increasing constantly since 2014, ASN considers that it is still insufficiently used by the industry professionals. Yet it can be used in place of iridium-192 in numerous industrial fields, especially the petrochemical or boilermaking industry, and it enables the safety cordoned-off area to be significantly reduced and facilitates intervention in the event of an incident. Operating schematic of a gamma ray projector 244  ASN report on the state of nuclear safety and radiation protection in France in 2018 08 – SOURCES OF IONISING RADIATION AND THEIR INDUSTRIAL, VETERINARY AND RESEARCH APPLICATIONS