ASN Report 2018

maintenance codes for industrial equipment, in order to promote the use of non-ionising inspection methods. ASN considers that the ordering customers have a key role to play in ensuring progress in radiation protection in industrial radiography. Through its 2018 inspections, ASN has noted that the drafting of occupational risk prevention plans with the user companies needs to be improved. This shortcoming shows that worksite preparation is not always commensurate with the risks of the activity. Enhancing the awareness of all the players is therefore a priority. The regional initiatives to establish charters of good practices in industrial radiography implemented for several years now at the instigation of ASN and the labour inspectorate, particularly in areas corresponding to the former regions of Provence-Alpes-Côte d’Azur, Haute-Normandie, Rhône-Alpes, Nord-Pas-de-Calais, Bretagne and Pays de la Loire, allow regular exchanges between the various stakeholders. The ASN regional divisions and other regional administrations concerned also regularly organise regional awareness-raising and discussion events which are attracting growing interest from the actors of this professional branch. According to the survey carried out by ASN in the sector, 70% of the industrial radiography agencies have a specialised fixed facility (bunker) and 70% of the agencies also operate in “worksite” configuration. 50% of the industrial radiography tests performed are in worksite configuration. In this configuration, devices with iridium-192 sources are the most commonly used, representing two-thirds of the worksites. X-ray generators are mainly used on the other worksites. Very few non-destructive tests are conducted outside bunkers using particle accelerators or gamma ray projectors with cobalt-60 or selenium-75. The worksites are primarily located in industrial units and processes and in BNIs. The large proportion of radiography work carried out in worksite configuration in industrial workshops suggests that the principle of justification is not sufficiently applied because, in many cases, the parts could very probably have been transferred to a protected bunker for inspection. Since the noteworthy incidents that occurred in the early 2010’s concerning blocked industrial gamma radiography sources, the stakeholders and IRSN have looked into defining, on the basis of experience feedback, typical loss of source control scenarios, developing the technical retrieval solutions and defining good practices in the event of a loss of control incident. Generic technical solutions to facilitate the retrieval of gamma radiography sources following loss of control (see box p. 247) have been identified. Several specific tools have been designed and implemented by the supplier for this purpose. It should be noted that in 2018, for the first time, no incident was rated level 1 or above on the INES scale. A relatively large number of significant events are still linked to loss of control of the source when using a gamma ray projector. Nevertheless, these events were correctly diagnosed by the operators and the persons concerned did not undertake any inappropriate or prohibited operations. The safeguarding operations were thus better mastered and no secondary incidents were observed. The causes of these events have not yet all been identified. Nevertheless, the worksite work conditions (difficult access, work at height, night work, etc.) and the maintenance of the equipment (spotlights and accessories) were contributory factors in at least two source jamming events that occurred in 2018. Gamma radiography: serious accidents abroad The number and consequences of gamma radiography accidents in France have remained limited since March 1979, when a worker had to have a leg amputated after having picked up a 518 GBq source of iridium-192 and put it in his pocket. This incident had led to a tightening of the regulations in effect at the time. ASN keeps a watchful eye for accidents occurring abroad which have had major deterministic effects. Recent examples brought to ASN’s attention include: ཛྷ ཛྷ In 2016, in Turkey, the operators had apparently not verified that the source had returned to the safe position after using a gamma ray projector. A 16-year old adolescent found the source the day after the inspection and took it home where several persons said they handled it. 20 people in all were reportedly exposed, with most severely exposed person reportedly receiving a dose of 1 gray (Gy). This event was rated level 2 on the INES scale. ཛྷ ཛྷ In 2015, in Iran, two operators were exposed to effective doses of 1.6 and 3.4 gray (Gy) respectively. The gamma ray projector source (iridium-192 of 1.3 TBq) became disconnected and remained blocked in the guide tube without the operators realising it. The operators then spent the night in their vehicle near the guide tube and the source. ཛྷ ཛྷ In 2014, in Peru, an employee was exposed to 500 mSv whole body and 25 Gy on the left hip when he moved a guide tube and a collimator without realising that the source was disconnected from the remote control cable and had remained in the collimator (iridium-192, 1.2 TBq, 30 minutes of exposure). ཛྷ ཛྷ In 2013, in Germany, an employee of a non-destructive testing company was exposed to more than 75 mSv whole body and 10 to 30 Gy at the extremities (hands) while attempting to release a source from a guide tube. ཛྷ ཛྷ In 2012, a Peruvian employee was admitted to Percy hospital in Clamart following exposure of 1 to 2 Gy (whole body) and of 35 Gy to the hand (70 Gy at the fingertips) after handling a guide tube with his bare hands, without first checking the position of the source. ཛྷ ཛྷ In 2011, 5 Bulgarian workers were admitted to Percy hospital in Clamart for major treatment following irradiation of 2 to 3 Gy owing to an error in the handling of a gamma ray projector, from which they believed the source had been removed. ཛྷ ཛྷ In 2011, in the United States, an apprentice radiographer disconnected the guide tube, noticed that the source was protruding from the source applicator and tried to push the source into the device with his finger. The estimated dose received at the extremities is 38 Gy. 246  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