ASN Report 2017

305 ASN report on the state of nuclear safety and radiation protection in France in 2017 Chapter 10  - Sources of ionising radiation and their industrial, veterinary and research applications A series of incidents recorded in 2014 caused by rupture of the plug on GAM 80/120 devices had led ASN to require the supplier to implement preventive measures during annual maintenance of the devices. Only one event of this type has been notified to ASN since 2015, and that was in 2016. Other source jamming incidents have been reported, caused by failures such as non-connection of the remote control cables or guides or of the guide tubes. These incidents were correctly managed by the operators and managers of the companies concerned, and were rapidly resolved. Even though the French regulations are on the whole adhered to and are more stringent than the international standards, ASN considers that improvements are still required in worksite preparation and incident management. Research activities ASN notes that the follow-up and reporting of events in this area are rarely carried out systematically. Nearly half the inspected licensees do not have procedures relating to the management of significant events. In 2017, ASN registered 15 significant radiation protection events concerning research activities, that is to say half as many as in 2016, which corresponds to the reporting trends observed for the years 2011 to 2014. FUNDAMENTALS 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. The industrial radiographer required partial amputation of the fingers of the left hand. 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. Number rated level 2 2011 2012 2013 2014 2017 2016 2015 0 5 10 15 20 25 30 35 GRAPH 10: Trends in the number of events notified to ASN in the research sector Number of facilities Number rated level 1 Number of significant events