ASN Report 2018

3.2  ̶  Industrial irradiators 3.2.1  –  The devices used Industrial irradiation is used for sterilising medical equipment, pharmaceutical or cosmetic products and for the conservation of foodstuffs. It can also be used to modify the properties of materials, such as for the hardening of polymers. These consumer product irradiation techniques can be authorised because, after being treated, the products display no residual artificial radioactivity (the products are sterilised by passing through radiation without themselves being “activated” by the treatment). Industrial irradiators often use cobalt-60 sources, whose activity can be very high and exceeds 250,000 terabecquerels (TBq). Some of these installations are classified as BNIs (see chapter 12). In many sectors, X-ray generators are gradually replacing high- activity sealed sources for the irradiation of products (see point 1.3.1). 3.2.2  –  The radiation protection situation BNIs excluded, ASN carried out five inspections in this area in 2018 at 16 licensed installations. These inspections show that the radiation protection organisation (in particular the appointing of a radiation protection advisor) and the zoning put in place on the premises of the inspected licensees are satisfactory; no significant deviations from the regulations were observed. The risk is well controlled, in particular thanks to the satisfactory verification, upkeep and maintenance of the facilities in accordance with the provisions of the files submitted with the licensing applications. In addition to this, no significant radiation protection events were reported in 2018. 3.3  ̶  Particle accelerators 3.3.1  –  The devices used A particle accelerator is defined as a device or installation in which electrically charged particles undergo acceleration, emitting ionising radiation at an energy level in excess of 1 megaelectronvolt (MeV). When they meet the characteristics specified in Article 3 of Decree 2007-830 of 11 May 2007 concerning the BNI nomenclature, these facilities are listed as BNIs. Loss of control of the source in gamma radiography Gamma radiography is a non-destructive testing technique consisting in positioning a radioactive source close to the element to be inspected in order to obtain a radiographic image which can subsequently be used to check the quality of the part. Loss of control of the sources is one of the main causes of incidents in this area. It can lead to significant exposure of the workers situated nearby, or even of the public when working in urban areas. This loss of control is primarily encountered in two situations: ཛྷ ཛྷ The radioactive source remains jammed in its guide tube. The cause of jamming is often the presence of foreign bodies in the tube, or deterioration of the tube itself. ཛྷ ཛྷ The source-holder containing the radionuclide is no longer connected to the remote control cable. The cable joining the source and the remote control is not correctly connected and the source can no longer be moved. In France, gamma radiography projectors comply with technical specifications that are stricter than the international ISO standards. However, equipment failures can never be ruled out, especially in the event of poor upkeep of the equipment. In the last few years, incorrect manipulations have also been observed further to source jamming incidents. Actual example of loss of control of a source during gamma radiography work at the SOBEGI chemical plant in Lacq (Pyrénées-Atlantique département ) Early on the night of 26 July 2018, a gamma radiography source jamming incident occurred at the SOBEGI chemical plant in Lacq, in the Pyrénées-Atlantique département . The radiography work was carried out by the company TENEO, using a GAM80 gamma ray projector loaded with a selenium-75 source of 2.247 TBq. The selenium source remained jammed a few centimetres from the projector, at a height of 4 metres on outdoor scaffolding. The jamming was correctly identified by the operator. The operators of the device immediately put new cordoning off means in place and alerted the site safety officers. The ASN on-call team was contacted during the night of 26 to 27 July via the toll-free emergency number provided for that purpose. The configuration of the gamma ray projector, situated at height and outdoors on a narrow platform, made the safeguarding operations difficult. Two intervention protocols were thus necessary and developed successively by ACTEMIUM (the device manufacturer) in collaboration with TENEO (the user company), then authorised by ASN. A safety perimeter was set up and placed under surveillance and permanently guarded throughout the duration of the event, that is to say for 17 days. The surface occupied by this perimeter hindered other work scheduled by the plant operator. An organisation dedicated to this event was therefore put in place and the ASN Bordeaux division organised regular conference calls with all the companies involved. ASN inspectors also performed an unannounced inspection on the site to check the adequacy and the surveillance of the cordoned-off area. The doses received by all the workers concerned by this event were satisfactorily controlled, with the collective dose remaining below 500 man-µSv. The in situ examination of the equipment showed that jamming was caused by the presence of a stone in the remote control guide tube, at the connection between the source holder and the remote control cable. ASN report on the state of nuclear safety and radiation protection in France in 2018  247 08 – SOURCES OF IONISING RADIATION AND THEIR INDUSTRIAL, VETERINARY AND RESEARCH APPLICATIONS 08