ASN Report 2018

AUVERGNE-RHÔNE-ALPES REGIONAL OVERVIEWOF NUCLEAR SAFETY AND RADIATION PROTECTION In addition, further to the waste management deficiencies detected in 2017, an unannounced inspection on this subject was carried out in March 2018. This inspection confirmed recurrent shortcomings in the implementation of the requirements relative to waste management. At the end of this latter inspection, ASN asked Orano Cycle to put in place a complementary plan, combined with inspection and monitoring measures, with the aim of lastingly reinforcing compliance with the rules for waste identification, management and storage. In 2019, ASN will check that this plan has been implemented and enables the required standard of conformity to be reached. Orano Cycle uranium fluorination plants Pursuant to the ASN requirement, the oldest fluorination facilities were shut down definitively before 31 December 2017. The shut down facilities have since been emptied of the majority of their hazardous substances and are now in the decommissioning preparation phase. In February 2014, Orano Cycle submitted a decommissioning file for BNI 105 (formerly Comurhex), which underwent a public inquiry in 2017 and its examination by ASN continued in 2018. The main issues associated with the decommissioning of BNI 105 are linked to the risks of dissemination of radioactive substances, exposure to ionising radiation and criticality, due to the residual uranium-bearing substances present in certain items of equipment. Under the effect of the hot summer temperatures, two drums of uranium-bearing materials stored in this facility developed leaks, leading in the case of one drum to the dispersion of contamination outside the storage building, with no consequences outside the site. This event was rated level 1 on the INES scale. ASN has asked for the creation of a containment chamber to store the drums pending their repackaging, and the renovation of the floor surfaces to achieve a satisfactory level of containment. More generally ASN expects the licensee, in 2019, to reinforce the containment of its old facilities and the means dedicated to their monitoring. The tests of the new production units of the Comurhex 2 project, grouping the facilities for converting uranium tetrafluoride (UF 4 ) into uraniumhexafluoride (UF 6 ), continued in 2018 with the introduction of UF 4 into the plant systems in autumn. Orano Cycle had difficulties in validating the operation of certain equipment items due either to processes which turned out to be ill-suited or to construction defects. The inspections carried out in 2018 showed that the validation processes prior to the commissioning of new facilities were satisfactory on the whole but should be applied with greater rigour. ASN also noted a lack of rigour in the first operating activities. The licensee must apply greater rigour in the operation of its facilities, both old and new. It must also, as of 2019, improve the containment of the old facilities until the radioactive substances stored in them have been definitively removed. Georges Besse I enrichment plant The Eurodif uranium enrichment facility (BNI 93) consisted essentially of a plant for separating uranium isotopes by the gaseous diffusion process. After shutting down production at this plant in May 2012, the licensee – Eurodif production – carried out, from 2013 to 2016, the Eurodif «Prisme» process of «intensive rinsing operations followed by venting», which consisted in performing repeated rinsing of the gaseous diffusions circuits with chlorine trifluoride (ClF 3 ), a toxic and dangerous substance, which allowed the extraction of virtually all the residual uranium deposited in the diffusion barriers. These operations are now finished. The licensee submitted its application for final shutdown and decommissioning of the facility in March 2015. The examination of this file continued in 2018. The decommissioning challenges concern the volume of Very-Low-Level (VLL) waste produced (which includes 160,000 tonnes of VLL metallic waste) and the decommissioning duration, which must be as short as possible (currently estimated at 30 years), considering the best scientific and technical knowledge available at the time and under economically acceptable conditions. Further to the Eurodif plant f inal shutdown and decommissioning preparation operations, which have been under way since 2017, ASN authorised, in August 2018, entry of the shut down facilities into a monitored standby phase which is to last until the start of the first decommissioning operations, planned for 2028. ASN ascertained beforehand, essentially through various inspections, that the facilities were in a safe state. It verified more specifically the prior removal of the operational waste. ASN will be attentive to the maintaining of rigour in facility monitoring and of a safety culture that is appropriate for the specific shutdown situation of the facilities. Putting in place a sole licensee With a view to simplifying the legal organisation of the Areva Group, a process to merge the Areva subsidiaries present on the Tricastin site was initiated in 2012, so that Areva NC could become the sole licensee of all the site BNIs. This process was completed for the Comurhex BNI in 2013. The process to change the licensee from Socatri, Eurodif and Société d’Enrichissement du Tricastin (SET) was completed in 2018. Orano Cycle, formerly Areva NC, is therefore now the sole licensee of all the cycle facilities on the site. 32  ASN report on the state of nuclear safety and radiation protection in France in 2018