ASN Report 2020

protection improved throughout the year 2020. Weaknesses are nevertheless still observed in the radiological cleanliness of the installations and the implementation of the radiation protection optimisation procedure during reactor outages, with diff iculties in establishing accurate and appropriate dosimetric estimates. ASN considers that the environmental protection performance of the NPP is in line with its general assessment of the EDF plants and has improved in comparison with preceding years. Control of liquid containment has improved. With regard to the control of activities relating to discharges and environmental monitoring, occasional deviations were observed in 2020, and ASN wants to see a return to a nominal effluent treatment situation after the difficulties encountered in recent years in the systems for evaporation treatment of radioactive effluents. Lastly, waste management is on the whole satisfactory, despite a persistent lack of rigour in the monitoring of the quantities of radioactive waste stored in the packaging auxiliaries building. ASN considers that the occupational safety results for the site are satisfactory. ASN notes that no serious accidents occurred in 2020 and that the accident rate, particularly during the reactor outages, was kept under control. With regard to worker protection in response to the health crisis, ASN noted that as of March 2020 the site had put in place appropriate protection measures, which evolved as knowledge progressed. THE “NUCLEAR FUEL CYCLE” FACILITIES The Tricastin fuel cycle installations mainly cover the upstream activities of the fuel cycle and, as of the end of 2018, they are operated by a single licensee, Orano Cycle, which became Orano Chimie-Enrichissement on January 2021 and is called Orano hereinafter. The site comprises: • the TU5 facility (BNI 155) for converting uranyl nitrate UO 2 (NO 3 ) 2 resulting from the reprocessing of spent fuels into triuranium octoxide (U 3 O 8 ); • the W plant (ICPE within the perimeter of BNI 155) for converting depleted UF 6 into U 3 O 8 ; • the former Comurhex facility (BNI 105) and the Philippe Coste plant (ICPE within the perimeter of BNI 105) for converting uranium tetrafluoride (UF 4 ) into uranium hexafluoride (UF 6 ); • the former Georges Besse I plant (BNI 93) for the enrichment of UF 6 by gaseous diffusion; • the Georges Besse II plant (BNI 168) for centrifuge enrichment of UF 6 ; • the uranium storage areas at Tricastin (BNI 178 and 179) for storing uranium in the form of oxides or UF 6 ; • the maintenance, effluent treatment and waste packaging facilities (formerly Socatri) (BNI 138); • the Atlas process samples analysis and environmental monitoring laboratory (BNI 176); • a Defence Basic Nuclear Installation (DBNI) which accom­ modates the nuclear materials storage areas in particular, virtually all of which are for civil uses. Following the inspections it conducted in 2020, ASN considers that the level of safety of the Orano facilities on the Tricastin site has remained stable. The industrial commissioning of new facilities with reassessed safety standards displayed contrasting results in 2020. ASN has checked the tests and the start of commissioning of the new waste treatment unit “Trident”, and the results are considered satisfactory. The results are less clear- cut for the Philippe Coste conversion plant however, where ASN has noted difficulties in the monitoring of the crystalliser replacement work and the corrective actions required for pollution prevention. In 2019, ASN authorised the application of a new version of the On-site Emergency Plan (PUI), adapted to the new organisation of the site, under the responsibility of Orano as sole licensee. This new organisation was inspected by ASN during a tightened inspection carried out on a Sunday along with an unannounced emergency exercise. The organisation is considered satisfactory on the whole, but ASN has requested several operational improvements. The campaign of unannounced inspections that ASN carried out simultaneously in BNIs 93, 105, 138, 155, 168 and 178 in 2020 showed that pollution prevention and the control of accidental spillages is generally satisfactory, except in the conversion plants. ASN also conducted several inspections in 2020 focusing on the organisation of Orano’s platform on the Tricastin site for managing its significant modifications. ASN noted that this organisation needs to be better harmonised on the site, but that the internal inspection body handles the modification files with greater efficiency. In 2021, ASN will ensure that Orano continues to deploy its action plans to improve safety management in order to further harmonise the practises of the BNIs on the platform. Lastly, in 2021 ASN plans engaging itself with the Defence Nuclear Safety Authority (ASND) in a new phase of delicensing of a significant proportion of the DBNIs. Orano uranium chemistry plants TU5 and W BNI 155, called TU5, can handle up to 2,000 tonnes of uranium per year, which enables all the uranyl nitrate (UO 2 (NO 3 ) 2 ) from the Orano plant in La Hague to be processed for conversion into U 3 O 8 (a stable solid compound that can guarantee storage of the uranium under safer conditions than in liquid or gaseous form). Once converted, the reprocessed uranium is placed in storage on the Tricastin site. The W plant situated within the perimeter of BNI 155 can process the depleted UF 6 from the Georges Besse II plant, to stabilise it as U 3 O 8 . ASN considers that the facilities situated within the perimeter of BNI 155 are operated with a satisfactory level of safety. The new unit of the Wplant, called EM3, commissioned inmid‑2018 and having necessitated hardware modifications in 2019, now functions nominally. For the TU5 plant, ASN continued to monitor the implement­ ation of the commitments made further to the periodic safety review of the facility. The progress with these commitments and the organisational setup for tracking them are satisfactory. 44 ASN Report on the state of nuclear safety and radiation protection in France in 2020 REGIONAL OVERVIEWOF NUCLEAR SAFETY AND RADIATION PROTECTION