The site’s results in occupational health and safety are satisfactory. The accident levels remain controlled, particularly during reactor outages. A handling accident occurred when carrying out work on the polar crane during the reactor 1 outage, without causing injury. Tricastin site The Tricastin nuclear site, situated in the Drôme and Vaucluse départements, is a vast industrial site accommodating the largest concentration of nuclear and chemical facilities in France. It is situated on the right bank of the Donzère‑Mondragon Canal (a diversion channel of the river Rhône) between Valence and Avignon. It occupies a surface area of 800 hectares covering three municipalities, namely Saint‑Paul‑Trois‑Châteaux and Pierrelatte in the Drôme département, and Bollène in the Vaucluse département. The site harbours a large number of installations, with a nuclear power plant comprising four 900 MWe reactors, “nuclear fuel cycle” facilities, and a facility which fulfilled maintenance and storage functions and is now undergoing decommissioning. TRICASTIN NUCLEAR POWER PLANT The Tricastin NPP comprises four 900 MWe PWRs: reactors 1 and 2, commissioned in 1980, constitute BNI 87, while reactors 3 and 4, commissioned in 1981, constitute BNI 88. ASN considers that the nuclear safety performance of the Tricastin NPP stands out positively with respect to its general assessment of the EDF plants, and that its radiation protection and environmental protection performance is in line with the ASN’s general assessment of the EDF nuclear fleet. As regards nuclear safety, ASN considers that the plant’s performance remains satisfactory, but has not improved with respect to 2022. With regard to maintenance, the second batch of modifications planned for under the fourth periodic safety review has been satisfactorily integrated on reactor 1. ASN considers that EDF satisfactorily carried out the planned activities for the three reactor outages of 2023 and complied with the corresponding safety requirements. Weaknesses in operating rigour were nevertheless observed, with several significant events linked to failure to apply the work error- reduction practices. With regard to radiation protection, ASN considers that the performance of the NPP has deteriorated slightly. Eight ESRs were reported compared with three in 2022, and deficiencies in the control of the radiological cleanliness of the work sites were identified during the reactor outages. The tightened inspection carried out in 2023 also revealed deviations in the upkeep of the facilities and the management of controlled areas. ASN considers that the environmental protection performance of the NPP has improved and on the whole is in line with the general assessment of the EDF plants. Although several ESEs were reported in 2023, ASN notes the efforts the site has made in this area. Furthermore, the ASN resolutions governing the site’s discharges were revised in 2023, in particular to adapt the environmental monitoring programme and to reassess the methods of controlling certain substances further to changes in the operating conditions. As far as occupational safety is concerned, ASN considers that the site’s results are satisfactory and stable with respect to the preceding year. Accident levels, particularly during the reactor outages, remain under control despite a slight increase. THE “NUCLEAR FUEL CYCLE” FACILITIES The Tricastin “fuel cycle” facilities mainly cover the upstream activities of the “fuel cycle” and are operated by Orano Chimie-Enrichissement, called “Orano” hereinafter. The site comprises: • the TU5 facility (BNI 155) for converting uranyl nitrate (UO2(NO3)2) resulting from the reprocessing of spent fuels into triuranium octoxide (U3O8); • the W plant (ICPE within the perimeter of BNI 155) for converting depleted uranium hexafluoride (UF6) into U3O8; • the former Comurhex facility (BNI 105) and the Philippe Coste plant (ICPE within the perimeter of BNI 105) for converting uranium tetrafluoride (UF4) into UF6; • the former Georges Besse I plant (BNI 93) for the enrichment of UF6 by gaseous diffusion; • the Georges Besse II plant (BNI 168) for centrifuge enrichment of UF6; • the uranium storage areas at Tricastin (BNIs 178, 179 and 180) for storing uranium in the form of oxides or UF6; • the Maintenance, liquid effluent treatment and waste conditioning facilities (IARU – BNI 138); • the Atlas process samples analysis and environmental monitoring laboratory (BNI 176); • a Defence Basic Nuclear Installation (DBNI), which more specifically accommodates former facilities undergoing decommissioning, radioactive substance storage areas and a liquid effluent treatment unit. ABSTRACTS – ASN Report on the state of nuclear safety and radiation protection in France in 2023 39 Regional overview of nuclear safety and radiation protection • AUVERGNE‑RHÔNE‑ALPES •
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