4.2.6 Analysis of transport events The safety of the transport of radioactive substances relies in particular on the existence of a reliable system for detecting and processing anomalies, deviations or, more generally, any abnormal events that could occur. Therefore, once detected, these events must be analysed in order to: ∙ prevent identical or similar events from happening again, by taking appropriate corrective and preventive measures; ∙ prevent a more serious situation from developing by analysing the potential consequences of events which could be precursors of more serious events; ∙ identify the best practices to be promoted, in order to improve transport safety. The regulations also require on-line notification to ASN of the most significant events so that it can ensure that the detection system, the analysis approach and the integration of Operating Experience Feedback (OEF) are effective. This also provides ASN with an overview of events so that the sharing of OEF can be encouraged between the various stakeholders –including internationally– and so that ASN can consider potential changes to the provisions governing the transport of radioactive substances (see box page 276). As requested in Article 7 of the Order of 29 May 2009, amended, concerning the transport of dangerous goods by land, any significant event concerning the transport of radioactive substances, whether the consequences are actual or potential, must be notified to ASN within four working days, as stipulated in its Guide No. 31 on the notification of events. This Guide, which was entirely revised in 2017, is available on asn.fr. After notification, a detailed report of the event must be sent to ASN within two months. Events notified in 2021 In 2021, in the field of radioactive substances transport, ASN was notified of 80 Significant Events for Transport safety (EST) rated “level 0” on the International Nuclear and Radiological Event Scale (INES) and four events rated “level 1”. A slight rise in the number of “level 0” events is observed by comparison with 2020, whereas the number of “level 1” events remains stable. Graph 4 shows the variations in the number of significant events notified since 2004. In addition, ASN was notified of 52 Events Relevant for Transport safety (EIT), a figure that was significantly up on the previous years. Given that they have no actual or potential consequences, these events are not rated on the INES scale. There is thus no obligation to notify ASN, but the latter does encourage periodic information so that it has an overview of the EITs and can detect any recurrence or trends which could be indicative of an issue. In 2020, for the first time, two Significant Events for On-site Transport (see point 2.6) rated “level 0” on the INES scale, were reported. This figure rose to three in 2021. The increase in the reported Events Relevant for Transport safety (EIT) and Significant Events for On-site Transport (EST) indicates an improvement in the culture of safety and reporting to ASN. Sectors concerned by these events Most of the significant events (EST) notified concern the nuclear industry. Only just over 10% are related to transports for the non-nuclear industry. By comparison with 2020, the number of transport events involving pharmaceutical products fell considerably and only represents barely 7% of the significant events (as against 21% in 2020). As for the events rated “level 1” on the INES scale, they concerned loss of a source during a journey back to the office by a real estate diagnostic technician, non-compliance with a package transport approval certificate, the poor design of a vent plug, and the under-estimation of the quantity of radioactive substances in a tanker. Graph 5 shows the breakdown of significant events reported per notification criterion and Graph 6 presents their breakdown according to content and mode of transport. INSPECTION ON THE TOPIC OF CRITICALITY A inspection was carried out at the Cattenom NPP on 8 June 2021. The topic was maintaining sub-criticality when using the TN 13/2 package for transport on the public highway and the aim was to conduct spot checks on compliance with the regulatory requirements applicable to the transport of radioactive substances. The TN 13/2 package model is designed to transport uranium oxide based spent fuel assemblies. It is notably approved by ASN as a type B(M) package for the transport of fissile material. The inspectors more particularly examined the manufacturing files for a packaging shipped by the NPP, and its internal arrangements. They then looked at the maintenance operations carried out on this packaging, and the loading of the fuel assemblies into the packaging, notably in order to verify the packaging cavity drainage and drying operations. During the inspection, both on the site and via audioconference with certain players, the inspectors were able to hold discussions with representatives from Orano Nuclear Packages and Services (Orano NPS), the designer and manufacturer of the TN 13/2 package model, representatives from the package consignor –the Cattenom NPP– and representatives from EDF’s head office support departments. The transport regulations notably state that the consignor must hand over to the carrier a shipment that complies with the regulatory requirements and that it only use approved packagings suitable for transport and carrying the regulation markings. If the consignor calls on the services of other contractors (loaders, packers), it must take appropriate measures to guarantee that the shipment meets the requirements of the transport regulations. The inspection was thus carried out on the package dispatch site. The ASN inspectors were accompanied by two experts from the IRSN office in charge of criticality studies, as well as an expert from the IRSN office in charge of transports. The inspection showed that the transport operation inspected, with significant safety implications in terms of maintaining sub-criticality, was on the whole carried out in accordance with the safety case produced for the TN 13/2 package model, on the basis of which ASN had issued the approval of compliance with international transport regulations. However, the inspectors consider that EDF and its subcontractor Orano NPS must, during maintenance operations, ensure that the packaging continues to comply with the package model to which it refers, notably with regard to the parameters that are important for demonstrating that sub-criticality would be maintained during shipments, notably concerning the dimensions and nature of materials. ASN Report on the state of nuclear safety and radiation protection in France in 2021 273 09 – TRANSPORT OF RADIOACTIVE SUBSTANCES 08 07 13 04 10 06 12 14 03 09 05 11 02 AP 01
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