ASN Report 2018

regulations do not therefore require that this type of package be able to withstand a severe accident. Due to the limited safety issues, type A and industrial packages are not subject to ASN approval: the design of the packages and the performance of the tests are the responsibility of the manufacturer. These packages and their safety case files are subject to spot checks during the ASN inspections. 2.3.3  –  Type B packages and packages containing fissile substances Type B packages are those used to transport the most radioactive substances, such as spent fuel or vitrified high- level nuclear waste. The packages containing fissile substances are industrial, A or B type packages, which are also designed to carry materials containing uranium-235 or plutonium and which can thus lead to the start of an uncontrolled nuclear chain reaction. These packages are essentially for the nuclear industry. Gamma radiography devices also fall into the type B package category. Given the high level of risk presented by these packages, the regulations require that they must be designed so that, including in the case of a severe transport accident, they maintain their ability to confine the radioactive substances and ensure radiological protection (for type B packages) as well as sub-criticality (for packages containing fissile materials). The accident conditions are simulated by the following tests: ∙ ∙ A 9m drop test onto an unyielding target. The fact that the target is unyielding means that all the energy from the fall is absorbed by the package, which is highly penalising. If a heavy package actually falls onto real ground, the ground will deform and thus absorb a part of the energy. A 9m drop onto an unyielding target can thus correspond to a fall from a far greater height onto real ground. This test can also be used to simulate the case of the vehicle colliding with an obstacle. During the 9m free-fall test, the package reaches the target at about 50 km/h. However, this corresponds to a real impact at far greater speed because, in reality, the vehicle and obstacle would both absorb a part of the energy. ∙ ∙ A penetration test: the package is released from a height of 1m onto a metal spike. The aim is to simulate the package being damaged by perforating objects (for example debris torn off a vehicle in the event of an accident). ∙ ∙ A fire test at 800°C for 30 minutes. This test simulates the fact that the vehicle can catch fire after an accident. ∙ ∙ An immersion test under 15m of water for 8 hours. This test is used to verify the pressure-resistance if the package were to fall into water (river by the side of the road or port during offloading from a ship). Certain type B packages must also undergo a more severe immersion test, which involves immersion under 200m of water for one hour. The first three tests (drop, penetration and fire test) must be performed in sequence on the same package specimen. They must be performed in the most penalising configuration (package orientation, ambient temperature, position of content, etc.). The type B package models and those containing fissile substances must be approved by ASN or, in certain cases, by a competent foreign Authority, before they can be allowed to travel. To obtain this approval, the designer of the package model must demonstrate the ability to withstand the above- mentioned tests in the safety file. This demonstration is usually provided by means of tests on a reduced-scale mock-up representing the package and by numerical calculations (to simulate the mechanical and thermal behaviour, or to evaluate the criticality risk). 2.3.4  –  Packages containing uranium hexafluoride Uranium hexafluoride (UF 6 ) is used in the fuel cycle. This is the form in which the uranium is enriched. UF 6 can thus be natural (i.e. formed from natural uranium), enriched (i.e. with an isotopic composition enriched in uranium-235) or depleted. Apart from the dangers arising from its radioactivity, or even its fissile nature, UF 6 also presents a significant chemical risk. The regulations thus set out particular prescriptions for packages of UF 6 . They must meet the requirements of standard ISO 7195, which governs the design, manufacture and utilisation of packages. These packages are also subject to three tests: ∙ ∙ a free-drop test of between 0.3 and 1.2 metres (depending on the mass of the package) onto an unyielding target; ∙ ∙ a thermal test, with an 800°C fire for 30 minutes; ∙ ∙ a hydrostatic resistance test at 27.6 bar. Packages containing enriched, and therefore fissile UF 6 , are also subject to the prescriptions previously presented (see point 2.3.3). The UF 6 is transported in type 48Y or 30B metal cylinders. In the case of enriched UF 6 , this cylinder is transported within a protective shell, which provides the necessary protection for withstanding the tests applicable to packages containing fissile materials. The package models containing UF 6 must also be approved by ASN or a competent foreign Authority, before they can be allowed to travel. 2.3.5  –  Type C packages Type C package models are designed for the transport of highly radioactive substances by air. In France there are no approved type C packages for civil uses. Breakdown of transported packages by type TYPE OF PACKAGE APPROXIMATE SHARE OF PACKAGES TRANSPORTED ANNUALLY Packages approved by ASN Type B packages, packages containing fissile materials and packages containing UF 6 2% Packages not requiring approval by ASN Type A packages not containing fissile radioactive substances 32% Industrial packages not containing fissile radioactive substances 8% Excepted packages 58% Table 2 ASN report on the state of nuclear safety and radiation protection in France in 2018  261 09 – TRANSPORT OF RADIOACTIVE SUBSTANCES 09