2.3.2 Type A packages and industrial packages containing non-fissile substances Type A packages can, for example, be used to transport radionuclides for medical purposes commonly used in nuclear medicine departments, such as technetium generators. The total activity which can be contained in a type A package is limited by the regulations. Type A packages must be designed to withstand incidents which could be encountered during transportation or during handling or storage operations (small impacts, package stacking, falling of a sharp object onto the packages, exposure to rain). These situations are simulated by the following tests: ∙ exposure to a severe storm (rainfall reaching 5 cm/hour for at least 1 hour); ∙ drop test onto an unyielding surface from a height varying according to the weight of the package (maximum 1.20 metres); ∙ compression equivalent to 5 times the weight of the package; ∙ penetration by dropping a standard bar onto the package from a height of 1 metre. Additional tests are required if the content of the package is in liquid or gaseous form. Industrial packages allow the transportation of material with a low specific activity, or objects with limited surface contamination. Uranium-bearing materials extracted from foreign uranium mines are, for example, carried in France in industrial drums with a capacity of 200 litres loaded into industrial packages. Three sub-categories of industrial packages exist according to the hazards presented by the content. Depending on their subcategory, the industrial packages are subjected to the same tests as type A packages, some of the tests or only the general provisions applicable to excepted packages. As a result of the restrictions on the authorised contents, the consequences of the destruction of a type A package or an industrial package would remain limited, provided that appropriate accident management measures are taken. The regulations do not therefore require that this type of package be able to withstand a severe accident. Due to the limited safety implications, 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 fuels or high-level vitrified 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 used by 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 subcriticality (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 drop 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 1 metre 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 15 metres of water for 8 hours. This test is used to test the pressure-resistance of the package if it 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 consists in immersion under 200 metres 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, outside 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 case. 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 UF6 is used in the “fuel cycle”. This is the form in which the uranium is enriched. UF6 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, UF6 also presents a significant chemical risk. The regulations thus set out particular prescriptions for packages of UF6. They must meet the requirements of the 2020 edition of standard ISO 7195, which governs the design, manufacture and utilisation of packages. These packages are also subject to three tests: ∙ a free-fall test of between 0.3 and 1.2 metres (depending on the weight 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 bars. ASN Report on the state of nuclear safety and radiation protection in France in 2023 275 09 • 09 • Transport of radioactive substances 05 15 08 11 04 14 06 07 13 AP 03 10 02 12 01
RkJQdWJsaXNoZXIy NjQ0NzU=