ASN Report 2018

2.4  ̶  The requirements ensuring the reliability of the transport operations 2.4.1  –  Radiation protection of workers and the public The radiation protection of workers and the public around shipments of radioactive substances must be a constant concern. The public and non-specialised workers must not be exposed to a dose exceeding 1 millisievert (mSv) per year. However, this limit is not intended to be an authorisation to expose the public to up to 1mSv. Moreover, the justification and optimisation principles applicable to all nuclear activities also apply to the transport of radioactive substances (see chapter 2). Radiation protection is the subject of specific requirements in the regulations applicable to the transport of radioactive substances. Thus, for transport by road, the regulations stipulate that the radiation at the surface of the package must not exceed 2 mSv/h. This limit may be raised to 10 mSv/h in “exclusive use” conditions (2) , because the consignor or consignee can then issue instructions to restrict activities in the vicinity of the package. In any case, the radiation should not exceed 2 mSv/h in contact with the vehicle and should be less than 0.1 mSv/h at a distance of 2 metres from the vehicle. Assuming that radiation at the surface of a transport vehicle reaches the limit of 0.1 mSv/h at 2 metres, a person would have to spend 10 consecutive hours at a distance of 2 metres from the vehicle for the dose received to reach the annual public exposure limit. These limits are supplemented by requirements relative to the organisation of radiation protection within companies. The companies working in transport operations are required to implement a radiological protection programme, comprising the steps taken to protect the workers and the public from the risks arising from ionising radiation. This programme is more specifically based on a forecast evaluation of the doses to which the workers and the public are exposed. According to the results of this evaluation, optimisation measures must be taken to ensure that these doses are As Low as Reasonably Achievable (ALARA principle): for example, lead-lined trolleys could be made available to handling staff to reduce their exposure. This evaluation also makes it possible to decide on whether to implement dosimetry to measure the dose received by the workers, if it is anticipated that it could exceed 1 mSv/year. Finally, all the transport players must be trained in the risks linked to radiation, so that they are conscious of the nature of the risks, as well as how to protect themselves and how to protect others. The workers involved in the transport of radioactive substances are also subject to the provisions of the Labour Code concerning protection against ionising radiation. On 29 March 2018, ASN published Guide No. 29 to help carriers meet their regulatory obligations relative to the radiation protection of workers and the general public. ASN intends to update this guide in 2019, to take account of the new provisions of the Labour Code and Public Health Code resulting from the transposition of EU Directive 2013/59/Euratom (known as the “BSS” Directive). In 2019, it will continue with measures to educate professionals, dealing more specifically with changes to the regulations. 2. Exclusive use corresponds to cases in which the vehicle is used by a single consignor. This consignor may then give specific instructions for all the transport operations. 2.4.2  –  Package and vehicle marking So that the workers can be informed of the level of risk arising from each package and so that they can protect themselves effectively, the regulations require that the packages be labelled. There are three types of labels, corresponding to different dose levels in contact and at 1m from the package. The personnel working in proximity to the packages are thus visually informed of those which lead to the highest dose rates, can thus limit the time they spend close to them and can put them as far away as possible (for example by loading them towards the rear of the vehicle). The packages containing fissile materials must also display a special label. This is to ensure that these packages are kept apart to prevent the triggering of a nuclear chain reaction. The special label enables compliance with this prescription to be easily verified. Finally, the markings on packages must comprise their type, the address of the consignor or consignee and an identification number. This enables delivery errors to be avoided and allows packages to be identified if lost. The vehicles carrying packages of radioactive substances must also have specific markings. Like all vehicles carrying dangerous goods, they carry an orange-coloured plate at the front and back. They must also have a placard with the radiation trefoil and the word “RADIOACTIVE”. The purpose of these vehicle placards is to provide the emergency services with the necessary information in the event of an accident. Prevention of risks of exposure to ionising radiation The joint ASN and Ministry for Labour instruction DGT/ASN/2018/229 of 2 October 2018, concerning the prevention of risks of exposure to ionising radiation, extends the scope of application of the notion of “zoning”, which aims to limit worker and public exposure, to the transfer of radioactive substances within a facility, its annexes or worksites. Thus, the phases of package loading or unloading on a conveyance, modification of a shipment, transhipment or temporary parking within the perimeter of a facility or its annexes can lead to the implementation of a “monitored” or “controlled” zone, depending on the characteristics of the packages carried. 262  ASN report on the state of nuclear safety and radiation protection in France in 2018 09 – TRANSPORT OF RADIOACTIVE SUBSTANCES