Radiological Protection during the Dismantling of Nuclear Facilities

ENRESA is the national company in charge of radioactive waste management in Spain. The company was set up in 1984, and one of its missions is the dismantling of nuclear facilities. ENRESA has carried out the dismantling of the Vandellós 1 nuclear power plant, several research installations and a pool type experimental reactor and is currently initiating the dismantling of the José Cabrera nuclear power plant, a pressurised water reactor facility. From the point of view of radiological protection, the dismantling of a facility presents a series of characteristics that set it aside from normal operation, such as for example the continuous variation of the type and level of the radiological and conventional risks and the fact that activities are performed on equipment and systems that have not been acted on previously. In addition, certain of the protection systems are left out of service and have to be replaced with mobile systems. It is also important to point out that many of the workers participating in dismantling projects are not accustomed to this type of work and may even not have worked before with ionising radiations. During dismantling there is also an increase in the risk of internal incorporation of alpha emitters, which are much more restrictive and difficult to determine than beta-gamma emitters, this implying the need to increase protective measures and to establish controls to determine as soon as possible whether any such incorporation has occurred. This article describes the radiological protection programmes implemented by ENRESA for dismantling projects and the organisation and resources available for their performance. There is also an analysis of the ALARA techniques implemented to prevent the incorporation of alpha emitters and the dispersal of contamination, as well as of the incorporation controls established. Finally, the results obtained are analysed, in terms of dose.