The dismantling of nuclear facilities, and in particular of nuclear power plants, involves new challenges for the nuclear industry. Although the dismantling of various activated and contaminated components is nowadays considered as almost industrial practice, the safety aspects of decommissioning bring some specific features which are not always taken into account in the operation of the plants. Moreover, most of the plants and facilities currently decommissioned are rather old and were never foreseen to be decommissioned. The operations involved in dismantling and decontamination, often imply new or unforeseen situations.On the nuclear, or radiological side, the radioprotection optimisation of the operations involved often requires to model the environment and to analyse different scenarios to tackle the operation. Recent 3-D software (like the Visiplan software) allowing representation of the actual environment and the influence of the various sources present, is really needed to be able to minimise the radiological impact on the operators. The risk of contamination spread, by opening loops and components or by the dismantling process itself, is also an important aspect of the radiological protection study.Nevertheless, the radiological aspects of the safety approach are not the only ones to be dealt with when decommissioning nuclear facilities. Indeed, classical industrial safety aspects are also important: the dismantling can bring handling and transporting risk (heavy loads, difficult ways, uneasy access, etc.) but also the handling of toxic or hazardous materials. For instance, the removal of asbestos in contaminated areas can lead to additional hazard; the presence of alkali metals (like Na or NaK), of toxic metals (like e.g. Beryllium) or of corrosive fluids (acid,...) have to be tackled often in unstructured environment, and sometimes with limited knowledge of the actual situation. This leads to approach the operations following the ASARA principle (As Safe As Reasonably Achievable) instead of the rather restricted ALARA principle.
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