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After the publication of its general recommendations on radiological protection in 2007 (Publication 103),the International Commission on Radiological Protection (ICRP) is now preparing a series of publications dedicated to different types of existing exposure situations such as radon exposure,cosmic exposure in aviation or NORM activities.In the revised system of protection the ICRP recommendations evolved from a process-based approach (practices/interventions) to an approach based on the characteristics of three types of radiation exposure situation,i.e.,planned,emergency,and existing exposure situations.As far as the source already exists when a decision on control has to be taken,exposure situations arising from NORM activities are a priori existing exposure situations.However,in some cases,the existing source is removed and modified with the objective to use it as a radiation source.In such cases the exposure situation should be managed as a planned exposure situation.The ICRP distinguishes between three categories of exposures: occupational exposures,public exposures and medical exposures of patients.As far as workers are concerned,the ICRP limits its use of "occupational exposures" to radiation exposures incurred at work as a result of situations that can reasonably be regarded as being the responsibility of the operating management.Workers who are not occupationally exposed should be managed as members of the public.In practice,in existing exposure situations such as radon exposure or NORM activities,the workers should be considered as occupationally exposed either when,despite all reasonable effort,the exposure cannot be maintained below the appropriate reference level (quantitative criterion) or when the work activity is in a positive list established at national level (qualitative criterion).Anyway two of the three principles of radiological protection,justification of decisions that alter the radiation exposure situation and optimisation of the protection,are source related and apply in all exposure situations.In the case of NORM activities,the justification of the reuse or the recycling of residues should be carefully considered.As far as the principle of optimisation is concerned,the ICRP now recommends the same approach controlling exposure situations whatever their type: constrained optimisation (optimisation under a dose restriction).The dose restriction may be a dose constraint or a reference level (same concept) depending on the type of exposure situation.The third principle of radiological protection,the application of dose limits,applies only in planned exposure situations.The ICRP provides guidance helping regulatory authorities in the choice of the relevant dose constraints or reference levels amongst three bands of acute or annual doses: I mSv or less,greater than 1 mSv t0 20 mSv,and greater than 20 mSv to 100 mSv.The factors influencing the choice are the characteristics of the exposure situation (controllability of the source or the pathways,benefit for the individuals or the society) and the radiological protection requirements needed (information,training,monitoring,health surveillance,etc.of the exposed individuals).The constrained optimisation should then be implemented through a graded approach including both prevention and mitigation of exposures.In its future publication on NORM activities,the ICRP will provide recommendations in that field.