PRELIMINARY OCCUPATIONAL RADIATION EXPOSURE EVALUATION RELATED TO NETITER TRITIUM SYSTEMS

This paper presents the criteria adopted to evaluate Occupational Radi ation Exposure (ORE) during normal operation and maintenance of NET/IT ER and some results concerning the fuel cycle systems located in the t okamak and tritium buildings. Prompt radiation, activity concentration , and intake situations as well as number of workers, number of events , and exposure time are considered. Many systems and components, whose location in the plant can affect radiological protection during maint enance and/or surveillance, are identified together with the operation s needed for each activity. Accidental conditions and equipment failur es have been considered in the special maintenance activity when they are due to events with a high probability of occurrence so that such e vents might be expected during the life of the plant. Some results are reported showing the ORE figures with reference to the main activitie s. The total man-Sv/y for the systems and activities considered is abo ut 0.5. Such a result, even if very preliminary and incomplete, means that ORE for the tritium systems of a machine like NET/ITER is not neg ligible and has to be continuously controlled during the design phase.