CORROSION RADIOACTIVE PRODUCTS IN A PRIMARY COOLING SYSTEM OF THE ITER PLANT - A PRELIMINARY ORE EVALUATION

In this paper a preliminary evaluation of the Occupational Radiation E xposure (ORE) of the personnel involved in working activities on secti ons of the ITER primary cooling systems (PCS) is presented. The analys is has been restricted to the primary cooling circuits of the first wa ll (FW) and of the shielding blanket (SB). The radioisotopes produced by activation in the pipe's material surfaces are identified using the available works and data, their amount is obtained with suitable comp uter codes. The calculation is performed using the combination of a 1- D discrete ordinate code and activation codes. The corrosion/erosion p roblem is faced with two different approaches: a simplified model with steady state conditions and a computer code that evaluates the non-ho mogeneous distribution of the activated corrosion products (ACP) in th e cooling circuit. The ORE is assessed for some working activities con sidering the direct irradiation from the ACP and the average distance of the workers from the cooling circuit. The results presented in the paper are useful in order to address experiments needed to evaluate th e main unknown parameters for the ACP evaluation and then to design th e primary cooling circuits. Furthermore the work outlines a methodolog ical procedure and presents some preliminary results for the ORE asses sment at the PCS of a fusion plant like ITER.