Radioactivity evaluation of the secondary sodium in DRACS of the Japan Sodium-cooled Fast Reactor

d This paper evaluates the secondary sodium activation in Direct Heat Exchanger (DHX), the radioactivity density and the dose rate around the secondary sodium pipes in Direct Reactor Auxiliary Cooling System (DRACS) of the Japan Sodium-cooled Fast Reactor (JSFR), by improving the exactness of a shielding calculation model with the Monte Carlo methodology. From this result, the prospects to meet the shielding design requirements for radioactivity free areas are obtained.