VALIDITY ASSESSMENT OF SHIELDING DESIGN TOOLS FOR ITER THROUGH ANALYSIS OF BENCHMARK EXPERIMENT ON SS316 WATER SHIELD CONDUCTED AT FNS JAERI/

To assess validity of the shielding design tools for ITER, the benchma rk experiment on SS316/water shield conducted at FNS/JAERI is analyzed . As far as a simple bulk shield of SS316/water is concerned, the foll owings are found assuming that no uncertainty is involved in the respo nse functions of the design parameters. Nuclear data bases of JENDL Fu sion File and FENDL/E-1.0 are valid to predict all the design paramete rs with uncertainties less than a factor of 1.25. At the connection le gs between shield blanket modules and back plates, both MCNP and DOT c alculations can predict helium production rate with uncertainties less than 10 %. For the troidal field coils on the midplane, all the nucle ar parameters can be predicted with uncertainties less than a factor o f 1.25 by MCNP and DOT with consideration of self-shielding correction of cross sections and energy group structure of 125-n and 40-gamma. T he uncertainties for toroidal field coils are considerably smaller tha n the design margins secured to the shielding designs under ITER/EDA.