Neutronic analysis of X-ray survey spectrometer for ITER using Attila

In order to ensure proper design and operation of ITER tokomak extensive neutronics analysis is warranted. Many of the ITER related calculations are carried out by Monte Carlo codes like MCNP. Along with MCNP, FEM 3D discrete ordinates codes like Attila are also being used for this purpose. At ITER-India, Indian domestic agency of ITER. An approximate neutronics analysis for XRCS system at (EPP-11) is carried out in order to understand the validity of such calculations for ITER related neutronics analysis. This is evoked due to the large memory and CPU requirements of Attila for more accurate calculations. Further calculations with 46 energy groups are also performed for accurate flux calculations in the port interspace and around XRCS detector s and crystals. Both the accurate and approximate calculations are performed with a geometry that corresponds to ITER 'blite model'. The results show a clear agreement of the present calculations with other available results using both MCNP and Attila. The Attila calculations with 46 energy groups are subjected to many standard tests. The flux levels are in a good agreement with the results published. Further calculations like neutron wall loading are also performed for completeness. Finally we have compared Attila results with the results from our previous MCNP calculations in the EPP region. Attila flux shows a general agreement with MCNP results up to a distance of 2m from first wall. The Attila fluxes are much higher than that of MCNP from the radial points after 2 m. The work is underway to understand these deviations. (author)