Calculation and Characteristic Analysis of Ex-Core Detector Spatial Response Function for High Temperature Gas-Cooled Reactor

The calculation model of ex-core detector spatial response function for the High-Temperature gas-cooled Reactor-Pebble-bed Module（HTR-PM） is constructed.Based on the adjoint transport theory,the ex-core detector spatial response function is calculated by the Monte Carlo method program（MCNP） and 3D discrete ordinate method program（TORT）.The characteristic analysis of ex-core detector spatial response function and comparison of these two results indicates that the result of 3D discrete ordinate method program accords with that of Monte Carlo method program,the adjoint transport theory is appropriate to construct the relationship of ex-core detector reading and in-core power distribution which is named as detector spatial response function,and the reading of ex-core detector is mainly contributed by the high energy group neutrons of the region facing to ex-core detector.