According to the actual situation of Qinshan reactor, pin-by-pin neutron transport calculation model for the whole core was set up by Monte Carlo codes, and the reliability of the model was validated. Based on geometric parameters, material parameters, neutron fluence rate distribution of structure parts, and under assumed reactor power operation history, burnup calculation codes are used to calculate the neutron activation products as estimation results analyze the 3D radiation field visualized model of of source term after shutdown, and to source term. The simulation results areconsistent wi...