Point-kernel integral method, which has been verified by authorities, is widely used in radiation shielding calculations. In this article, we introduced point-kernel integral method in detail. Calculations have been performed for the radiation shielding design of TEG (gaseous waste processing system) system of one Chinese CRP1000 reactor, using the point-kernel integral codes QAD-CGA and Microshield 9. Dose results calculated by the two representative codes are compared from several aspects. We also focus our discussion on the impact of buildup factors that are fitted by different kinds of methods, which are the most important parameters in point-kernel integral method.
From the discussion in this article, we can draw the conclusions that 1)both of the two codes are of accurate and consistent calculation results, shielding calculation results are convinced; Microshield 9 proved to be reasonably reliable compared to results of traditional code QAD-CGA; 2) compared with QAD-CGA, Microshield 9 uses the latest database and simpler input form, but cannot calculate more than one source at one time; 3) buildup factor plays the most important role in point-kernel integral method; the two codes adopt different kinds of buildup factor fitting method; for the difference of dose calculation results using buildup factor or not, QAD-CGA is a little higher than Microshield 9 because of the different buildup factor calculation principles; 4) besides, the buildup factor reference material is advised to use either the last or the most dominant shielding.