Abstract: The content per intake calculating program of the new transuranic elements' biokinetic model in ICRP Publication No.141 is established using Matlab Simulink software. Then program is used to calculate the content per intake of Am-241 inhaled by reference worker (breathing rate 1.2 m³/h, AMAD 5 μm), and the new model’s results are compared with the old models’ results. The new model’s retention indicates: (1) the factors of absorbing type and the AMAD size have big influence on calculation of content per intake in lung, skeleton, liver. It is necessary to make clear the two factors of the radiation source before internal dose evaluation; (2) Type S Am aerosol inhaled mainly remains in lungs, skeleton after 1 000 days; Type F Am aerosol inhaled is mainly absorbed in skeleton and liver; Type M Am aerosol inhaled distributes quite similar amount in lung, skeleton and liver in the early 300 d. Therefore the internal dose direct monitoring methods should be different for Type S, M and F Am inhaled. The comparing of the new and old biokinetic models indicates: (1)for the lung content per intake calculated, the short-term results (＜1 000 days after inhalation) of Type S and M are similar for the two models, the results of the middle and long-term (≥1 000 days after inhalation) from the new model is much higher than that of the old model, and the difference of the two models’ predictions are more obvious for Type S than Type M of Am; for Type F the difference of the two models are very big at any day. (2) For skeleton and liver content per intake calculated, for the Type S Am inhaled, the middle and long-term results of the new model are quite higher than the old model’s, while the two models’ short-term predicts are similar. For Type M and Type F of Am,the skeleton (liver also the same) content per intake predicted by the new model is lower than the old model’s, and the models’ difference of Type F Am is more obvious than that of Type M Am.

Key words: ICRP 141 Publication, HATM, retention per intake, new and old models