[en] A description is made of the methods of calculating the internal radiation dose in man to be put together with the external dose, concerning the guideline dose values of the Atomic Energy Commission of Japan in connection with the principle of keeping the releases of radioactive materials in effluents of light-water-cooled nuclear power reactors to the environment as low as is reasonably achievable. A comparison is then made between the dose calculation methods announced by the Atomic Energy Commission of Japan and those by the U.S. Nuclear Regulatory Commission (Regulatory Guide 1.109). Features of the methods by the Atomic Energy Commission of Japan are: calculation of the doses in individuals of the critical groups outside of the reactors through critical exposure pathways due to major radionuclides in the effluents, usage of calculational models based on specific activities of radionuclides to estimate the doses via seafoods pathways, i.e. radioiodine in seaweed, and presentation of parameters for estimating the doses in Japanese people. (auth.)