Pu238-based small-size RTG for `artificial heart´ (AH) systems and assisted blood circulation (ABC) systems

The parameters of a radionuclide thermoelectric generator (RTG) equipped with single-stage Bi-Te semiconductive thermoelectric piles (STEP) have been calculated using a one-dimensional RTG model. Calculations have also been performed for an RTG equipped with two-stage STEP made of Bi-Te (low-temperature stage) and GeTe+PbTe (average-temperature stage). The operating temperature was up to 723 K. Results of the calculations have shown that an RTG equipped with a single-stage STEP is capable of producing 1.5 W of electric power. An RTG equipped with a two-stage STEP is capable of producing up to 3 W of electric power, which is quite sufficient to ensure independent operating of ABC systems. The calculation results are confirmed by test results on prototype RTGs. The equivalent dose rate produced by an unshielded 3 W RTG at a distance of 1 m is 5×10^-9 Sv/s, which complies with the maximum permissible dose of ionizing radiation permitted in the USSR