The transportation of Kozloduy NPP’s WWER-1000 spent nuclear fuel requires design and validation of a special
transport equipment. The exploitation of such equipment requires the fulfillment of IAEA Safety Standards Series Safety
Guide No. NS-G-1.4 recommendations and compliance with the Bulgarian legislation, which states that the maximal dose
rate at the external cask surface shall not exceed 2 mSv/h at any point. The cask TK-13/3 together with the internal basket
37/3 are used for the transportation of spent nuclear fuel from the spent fuel pool in the reactor building to the spent fuel
storage facility. The dose rate distribution around the TK-13/3 cask is calculated with the widely used and validated for
similar analyses software system SCALE. The analysis is done using the latest version of SCALE – 6.2.3 with the application
of modules ORIGAMI->ORIGEN->MAVRIC. The results show that all normative requirements and recommendations are
met.
Keywords: dose rate, spent fuel, SCALE 6.2.3, radiological analysis.