For the transport of spent nuclear fuel, it is necessary to evaluate the amount of radioactivity for each assembly and the total amount of radioactivity for each cask. Currently, KHNP is evaluating the radioactivity using the Express mode of the OrigenArp program in the SCALE6.1 code. Express mode is a method to evaluate the radioactivity assuming that it has been burned with the same power per cycle, and Detail mode is a method to evaluate the actual combustion history such as power and cooling time for each cycle. For a total of 3,795 assemblies, including 1,391 assembliess for Kori Unit 1, 1,427 assemblies for Hanbit Unit 2, and 977 assemblies for Hanul Unit 3, the radioactivity was evaluated in Express mode and Detail mode, respectively, and the results were compared. As a result of the evaluation, it was confirmed that the results of the Express mode were evaluated more conservatively by 2.5~12.9% than that of the Detail mode. Accordingly, KHNP established a plan to change the evaluation method from Express mode to Detail mode in order to improve the accuracy of the radioactivity assessment results and eliminate conservatism.

• Jongho Hong(Korea Hydro & Nuclear Power (KHNP))
• Sangil Ahn(Korea Hydro & Nuclear Power (KHNP)) Corresponding author
• Jaechoon Lee(Korea Hydro & Nuclear Power (KHNP))
• Kiyoung Kim(Korea Hydro and Nuclear Power (KHNP) Central Research Institute (KHNP-CRI))