Performance Evaluation for New Design of 37-element Fuels

As a CANDU reactor ages, the thermal margin has reduced due to an aging phenomena such as pressure tube diametral creep, which increases bypass coolant flow to the fuel bundle in the channel. To mitigate this problem, Korea Hydro and Nuclear Power Co. Ltd. (KHNP) decided to load the new design of fuel bundle into the Wolsong NPP site in 2013. The new design of 37-element fuel bundle was developed by Canadian utilities, which is the same as the existing 37-element fuel bundle but for smaller center pin diameter. As the licensing process, KHNP performed the demonstration irradiation (DI). The fuel performance parameters, which had been monitored about 6 months, showed that the new design fuel in P17 was being burnt with no significant or remarkable problems. The behavior of the new design fuel bundles was nearly the same as that of the existing fuel bundles. After DI test, KHNP had performed visual inspection at the spent fuel bay. There are no sign of defect fuel. Therefore, based on the monitored parameters and visual inspection, the new design fuel can be loaded in the Wolsong reactors. The final fuel performance evaluation report will be issued