Status of the Demonstration Irradiation of the CANDU New Fuel Bundle CANFLEX-NU in Korea

Abstract

A demonstration irradiation (DI) of 24 KNFC made CANFLEX-NU fuel bundles in the Wolsong Power Generation Station-1 has been conducted jointly by KEPRI/KHNP/KAERI since July 10, 2002. By selecting the Q07 (high power) and L21(low power) channels, the total 24 and 16 CANFLEX bundles were respectively loaded into and discharged from the reactor by 2003 August, and the final discharge of the other 8 CANFLEX bundles is expected on around February 2004. Tracking the reactor operation data, it is noted that the reactor has been stably operated during the DI. One CANFLEX bundle irradiated in the Q07 channel had a typical history of high power and high burnup, having the outer element power rating of ~41 kW/mat the fuelling, ~42 kW/mas a maximum power rating at the burnup of ~50 MWh/kgU, and ~35 kW/m at the discharge burnup of ~210 MWh/kgU. While, another CANFLEX bundle also irradiated in the Q07 channel had a typical history of power ramping, having a outer element power rating of ~7 kW/m from the fuelling to the burnup of ~48 MWh/kgU at which the element powers were ramped to a ~35 kW/m maximum element power rating, and ~30 kW/mat the discharge burnup of 188 MWh/kgU. An unusual performance and integrity of the CANFLEX elements could not be found in the ELESTRES predictions. By looking at the discharged CANFLEX bundles in the bay, all the bundles were intact, free of defects and appeared to be in good condition. A detailed in-bay visual examinations and dimensional measurements of the discharged CANFLEX bundles will be made at the end of 2003.