Generation of Incremental Cross Sections for Modified 37-element Fuel of CANDU6

In order to make margin of ROP (Regional Overpower Protection) trip setpoint, new type of fuel, modified 37-element (37M) bundle, has developed for CANDU6 reactor. 37M fuel is modified as reduction of the central element diameter size in comparison with one of standard 37-element (37R) bundle. More central coolant of 37M fuel bundle opens sub-channels up more flow in the middle of the bundle. It makes greater margin to critical heat flux (CHF) in the core. And there are small effects on bundle power and coolant void reactivity. In this study, incremental cross sections of reactivity control devices for 37M fuel bundle are calculated with the new versions of CANDU reactor physics codes and ENDF/B-VII based library. The incremental cross sections for reactivity devices of new 37M fuel bundle, adjuster rods, the liquid zone controllers, the shutoff rods, the mechanical control absorbers and various structural materials have been generated and these values will be used for full-core reactor simulations of modified 37-element fuel bundle by using RFSP