Sensitivity analysis for AHWR fuel cluster parameters using different WIMS libraries

India is presently engaged in the design of an advanced heavy water reactor (AHWR) which utilises thorium as fuel. The AHWR is a boiling light water cooled heavy water moderated reactor where the heat is removed through natural convection. Dysprosium is used as burnable absorber to get a reduction in void reactivity. The design needs to be well validated. The 69 group old WIMS library distributed by NEA in 1980's is presently being used for the design and analysis of AHWR. We have now undertaken an exercise to study the sensitivity of the design parameters, such as k-infinity and void reactivity with respect to the various datasets which have been made available as part of the IAEA CRP on the final stage of the WIMS library update project (WLUP). The k-infinity variations are within 1% both at the beginning of cycle (BOC) and at the end of cycle (EOC). The results for the coolant void reactivity, however, show significant differences between the different datasets at BOC itself which increases further with burnup. In comparison, the differences for natural uranium fuelled pressurised heavy water reactor (PHWR) lattice are relatively lower. Major source of variations in AHWR lattice are probably coming from Th-233U data