Transition to thorium fuel cycle on a heavy water moderated molten salt reactor by using low enrichment uranium

•Transition to thorium fuel cycle on a HWMSR by using low enrichment uranium (LEU) is studied.•LEU with U-235 enrichment no lower than 5% can successfully achieve transition on HWMSR.•By raising LEU enrichment from 5% to 19.75%, the DT shortens from 58 years to 17.3 years at RT of 10 days.•The fuel cycle cost is comparable to that of AP1000 when the RT is longer than 30 days.•The material attractiveness of U and Pu increases and decreases respectively as raising LEU enrichment.