Natural Uranium being a limited resource on earth needs to be conserved and utilized optimally when used in the reactor core. Pressurized heavy water reactors (PHWRs) are fueled with natural Uranium (NU) in the form of short length bundles. Features like online refueling and short length bundles in PHWRs, provide the flexibility in towards optimizing the fuel requirement and the discharge burn-up during any stage of operation. In equilibrium core conditions, nearly fifty percent of fuel bundles have achieved burnup <3.5 GWD/TeU which is half of their target value of ~7GWD/TeU. There are instances like En-masse coolant channel replacement (EMCCR) or planned de-commissioning, where the full core has to be emptied. A small modification in fuel management scheme months before long shutdown activity can help in utilizing the low burn-up bundles present in the core for extended operation of reactor and save NU bundles. In this paper, a novel scheme for refueling and reshuffling of fuel bundles has been developed based on heuristic approach which is further supported by numerical simulation. This modified in-core fuel management (ICFM) scheme leads to a net economic benefit in terms of saving of fresh NU bundles as the feed rate of fresh NU bundles will be reduced to ~35% of feed rate during normal ICFM.