Reactor Physics and Safety Aspects of Fast Neutron Reactors with Associated Closed Fuel Cycle

India is aiming to reach at least per capita electricity consumption equal to the present world average (2200 kWh/y) by around 2030 from the current value of (660 kWh/y). The Government of India is encouraging exploitation of all the energy resources in a comprehensive and complementary fashion. This calls for the electricity generation capacity of at least ∼500 GWe by 2030. As a responsible country, having sensitivity to environment degradation and with high capacity and capability in nuclear energy and associated closed fuel cycles, we foresee a significant role of nuclear energy. But the maximum installed nuclear capacity is limited to about 10 GWe for about 40 years with currently confirmed U-resources (60,000 t) using a once through fuel cycle. India places high emphasis on uranium exploration with advanced techniques and technologies to enhance nuclear energy production through indigenous resources. In the first stage, 14 Pressurised Heavy Water Reactors (PHWRs) are now operating employing the once through fuel cycle. If all the U resources along with Pu generated in PHWRs is invested in Fast Breeder Reactors (FBR) with closed fuel cycle, capacity can be increased to about 250 GWe for 200 years or 1000 GWe for 50 years (second stage). FBRs in India will be deployed on U-Pu cycle for rapid growth of nuclear power capacity and generate enough fuel for Th-U cycle in the third stage. The Th-U cycle can be sustained for 3000 GWe for 50 years. Thus, FBRs working in a closed fuel cycle is capable of sharing significant portion of total electricity generation beyond 2030. In this paper, the reactor physics and safety aspects related to actinide management in the second stage of the large FBR programme are examined. Some safety and physics aspects of the oxide fuelled Prototype Fast Breeder Reactor (PFBR) under construction at Kalpakkam are presented. The validation of the computer code for core simulation and fuel management is also discussed. The Pu composition change in the closed fuel cycle with many recycling is examined. The need and possibility of using high breeding metallic fuels to substantiate the share of FBR in the total nuclear power is discussed. This paper also describes the studies conducted to dispel the apprehension on safety of metallic fueled FBR due to its higher coolant void reactivity effect. Possible use of valuable fission products for societal applications and a modified FBR design for minor actinide(MA) incineration is also briefly described. It is shown that the partitioned minor actinides from PHWRs can be burned in the core concurrently with Th utilization in the blankets. Cost reduction of FBR and its fuel cycle is a important step for sustainability of nuclear power. The planned road-map for this objective is briefly described. (authors)