Sodium Cooled Fast Breeders Advanced Technologies for Safer & Cleaner Nuclear Energy - Sodium Cooled Fast Breeders Arun Kumar Bhaduri Indira Gandhi Centre for Atomic Research Kalpakkam 8th Nuclear Energy Conclave India Energy Forum 30 Sep 2016, New Delhi

Current Electricity Scenario in India (2016) Energy Source Installed Capacity (MWe) Capacity (%) Generation Apr15-Mar16 (BU) Apr15-Mar16 (%) Thermal (Coal, Oil & Gas) 211671 69.9 943.4 85.2 Hydro 42783 14.1 121.3 11.0 Nuclear 5780 1.9 37.4 3.4 Renewables 42849 5.2 0.4 Total 303083 100.0 1107.3 Fossil fuels remain as the principal energy resource – Coal reserves in India ~ 300 billion tons Government promoting non-fossil resources i.e. nuclear and renewables Renewables – significant growth in recent years

Need for Nuclear & Nuclear Resources Required growth in electricity capacity compels to go for nuclear in larger way and renewables as far as possible Nuclear Resources in India Uranium resources 235,174 tons in-situ U3O8 (199,428 tons U) reserve as on Jan-2016 Thorium resources 11.93 million tonnes of monazite as on Feb-2016 Indian Monazite contains about 9-10% of Thorium oxide (ThO2) which in turn results in about 1.07 million tonnes of Thorium oxide (ThO2) Moderate Uranium reserves & Large Thorium reserves Comparison of Life- Cycle Emissions (Source: University of Wisconsin)

India’s Three Stage Nuclear Program & its Energy Potential Strategy for nuclear power program – designed with moderate Uranium & large Thorium reserves Types of reactor technology for the first two stages selected appropriately Focus on self reliance

FBR : A Vital Stage in Indian Nuclear Power Program Provides a perfect link covering the natural nuclear resources of India Effective utilization of uranium – better resource management Long term energy supply Higher growth rate with breeding Waste management – Incineration of radioactive waste from spent fuel and reduction of long-term storage requirements Enhanced performance parameters – high temperature of operation leading to higher thermodynamic efficiency Closed fuel cycle program is essential in the 2nd and 3rd stage Nat U Pu & Depleted U U233 Th Stage I Stage II Stage III Pu FBRs : Inevitable for long-term security & sustainability of nuclear power

Growth & Waste Minimization Strategy Higher growth rate possible only if fuel generation is more Hence, breeders are essential (with high breeding ratio) Recycling & Waste Minimization Effective incineration with higher energy spectrum; FBRs are high energy systems Key Parameters: Burnup, Breeding Ratio & Doubling Time (Growth)

FBR Evolution in India Test loops to get experience in Na technology Fast Breeder Test Reactor (FBTR) to get comprehensive experience in construction, operation and decommissioning experience and material irradiation data including reactor and energy conversion systems. Prototype Fast Breeder Reactor (PFBR) for techno-economic demonstration of large size plants Commercial size serial constructions. Synthesis of Operating Experiences Synthesis of Emerging Concepts (Ex. GEN-IV) Introduction of advanced design & simplification FBR-Metal 1000 MWe Pool Type Metallic fuel Serial constr. Indigenous FBR-MOX 600 MWe Pool Type UO2-PuO2 3 twin units Indigenous FBTR 40 MWt h 13.5 MWe Loop type PuC – UC Design: CEA Since 1985 PFBR 1250 MWth 500 MWe Pool Type UO2-PuO2 Indigenous

Fast Breeder Test Reactor (FBTR) Reactor Power 40 MWth 13.2 MWe Fuel Composition Mixed Carbides of Pu & U Concept of Primary Circuit Loop Total Sodium Inventory 150 t No. of Primary & Secondary Loops 2 No. of Steam Generator Modules per Loop Primary Sodium Temperature at Reactor Inlet / Outlet 483 / 515 C Secondary Sodium Inlet / Outlet Temperature to IHX 285 / 510 C Steam Temperature 480 C Steam Pressure 125 kg/cm2

Operating Parameters Achieved in FBTR Power: 26.1 MWth / 5.1 MWe Peak LHR: 400 W/cm Peak Flux: 3.15 x 1015n/cm2/sec Peak burn-up: 165 GWd/t Total operating time: ~53,500 h High Power Operation: ~35,000 h Thermal energy: ~520 GWh Electricity generation: ~ 35 million units Reactor inlet / outlet temp.: 393 / 490 C Feed water flow: 33 t/h Feed water temperature: 195 C Steam conditions: 470 C & 120 kg/cm2

Progressive Performance of FBTR Carbide Fuel The fuel chosen for FBTR is unique and without any international parallel Due to lack of irradiation experience, LHR was initially limited to 250 W/cm & burn-up to 25 GWd/t LHR was raised to 320 W/cm in 1995 after out-of-pile simulation tests Burn-up limit progressively raised up to 155 GWd/t based on Post-Irradiation Examination at 25, 50 & 100 GWd/t Except one pin failure at 146 GWd/t, more than 1400 pins have reached this limit without any failure FUEL CYCLE WAS SUCCESSFULLY CLOSED IN 2010

PFBR Flow Sheet

Main Characteristics Electrical power : 500 MWe (1250 MWth) Primary circuit concept : Pool Reactor coolant : Sodium Fuel : UO2 – PuO2 No. of Primary Sodium Pumps : 2 No. of Intermediate Heat Exchangers : 4 Number of secondary loops Number of Steam Generators per loop Number of Turbo-Generators : 1 Steam condition at SG TSV : 490 ºC at 16.7 MPa In-vessel fuel handling : 2 Rotatable plugs & 1 Transfer Arm Containment building : RCC rectangular shape Reactor Site : Kalpakkam Design Life : 40 years

Prototype Fast Breeder Reactor (PFBR) 13

Reactor Top View

Main Control Room

Future FBRs – MOX: Approach & Evolution of Reactor Design Power : 600 MWe Expanded core Targets: Higher Breeding & Lesser Sodium void coefficient of reactivity (compared to PFBR) Vessel size: Close to PFBR Core type: Homogeneous / Heterogeneous type Advantages: Existing MOX technology with higher Breeding Ratio till Metal Fuel Cycle technology matures PFBR: 500 MWe FBR- 600 MWe Improved Economy Advanced Reactor Assembly design features Technology development for improved Reactor Assembly components carried out Higher safety level desired – post Fukushima Higher power feasibility with about same vessel dimensions Twin advantage of economy & manufacturing technology availability

Enhancement of Design Objectives for Future FBRs Enhanced safety aiming Gen-III+ or possible higher safety level Improved economy by design optimisation & higher power output with same reactor assembly size Sodium Void Reactivity < 1 $ : enhanced safety demonstration to practically eliminate severe energetic accidents Breeding Ratio as high as possible (higher than PFBR) (for lower doubling time) & optimum fuel inventory by core design optimisation Possible higher operating temperatures towards higher efficiency Optimum number of heat transport systems & components No major R&D requirement for design as well as Technology Development beyond those planned for 500 MWe reactors Reduction of capital cost & construction time Core type: Heterogeneous concept as an option with MOX fuel Advantage : Adopting existing MOX technology & improved economy 600 MWe capacity MOX Fuelled reactor is preferred choice

Major Safety Objectives of Future FBRs Ultimate objective in design is elimination of need for off-site emergency response. This is planned to be achieved through the comprehensive safety approach encompassing the three levels, viz., Highly reliable engineered safety systems and robust design of critical structures. Natural behavior (inherent and / or passive feature) to terminate Severe Accidents Severe Accident Management.

Safety Enhancements & Augmentation of Shutdown Systems 1 2 3 4 Grip per B4C SS 316 ARMCO IRON BOBBIN COIL SENSOR Mo CONTACT RING CERAMIC INSULATION Mo CONTACTS ARMATURE TSMS (1) CSRDM with Stroke Limiting Device: Terminates inadvertent withdrawal of absorber rod to specified max. limit thus protecting reactor from UTOP event (2) Power supply to electromagnet holding the DSR is fed through Temperature Sensitive Magnetic Switch – Passive feature (3) Hydraulically Suspended Absorber Rod: – For LOF events during DEC (4) Ultimate Shutdown System (with Liquid / Granule absorber) – To prevent energetics

Design Improvements in Reactor Assembly of FBR-600 MWe Box type –> Dome shape Conical–> Single torus Welded Grid Plate Bolted Grid Plate Headers: 2 to 3 PFBR FBR-600 MWe GP- bolted -> welded

Road Map for Metal Fuel Reactor & Metal Fuel Cycle Technologies Pin level irradiation in FBTR Assembly Level in Irradiation in FBTR Loading as part of driver core in FBTR Initiation Phase Development of pyro-processing technology in laboratory & pilot scale Feasibility of aqueous reprocessing of metal fuels Demonstration of closed fuel cycle technology Metal Fuel Test Reactor Demonstration of fuel cycle closure along with test reactor Demonstration Phase Metal Fuel Breeder Reactor (1000 MWe) Deployment Phase

FBR and Associated Fuel Cycle Program FRFCF FBTR (40 MWt) Since 1985 PFBR – 500 MWe FBR-600 MWe ABTR (~100 MWt) Metal Fuel Power Reactors (along with Fuel Cycle facilities) CORAL Since 2003 DFRP Fuel Cycle

FRFCF Consists of cluster of fuel cycle plants co-located with PFBR at Kalpakkam and is self-contained with all facilities for recycling fuel. Plants and Facilities in FRFCF Core Subassemblies Plant (CSP) Fuel Reprocessing Plant (FRP) Reprocessed Uranium oxide Plant (RUP) Waste Management Plant(WMP) Common Services, Support & Utilities Fuel Fabrication Plant (FFP) Objective To close the PFBR fuel cycle & operate on a sustained basis PFBR FBRs 1&2 FRFCF Reservoir

Summary Fast Breeder Reactors – Essential for India’s Energy Security and Sustainability Experience from FBTR operation and PFBR design, manufacture, construction & safety review have given confidence for FBR deployment in series in closed fuel cycle mode. No technological constraints are foreseen. Towards ensuring higher growth rate, R&D on metal fuel with high breeding potential along with associated fuel cycle technologies is in progress. Comprehensive & Challenging R&D activities are taken up in several areas DAE’s strong emphasis on the R&D towards building up a substantial fast reactor program in the future

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