1. Clean and Sustainable Nuclear Power
Srikumar Banerjee
Homi Bhabha Chair Professor,
Bhabha Atomic Research Centre
6th Nuclear Energy Conclave,
October 14, 2014

2. World Electricity Distribution
% Population not having access to electricity
20% of World population (1300 million)
25% of India’s population (300 million)
Earth at night
Per Capita Electricity Consumption in kWh

3. Near-Term Energy Supply– Indian Scenario
Meeting this requirement by burning fossil fuels (Coal) would result in 3-4 billion tonnes of CO2 emission
Solution lies in enhanced deployment of primary energy sources :
Solar
Wind
Nuclear
9% Growth
8% Growth
Renewable + hydro potential
Currently Installed Capacity ~ 220GWe
66%
12%
19% 3%

4. Projected Electricity Demand in 2032
Population in India in 2030 : Billion (lower bound estimate)
Per Capita Electricity Consumption
to match present world average : KWh
Total Demand of Electricity : TWh
Total Electricity Consumption in : TWh
India needs at least 4 fold increase in electricity consumption / production in next two decades
To control Carbon foot print capacity enhancement to be targeted
Solar : 5 to 50 GW
220 TWh per year % capacity factor (intermittent)
Wind : 15 to 50 GW
Nuclear : 5 to 60 GW TWh per year % capacity factor

5. Average Capacity Factors
Wind : 25%
Solar : 20%
Nuclear : 90%
Average Capacity Factors
Footprint for 10 GW Installations
Primary Energy Sources
Distributed & Intermittent Source
Concentrated & Continuous Source
5000 sq.Km
400 sq.Km
1 sq.Km

6. Conversion from fertile to fissile materials  
232Th
233Th
233Pa
233U
1.4 x 1010 y
7.37 barns
22.3 min
1500 barns
27 days
20 barns
1.59 x 105 y
a 47 b ; f 530 b
Fertile
Fissile  
238U
239U 
239Np
239Pu n
4.5 x 109 y
2.7 barns
23.5 min
22 barns
2.36 days
32 barns
2.4 x 104 y
a 270 b ; f 752 b
Fissile
Fertile

7. Fertile partly converted Once Through Fuel Cycle
Fuel cycle options
Fuel
Fissile+Fertile
Fissile partly spent
Fertile partly converted
Spent Fuel Repository
Nuclear Reactor
Huge energy potential !!
Once Through Fuel Cycle
Fuel
Fissile+Fertile
Fissile partly spent
Fertile partly converted
Reprocessing
Nuclear Reactor
Fertile + Fissile
Long lived waste Repository
Fuel Manufacturing
Closed Fuel Cycle

8. Adopting closed fuel cycle also reduces nuclear waste burden.
Natural decay of spent fuel radiotoxicity
With early introduction of fast reactors using (U+Pu+Am) based fuel, long term raditoxicity of nuclear waste will be reduced.
300 years
Radiotoxicity of spent fuel is dominated by : FPs for first 100 years. subsequently, Pu (>90%) After Pu removal Minor Actinides specially Am (~ 9%)
200,000 years

9. Attractive Features of Thorium / Thoria
High Abundance
Uniformly distributed in earth crust
3 to 4 times abundant than uranium
Better Fuel Performance Characteristics
Higher melting point
Better thermal conductivity
Lower fission gas release
Good radiation resistance
Dimensional stability
Better compatibility with coolant
Relative ease in Waste Management
No oxidation -Superior behavior
Direct disposal in repository
Generates less Pu and minor actinides
Proliferation Resistant
Spent fuel difficult to divert for weapon applications
Sand containing monazite in Kerela (India) beach
Minor actinide (g/T)
U235 +
U 238
U233 + Th232 Np
900 3 Am
470
0.0018 Cm
220
Minor Actinides in Spent Fuel

10. Th based Fuels are attractive for both Thermal & Fast Reactors
U233 has excellent nuclear characteristics both in thermal and fast neutron spectrum.
Th is excellent host for Pu and enables deeper burning of Pu.
Using external fissile material U235, Pu or an external accelerator driven neutron source,Th-U233 cycle can be made self sustaining .

11. Deploying Thorium Energy: Three approaches
Thorium fuel in solid form in conventional reactors
Thorium as fuel in molten salt reactors
Accelerator-driven subcritical reactors using thorium fuel
Irradiated in Indian power reactor
KAMINI reactor in India (1996)
ThO2-PuO2 fuel
Burnup 18,400MWd/t
UO2 fuel
Burnup 15,000MWd/t
30kW experimental
U233 (20wt%)-Al fuel
Light Water Moderator and coolant
Higher fission gas retention capability in ThO2 fuel

12. Thorium in Solid Fuel Reactor Advanced Heavy Water Reactor (AHWR)
AHWR is a 300 MWe vertical pressure tube type, boiling light water cooled and heavy water moderated reactor using 233U-Th MOX and Pu-Th MOX fuel, and Low enriched U with Th.
Major design objectives
A large share of power from Thorium based fuel
Several passive features
No radiological impact in public domain
Passive shutdown system to address extreme threat scenarios.
Design life of 100 years.
Easily replaceable coolant channels.
Th-233U MOX
Pu-Th MOX
AHWR can be configured to accept a range of fuel types including enriched U, U-Pu MOX, Th-Pu MOX, and 233U-Th MOX in full core
Low Enriched Uranium (LEU)
Inner ring:18.0% LEUO2
Middle ring: 22.0% LEUO2
Outer 22.5% LEUO2

13. Thorium in Molten Salt Reactor
Emergency Tanks
Heat Exchanger-1
Heat Exchanger-2
To Turbine and generator
Reactor Tank containing Fuel Salt under circulation
Reprocessing plant
Fission product removal
Addition of fissile material
Safe : Liquid fuel, No meltdown possibility,
Passive shutdown by fuel dumping
Minimal Waste : Online burning of long lived isotopes,
Reduced higher Actinides
Efficient : Higher operating temperature

14. Thorium utilization in Accelerator driven subcritical system
In a sub-critical nuclear reactor, fission neutrons supplemented by external supply of neutrons produced in a spallation reaction, High neutron yield (~20 per proton)
Neutrons used for fertile to fissile conversion – Th232 to U233 (Fissile factory)
Incineration of long lived radio isotopes
Spallation reaction
1 GeV proton
beam
Accelerator
Subcritical reactor
Spallation target

15. Indian Prototype Fast Breeder Reactor
Core Layout
Radial Blanket (U238/Th232)
Axial Blanket
Thermal Power (MWth) : 1250
Electrical output (MW): 500
Fuel material : (U,Pu)O2
Coolant : Molten Sodium

16. Indian Three Stage Nuclear Programme
Stage 1 : Power generation and building fissile inventory for Stage 2
Stage 2 : Expanding power programme and building U233 inventory
Stage 3: Thorium fuel for sustainable nuclear energy
2/3 energy from Thorium fuel
Passive cooling and shutdown for safety
540 MW pressurized Heavy Water reactor (PHWR)
Advanced Heavy Water Reactor (AHWR)
Fast Breeder Reactor

17. Summary
The Closed Nuclear Fuel Cycle can be a sustainable and environmentally benign energy source which can meet the base load requirement for the entire world for several centuries
The Thorium – Uranium 233 fuel cycle is associated with significantly reduced radiotoxicity of the nuclear waste
For the long term sustainability of Thorium – Uranium 233 fuel cycle a sufficient inventory of fissile materials (U235 and Pu239) needs to be generated
Spallation neutrons from high energy accelerators can augment fissile inventory and can make Thorium – Uranium 233 fuel cycle self sustaining

18. Paradigm Shift Burning fossil fuel Usage of primary energy
Forest Fire
Thermal Power
Fire Stone Discovery
Wind Energy
Solar Energy
Nuclear Energy
Thank you for your attention…