AHWR
• Developed to use Thorium for generation of commercial nuclear power
• 300 MWe• Pressure Tube type reactor: vertical PT• Boiling Light Water: BLW• Passive Safety Features
09/10/12 RE-4, Le-22 2
Safety Features AHWR
• negative void coefficient of reactivity. • Passive safety systems• Heat sink in the form of Gravity Driven Water
Pool GDWP• Removal of core heat by natural circulation. • ECCS injection directly inside the fuel. . • Two independent shutdown systems.
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+ Features of AHWR
• No Hi Pressure D2O as coolant, no leakage loss / recovery systems
• Recovery of heat generated in Moderator System for feed-water heating
• Shop assembled coolant channels, quick replacement of pressure-tube
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+ Features of AHWR
• Steam Drums in place of steam-generators• Higher Steam pressure than in PHWR• Production of 500 m3/day of DM Water in
Desalination Plant, by using steam from LP Turbine
• Design Life : 100 Years• No exclusion Zone, due to advanced safety
features
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Specifications of AHWR
• Power: 920 MWth, 300 MWe• Core: Vertical, Pr. Tube; ID: 120 mm• Coolant: Boiling Light Water• No. of Coolant Channels: 452• Fuel Pins: 54 = 24 (Th+Pu) + 30 (Th+U233)• Fuel Length: 3.5 m• Core Flow Rate: 2230 kg/s
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Specifications of AHWR
• Coolant Inlet: 259 Deg. Cel.; Outlet: 130 Deg. Cel.
• Steam Quality: 18.6 %• Steam Generation Rate: 414.4 kg.• Steam Pressure: 70 bar• PSS: 40 Shutoff Rods (Boron Carbide)• SSS: Liquid Poison Injection in Moderator• Control Rods: 1309/10/12 RE-4, Le-22 7
Specifications of AHWR
• Lattice Pitch: 245 mm• Discharge Burnup: 24000 MWd/t
• -- up-to 40,000
• Dysprosium is used as burnable poison Dy2O3 in ZrO2
• Natural Dysprosium has 5 isotopes 160 – 164
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Fuel
• 54 pins– Innermost Ring: 12 Pins (Th233 U)O2, U233 enrichment
3.0 %
– Middle Ring: 18 Pins (Th233 U)O2, U233 enrichment 3.75 %
– Outermost Ring: 24 Pins (Th Pu)O2, Pu enrichment 2.5% in upper-half & 4.0% in lower-half
– Central Rod has burnable poison Dy2O3
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PHW Reactor Components
• Inlet header• Feeders• Coolant Channel• Outlet feeders called “tail-pipes”– End-Shield– Feeder Vault– Calandria Vault
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Reactor Structure
• Cylindrical Aluminum Tank: 330cm ID & 500 cm high
• Tank is adequately sized to provide 40 cm D2O radial reflector around the core
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Calandria Vault
• Concrete block, for shielding• Two movable shield trolleys, at the top • Water Filled Reactor Vault Tank, open at top
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Instrument & Control
• Neutron (flux) Power measurement– For reactor regulation and Control– Detectors are located in Graphite fillers below
Reactor– In-Core: flux mapping system
• 25 LEU based, fission counters
– Source range monitors: pulse channels
• Conventional Instrumentation– Flow, Pressure, Temperature & Level– To generate: ALARM (Hi, V-Hi), TRIP
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Range overlap of channelsSource Range: Pulse ChannelInter. & Power Range: Six DC Channels (Multi Range DC Channel: MRDC)
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Shutdown Devices
• Shut-Off rods – Six: Cadmium (encased in Al) Rods– 68 mk –ive reactivity addition
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AHWRAHWR
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15
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6
10
911
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16
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2
7
1
2 Primary Containment1 Secondary Containment
3 Gravity Driven Water Pool4 Isolation Condenser
5 Passive Containment Isolation Duct6 Vent Pipe7 Tail Pipe Tower8 Steam Drum9 100 M Floor
10 Fuelling Machine
11 Deck Plate
13 Header 14 Pile Supports
15 Advanced Accumulator
17 Passive Containment Cooler
16 Pre - Stressing Gallery
12 Calandria with End Shield
Status
09/10/12 RE-4, Le-22 22
• Structured peer review completed• Pre-licensing design safety appraisal by AERB
in progress
AHWR: a quick, safe, secure and proliferation resistant solution
AHWR is a 300 MWe vertical pressure tube type, boiling light water cooled and D2O moderated reactor (A configuration to provide low risk nuclear energy using available technologies)
AHWR can be configured to accept a range of fuel types including LEU, U-Pu , Th-Pu , LEU-Th and 233U-Th in full core
AHWR Fuel assembly
Bottom Tie Plate
Top Tie Plate
Water
Tube
Displacer
Rod
Fuel Pin
Major design objectives
Significant fraction of Energy from Thorium
Several passive features 3 days grace period No radiological impact
Passive shutdown system to address insider threat scenarios.
Design life of 100 years.
Easily replaceable coolant channels.
24
PSA Level 3 calculations for AHWR indicate low probability of impact in public domain
Plant familiarization & identification of design aspects important to severe accident
Plant familiarization & identification of design aspects important to severe accident
PSA level-1 Identification of significant events with large contribution to Core Damage Frequency
PSA level-1 Identification of significant events with large contribution to Core Damage Frequency
Level-2 : Source Term (within Containment) Evaluation through Analysis
Level-2 : Source Term (within Containment) Evaluation through Analysis
Release from Containment Release from Containment
Level-3 Atmospheric Dispersion With Consequence Analysis
Level-3 Atmospheric Dispersion With Consequence Analysis
Level-1, 2 & 3 PSA activity block diagram
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SWS: Service Water System (63 %)
APWS: Active Process Water System
ECCS HDRBRK: ECCS Header Break
SLOCA: 15 %
LLOCA: Large Break LOCA
MSLBOB: Main Steam Line Break Outside Containment
Contribution to CDF
AHWR 300-LEU is a 300 MWe system fuelled with LEU-Thorium fuel, has passive safety features, high degree of operator
forgiving characteristics, no adverse impact in public domain, high proliferation resistance and inherent security strength.
Peak clad temp. hardly rises even in the complete station blackout and failure of primary and secondary systems.
ECCS
• Passive mode during first 15 minutes, from accumulators– 4 Accumulators, 240 m3, Nitrogen at 5.0 MPa
• From Gravity driven water pool for next three-days (low pressure injection)– Passivity is obtained by “Fluidic Flow Control
Device”– 6000 m3 of water– 4 loops. HX, pump, filter, IX & chemical addition
tank in each loop09/10/12 RE-4, Le-22 31
AHWR: Design evaluation by INPRO method
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• IAEA initiated project on, International Project on Innovative Nuclear Reactors & Fuel Cycles
• Evaluation criteria in six areas– Economics -- Environment & Sustainability– Safety -- Waste Management– Proliferation -- Cross cutting issues
• Reports have been sent to IARA for AHWR
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