Automated Fabrication of Thorium Based Fuel:Automated Fabrication of Thorium Based Fuel:Challenges and InitiativesChallenges and Initiatives

K. JayarajanDivision of Remote Handling and Robotics

Bhabha Atomic Research Centre

K. JayarajanDivision of Remote Handling and Robotics

Bhabha Atomic Research Centre

Outline of Presentation

Problems with Thorium-based Fuel AHWR Fuel Cluster AHWR Fuel Facilities Automation in Hot Cell Mock-up Pellet Fabrication Pellet Handling & Inspection Pin Handling & Inspection Cluster Assembly & Disassembly

Video of Pin Handling & Inspection Conclusion

Problems with Thorium-based Fuel AHWR Fuel Cluster AHWR Fuel Facilities Automation in Hot Cell Mock-up Pellet Fabrication Pellet Handling & Inspection Pin Handling & Inspection Cluster Assembly & Disassembly

Video of Pin Handling & Inspection Conclusion

Radiological concerns of Thorium

Thorium (232Th ) is not a fissile material. Fissile material 233U, is made from 232Th in reactor. 233U produced in reactor is contaminated with 232U. Daughter products of 232U, Thallium-208 and Bismuth-212

emits gamma. Energy of 208Tl gamma: 2.6 MeV Activity increases with time. 228Th produced in reactor also emits . Activity of reprocessed Th is much higher than mined Th.

Thorium (232Th ) is not a fissile material. Fissile material 233U, is made from 232Th in reactor. 233U produced in reactor is contaminated with 232U. Daughter products of 232U, Thallium-208 and Bismuth-212

emits gamma. Energy of 208Tl gamma: 2.6 MeV Activity increases with time. 228Th produced in reactor also emits . Activity of reprocessed Th is much higher than mined Th.

Why Mock-up Facility?

Shielded facility with remote handling tools is essential Limited experience of fuel fabrication in shielded facility

A mock-up facility is being developed todemonstrate fully automated fuel fabrication

in shielded facility.

A mock-up facility is being developed todemonstrate fully automated fuel fabrication

in shielded facility.

The technology developed will be useful for enhancing thelevel of automation in fabrication of other type of fuels.

AHWR Composite Fuel Cluster

Fuel Clusters in the Core: 452 Length: 4.3 m Diameter: 118 mm Weight: 190 kg

Fuel Pins in Cluster: 54 Mixed Oxide (MOX) Pins In 3 Rings

1. 12 Th-Pu2. 18 Th-Pu3. 24 Th-233U

Fuel Pin

Diameter: 11.2 mm Length: 3835-3865 mm Weight: ~2.5 kg

Fuel Pellet

Diameter: 9.8 mm Length: 13 mm Density: 9.6 gm/cc

Diameter: 9.8 mm Length: 13 mm Density: 9.6 gm/cc

Mock-up Facilities Made/ Being made

1. Powder: Fabrication of sintered pellets2. Pellets: Inspection, degassing, handling, etc.3. Pins: Pellet insertion, welding, inspection, etc.4. Cluster: Assembly, disassembly

Radio Metallurgy Division (RMD) Division of Remote Handling and Robotics (DRHR)

Engineering Design and Development Division (ED&DD)

Acknowledgement: AFFF, RED, NFC, Reactor Group

Closed Fuel Cycle: Uses Self-Generated 233U Fuel

DisassembleCluster

Fuel theReactor

Reprocess &Extract 233U

Make (Th-233U) MOX

Pin

AssembleCluster

AHWR Site: Co-located Facilities

Plants for Fabrication and Handling of Fuel

Glove Box and Hot Cell

Wall thickness: ~ 3 mm Protects operator from alpha Suitable for Pu fuel fabrication

Wall thickness: 1-2 m Protects operator from gamma Suitable for 233U fuel fabrication

Hot Cell: Typical Components

In-cell Crane Master Slave Manipulators Radiation Shielding Window Roof Plug Personal Access Door External Transfer Drawer Inter-cell Transfer Drawer Wall sleeves & Plugs

In-cell Crane Master Slave Manipulators Radiation Shielding Window Roof Plug Personal Access Door External Transfer Drawer Inter-cell Transfer Drawer Wall sleeves & Plugs

General Considerations in Design

Design for remote maintenance/ replacement Optimum use of hot cell space Level of contamination progressively deceases Powder Pellet Pin Cluster Avoid cross contamination

Provision for isolating one cell from its adjacent cells Removal of active components using remote handling tools In cells of pellet, pin and cluster

Design for remote maintenance/ replacement Optimum use of hot cell space Level of contamination progressively deceases Powder Pellet Pin Cluster Avoid cross contamination

Provision for isolating one cell from its adjacent cells Removal of active components using remote handling tools In cells of pellet, pin and cluster

Remote Maintenance

Modular construction Remotely replaceable components Quick connection of couplings Mechanical, electrical, pneumatic

Handling by MSM & Cell Crane Weight, access, visibility

Standardisation Components, sub-assemblies, fasteners, connectors, etc.

Modular construction Remotely replaceable components Quick connection of couplings Mechanical, electrical, pneumatic

Handling by MSM & Cell Crane Weight, access, visibility

Standardisation Components, sub-assemblies, fasteners, connectors, etc.

Radiation Tolerance, Contamination, Vacuum

Radiation tolerant material Avoid organic materials Selection of motors, sensors, cameras, cables, electronic components

Accumulation of contamination Avoid hydraulic actuators Avoid crevice, blind holes

Decontamination Washable by water

Maintaining negative pressure Pneumatic actuators: leakage should not increase pressure

Radiation tolerant material Avoid organic materials Selection of motors, sensors, cameras, cables, electronic components

Accumulation of contamination Avoid hydraulic actuators Avoid crevice, blind holes

Decontamination Washable by water

Maintaining negative pressure Pneumatic actuators: leakage should not increase pressure

Other Hotcell Constraints/ Requirements

Layout Limited space of Hot Cell Hot cell width is limited by MSM reach Expensive to construct and to maintain

Interference with MSM, in-cell crane, etc. Visibility through radiation shielding window

Shielding integrity Material transfer between hot cell and outside between hot cells

Mechanical power transfer from outside to hot cell

Layout Limited space of Hot Cell Hot cell width is limited by MSM reach Expensive to construct and to maintain

Interference with MSM, in-cell crane, etc. Visibility through radiation shielding window

Shielding integrity Material transfer between hot cell and outside between hot cells

Mechanical power transfer from outside to hot cell

Types of Equipments (1/ 2)

Process Modification for automation & remote maintenance

Inspection Modification for automation & remote maintenance Development of a new method

Machine loading and unloading Robots, bowl feeder, pushers, etc.

Material transfer Screw conveyor, bucket elevator, roller conveyor, rail & vehicle,

robot

Process Modification for automation & remote maintenance

Inspection Modification for automation & remote maintenance Development of a new method

Machine loading and unloading Robots, bowl feeder, pushers, etc.

Material transfer Screw conveyor, bucket elevator, roller conveyor, rail & vehicle,

robot

Types of Equipments (2/ 2)

Containers with features for automated loading/ unloading Sintering boat, degassing cage, pin cage, pin tray, etc.

Remote handling Master Slave Manipulator In-cell crane

Remote viewing Radiation Shielding Window CCTV Cameras

Controller User interface Safety features, interlocks Feedback

Containers with features for automated loading/ unloading Sintering boat, degassing cage, pin cage, pin tray, etc.

Remote handling Master Slave Manipulator In-cell crane

Remote viewing Radiation Shielding Window CCTV Cameras

Controller User interface Safety features, interlocks Feedback

Mock-up Facility: Relaxations

Used components of inactive material for demo Powder, pellets and pins

Not demonstrated the proven processes and NDTs Demonstrated necessary movement of material & tool Demonstrated all dimensional inspection

Avoided duplication of tools, wherever possible Modified the layout to accommodate in the space available A few components are not radiation tolerant Ensured that equivalent radiation tolerant components are available

Used components of inactive material for demo Powder, pellets and pins

Not demonstrated the proven processes and NDTs Demonstrated necessary movement of material & tool Demonstrated all dimensional inspection

Avoided duplication of tools, wherever possible Modified the layout to accommodate in the space available A few components are not radiation tolerant Ensured that equivalent radiation tolerant components are available

Clean RejectOxide ThO2 Powder U233O2 Powder

Spacer weldedzircaloy Tubes &

Hardwares

Degassing

Bottom End PlugWelding

Weighing

Mixing andMilling

Precompaction

Final Compaction

Sintering

CenterlessGrinding

MOX PelletsDegassing

Fuel PinInspection and

StorageAssembly

Stack Making

Top End PlugWelding

Decontamination

PowderCharacterization &Chemical Analysis

Composition Check Visual, He Leak,Metrology, X-Radiography

Th, U Analysis, DissolutioonTest, Visual, Dimensional, Linear

Mass, Metallography, Alpha-Autoradiography

O/M, Total Gas,Metallic & Non-

metallic impurities

Stack Length check

Visual, He Leak,XGAR, Metrology, X-

Radiography,Gamma- Scan, Cover

Gas in Pins

Contamination Check

Granulation

StackLoading

Powder

Compact

Welded Pin

Inactive

Quality Check

Precompacts &Granules

Oversized

Clean RejectOxide ThO2 Powder U233O2 Powder

Spacer weldedzircaloy Tubes &

Hardwares

Degassing

Bottom End PlugWelding

Weighing

Mixing andMilling

Precompaction

Final Compaction

Sintering

CenterlessGrinding

MOX PelletsDegassing

Fuel PinInspection and

StorageAssembly

Stack Making

Top End PlugWelding

Decontamination

PowderCharacterization &Chemical Analysis

Composition Check Visual, He Leak,Metrology, X-Radiography

Th, U Analysis, DissolutioonTest, Visual, Dimensional, Linear

Mass, Metallography, Alpha-Autoradiography

O/M, Total Gas,Metallic & Non-

metallic impurities

Stack Length check

Visual, He Leak,XGAR, Metrology, X-

Radiography,Gamma- Scan, Cover

Gas in Pins

Contamination Check

Granulation

StackLoading

Powder

Compact

Welded Pin

Inactive

Quality Check

Precompacts &Granules

Oversized

AHWR FuelFabrication FlowSheet for (Th-U233)O2

Pellet FabricationPellet Fabrication

RMD and ED&DDRMD and ED&DD

Schematic of Pellet Fabrication System

Weighing Mixing Milling Pre-compaction Granulation Final compaction Sintering

Photographs

Pellet Handling and InspectionPellet Handling and Inspection

Operations on Sintered Pellets

Unloading from sintering boat Diameter inspection and sorting Mechanical, LVDT, Laser

Visual inspection of surfaces Degassing Loading into a degassing cage Cage handling Degassing in furnace Unloading from the cage

Pellet stacking (3500 7 mm) Stack length measurement

Unloading from sintering boat Diameter inspection and sorting Mechanical, LVDT, Laser

Visual inspection of surfaces Degassing Loading into a degassing cage Cage handling Degassing in furnace Unloading from the cage

Pellet stacking (3500 7 mm) Stack length measurement

Layout of Equipment

Degassing Cage

Pellet UnloadingStation

Degassing Cage

Stacking Table

Boat with Pellets

Visual InspectionStation and Monitor

Pin Handling and InspectionPin Handling and Inspection

Components to be Handled

Clad Tube (without Top End Plug) 11.2 dia, 3.45 m long

Dummy Pin 11.2 dia, 3.86 m long

Pin Tray 6 pins/ clad tubes Moved across cells/ within a cell

Pin cage 36 pins/ clad tubes Moved from one plant to

another in a cask Automated doors

Clad Tube (without Top End Plug) 11.2 dia, 3.45 m long

Dummy Pin 11.2 dia, 3.86 m long

Pin Tray 6 pins/ clad tubes Moved across cells/ within a cell

Pin cage 36 pins/ clad tubes Moved from one plant to

another in a cask Automated doors

Demonstrated Operations

Material handling Pin Cages and Pin Trays between Cells Pin Cages with in the cell

Transverse, vertical

Clad Tubes, Pins and Pin Trays within the cell Axial (up to 4m), transverse, vertical

Pin Inspection Length Bow Concentricity of Top

End Plug Weld bead size Weight

Pin Cages and Pin Trays between Cells Pin Cages with in the cell

Transverse, vertical

Clad Tubes, Pins and Pin Trays within the cell Axial (up to 4m), transverse, vertical

Length Bow Concentricity of Top

End Plug Weld bead size Weight

Remotely inspect the imagesfrom CCTV cameras

Inter-cell door operation Buffing welded area Opening/ closing Pin Cage Cover

Remote Visual Inspection

Simulated Operations

Top-end plug welding X-ray radiography Helium leak detection Gamma scanning

Demonstrated Automated movement of pin, Automated closing/ opening of He-chamber

Top-end plug welding X-ray radiography Helium leak detection Gamma scanning

Schematic of the Mock-up System

Automation Mock-up System

Equipments Developed (1/2)

Rail Guided Vehicle (RGV) Transfer pin cages/ pins between cells Payload: 250 kg Travel: about 20 m

Inter –Cell Door Material transfer between adjacent cells Shields one cell from another

Robot Arm Pairs Handle 4 m long pins/pin trays Payload:40 kg

Cage Transfer Tool Transfer pin cage with in a cell Payload: 250 kg

Rail Guided Vehicle (RGV) Transfer pin cages/ pins between cells Payload: 250 kg Travel: about 20 m

Inter –Cell Door Material transfer between adjacent cells Shields one cell from another

Equipments Developed (2/2)

NC Table Pin insertion and removal into/from pin cages

Stroke: 4 m

Tool for opening/closing the cover of pincage

Various tools for transfer, rotation andclamping of pins

Inspection systems

NC Table Pin insertion and removal into/from pin cages

Stroke: 4 m

Tool for opening/closing the cover of pincage

Various tools for transfer, rotation andclamping of pins

Inspection systems

Control and Operator Interface

Automated operation of individual stations Coordination of various stations Safety Interlocks Record & maintain database of material processed and material

available at each station

Automated operation of individual stations Coordination of various stations Safety Interlocks Record & maintain database of material processed and material

available at each station

SCADA Screen ofone of the cells

Assembly and Disassembly of ClusterAssembly and Disassembly of Cluster

Assembly of Fuel ClusterAssembly of Fuel Cluster

ThTh--U PinsU PinsDummy PinsDummy Pins

30 (Th-Pu) pins +24 SS Pins +Structural parts

30 (Th-Pu) pins +24 (Th-233U) +Structural parts

Assembly and Disassembly of Fuel ClusterAssembly and Disassembly of Fuel Cluster

Automated Activities

Assembly & Disassembly of cluster components Fuel Pin Connecting Plug Top Tie Plate Springs

Material handling Handling of Pin Cage/ Cluster cage with in the cell Handling Pins within the cell

Cage cover opening/ closing

Assembly & Disassembly of cluster components Fuel Pin Connecting Plug Top Tie Plate Springs

Material handling Handling of Pin Cage/ Cluster cage with in the cell Handling Pins within the cell

Cage cover opening/ closing

Equipment LayoutEquipment Layout

Scheme for Cluster Assembly/ DisassemblyScheme for Cluster Assembly/ Disassembly

Hotcell WallCharging Cask

Tool Magazine

Transfer Port

AssemblyPlatform

Pin Tray-2

Pin Tray-1

Tool Magazine

CloseupCloseup

PinMagazine-1

PinMagazine-2

FuelCluster

DummyPin Tray

Fuel PinTray-1

Fuel PinTray-2

Conclusion (1/2)

Prepared a layout for automation and remote handling inhot cell Provides access for remote maintenance Reduces spread of contamination Avoids interference with operation of in-cell equipments Optimises hot cell space

Prepared a layout for automation and remote handling inhot cell Provides access for remote maintenance Reduces spread of contamination Avoids interference with operation of in-cell equipments Optimises hot cell space

Conclusion (22)

Modified process equipment for remote operation and maintenance Modified inspection tools and techniques to suit automation Developed tools for automated machine loading Developed tools for automated material transfer:

across adjacent cells and within a cell

Developed/ modified containers for automated operation and handling Pellet boat for sintering Cage for pin transfer across facilities Cage for pellet degassing

Modified process equipment for remote operation and maintenance Modified inspection tools and techniques to suit automation Developed tools for automated machine loading Developed tools for automated material transfer:

across adjacent cells and within a cell

Developed/ modified containers for automated operation and handling Pellet boat for sintering Cage for pin transfer across facilities Cage for pellet degassing

ThanksThanks

JayarajanJayarajan