robots in radioactive environments. introduction in a critical place such as a nuclear power plant,...
TRANSCRIPT
ROBOTS IN RADIOACTIVE
ENVIRONMENTS
INTRODUCTION
In a critical place such as a nuclear power plant , where the manual work is quite difficult the application of robots are really worth mentioning.
Robots are used to prevent exposure of humans to radiations in Nuclear Power plants
CONCEPT
Webster’s dictionary definition “An automatic device that performs functions ordinarily described to human beings”
Robotic Institute of America definition“It is a reprogrammable multifunctional manipulator designed to move materials, parts, tools etc through variable programmed motion of the performance of a variety of tasks
CONTENTS Minimize human exposure Maintenance activities Steam Generators Tele-operation platform End effectors Remove fallen objects in
primary circuit nozzle PWR reactor vessel
MINIMIZE HUMAN EXPOSURE
Risk of contamination which is accidental
Irradiation affects operators work areas
Professional workers are few in number and require years of experience
International laws exist which limit the max exposure rate of workers
Reduce working time and increase maintenance cost
PREVENTIVE MAINTENANCE AND UNFORSEEN INCIDENTS Periodic maintenance require
Careful preparation Safety
Well known working environment Prepared using a full scale mockup For telerobotics there is
• Geometric model of the remote site• Mission is programmed
Operates in supervision mode
WHAT IS THE NEED OF ROBOTS IN STEAM GENERATORS ?
Steam Generators use U bent tubes. U bent tubes in WSG made using inconel alloy
to ensure High thermal efficiency of heat exchanger
Multiple stresses Mechanical and thermal loading vibrations &
corrosion Maintenance jobs during plant refueling
are complex Water cleaning, nozzle dam insertion etc.
Remote user interface
Control six axis arm
ROSA in proximity to the nozzle dam,
positioning gripper to remove it
ROSA NOZZLE DAM INSERTION
• Arm base is attached to tube sheets by means of four hydraulic cam locks
• Arm is equipped with a remote quick connector to facilitate the assembly and disassembly of such tools
JUMPER EXECUTING THE TASK
TELEOPERATION PLATFORM New platform developed using
Hewlett Packard UX operating system
Local area network connects with teleoperation platform with robot control unit
Graphic models of arm, loader, tube sheet & channel head was developed using ROBCAD
The Sequence of observation made by the operator when robot is loaded at tube sheet of SG
•Critical & Needs careful programming
•Arm should be manually inserted in the channel head through a narrow man way
• One inside the RQC is attached to a loader
• Hence the cinematic tree is inverted
• Operator moves the loader
• Arm should perform a predefined motion scheme
• Operator moves the base until the camlocks are inside the anchor tubes and expand them
• After last motion the arm base should be
perfectly aligned with the tube sheet
END EFFECTORS
Develop tools that could operate on tube sheets of SG
Operations include Detecting wrong tubes Canceling wrong tubes Recovering them Drilling plugs Placing the nozzle dams
ELECTRO DISINTEGRATION MACHINE
• To disintegrate foreign elements located in the tubesheet
PARTS OF EDM
Remote Quick Connector (RQC) to attach to robot end, a fixed platform where vision are installed
CONTD….
Potentiometer for alignment with the tubesheet & Camlocks for anchoring to it
Commands are provided to fit & activate EDH, to fit intensity and voltage parameters and to load and unload the tool
REMOVAL OF FALLEN OBJECTS IN PRIMARY CKT NOZZLE
Objects may fall inside primary nozzle during maintenance operation, if dam not installed
Necessary to develop special tools. Tools are handled by jumpers from
channel head nozzle so accumulated doses are high
INSPECTION & RETRIEVING VEHICLE
It is highly robust & fail safe.
REMOVAL OF FALLEN OBJECTS INSIDE PWR VESSEL
Parts of tools may fall inside vessel during refuelling because of human error
• Teleoperated and robotized system for maintenance operation in nuclear powerplant vessels (TRON) is a four joint of robotised pole
• Used to retrieve fallen objects from the PWR reactor vessel• It comprises jointed pole, end effectors & computer vision navigation system
APPLICATIONS STEAM GENERATORS:• Primary tube inspection &
maintenance.• Channel head cleaning .• Nozzle dam insertion. REACTOR CAVITY:• Fuel transfer channel cleaning &
underwater inspection. REACTOR VESSEL:• Underwater inspection & repair.• Foreign fallen object removal.
CONCLUSION
With improving technology & growing perception of the need to keep human workers away from high radiation areas, more competitive robotic systems are increasingly becoming available
THANK YOU