ROBOTS IN RADIO-ACTIVE ENVIRONMENTS

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ROBOTS IN RADIOACTIVE ENVIRONMENTS
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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

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CONCEPT

• Websters 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

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CONTENTS

• Minimize human exposure
• Maintenance activities
• Steam Generators
• Tele-operation platform
• End effectors
• Remove fallen objects in
• primary circuit nozzle
• PWR reactor vessel

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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

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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

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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.

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ROSA in proximity to the nozzle dam,
positioning gripper to remove it
ROSA NOZZLE DAM INSERTION

• Remote user interface
• Control six axis arm

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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

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JUMPER EXECUTING THE TASK
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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

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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

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• 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

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• After last motion the arm base should be
• perfectly aligned with the tube sheet

• Operator moves the base until the camlocks
  are inside the anchor tubes and expand them

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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

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ELECTRO DISINTEGRATION MACHINE

• To disintegrate foreign elements located in
  the tubesheet

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PARTS OF EDM

• Remote Quick Connector (RQC) to attach to robot
  end, a fixed platform where vision are installed

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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

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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

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INSPECTION RETRIEVING VEHICLE

• It is highly robust fail safe.

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REMOVAL OF FALLEN OBJECTS INSIDE PWR VESSEL

• Parts of tools may fall inside vessel during
  refuelling because of human error

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• 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

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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.

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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

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THANK YOU