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
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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.
ROSA NOZZLE DAM
INSERTION
 Remote user
interface
 Control six axis
arm
ROSA in proximity to the nozzle dam,
positioning gripper to remove it
• 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
• 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
END EFFECTORS
 Develop tools that could operate on
tube sheets of SG
 Operations include
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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