robots in radio-active environments
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Transcript robots in radio-active environments
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.
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
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