ROBOTS IN RADIO-ACTIVE ENVIRONMENTS - WordPress.com

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13 Νοε 2013 (πριν από 3 χρόνια και 4 μήνες)

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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