2INTRODUCTIONIn 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
3CONCEPT 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
5MINIMIZE HUMAN EXPOSURE Risk of contamination which is accidentalIrradiation affects operators work areasProfessional workers are few in number and require years of experienceInternational laws exist which limit the max exposure rate of workersReduce working time and increase maintenance cost
6PREVENTIVE MAINTENANCE AND UNFORSEEN INCIDENTS Periodic maintenance requireCareful preparationSafetyWell known working environmentPrepared using a full scale mockupFor telerobotics there isGeometric model of the remote siteMission is programmedOperates in supervision mode
7WHAT IS THE NEED OF ROBOTS IN STEAM GENERATORS ? Steam Generators use U bent tubes. U bent tubes in WSG made using inconel alloyto ensure High thermal efficiency of heat exchangerMultiple stressesMechanical and thermal loading vibrations & corrosionMaintenance jobs during plant refueling are complexWater cleaning, nozzle dam insertion etc.
8ROSA in proximity to the nozzle dam, positioning gripper to remove it ROSA NOZZLE DAM INSERTIONRemote user interfaceControl six axis armROSA in proximity to the nozzle dam, positioning gripper to remove it
9Arm 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
11TELEOPERATION PLATFORM New platform developed using Hewlett Packard UX operating systemLocal area network connects with teleoperation platform with robot control unitGraphic models of arm, loader, tube sheet & channel head was developed using ROBCAD
12Critical & Needs careful programming The Sequence of observation made by the operator when robot is loaded at tube sheet of SGCritical & Needs careful programmingArm should be manually inserted in the channel head through a narrow man way
13One inside the RQC is attached to a loader Hence the cinematic tree is invertedOperator moves the loaderArm should perform a predefined motion scheme
14After last motion the arm base should be perfectly aligned with the tube sheetOperator moves the base until the camlocks are inside the anchor tubes and expand them
15END EFFECTORS Develop tools that could operate on tube sheets of SG Operations includeDetecting wrong tubesCanceling wrong tubesRecovering themDrilling plugsPlacing the nozzle dams
16ELECTRO DISINTEGRATION MACHINE To disintegrate foreign elements located in the tubesheet
17PARTS OF EDMRemote Quick Connector (RQC) to attach to robot end, a fixed platform where vision are installed
18CONTD….Potentiometer for alignment with the tubesheet & Camlocks for anchoring to itCommands are provided to fit & activate EDH, to fit intensity and voltage parameters and to load and unload the tool
19REMOVAL OF FALLEN OBJECTS IN PRIMARY CKT NOZZLE Objects may fall inside primary nozzle during maintenance operation, if dam not installedNecessary to develop special tools.Tools are handled by jumpers from channel head nozzle so accumulated doses are high
20INSPECTION & RETRIEVING VEHICLE It is highly robust & fail safe.
21REMOVAL OF FALLEN OBJECTS INSIDE PWR VESSEL Parts of tools may fall inside vessel during refuelling because of human error
22Teleoperated and robotized system for maintenanceoperation in nuclearpowerplant vessels(TRON) is a four joint ofrobotised poleUsed to retrieve fallen objectsfrom the PWR reactor vesselIt comprises jointed pole, endeffectors & computer visionnavigation system
23APPLICATIONS 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.
24CONCLUSION With improving technology & growing perception of the need to keep humanworkers away from high radiation areas,more competitive robotic systems areincreasingly becoming available