from the director’s deskzindia-japan specialists’ meeting on safety in nuclear energy zvisit of...

NEW YEAR MESSAGE

ISSN 0972-5741 Volume 75 January 2008

From the Director’s Desk

Dear Colleague,

It gives me a great pleasure in wishing you and your family a veryhappy, healthy and prosperous New Year 2008. A new year always ushersin a sense of hope and expectation for fulfilling our dreams, which dependupon the foundations of our experiences, capabilities and past successes.

We have made rapid strides in various areas of fast reactor science,engineering and technology development over the last one year. FBTRhas been successfully operated, thus, realizing its objectives and in theprocess establishing new benchmarks. Challenging campaigns have beenplanned in the areas of testing and evaluation of fuels, materials andcomponents, achieving higher operating temperatures and safetyperformance. The current major mission of FBTR is to irradiate the fuelsimulating PFBR fuel composition and towards this, the core has beenexpanded by adding two fresh Mark-I and eight fresh MOX subassemblies,after discharging one high burn-up (155 GWd/t) Mark-I subassembly forPost Irradiation Examination (PIE). From the safety point of view, theseismic re-evaluation of the plant is in progress. The neutron detectorsdeveloped for PFBR have been tested in FBTR and the response is foundto be acceptable.

With regard to our committed mission of contributions to the designand construction of 500 MWe PFBR, we have been on the right path. ThePFBR design review has continued, focusing on the issue of regulatoryconsent for “Erection of major equipment”. Detailed analysis of thermal

Forthcoming Symposia/ConferencesSixteenth National Symposium & Workshopon Thermal Analysis THERMANS 2008,February 4-6, 2008 (Symposium), February7-8, 2008 (Workshop)International Conference on Nanoscienceand Technology ICONSAT-2008, February27-29, 2008

Awards & Honours

CEA-DAE Collaborative meeting on “Nanoscience:nanomaterials – production and characterization;interfaces - self-assembled monolayers”Visit of CEA, France delegationIndia-Japan Specialists’ Meeting on Safety in NuclearEnergyVisit of Parliamentary Standing Committee on Science& Technology, Environment & ForestsAcademia-IGCAR Meet (AIM 2007)

INSIDE

Technical ArticlesTowards Developing an Improved D9 SSfor Clad and Wrapper Tubes of PFBRPFBR Full-scope Training Simulator

Forum for Young OfficersIntegrity of Fuel Pellet

Conference/Meeting Highlights

INDIRA GANDHI CENTRE FOR ATOMIC RESEARCHhttp://www.igcar.gov.in/lis/nl75/igc75.pdf

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leak into sodium. These tests willprovide us valuable inputsregarding the performance of themeter and this indigenous sensordevelopment. Further, the entireinstrumentation package for oillevel sensing, including the actualsensors for deployment in PFBR,were made in-house withremarkable performance. Theoperator information system forBoron Enrichment Plant wasinstalled and commissioned.Innovations in electronics &instrumentation and sensordevelopment have been thehallmark of our Centre, widelyacclaimed nationally andinternationally.

We have been believing andpracticing the mantra of synergisticcollaborations within the DAE aswell as other academic institutesfor innovative contributions in fastreactor science & technology. Forexample, the Kalman filtertechnique, developed incollaboration with BARC to confirmthe dropping of the Diverse SafetyRods into the core of PFBR duringa scram, has been tested andresults indicate that the techniqueis suitable for practicalimplementation. Also, a lasertriangulation system, capable ofgenerating profile images ofcorrosion wall loss and chemical/scale build-up in vessels with anaccuracy of ±0.1 mm has beendeveloped jointly by IGCAR andRRCAT, for planar surface profilingof Titanium dissolver vessel ofreprocessing plants of fastreactors.

The successes achieved by ourDepartment is largely due to thedevelopment and management ofquality manpower. On humanresources development front, it ismatter of great pride that we havemade commendable progress. TheTraining School of Bhabha AtomicResearch Centre (BARC) at IGCARcampus has turned out its firstbatch officers in September 2007,

regard to mechanical propertiesand void-swelling behavior. We areutilizing atomistic experimentaltechniques to explain the observedtrends. A new methodology basedon ultrasonic C-scan presentationwas identified to image themicrostructure evolution duringdynamic recrystallization of alloyD9. Our Centre has also embarkedon fabrication of metallic alloy fuelpins for test irradiations. Thefacility would be commissionedbefore the end of the year 2008.This achievement will mark thebeginning of an importantprogramme of introduction ofmetallic fuel in FBTR ultimately andpaving way for the design andconstruction of FBRs with metallicfuels.

Reprocessing is a central andimportant issue in closing the fuelcycle. The success of fast breederreactors depends on successful,cost-effective and robust closure ofthe fuel cycle. Enhanced researchand development with largemanpower for reprocessing activityis a priority for next few years. Wehave made significant progress bydemonstrating reprocessing thehigh burn-up carbide fuel andnecessary steps are being taken toimprove the facilities to take onthe reprocessing of the oxide fuelsfor PFBR. Polyvinyl pyridine (PVP)resins for plutonium processing andprecious metal recovery are beingdeveloped. Innovative separationtechniques such as recovery of Puand Am by supercritical fluidextraction have also beendemonstrated, on a laboratoryscale. The plant layout for the FastReactor Fuel Cycle Facility (FRFCF)is taking good shape.

Indigenous development ofcompact and reliable sensors hasbeen an important programme ofour Centre. It is a matter of pridethat the electrochemical hydrogenmeter developed in our Centre hasbeen installed in the Phenix reactorin France for detection of steam

hydraulics and structural mechanicshas been carried out for resolvingthe issues raised by Project DesignSafety Committee, CivilEngineering Safety Committee andvarious specialist groups,constituted by Atomic EnergyRegulatory Board. With respect tomanufacturing technology, the hardfacing of grid plate on two annulartracks has been successfullyachieved - a crucial milestone,paving the way for smooth progressof activities related to finalmanufacturing stage of grid platefor PFBR. The completion of themanufacture of safety vessel, oneof the large diameter thin shellcomponents of reactor assembly,conforming to the tolerances higherthan international nuclearstandards is another significantmilestone in our FBR programme.This has demonstrated indigenousmanufacture capability and hasgiven confidence towardssuccessful completion of otherimportant large sized vessels ofPFBR Reactor Assembly. A realtime Decision Support System (DSS)comprising the most advancedmeteorological forecasting moduleand a dispersion and doseprediction module along with realtime meteorological dataacquisition and archival system wasdeveloped and demonstrated forradiological emergency. We arecommitted to robust synergy withBHAVINI as well as industries torealize the PFBR with the designspecifications on time, with a firmcommitment to safety andeconomy.

On materials front, we areworking on modified D9I steels withactive support from M/S MIDHANI.The base composition is similar tothat of D9 SS with respect to allelements, except that titanium,silicon and phosphorouscompositions have beenoptimized. Based on the synergyacross various laboratories of ourCentre, we are investigatingvarious modified D9I heats with

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Centre. Our civil, electrical and air-conditioning requirements for XIplan are quite large and the groupsare committed to muster all itsresources to meet the envisagedtargets.

The General ServicesOrganization (GSO) is doing itsbest to improve the housingsituation at the townships. In viewof envisaged housing demands inXI plan, we are committed toprovide good quality of housing toour employees. The hospital hasenhanced its services with betteramenities. The Schools are makingsignificant contributions byproviding quality of education tothe students, with due emphasis onmolding their character andpersonality in a holistic manner.

Over the last one year, we haveshown high commitment to realizegoals, strategic sectors,collaboration with academia andresearch institutes and industries.It has been a 360° progressexperience for the Centre. The year2008 would see milestoneachievements in basic science,FBTR campaigns towards valuablecontributions to realize PFBR andfuture FBRs, robust reprocessing ofoxide and metallic fuels. I amlooking for more passion, higherquality, enhanced commitment toscience, technology and mission-mode programmes, innovation andimagination, increasedproductivity and above all more

which is a momentous occasion forthe Centre. Further, we have addedtwo new disciplines for post-graduates in Physics and Chemistryviz., Nuclear Reactor Physics withemphasis on Reactor Physics &Safety, as well as Nuclear Fuel cyclechemistry with emphasis onnuclear fuels, chemical separationsand associated fuel cycletechnologies. It is also hearteningto realize the academicprogrammes of Homi BhabhaNational Institute (HBNI), thusimparting multidisciplinary trainingcourses both for employees andstudents. We have startedUniversity Grants Commission(UGC)-Department of AtomicEnergy (DAE) Consortium forScientific Research (CSR) Node,which will help to strengthen thequality and quantity of research invarious Indian Universities in theareas of Physical, Chemical andEngineering Sciences. This wouldfacilitate high quality research withuniversities and in turn, providevital inputs to our missionprogrammes. This will fulfill thecherished commitment of the DAEto enhance the research at variousuniversities across the country andin particular, for South India. In itscommitment to harness qualitymanpower for science andtechnology, the DAE continues to beimaginative and innovative.

The service groups are doingcommendable job in developingvaluable infrastructure for the

happiness and fulfillments for youand your families in the year 2008.I would like to quote GeorgeBernard Shaw – “Imagination is thebeginning of creation. You imaginewhat you desire, you will what youimagine, and at last you createwhat you will...”.

Successful realization of themission of the Centre, namelyrobust Sodium Cooled Fast BreederRector Science & Technology withClosed Fuel Cycle and the vision ofthe world leadership in thistechnology needs a good connectingbridge between the mission and thevision. Moreover, connectingbridge between the mission and thevision has to be short in span oftime to reap the benefits. I aminspired by Albert Einstein’squotation - “I never think of thefuture. It comes soon enough”.We would realize the mission andthe vision of the Centre soonenough.

May you fulfill all your dreamsand facilitate the country to realizeits dreams with your valuablecontributions in the year 2008.

Baldev Raj Director,

IGCAR & GSO


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D9 SS with respect to all elementsother than titanium, silicon andphosphorous.

CREEP PROPERTIESThe influence of titanium content

on creep properties of modified D9SS has been studied at 973 K atdifferent stress levels in the rangeof 150 to 250 MPa. All the heatscontained about 0.75 wt% silicon and0.025 wt% phosphorous. Figure 1shows the influence of titanium onthe creep curves at 973 K. Maximumrupture life was obtained when thetitanium content was about 0.22 to0.24 wt%; rupture life decreased byincreasing/ decreasing the amountof titanium from 0.23 wt%. The peakin rupture life was more pronouncedat lower creep stresses as shown inFig.2. Since titanium is a strongcarbide former and the carbideprecipitates have a strong influenceon creep properties, Ti/C ratio isconsidered as important parameterto assess the influence of titanium.From Fig. 2, it is seen that Ti/C ratioof about 5.5 to 6 provides maximumcreep strength to modified D9 SScontaining 0.025 wt% phosphorousand 0.75 wt% silicon. The variationof minimum creep rate with titaniumcontent exhibited the lowest ratecorresponding to 0.22 to 0.24 wt%titanium (Fig. 3). Creep ruptureductility generally decreased withincrease in titanium content.

for FBTR. The target burn-up is100,000 MWd/t and the dose is 85dpa.

For future cores of PFBR, thereis a need to use a differentcomposition of alloy D9 SS whichswells less and has better creepresistance so that burn-up levels upto150,000 MWd/t can be realized. Atask force was constituted todevelop a modified composition ofD9 SS which is superior to D9 SS, aftercarrying out detailed studies on voidswelling, thermal creep properties,tensile properties, microstructuralstability and weldability. As part ofthis mandate, the influence of minorelements, namely, titanium in therange of 0.16 to 0.30 wt%, silicon inthe range 0.75 to 0.95 wt % andphosphorous in the range of 0.025to 0.04 wt%, on these properties arebeing studied to optimise thecomposition. Fifteen laboratoryheats of modified D9 SS wereprepared using double vacuummelting process consisting of vacuuminduction melting followed byvacuum arc remelting. The basecomposition was similar to that of

Economic operation of fastbreeder reactors (FBRs) is largelydependent on the performance ofcore structural materials, i.e., cladand wrapper materials of the fuelsubassembly, which are subjected tointense neutron irradiation. Thisleads to unique materials problemslike void swelling, irradiation creepand helium embrittlement. Theoperating temperatures are high andstresses of sufficient magnitude arepresent so that creep strength,tensile strength and tensile ductilityare also important requirements forthe core structural materials. Inorder to increase the burn-up of thefuel and thereby reduce the fuelcycle cost, it is necessary to employmaterials which are more resistantto void swelling and have better hightemperature mechanical properties.The core structural material chosenfor fuel clad and wrapper tubes ofPFBR is 20% cold-worked alloy D9stainless steel (SS) for the initialcore. This material has been chosenin view of its better swellingresistance as compared to 316 SS,which is the core structural material

Towards developing animproved alloy D9 SS for cladand wrapper tubes of PFBR

Fig.1 : Influence of titanium on Creep curves of D9 I SS (phosphorous =0.025 wt%, silicon = 0.75 wt% and carbon = 0.04 wt%).

Fig. 2 : Influence of titanium on creep rupture life of D9I SS (phosphorous=0.025 wt%, silicon = 0.75 wt% and carbon = 0.04 wt%).

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helium produced by (n, alpha )reactions in a reactor, was carriedout at room temperature byimplanting helium at differentenergies from 200 keV to 700 keV inorder to obtain a uniformconcentration of 30 appm heliumaround the peak damage region of5.0 MeV Ni2+ ions. These pre-injected specimens weresubsequently irradiated with 5.0 MeVNi2+ions, using a 1.7 MV Tandetronaccelerator, to a dose of about9.0×1016 ions/cm2 which correspondsto ~100 dpa at the damage peak, ascalculated invoking modified Kinchin-Pease analytic solution for thecalculation of damage. The ionirradiations were conducted at adamage rate of 7 × 10-3 dpa/s atvarious irradiation temperaturesbetween 700 and 970 K. For carryingout the step height measurements,the specimen was partially maskedwith a stainless steel mask with aknife edge during ion irradiation, sothat only the unmasked region wasirradiated. As the bombarded regionswells, the surface becomeselevated and a step forms at theinterface between the masked andunmasked regions. Measurement of

VOID SWELLINGStudy of radiation damage up to

high doses of about 150 dpa, wouldrequire three to four years in anuclear reactor. In contrast, a fewhours of ion irradiation in anaccelerator can effectively simulatesome crucial aspects of the neutrondamage. The ion-irradiation damagethus produced is characterized bymany techniques like precisionprofilometry, position lifetimespectroscopy, high resolutionelectron microscopy, besidestheoretical modeling, which enablea meaningful inter-comparison ofresults from accelerator and nuclearreactors. Accelerator experimentscan play a useful role in short listingthe most potential swelling resistantcandidate alloys for further extensiveresearch. On a per atom basis,silicon and phosphorous are mosteffective to suppress void growthover the entire temperature rangeof swelling in austenitic SS. Initiallywe have taken up study of two heatsof modified D9 SS which have 0.034and 0.047 wt% phosphorous content,the composition of other elementsbeing similar. The pre-injection ofhelium, to simulate the effect of

Fig. 3 : Influence of titanium on minimum creep rate of D9I SS(phosphorous= 0.025 wt%, silicon = 0.75 wt% and carbon =0.04 wt%).

Fig 4 : Temperature dependence of void swelling measured by surfaceprofilometry for the D9I SS alloys with two different phosphorousconcentrations. The chemical composition of heats are G3088T:P=0.034, Si=0.74,Ti=0.25; M58T: P=0.047, Si=0.77 and Ti=0.31.

this step height provides the totalintegrated swelling that hasoccurred along the path of thebombarding ion. The step heightwas measured using a surfaceprofilometer. The one-dimensionalstep height measurement gives thevolumetric swelling. Temperaturedependence of void swelling isplotted in Fig.4. The void swellingwas found to be lower for the heatcontaining higher amount ofphosphorous and the peak swellingis also lower at 2.5 %. The reductionin swelling by phosphorous additionis more pronounced above 800K.

SUMMARYCreep properties of modified

alloy D9 SS at 973 K varied significantlywith the titanium content in therange of 0.16 to 0.30 wt%. Maximumcreep rupture life was obtainedwhen the titanium content wasabout 0.22 to 0.24 wt%. Void swellingreduced with increase in thephosphorous content from 0.034and 0.047 wt%.

(Reported by M.D. Mathew,Convener, Task Force on Development

of Advanced Materials for Clad andWrapper Applications)

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Simulator ArchitectureThe full-scope, replica simulator

consists of Simulation Computer,Process Computers, I/O system,Distributed Digital Control System,Instructor Station and Control RoomPanels & Consoles, with a SimulatorNetwork to interconnect all thecomponents.

The simulation computerexecutes the integrated simulatorcode in real time to mimic the plantdynamics. It is based on powerfulcomputer system with UNIX asoperating system. The processcomputers receive the plantinformation from Simulator system,process, and update the stored ‘plantparameter database’. The graphicdisplay stations on the operatorconsole and panels receive the data

simulation involves developing modelsfor various sub-systems likeNeutronics, Primary & SecondarySodium Systems, Steam WaterSystem, Electrical System andassociated control logics. PFBRTraining Simulator is designed tosimulate the steady state anddynamic responses of the plant inreal-time to operator actions.

To ensure safety in real plantoperations, it is mandatory as perAERB guidelines to train and qualifythe operators in plant operationsbefore commissioning the real plant.The simulator is helpful in trainingthe operators about the processdynamics, operations in normal andabnormal situations, variousmalfunctions & incidents as well asplant start-ups etc.

IntroductionPFBR Operator Training Simulator

is a full-scope, replica type simulatorbeing developed at ComputerDivision with the objective ofproviding comprehensive training tooperators in the Prototype FastBreeder Reactor plant operations.The scope of simulator covers theentire plant. Being a replicasimulator, it completely replicatesthe reference plant configuration,control system, operator interfaceand information systems. It will havethe control room identical to theactual plant.

The simulator is essentially madeup of mathematical models of PFBRsubsystems running in a computersystem to replicate the operationalcharacteristics of the plant. PFBR

PFBR Full-scope Training Simulator

Fig. 1 : Simulator Hardware Layout

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from these process computers anddisplay the plant information indifferent formats. The processcomputers are based on Dual IntelXeon processors.

The input/output system takescommands from the control panel/console, perform appropriate actionand show the results on the panel/console. The I/O system containsthe required number of digital input,digital output, analog input, analogoutput signal boards, and is placedbehind the control panel. The I/Osystems are connected to thesimulator network (Fig-1) along withsimulation computer, processcomputer etc. For interconnectingthe various systems including LocalControl Centres(LCC), separateSafety Class-1, Safety Class-2, andNon-Nuclear Safety systems datahighways and plant backbone areestablished as Distributed DigitalControl System (DDCS)). LCCprovides interface between the fieldand the control room. In thesimulator the signal processinghardware and other hardwiredinstruments are simulated throughcomputers located in LCC. The plantdata is communicated through datahighways and plant backbone to thecontrol room.

The instructor station is used byinstructor to control and monitorthe operations of simulator andcreate various incidents/

malfunctions during training sessions.The important operations includerun, step, back track, freeze, replayand snapshot. The station is basedon PIV @ 3GHz and 21" monitor etc.The simulator control room panelsand consoles provide the human-machine interface using which thetrainees operate and monitor theplant operations. They are exactreplica of PFBR control room panelsand consoles. It includes hardwiredinstruments, window annunciationsand display stations. Fig.1 depicts thehardware layout of the simulator.

The modeling software providessimulation model libraries, tools tobuild and integrate components andenvironment for running thesimulator in real time. It includesInstructor, Executive, DatabaseServer, IC logger and Messaging &Data Sharing Mechanism.

The Executive controls andsynchronizes operation of thevarious simulator components. Itensures process synchronization andexchange of messages and databetween real-time processes of thesimulator. The Instructor moduleprovides user interface to thesimulator executive to control andmonitor operations of simulator andconduct training sessions. TheMessaging and Data SharingMechanism is an essential part ofsimulator which enables processesto exchange messages and share

data between them. The Databaseserver provides a single database forall the components of the simulatorwith multi-user access. The Loggerprovides a uniform, centralizedmechanism to save and restoreinformation about the state of thesimulator and the user input.

The modeling software providesthe application-specific tools for:

o simulating the process models ofconventional plant systems

o simulating plant controls

o emulating control panels and FDTwith soft-screens

Process models for non-conventional nuclear subsystems aredeveloped as External or Foreignmodels and integrated into thesimulator environment.

The organization of simulatorsoftware components are shown inFig 2.

Reference Plant Subsystemsbeing simulated

The PFBR subsystems identifiedfor simulation are listed below:

o Neutronics System

o Reactor Assembly

o Primary Sodium System

o Secondary Sodium Circuit – 2 Nos

o Safety Grade Decay Heat RemovalCircuit – 4 Nos

o Steam Water System

o Generator and Electrical Systems

o Operation Grade Decay HeatRemoval System

o Condenser Cooling Water System

o Instrumentation & Control of RealTime Computer Systems andSafety Logic Systems

o Fuel Handling Operation

The malfunctions and incidentsrepresent the unusual occurrencesexperienced during the plantoperation which require adequatehandling by the plant operator. Inorder to train the operator for suchan eventuality, an exhaustive list ofsuch possible incidents andmalfunctions related to PFBR has

Fig. 2 : Architecture of Simulator Software


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Fig. 4 : Primary & Secondary Heat Transport Systems ModelingFig. 3 : Neutronics Modeling

Fig. 6 : Electrical System ModelingFig. 5 : Steam Water System Modeling

The simulator development is inprogress and models are beingintegrated and tested. The simulatorbeing developed will go a long wayin providing the required training tooperators & engineers for smoothoperation of PFBR. Simulator can alsobe used to verify the effect of designmodifications in PFBR. Thedeveloped simulator models will beverified and validated by anindependent team consisting ofexperts from NPCIL and BARC.

(Reported by S. Athinarayanan,Computer Division, EIG)

external models in the simulatorenvironment.

During the development stage ofsimulator, the functions of thereference plant control room andoperator interface are emulatedusing VDU based graphics systemscalled virtual panels. Virtual Panelsare screen based soft-panels whichemulate control panels and consoleswith animated panel equipmenticons. The virtual panels of thesimulated subsystems of PFBR areshown in Fig. 3, 4, 5 & 6.

been identified for modeling andtheir simulation is in progress.

Development of ModelsAll conventional sub-systems like

hydraulic, steam, air/gas andelectrical as well as non-processelements such as actuators andtransducers are simulated using themodeling software. Process Modelsfor nuclear subsystems such asNeutronics, Core, Primary Sodium,Secondary Sodium, Safety GradeHeat Removal Systems are developedfrom scratch and adopted as

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Young OfficersYoung OfficersYoung OfficersYoung OfficersYoung OfficersFFFFForum fororum fororum fororum fororum for

Integrity of Fuel Pellet

D. Naga Sivayya

D. Naga Sivayya obtained hisB.Tech. degree in MechanicalEngineering from JawaharlalNehru TechnologicalUniversity, Hyderabad in2004. He is from 48th batchof BARC Training School andjoined IGCAR as ScientificOfficer (SO/C) in September2005.

1470 K to 1670 K, it is sub-brittle whichis characterized by measurable plasticstrain before fracture. After 1670 Kthe fuel behaves almost ductile andconsiderable amount of plasticdeformation occurs before fracture.The regions in the fuel pellet areshown in the Fig. 1. The extent ofthe regions will change depending onthe power.

Ceramic fuels are inherentlybrittle, and therefore they are proneto crack during power rise due tohigh thermal stresses. In a typical FastReactor fuel pin with mixed oxidefuel, the centreline temperature isin the order of 2500 K and the fuelsurface temperature is around 1223K during normal operating condition.However during over-powertransients, the centrelinetemperature may reach up to meltingpoint. Even during normal operatingcondition, large temperature gradientacross the pellet radius induces highthermal stress, which leads to pelletcracking. The radial pellet crackingaids in establishing the fuel-cladcontact, there by improving the gapconductance. But if the crackingleads to pellet fragments, which mayoccupy the adjacent fuel-clad gap,then it may obstruct the expansionof the pellet and may even lead toclad failure due to local stress. Thecracking of fuel pellets is alsoimportant to evaluate the FCMI (Fuel-Clad Mechanical Interaction), fissiongas release, and hence swelling. Soto check and ensure the fuel integrityat high thermal gradients, a study wascarried out to find the crackinitiation, propagation, number ofcracks forming and their lengths asfunction of power.

The fracture behaviour of the fueldepends on the temperature. Up to1470 K, of fuel is brittle and from

Temperature ProfileDuring power increase from

startup to full power at 450 W/cmLinear Power (LP), the thermalgradient keeps on changing. For thelinear power up to 200 W/cm, thefracture behaviour of the entirepellet cross section is brittle. At 450W/cm, the brittle region is limited toonly 0.4 mm from the periphery ofthe pellet. The temperature profileat the linear power 450 W/cm is shownin Fig. 2.

Fig. 1 : Cracking regions in Fuel Pellet


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calculated and compared with thefracture toughness (KIC).

If KI < KIC No Crackpropagation.

KI > KIC Crack Propagationcontinues.

The crack length for differentcracks is incremented by changingthe mesh until the stability of crackis reached. Up to 50 W/cm LP, thetensile strength in the pellet doesnot exceed the fracture strength ofthe pellet, so there will be nocracking. At 100 W/cm LP, crackingtakes place as the tensile stress

Finite Element code CAST3M isused for the thermal and structuralanalysis. The fuel pellet is modeledusing 3D CUB8 elements. The meshingis done in such a way that cracklength can be modified easily as andwhen required. And also provisionsare made to have multiple crackswith varying crack lengths.

Criteria for the crackinitiation and propagation

Due to thermal gradient in radialdirection, tensile stress is inducedin the outer layers of fuel pellet andcompressive stress is induced in theinner layers. The magnitude of thesestresses will increase with powerrise. At particular power when thestresses are more than the fracturestrength, a crack will initiate at themaximum flaw location due to stressconcentration. Crack initiationrelieves the tensile stress in thecracked portion. And as the powerrises further, these stresses will againincrease leading to another crackformation mostly random in real casebut for the analysis it is assumed thatthe cracks form symmetrically.

Fracture mechanics approach isused for the crack propagation. Fromthe nominal stress around the cracktip, Stress Intensity Factor (KI) is

Fig. 2 : Temperature Profile at 450 W/cm

crosses the fracture stress. Withinitial approximation of minimum of0.1 mm crack length, the crackpropagation was checked. Fig. 3explains a case of crack advancementfrom 0.5 mm to 0.7 mm.

The stress intensity factor at thecrack tip of 0.5 mm is 2.2 MPa√m,where as fracture toughness is1.2 MPa√m. So, the crack advances.The analysis was carried out forincreasing power levels and verifiedmore crack formation & propagation.With increase in power, the pelletas well as the clad expands. In

Fig. 3 : Stress intensity factor as a function of Radial crack length at 100 W/cm

Fig. 4 : No. of cracks and Fuel-Clad gap variation with Linear Power

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addition, cracking promotes furtherexpansion of pellet, which decreasesthe Pellet-Clad gap. Fig. 4 shows themaximum pellet expansion, clad

expansion and minimum pellet-cladgap variation with the linear powerof the pellet. On the top of the plot,the number of cracks formed isindicated.

ConclusionThis analysis is carried out to

establish the analystical capability ofCAST 3M for fuel modelling studies.From the analysis, at 450 W/cm,totally 8 cracks are formed with amaximum crack length of 0.75 mm fromperiphery of the pellet. The integrityof the pellet is ensured by theremaining un-cracked portion (with1.1 mm radius) of the pellet. Thedeformation of the pellet is shown inFig. 5. Parametric study carried outon the number of cracks and cracklength reveals that the increase innumber of cracks decreases themaximum radial expansion andincrease in crack length widens thecrack opening which in turnincreases the maximum radialexpansion of the pellet.

(D. Naga Sivayya and Colleagues,Nuclear Engineering Group)

Fig. 5 : Pellet Deformation at 450 W/cm

A meet on the CEA-DAEcollaboration on the theme,“Nanoscience: nanomaterials –production and characterization;interfaces - self-assembledmonolayers” was held at IGCARKalpakkam on October, 4, 2007. A sixmember CEA Delegation comprising ofDr. Pascal BOULANGER:CEA/DSM/DRECAM, Dr. Nathalie HERLIN-BOIME :CEA/DSM/DRECAM, Dr. AriannaFiloramo: CEA/DSM/DRECAM, Dr.Roberto Calemczuk : CEA/DSM/DRFMC, Doris Neumann-Maazi : CEA/DRI and Hughes de Longevialle: CEA/DRI, along with Dr. J.V. Yakhmi,Associate Director (P), BARC,participated in the one day meet atKalpakkam. The technical programmecomprised of presentations by CEA

Events&NEWSCEA-DAE Collaborative meeting on

“Nanoscience: nanomaterials –production and characterization;

interfaces - self-assembled monolayers”October 4, 2007

and IGCAR scientists and visits to thelaboratories. Topics for collaborationin the area of Chemical Sensors andparticipation in Synchrotron

Shri. S.C. Chetal, Director, Reactor Engineering Group, IGCAR with the CEA Delegationof CEA-DAE Collaborative meeting on “Nanoscience: nanomaterials – production and

characterization; interfaces - self-assembled monolayers”

experiments were discussed.

(Reported by C. S. Sundar, MaterialsScience Division)


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Visit of CEA, France delegationOctober 17-18, 2007

A three member CEA delegation comprising ofDr A. Alamo (DEN/DSOE), Dr. P. Chaix (DEN/DSOE) andDr. C. Robertson (DEN/DMN) visited IGCAR during October 17and 18, 2007. Presentations on “CEA Basic Research Programsfor Nuclear Energy Applications”, “Advanced Steels and ODSAlloys for Nuclear Applications”, and “Strain Localization inIrradiated Austenitic Stainless Steels, were made by the visitingCEA Scientists, followed by in-depth discussions. The mainobjective of the discussion session was to put into action theImplementing Agreement “Investigation of irradiation-inducedmicrostructure in ODS materials using JANNUS facilities andmulti-scale modelling” that was signed in Cadarache on 24th

September 2007. The scientific and technical aspects of thecollaborative programme that deals with investigation of thestability of nano-sized yttria particles in iron matrix, undervarious irradiation conditions and mechanical loading wasdiscussed in detail to evolve the various steps ofexperimentation and simulation.

French delegation seen along with Shri S.C. Chetal,Director, Reactor Engineering Group

India-Japan Specialists’Meeting on Safety in Nuclear Energy

November 12-13, 2007

The India-Japan Specialists’ meeting on Safety in Nuclear Energy washeld at IGCAR, Kalpakkam during 12-13 November, 2007. A thirteen-memberJapanese delegation led by Prof.Y.Fuji-ie, Former Chairman, Atomic EnergyCommission of Japan participated in the specialist meeting. From Indianside twenty members from IGCAR and BHAVINI attended the meeting.The meeting started with introductory remarks by Dr. Baldev Raj, Director,IGCAR and Prof. Fuji-ie, leader of the Japanese delegation. In hisintroductory remarks Dr. Baldev Raj, gave an overview of the currentstatus of fast reactor development in India. In his talk Prof. Fuji-ie,touched upon “Nuclear Development in Japan” and “Basic idea ofsecuring nuclear system safety”. In all there were eight presentations,four from Japanese delegation and four from Indian participants. Mr. A.Yoshida from O-arai Research and Development Center, JAEA, talked on“The Operating experience of Japanese fast experimental reactor Joyo”

and Dr. Y. Kani, Leader of the Fast ReactorProgramme in Japan and the Deputy DirectorGeneral, Fast Breeder Reactor Research andDevelopment Center, JAEA gave a talk on“Safety approach and safety evaluation ofJapanese prototype fast reactor Monju”.Mr. N. Suda from the Nuclear SafetyTechnology Centre, Japan, in his talk gavethe details of the “System for prediction ofenvironmental emergency dose information(SPEEDI)”. Shri S.C. Chetal, Director, ReactorEngineering Group, discussed the “Safetycriteria & design provisions of Prototype FastBreeder Reactor in India” and Shri. P.V.Ramalingam, Director, Reactor Operation &Maintenance Group, in his talk covered the“Operating experience of Fast Breeder TestReactor”. Shri. M. Rajan, Director, SafetyGroup touched upon the “R&D studiesconcerning sodium fire at Indira GandhiCentre for Atomic Research” and Dr. P.Chellapandi, Associate Director, NuclearEngineering Group, REG discussed “Beyonddesign basis events and containment relatedaspects of Prototype Fast Breeder Reactorin India” in his talk.

Possible areas for further cooperationwere discussed in the concluding session.The members of the Japanese delegationvisited Fast Breeder Test Reactor andPrototype Fast Breeder Reactor, underconstruction by BHAVINI.

(Reported by M. Sai Baba, S&HRPS)

Dr. Baldev Raj, Director, IGCAR and Prof.Y. Fuji-ie, Former Chairman, Atomic EnergyCommission of Japan, with the participants of the “India-Japan Specialists’

Meeting on Safety in Nuclear Energy”

(Reported by C. S. Sundar, Materials Science Division)


IGCNEWSLETTER

A delegation of members of the “Parliamentary Standing Committee onScience & Technology, Environment and Forests” under the Chairmanship ofHonourable Member of Parliament, Dr. V. Maitreyan visited the Centre on 21December, 2007. The delegation was received by Dr. Baldev Raj, Director, IGCAR,

Visit of Parliamentary Standing Committee onScience & Technology, Environment & Forests

December 21, 2007

Heads of other DAE units at Kalpakkamand senior colleagues of the Centre.Dr. Baldev Raj, Director, IGCAR in histalk presented a status report on theFast Breeder Test Reactor and theR&D activities of the Centre and gavea perspective of the future growthof fast breeder reactor program. Aninteresting and thought provokingdiscussion followed the presentation.The members of the standingcommittee expressed theirappreciation for the progress madeby the Centre in the development offast breeder reactor and associatedfuel cycle technologies

The members of the delegationvisited; Fast Breeder Test Reactor,Radiometallurgy Laboratory andEngineering development and testingfacilities of Fast Reactor TechnologyGroup. They also visited the PrototypeFast Breeder Reactor, underconstruction by BHAVINI.

(Reported by M. Sai Baba, S&HRPS)

Dr. V. Maitreyan, Chairman and Members of the “Parliamentary Standing Committee on Science& Technology, Environment & Forests” with Dr. Baldev Raj, Director, IGCAR and senior

colleagues of IGCAR during their visit to IGCAR

Remarks by Dr. V. Maitreyan, MP, Chairman,Department related Parliamentary Standing Committee on S & T

Reproduced Message:

“The committee is proud of the achievements of our scientists and appreciates theteam work in keeping with the glory of the country up. The target of nuclear

technology leadership by 2020 is really commendable” - Dr. V. Maitreyan, MP


IGCNEWSLETTER

Nanoscience and TechnologyNanoscience and TechnologyNanoscience and TechnologyNanoscience and TechnologyNanoscience and Technology(ICONSAT-2008)(ICONSAT-2008)(ICONSAT-2008)(ICONSAT-2008)(ICONSAT-2008)

Convention Centre, Chennai Trade Centre, Chennai

February 27-29, 2008

International Conference on

An International Conference onNanoscience and Technology(ICONSAT-2008) is to be held atConvention Centre, Chennai TradeCentre, Tamil Nadu, INDIA duringFebruary 27-29, 2008. ThisConference, sponsored by theNational Mission on Nano Science andTechnology of the Department ofScience and Technology, Govt. ofIndia, is being organized by IndiraGandhi Centre for Atomic Research,Kalpakkam. ICONSAT-2008 which willbring together leading researchers

from all over the World, in additionto the Indian scientists and students,will provide a forum to interact onthe current developments and futuretrends in the multidisciplinary areaof Nanoscience and Nanotechnology.The details of the technicalprogramme can be found in theConference Website: http:/www.iconsat2008.com

As a part of ICONSAT-2008, twosatellite events are also beingorganized: On February 26th, a dayprior to the Conference, we are

conducting a Workshop on “NanoScience & Technology for Health Care: Medical Diagnosis, Imaging and DrugDelivery”, which will be for thebenefit of Research scholars andprofessionals from medical andpharmaceutical fraternity. OnFebruray 28th, the National ScienceDay, Prof. C.N.R. Rao will conduct aprogramme entitled “Nano World”.About 250 students from variousschools and Colleges in the Chennairegion are expected to participatein this interactive session.

The Sixteenth National Symposiumand Workshop on Thermal Analysis-THERMANS - 2008 is being organizedat Indira Gandhi Centre for AtomicResearch, Kalpakkam, India duringFebruary 4-8, 2008. The Symposium andWorkshop is sponsored by Board ofResearch in Nuclear Sciences (BRNS),Department of Atomic Energy (DAE)in association with the Indian ThermalAnalysis Society (ITAS). In thisSymposium, it is planned to focus onthe theme “Thermal Analysis inNuclear Technology and Allied Areas”.The deliberations of the symposiumwill cover the following topics:

o High temperature thermochemistry and phase equilibrium studies.

o Thermochemical and thermophysical properties of nuclear materials.

o Solid state reactions and kinetics.

o Novel materials such as conducting polymers, ionic liquids.

o Nanomaterials.

o Polymers, composites and high energy materials.

o Glass and ceramics

o Catalysts

o Bio materials.

o Molten salts.

o Phase diagram computations and modeling.

For more information please visit the conferenceURL : http://www.itasindia.org

Symposia/ConferencesSixteenth National Symposium & Workshop on Thermal Analysis(THERMANS 2008)

Indira Gandhi Centre for Atomic Research, Kalpakkam

February 4-6, 2008 (Symposium)February 7-8, 2008 (Workshop)


IGCNEWSLETTER

Academia-IGCAR Meet (AIM-2007) October 12, 2007

scientists. The day’s programme included brain-storming session with Dr.Baldev RajDistinguished Scientist and Director IGCAR, visits to laboratories of their interest,technical presentations by the Heads of the respective facilities, one-on-one interactionswith their chosen scientists, business networking, feed-back session and panel discussionfor formulating the roadmap to take the initiatives ahead. The progress of thecollaborative ventures and the offshoots of AIM-2007 will be documented for periodicmonitoring and further directions by the Centre.

(Reported by J. Daniel Chellappa and P.V.Ramalingam, PRAI Committee )

Chief Guest Prof. Dr. Tmt. Nalini Ravindran, Director of CollegiateEducation, Govt of TN listening to Director IGCAR’s address

Guided by the success of theCentre’s major initiative launched onOctober 2nd last year, IGCAR organizedOne-Day Academica-IGCAR Meet (AIM-2007) at Kalpakkam on Friday,October 12, 2007 for the Academiain science and engineering disciplines.A team of 250 resolute researchers,from various colleges and universitiesin Tamil Nadu, with excellent trackof research and promising problemsfor exploration were short-listed forparticipation. The Meet focused onreinforcing the existingcollaborations, and also on identifyingnew enabling partners in India’smarch towards its cherished visionof becoming a global leader inSodium Cooled Fast Breeder Reactor(FBR) and associated fuel cycletechnologies by 2020 AD. Academiafrom various others districts of theState, who have a strong desire tocollaborate, also joined their Chennaicolleagues in large numbers.

AIM-2007 provided an excellentplatform for showcasing theirexpertise and the infrastructure oftheir institutions. They presentedrelevant project proposals for jointventures and shared theirexcitements in pursuing science andengineering R & D with IGCARscientists. They were keyed-up atthe Centre’s top-notch researchculture and the commitment of our

IGCAR has been awarded the First prize in the category ofMass Awareness Campaign for the year 2007 by PublicRelations Society of India (PRSI). Shri J. Daniel Chellappa,Technical Co-ordination & Public Awareness Cell, IGCAR isseen receiving the award from Shri K.K. Acharya, ManagingDirector of Chemical Petroleum Corporation Ltd. In thepresence of Dr. Ajit Pathak, the President of PRSI on December15, 2007 during 29th All India Public Relations Conference,December 13-15, 2007 at Chennai.


IGCNEWSLETTER

Dr P.R.Vasudeva Rao, Chairman, Editorial Committee Members: Dr.G.Amarendra, Shri M.Ganapathy, Dr.K.V.G.Kutty, Dr.Mary Mohankumar,

Shri G.Padma Kumar, Shri Shekar Kumar, Shri M.Somasekharan, Shri R.Srinivasan, Shri R.V. Subba Rao, Shri K.V.Suresh Kumar.

Published by Scientific Information Resources Division, IGCAR, Kalpakkam - 603 102

Dr. Baldev Raj has been awarded the prestigious the

National Metallurgist Award-2007 (Research-Academy) by Ministry of Steel, Govt. of India and IndianInstitute of Metals. He has been awarded the prestigious

Life Time Achievement Award of Indian Institute ofWelding. He has also received Stanley Ehrilich Gold Medal

during the National Symposium on Acoustics (NSA-2007).

Shri S.C. Chetal, Reactor Engineering Group has beenconferred National Design Award by the Institution ofEngineers, India.

Dr. M. Vijayalakshmi, Physical Metallurgy Division has

been awarded the Metallurgist of the Year Award forthe year 2007 by Ministry of steels, Govt. of India and

Indian Institute of Metals.

Dr. C.K.Mukhopadhyay, Non-Destructive ExaminationDivision has been selected to receive the ISNT NationalNDT Award under the category excellence in

contribution to research & development, jointlysponsored by ISNT & M/s. Electronic & Engineering

Co., Mumbai, for the year 2007.

Dr. A. K. Tyagi, Materials Science Division has beenawarded the MRSI Medal for the year 2008 by MaterialsResearch Society of India (MRSI).

IGCAR has won the First Prize for the category “Mass

Awareness Campaign” for the year 2006-07. The apexnational PR body, Public Relations Society of India (PRSI)

has honoured the Centre for its team efforts in themass campaign for the role of Fast Breeder Reactorsin ensuring the energy security for India.

AWARDS AND HONOURSq

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