Volume 93 - Indira Gandhi Centre for Atomic Research

ISSN 0972-5741 Volume 90 October 2011 

ISSN 0972-5741 Volume 93 July 2012 

IGCNewsletter 

IGCNewsletter 

IN THIS ISSUE 

Technical Articles 

• Performance Testing of Primary Ramp and Primary Tilting 

Mechanism of Inclined Fuel Transfer Machine 

of Prototype Fast Breeder Reactor 

• Science of Metal Nanoclusters 

Young Officer’s Forum 

• Design of Elliptical Heat Exchanger for Future Fast Breeder 

Reactors 

Young Researcher’s Forum 

• Enhanced Transmission with Tunable Fano like Profile 

in Magnetic Soft Matter 

Conference/Meeting Highlights 

• Theme Meeting on Severe Accident Analysis and Experiments 

• Theme Meeting on Robust Instrumentation and Control for 

Nuclear Facilities 

• Theme Meeting on Technological Advancement in Production 

of Enriched Boron for the Control Rods of Fast Reactors 

Visit of Dignitaries 

Awards & Honours 

INDIRA GANDHI CENTRE FOR ATOMIC RESEARCH 

http://www.igcar.gov.in/lis/nl93/igc93.pdf

From the Editor 

Dear Reader 

IGC Newsletter 

From the Editor 

It is my pleasant privilege to forward a copy of the latest issue of IGC Newsletter (Volume 93, July 2012 issue). 

In the Director’s Desk, Shri S. C. Chetal, Director, IGCAR has highlighted the contributions made by Chemistry Group towards 

supporting the fast reactor programme and closing the fuel cycle. The significant inputs provided by the Group in the last five years like 

fuel-fission product interaction studies, development of failed fuel detection system, production of useful radioisotopes, development 

of chemical sensors, decontamination and sodium cleaning studies, boron chemistry, cover gas purification system, studies related 

to fuel cycle with special emphasis on metallic fuel fabrication, separation studies, waste immobilization and other important research 

activities towards unravelling the basics in chemistry. 

Shri B.K. Sridhar and Shri S. Raghupathy have shared their experience on successful completion of the performance testing of primary 

ramp and primary tilting mechanism in air and sodium, and the effective in situ removal of sodium from primary ramp and primary 

tilting mechanism by water vapor and carbon dioxide process. 

In the second technical article, Dr. P. Gangopadhyay has discussed the Science of Metal Nanoclusters by analyzing and interpreting 

the results of the photoluminescence, optical absorption spectroscopy and Rutherford backscattering experiments of silver ionexchanged/implanted 

soda-glass samples and Raman scattering spectroscopy of cobalt implanted silica samples. 

In the young officer’s forum, Shri V. Sudharshan gave an account of optimising the configuration of intermediate heat exchanger for 

economy and designed an elliptical heat exhanger for future fast breeder reactors with design life of 60 years at 85% load factor. 

Dr. Junaid Masud Laskar, in the young researcher’s account, has presented the first experimental evidence for tunable fano resonance 

in magnetically polarizable soft matter system and explained the variation of different fano paramenters with external magnetic field on 

the basis of change in interference due to varying waveguide dimension and their dimensional distributions. 

This Newsletter carries reports on the Theme Meetings on “Severe Accident Analysis and Experiments", "Robust Instrumentation and 

Control for Nuclear Facilities” and “Technological Advancement in Production of Enriched Boron for the Control Rods of Fast Reactors”. 

Honorable Justice Shri S. Tamilvanan from Madras High Court and Prof. V. Manimozhi visited the Centre during the last quarter. 

We are happy to share with you the awards, honours and distinctions earned by our colleagues. We look forward to your feedback, 

continued guidance and support. 

With my best wishes and personal regards, 

Yours sincerely, 

(M. Sai Baba) 

Chairman, Editorial Committee, IGC Newsletter 

& 

Associate Director, Resources Management Group

From the Director's Desk 

Director’s Desk 


Chemistry Programme at IGCAR 

The importance of chemistry as a key discipline in the 

development of fast reactor technology and the fuel cycle was 

recognised by our department in the very early stages of the 

fast reactor programme. The Radiochemistry Laboratory (RCL) 

was one of the first set of laboratories built at IGCAR. At that 

stage, the chemistry laboratory was intended to provide support 

for the development of the fast reactor programme through R&D 

activities related to fuel materials, liquid sodium and other alkali 

metals, and the fuel cycle for fast reactor. Over the years, the 

Chemistry Group (CG) has not only met this mandate, but also has 

provided key technological inputs to several other aspects of the 

fast reactor programme. The work on plutonium chemistry was 

initiated in the year 1983. The historical evolution of the chemistry 

programme at IGCAR and the contributions of CG in the first 25 

years were covered in the article that appeared in the newsletter 

in April 2005. In the present article, I have focused more on the 

achievements of CG in the subsequent period, while providing 

some idea of the earlier work in order to present a comprehensive 

perspective. 

CONTRIBUTIONS TO FBTR 

The Chemistry Group provided key inputs to the decision on the 

composition of the carbide fuel for FBTR. The knowledge base 

on the thermochemical properties of the fuel and fission product 

systems, and the strengths in thermochemical modeling were 

instrumental in arriving at an understanding of the chemical 

state of the carbide fuel at high burn-up. This was particularly 

necessary for extension of the burn-up of FBTR fuel beyond 

150 GWD/t. The equilibration experiments carried out to study 

the chemical interaction of (U 0.56 

Pu 0.44 

)O 2-x 

with liquid sodium 

were useful in obtaining safety clearance for the introduction of 

plutonium rich oxide fuel in FBTR. 

Chemistry Group was also responsible for the characterization 

of the sodium that was charged into FBTR and the chemical 

characterization of various structural materials. Over the years, 

the group has continued to provide characterization support 

for the sodium coolant in FBTR. Various impurities in sodium 

have been measured periodically, and gamma spectrometry 

measurements have been carried out on radioactive sodium from 

the primary sodium loop of FBTR. 

The Chemistry Group was involved in the development of a failed 

fuel detection system for FBTR, based on the measurement of 

Kr 87 /Kr 85 and Kr 88 /Kr 85 ratios in the cover gas by gamma 

spectrometry. This development proved to be crucial in the 

localization of the failed fuel in FBTR, in the first incidence of 

carbide fuel pin failure. The measurement of the krypton isotope 

ratios combined with the reactor power history led to an estimate 

of the age of failed fuel and burn-up of the breached sub-assembly. 

The age of the failed fuel computed from Cs 136 /Cs 137 ratio present 

in primary sodium confirmed this measurement. 

In the recent past, the CG has also started a programme to utilize 

FBTR for the production of societally beneficial radioisotopes. As 

a part of this programme, Sr 89 , a beta emitter used for alleviating 

pain in bone cancer patients, was produced in FBTR through 

the irradiation of yttria. CG has demonstrated the separation of 

Sr 89 from the irradiated yttria in the hot cells and its subsequent 

purification by ion-exchange. Characterisation of the Sr 89 is now 

in progress, and in the near future, the process know-how would 

be passed on to the Board of Radiation and Isotope Technology. 

CONTRIBUTIONS TO PFBR AND FUTURE FAST REACTORS 

Chemical Sensors 

The development of electrochemical meters for monitoring 

hydrogen, carbon and oxygen in sodium has been a major 

highlight of the contributions of CG. In particular, the development 

of the Electrochemical Hydrogen Meter (ECHM) to detect water- 

1


Figure 1: Electrochemical hydrogen meter ECHM 

steam leak in the steam generator at the incipient stage is one 

of the excellent contributions from the CG. Several versions 

of these meters were fabricated and tested for their long term 

performance in bench top loops as well as in large sodium loops 

in the Centre, and FBTR. This development had demanded 

several years of basic studies on various electrolyte systems 

including their phase diagrams and electrical conductivity 

measurements. This work has finally resulted in a robust ECHM 

(Figure 1) that can measure a change in ~ 10 ppb of hydrogen in 

sodium in a background of around 50 ppb. One hydrogen meter 

has been installed in the PHENIX reactor in France as a part of 

the collaboration programme between IGCAR and CEA, and its 

performance was as good as that of the hydrogen meter based 

on mass spectrometer. The excellent performance of the ECHM 

has provided us confidence to introduce the same as the primary 

steam generator tube leak detection system in the PFBR. 

A diffusion based hydrogen detection system has been developed 

to monitor the hydrogen concentration in the argon cover gas 

during start up or low power operation of the fast reactor. Four 

units of this system are now being fabricated for integration 

in PFBR. An electrochemical meter for the measurement of 

carbon activity in sodium has also been developed. The activity 

of carbon measured by this meter has been compared with 

the data obtained by foil equilibration measurements. From the 

temperature response of the cell the nature of carbon species 

in molten sodium was also evaluated. For the measurement of 

oxygen in sodium, a yttria doped thoria (YDT) solid electrolyte 

based electrochemical sensor has been developed and is 

undergoing tests in various loops. 

Chemistry Group is also engaged in the development of compact 

chemical sensors for a wide variety of other applications, besides 

basic research on sensor materials and sensing processes. 

Sensors based on thin films of semiconducting oxides (eg. tin 

oxide) have been developed. Thin film hydrogen sensor based 

on tin oxide has extended the detection limit of the hydrogen 

detection system for cover gas (based currently on Thermal 

Conductivity Detection) down to a few vppm. The sensor has 

performed satisfactorily in different engineering scale facilities of 

our Centre for more than five years. Promising semiconducting 

oxide formulations have also been identified for sensing oxides 

of nitrogen (NOx), oxygen, ammonia and hydrogen sulphide. The 

sensor systems will be useful for the reprocessing plants, reactor 

operating areas and heavy water production plants. 

Cleaning of Sodium Wetted Components 

Components exposed to liquid sodium in coolant circuits of fast 

reactors need to be cleaned free of sodium when removed from 

coolant circuits for periodic maintenance or replacement. A water 

vapour-CO 2 

process for cleaning sodium from reusable large 

components has been studied at CG. A pilot plant (Figure 2) was 

constructed and the sodium cleaning experiments carried out in 

the pilot plant showed that the cleaning process could be carried 

out in a controlled manner by manipulating injection of moisture 

into the reaction chamber. Accordingly, this process has been 

recommended for cleaning sodium wetted components of PFBR. 

Chemical and Electrochemical Decontamination 

A chemical decontamination method for primary components 

of PFBR using sulpho-phosphoric acid was standardized with 

inactive SS316LN specimens exposed to sodium. The process 

conditions such as chemical composition of the decontamination 

solution, temperature and the process time were optimized for 

various sodium sensitized cold worked specimens. The chemical 

decontamination formulation, evolved based on these studies has 

been recommended for decontamination of primary components 

of PFBR. An electrochemical brush decontamination method was 

also standardized for decontamination of hot spots of primary 

components of PFBR using SS316LN material, in collaboration 

with CECRI, Karaikudi. 

Boron Chemistry 

One of the important contributions of the Chemistry Group towards 

PFBR was the development of the technology for the production 

of elemental boron required for fabricating the absorber rods, in 

association with BARC and Heavy Water Board (HWB). Figure 3 

shows the pilot plant for elemental boron production. The process 

for the conversion of boric acid to potassium tetrafluoroborate 

(KBF 4 

) and its subsequent conversion to elemental boron through 

molten salt electrowinning route were optimized at the laboratory 

and the know-how transferred to HWB, which is presently 

engaged in regular production of elemental boron through this 

route. During this process, a few kilogram of pure enriched 

elemental boron was also produced and characterized and the 

Figure 2: Pilot plant for sodium wetted component cleaning: water 

vapour - CO 2 

process 


2



Figure 3: Pilot plant for elemental boron production 

material was sent to BARC for conversion to boron carbide. The 

group was responsible for the determination of B 10 /B 11 ratios in a 

large number of samples, generated during the development of 

the ion-exchange based enrichment process at IGCAR, and the 

determination of the ratio also in the boron produced at Manuguru 

as well as boron carbide fabricated at BARC. Experiments to 

assess the chemical compatibility of high-density boron carbide 

pellets with D9 clad material in the presence of sodium were also 

carried out. 

The Chemistry Group also set up a unique facility for measuring 

the isotopic ratio of boron in irradiated boron carbide pellets, 

using the home built reflectron time of flight mass spectrometry. 

Using this facility, the analysis of the isotopic ratio of B 10 to B 11 in 

the carbide pellets in the control rod of FBTR that was discharged 

from the reactor was measured. These data have provided 

important inputs about the feasibility of recycling of the enriched 

boron carbide. 

Cover Gas Purification System 

The cover gas purification system in PFBR uses activated charcoal 

at cryogenic temperatures to delay the passage of radioactive 

isotopes of krypton and xenon which ensures that they decay 

considerably before they are let out into the atmosphere. In 

collaboration with FRTG, CG has carried out the demonstration 

of the cover gas purification system on a pilot plant scale. The 

dynamic adsorption coefficient of charcoal for krypton and 

xenon was measured and the data have been used to arrive at the 

amount of charcoal required for the purification for PFBR. 

FAST REACTOR FUEL CYCLE 

In the Indian context, the fuel cycle of fast reactors pose many 

unique challenges. The first Indian experience of fast reactors 

was with high plutonium content mixed carbide fuel for FBTR; 

the PFBR would use mixed oxide fuel, while future fast reactors 

are expected to use metal alloys as the fuels. Thus, the group 

has engaged itself in the study of all these fuel systems as well 

as their fuel cycle aspects. In the recent past, the CG has been 

playing a key role in the development of fabrication routes for fuel 

Figure 4: Spot technique for measurement of solidus- liquidus 

temperature of fuel materials 

materials and also fabrication of test fuel pins in collaboration 

with BARC. 

Fuel Chemistry 

Chemistry Group has carried out thermophysical and 

thermochemical property measurements of a variety of fuel 

materials, fission product systems and compounds of alkali 

metals. Heat capacity and thermal conductivity data of U-Pu mixed 

oxides, carbides and nitrides, as well as oxygen potential over 

mixed oxide have been measured in the Chemistry Group. More 

recently, the novel “SPOT technique” (Figure 4) was established 

for the first time to measure the solidus liquidus temperatures 

of fuel materials. The U-Zr system was comprehensively studied 

using this technique. Efforts are now on to make measurements 

on the carbide fuel of FBTR and metal alloy systems. 

Fuel Cycle Chemistry 

In collaboration with BARC, CG has set up a unique lab scale 

facility for the fabrication of test fuel pins using fuel materials 

synthesized through SOL-GEL route. The fabrication of test fuel 

pins with (U 0.6 

Pu 0.4 

) mixed oxide is being pursued and the test 

fuel pins will be introduced in FBTR for irradiation in the coming 

months. The group has also demonstrated lab scale synthesis of 

U-Pu mixed oxide microspheres with 28% Pu, and U-Am mixed 

oxide microspheres with 5% Am. 

Extensive investigations were carried out on the extraction 

of actinides by tri-n-butyl phosphate (TBP) extractant used in 

the PUREX process for reprocessing and also other members 

of trialkyl phosphate family. A thorough investigation on the 

phenomenon of third phase formation in the extraction of 

plutonium by TBP generated the understanding that was vital in 

the design of the process flow sheet in the reprocessing of fast 

reactor fuels. To avoid the possibility of third phase formation, 

several other trialkyl phosphates and especially tri-isoamyl 

phosphate (TiAP) were investigated. Counter current liquid - 

liquid extraction experiment, carried out with TiAP solvent under 

the conditions simulating the PUREX process, has indicated 

satisfactory behaviour of the TiAP. 

3



Figure 5: The setup used for minor actinide 

partitioning in hot cell 

Figure 6: Mixer-settler facility used for flow 

sheet development studies with TiAP for fast 

reactor fuel reprocessing 

Figure 7: Supercritical fluid extraction facility in 

glove box for recovery of actinides from waste 

matrices 

The Chemistry Group has also been active in the area of minor 

actinide partitioning (Figure 5) from high-level liquid waste. 

The group has synthesized the extractant octyl(phenyl)-N,Ndiisobutyl 

carbamoyl methyl phosphine oxide (OΦCMPO) and 

carried out several extraction experiments with americium and 

other lanthanides such as neodymium. Recently, a typical high 

active waste arising from the reprocessing of the carbide fuel of 

FBTR irradiated to a burn-up of 155 GWD/Te was transported 

from the CORAL facility to RCL. A mixer settler run was carried 

out in the hot cells of RCL using the CMPO extractant, which 

established the recovery of over 99% of the minor actinides (Figure 

6). For this experiment, CG developed a complex formulation that 

enabled the stripping of the actinides and lanthanides without the 

formation of interfacial crud. The group has also synthesized 

novel and unsymmetrical diglycolamide and diglycolamic acid 

extractants. The extraction data on various solvent systems 

generated will be very useful for arriving at a partitioning scheme 

for the minor actinides from the high-level waste generated in 

fast reactor plants. 

Development of Glass and Ceramic Matrices for Radioactive 

Waste Immobilization 

Borosilicate glass is the accepted matrix world over, for the 

immobilization of the high-level radioactive liquid waste generated 

in nuclear fuel reprocessing. However, this matrix may have many 

limitations for the immobilization of high-level liquid waste from 

fast reactor fuel cycle. Chemistry Group has been carrying out 

a systematic study on alternate matrices to address this issue. 

Iron phosphate glass and crystalline synthetic rock (synroc) 

are examples of matrices that have been explored. Simulated 

waste forms based on these two have been fabricated, and 

their thermophysical and thermochemical properties have been 

studied using a number of techniques. The matrices have also 

been subjected to rigorous chemical durability studies in order to 

evaluate their potential. 

Advanced Separations 

The Chemistry Group has also made several original contributions 

in the development of a variety of advanced separation techniques. 

The group has demonstrated high resolution, fast separation of 

individual lanthanides and actinides based on high-level liquid 

chromatography. In fact, CG was the first to demonstrate rapid 

separation of all the lanthanides using small particle columns and 

monolith columns. A separation time of 2.7 minutes for all the 

fourteen lanthanides achieved by the Chemistry Group is, as of 

now, the shortest reported in liquid chromatographic separation 

of the lanthanides. These techniques have been very valuable for 

the determination of the burn-up of FBTR fuel with considerable 

reduction in analysis time and consequent reduction in the 

radiation dose to the operator. 

The Chemistry Group has also set up for the first time, a 

supercritical fluid extraction facility (Figure 7) inside the glove 

box for recovery of actinides from various waste matrices and 

was the first to demonstrate quantitative recovery of uranium, 

plutonium and americium from tissue waste, and a novel modifier 

free approach for application to systems where the extractant is a 

solid. The extraction procedure developed was demonstrated on 

actual waste generated in the fuel cycle operation. 

The Chemistry Group has also carried out pioneering work on the 

applications of room temperature ionic liquids (RTIL) for actinide 

and fission product separations. The use of RTILs as a diluents, 

extractant and electrolytic medium has been investigated. The 

Chemistry Group was the first to demonstrate the extraction 

and electrodeposition technique for the recovery of uranium and 

palladium from nitric acid medium. The electrowinning of uranium 

oxide by oxidative chlorination of the oxide to chloride form in 

ionic liquid medium followed by electrodeposition as oxide was 

also demonstrated. 

Fuel Cycle for Metal Alloy Fuelled Fast Reactors 

Metallic fuels will be introduced in future commercial fast reactors 

in India to exploit their high breeding potential and enhance the 

growth of fast reactors in the country. Towards the development 

of the front end of the metal fuel cycle, IGCAR has taken up a 

programme in close collaboration with BARC to fabricate sodium 

4



a) b) 

Figure 8: Glove box train facility for sodium bonded metallic test fuel 

pin fabrication 

bonded and mechanically bonded test fuel pins and irradiate 

them in FBTR. A lab scale facility for fabrication of test fuel pins 

with sodium bonding has been set up by the Chemistry Group 

(Figure 8). U-Zr alloy slugs supplied by BARC have been 

encapsulated in the pins and currently six of these pins are now 

being irradiated in FBTR. It is now planned to take up fabrication 

of test fuel pin containing enriched U-Zr alloy and subsequently 

U-Pu-Zr alloy. 

Unlike the oxide and carbide fuels that are processed by 

the conventional PUREX process, the metallic fuel will be 

processed by pyroelectrochemical route. CG has been engaged 

in the R&D of pyrochemical processing of metal fuels for 

nearly two decades. Starting with a lab scale facility, in which 

electro-refining of uranium was demonstrated on 200 gram 

scale, an engineering scale demonstration facility (Figure 9) for 

process studies on a one kilogram scale has been commissioned. 

Electrorefining experiments have been carried out on kilogram 

scale with U metal as well as U-6%Zr alloy. Studies on the 

electrorefining of plutonium and its rare earth alloys on lab 

scale to understand the chemical behaviour before scaling 

up the process were carried out. The group is now engaged in 

setting up facilities, along with Fast Reactor Technology Group, 

for electrorefining and consolidation studies on ten kilogram 

scale. Several studies have been taken up on a fundamental 

plane on molten salt chemistry and thermochemistry relating to 

pyroprocessing. Studies on electrochemical reduction behavior 

of plutonium and zirconium ions in LiCl-KCl molten salt at various 

temperatures have been carried out by transient electrochemical 

techniques such as cyclic voltammetry and chronopotentiometry. 

Towards modelling the electrorefining process, a code, based on 

thermochemical equilibria (PRAGAMAN) and a code based on 

diffusion layer theory (DIFAC) have been developed. 

Direct Electrochemical Reduction of Uranium Oxides 

Currently, the actinide metals are produced by the calciothermic 

reduction of their respective fluorides which in turn are produced 

from their oxides. The direct electrochemical reduction of 

uranium oxides by making them as the cathode of an electrolytic 

Figure 9: a) Engineering scale demonstration facility for pyroprocess 

studies on uranium alloys and b) uranium metal ingot consolidated from 

electrorefining 

cell using platinum/graphite as anode and the molten salt LiCl 

or CaCl 2 

containing small amounts of lithium oxide or calcium 

oxide as the electrolyte has been studied, and efforts are on to 

optimize the process parameters to achieve complete reduction 

and extend the process for PuO 2 

. 

BASIC RESEARCH 

Thermochemistry 

The Chemistry Group has pursued a number of programmes 

in basic research related to the mission programmes. 

High temperature mass spectroscopy has been an area of 

specialization in Chemistry Group. Using the Knudsen mass 

spectrometer established for the first time in the country, a 

large number of systems of relevance to fuel cycle interaction 

in oxide fuels such as tellurides of iron, nickel and chromium 

have been studied. Phase diagrams and vaporization behaviour 

have been established for the first time in several systems. The 

thermal expansion behavior of (U,RE) mixed oxides as well as the 

solubility limits of rare earth oxides were also determined using 

high temperature X-ray diffraction. The heat capacity data of 

these mixed oxides by differential scanning calorimetry have also 

corroborated the solubility limits of rare earth oxides. 

Separation Science 

Third phase formation during the extraction of Th(IV) and 

Pu(IV) by several trialkyl phosphates such as TBP, tri-iso-butyl 

phosphate (TiBP), tri-sec-butyl phosphate (TsBP), TAP, T2MBP, 

TsAP etc., were studied in a comprehensive manner. Studies have 

also been carried out on third phase formation in the extraction 

of trivalent lanthanides by CMPO based solvents. A number of 

phosphonate extractants such as Dibutylbutyl phosphonate 

(DBBP), Dibutylhexyl phosphonate (DBHeP), Dibutyloctyl 

phosphonate (DBOP) and Diamylamyl phosphonate (DAAP) have 

been synthesized and studies on extraction of actinides (U, Th, 

Pu and Am) and third phase formation have been carried out in 

detail for the first time. A unique instrument has been developed 

for the measurement of phase separation time of solvents based 

on light scattering technique. The thermal decomposition of TBP- 

5


nitric acid systems was also studied by adiabatic calorimetry. 

Enthalpy and activation energy of decomposition of nitric acid 

solvated TBP were reported for the first time. 

A laser mass spectrometry system comprising in-house 

developed reflectron time-of-flight mass spectrometer was used 

to study solid and liquid samples containing UO 2 

doped with 

lighter rare earths, towards developing a method for the direct 

determination of burn-up of irradiated nuclear fuel, without 

chemical separations on the fuel solution. 

Boron Chemistry 

Besides demonstrating the production of enriched elemental 

boron, a number of basic studies on the electrochemistry of boron 

in the molten salt medium as well as vaporization chemistry of 

boric acid were carried out. The vaporization behavior of H 3 

BO 3 

(s) 

was studied by the transpiration method (using a commercial 

thermo gravimetric apparatus) as well as Knudsen Effusion 

Mass Spectrometry (KEMS). Using Ag/AgCl reference electrode 

developed in-house, for the first time, the cyclic voltammogram 

of boron deposition on a platinum electrode from KCl-KF-KBF 4 

molten salt mixture was recorded. The influence of oxideion 

impurity in the KCl-KF-KBF 4 

melt system on the electrode 

potentials was also investigated by linear sweep voltammetry. 

Matrix Isolation Infrared Spectroscopy 

A Matrix Isolation – Fourier Transform Infrared Spectroscopy 

facility (MI-FTIR) has been set up to study the conformations 

of organic molecules and intermolecular interaction between 

the molecules. Using this facility, conformations and structures 

of trimethyl phosphate, triethyl phosphates, tributyl phosphate, 

phosphites, phosphonates, methoxy compounds, carbonates 

and silanes were studied. By controlled annealing experiments, 

weak and strong hydrogen bonded complexes and van der Waals 

complexes have also been studied. CG is now in the process 

of setting up a MI-FTIR facility at RRCAT, Indore to carry out 

photochemical studies on some of the systems indicated above, 

using the Synchrotron facility. 

Fluorescence Spectroscopy 

Fluorimetric methods were developed to detect uranium and 

lanthanide ions such as terbium, dysprosium, europium, and 

samarium at trace levels (

Technical Article 


Performance Testing of Primary Ramp and Primary Tilting Mechanism 

of Inclined Fuel Transfer Machine of Prototype Fast Breeder Reactor 

Prototype Fast Breeder Reactor employs two machines for 

handling fuel sub-assemblies within and out of the main 

vessel, viz. (i) transfer arm – for in-vessel handling of fuel, 

blanket and control sub-assemblies within the main vessel 

and (ii) inclined fuel transfer machine – for transfer of spent 

sub-assemblies out of the main vessel and replacing them with 

fresh sub-assemblies (Figure 1). The primary side of the inclined 

fuel transfer machine consists of: primary tilting mechanism, 

primary ramp, shield plug, inter connecting piece, bellows and 

primary gate valve. Primary tilting mechanism is bolted to the 

grid plate and primary ramp is located on the primary ramp liner 

of roof slab. The bottom of the primary ramp engages with the 

guide funnel of the primary tilting mechanism to form a sliding 

joint that accommodates the differential thermal expansion 

between primary ramp and primary tilting mechanism from room 

temperature to various operating conditions (normal operation/ 

fuel handling ). The secondary side of the inclined fuel fransfer 

machine consists of secondary gate valve, secondary ramp 

and secondary tilting mechanism, which are located inside the 

fuel building. Primary side and secondary side of inclined fuel 

transfer machine are interconnected through the rotatable shield 

leg, which includes a rotatable table supported on a slewing ring. 

During fuel handling, the spent fuel sub-assembly is loaded 

into the transfer pot, which is inside primary tilting mechanism 

by transfer arm. Transfer pot containing the sub-assembly and 

sodium to remove decay heat from the spent sub-assembly is 

hoisted through primary ramp into rotatable shield leg which then 

rotates by 180 o to engage with secondary side. Transfer pot with 

sub-assembly is then lowered into the secondary tilting 

mechanism thus transferring the spent sub-assembly from the 

in-vessel transfer position located in the periphery of the core 

to the ex-vessel transfer position located in fuel building. The 

transfer pot is then loaded with a fresh sub-assembly and the 

above sequence of operations is then reversed to transfer a fresh 

sub-assembly back into the reactor. 

Two tilting rails and one guide rail are provided on both the 

primary and secondary sides of inclined fuel transfer machine 

and corresponding tilting and guide rollers are provided on 

the transfer pot. The rollers are high temperature ball bearings 

designed to work in sodium. Material selection of rollers and 

hard facing of the rails is based on tribological considerations 

suitable for sodium service. Rails of primary/secondary tilting 

mechanism are designed such that transfer pot is tilted from 

17 o 23 ’ inclination to vertical while lowering in them and 

vice-versa. 

Primary ramp and primary tilting mechanism (Figure 2) were 

fabricated by M/s MTAR, Hyderabad. After completion of shop 

Figure 1: Inclined fuel transfer machine 

Figure 2: Schematic of primary ramp/primary tilting mechanism test 

set-up 

7



Figure 3: Primary ramp with 

primary ramp liner 

Figure 4: Ramp extension piece, 

drive mechanism and support 

structure 

floor testing, performance testing was carried out in test vessel-2 

of the large component test rig under reactor simulated conditions. 

The testing was limited to ~10 % of the total number of cycles 

expected in the reactor life of 40 years as the same components 

are to be installed in the reactor after testing. 

Primary ramp and primary tilting mechanism were assembled in 

test vessel-2 of large component test rig along with additional 

components like ramp extension piece, gate valve, simplified 

hoisting system with support structure and transfer pot with 

dummy sub-assembly. Schematic of test set-up is shown 

in Figure 2. Test vessel-2 is a vessel of 2 meter diameter and 

12 meter height. It is provided with a branch pipe at 17 o inclination 

to simulate the assembly of primary side of inclined fuel transfer 

machine. Primary tilting mechanism was bolted to the grid plate 

inside test vessel-2 while primary ramp was mounted on a 

specially fabricated liner simulating the rigid support in the reactor 

(Figure 3). The entire length of primary ramp was housed in the 

branch pipe at 17 o inclination to vertical. Relative motion between 

primary ramp and primary ramp liner was arrested by two locking 

pins. Transfer pot with dummy sub-assembly was lowered into 

the primary tilting mechanism through primary ramp followed 

by sequential assembly of gate valve and ramp extension piece 

(Figure 4). The top of ramp extension piece was connected to 

the structure supporting the hoisting mechanism through another 

sliding joint with O-ring sealing. The assembly of the primary 

ramp, primary tilting mechanism and ramp extension piece was 

carried out such that inclination of 17 o to vertical of primary ramp, 

ramp extension piece and alignments of the rails were achieved. 

The alignment of guide rails between primary ramp and primary 

tilting mechanism was critical and was achieved within 0.5 mm. 

The hoisting mechanism consists of chain and sprocket 

arrangement, sprocket shaft, motor (3.7 kW, 1440 RPM) with 

brake and speed reduction gear train (helical gears with worm 

reducer, reduction ratio of 1000:1). A torque limiting safety 

coupling is provided between the motor and driving end of 

gear train. The sprocket and sprocket shaft are housed inside a 

leak tight housing with viewing windows. Operation of the test 

set-up was carried out through a control console incorporated 

with safety interlocks. 

The instrumentation provided for the hoisting mechanism 

includes continuous on-line monitoring of transfer pot position 

using potentiometer, automatic stop of transfer pot at top limit 

using reed switch and potentiometer, and at bottom limit using 

tension sensing mechanism, potentiometer, and limit switches to 

identify open and closed positions of gate valve. In addition to 

the above, thermocouples are provided at various locations along 

the vessel, branch pipe and ramp extension piece to monitor 

temperature. An arrangement consisting of dial gauges and 

linear variable differential transformer is provided to monitor the 

deflection of test vessel-2 at the elevation of the grid plate during 

high temperature operation. 

One cycle of testing consisted of the following operations: 

• Hoisting of transfer pot with dummy sub-assembly from 

inside primary tilting mechanism at 29.2 mm/s speed 

(corresponds to motor speed of 600 RPM) from bottom 

position i.e. 22400 to 24279 mm elevation 

• Hoisting through sliding joint between primary ramp 

and primary tilting mechanism at 7.3 mm/s speed 

(corresponds to motor speed of 150 RPM) up to 

29550 mm elevation 

• Hoisting inside primary ramp at 29.2 mm/s speed up to 

29550 mm elevation 

• Hoisting at gate valve location at the speed of 7.3 mm/s up 

to 31400 mm elevation 

• Hoisting inside ramp extension piece at 29.2 mm/s speed 

up to topmost location i.e. 35800 mm elevation. During 

hoisting, transfer pot was parked for 150 s at 29660 and 

32405 mm elevations respectively for siphoning and 

dripping of sodium from it 

• Lowering of transfer pot from top most elevation to bottom 

elevation with different speeds at different elevation as 

mentioned above 

Elevation details of primary ramp/primary tilting mechanism test 

set-up for set value and observed value during testing are given 

in Table-1. 

Performance testing of primary ramp and primary tilting 

mechanism was carried out in various stages viz. in air at room 

temperature, in hot air and in sodium at 200 o C which is the fuel 

handling temperature of Prototype Fast Breeder Reactor. The 

8



Table-1: Elevation details of primary ramp/primary tilting mechanism test set-up 

Position of transfer pot Set point Raising Lowering 

Top 35800 stop by potentiometer signal manual start at 600 RPM 

Dripping 32045 stop 150s for dripping NA 

Speed change-3 31400 speed to 600 RPM speed to 150 RPM 



Bottom 22400 manual start at 150 RPM stop by potentiometer signal 

performance of the system was monitored continuously by 

measuring the current drawn by motor (measure of motor torque) 

and monitoring the system for noise and vibration. A total of 

100 cycles of air testing was carried out at room temperature. 

Current drawn by the motor was within 4.4 A. Measured value 

of torque was within 15 to 16 N-m. No rubbing marks or scoring 

marks were observed on the rails and rollers. Overall performance 

of the system was satisfactory. 

In order to conduct sodium tests, pressure hold test of the 

system was conducted for 24 hours duration with compressed 

air at a pressure of 200 mbar (g). Hot purging was done which 

reduced the moisture and oxygen levels in the system to 118 and 

487 vppm, respectively. Prior to the start of sodium tests, hot air 

test was carried out for 24 cycles at different temperatures of 65, 

95, 110, 125 and 150 o C. Overall performance of the system was 

satisfactory. Current drawn by the motor and torque values were 

well within the acceptable limits. 

In sodium performance testing was carried out at 200 o C. Oxygen 

level in sodium was maintained to less than 2 ppm. The effect of 

reactor operation at rated temperature of 547 o C on the aerosol 

deposition in cold regions like gate valve was also simulated 

by means of two dwell period tests each of 150 hours duration 

at 547 o C. The dwell periods were interspersed between the 

cyclic tests. The system was tested for a total of 510 cycles in 

sodium. The performance of the system was along expected 

lines. Maximum current drawn by the motor was within 4.5 A. 

Measured values of torque were within 14 to 19 N-m. 

(a) 

(b) 

After completion of the testing, the sodium in test vessel-2 was 

drained and vessel cooled to 60 o C. Test vessel-2 was isolated 

from large component test rig loop and connected to a specially 

fabricated system for sodium removal using water vapor-CO 2 

process. The cleaning process was very effective (Figure 5). A 

total of 3 kg of sodium was removed by this method. The value 

obtained experimentally (from H 2 

monitoring during the process) 

was close to that obtained by estimation. The time taken for vapor 

phase reaction was 85 hours. The vapor phase reaction was 

followed by water wash using fine spray followed by washing in 

distilled water in a jet facility erected for the purpose as well as in 

a specially fabricated water tub. The rollers of transfer pot were 

dismantled and cleaned in ultrasonic bath. 

After cleaning and drying, primary ramp and primary tilting 

mechanism were inspected by Quality Assurance Division. Visual 

examination of the primary ramp and primary tilting mechanism 

revealed no scoring or rubbing marks on the rails. The weld 

between the primary tilting mechanism body and base plate 

was subjected to liqiud penetrant inspection examination and 

found to be defect free. Liqiud penetrant inspection examination 

of accessible portion of the primary ramp and primary tilting 

mechanism rails indicated absence of cracks. All screws holding 

the rails of primary tilting mechanism and primary ramp to the 

body were tack welded and the components cleaned by acetone, 

packed and dispatched to BHAVINI. 

The successful completion of the performance testing of primary 

ramp, primary tilting mechanism in air and sodium, and the 

effective in situ removal of sodium from primary ramp and primary 

tilting mechanism by water vapor and CO 2 

process have qualified 

the component for reactor operations. Visual examination followed 

by the subsequentliqiud penetrant inspection examination of 

components after cleaning has confirmed the healthiness of the 

components. 

Figure 5: Primary tilting mechanism inside the test vessel a) before 

reaction and b) after reaction 

Reported by B.K.Sreedhar, Fast Reactor Technology Group and 

S.Raghupathy, Reactor Design Group 

9



Science of Metal Nanoclusters 

Now it may be the time we say goodbye to the well-known 

old proverb: Big is Beautiful. Almost everyday the world is 

witnessing advancement and breakthrough discoveries that 

lead to miniaturization of devices through the knowledge of 

nanoscience and nanotechnology. 'Nano' is a generic buzz-word 

in this context. As we know, nanomaterials are nothing different 

from the parent phase of materials except its’ physical dimension 

ranges between 1-100 nm (1 nm=10 -9 m), at least in one direction. 

At the nanoscale, physical, chemical and biological properties 

of materials differ from the properties of individual atoms and 

molecules or bulk matter. That brings up spiraling applications 

of various nanoscale materials in almost every sphere of life. So, 

understanding the science of synthesis and novel properties of 

matters at nanoscales is one of the most active areas of research 

today. It brings out abundance of unexpected results to ponder. 

In this perspective, metal nanoclusters that form an important 

class in the world of nanomaterials may deserve special attention 

for a comprehensive research study. Metal nanoclusters may be 

synthesized as embedded in various matrices or supported on 

functional substrates of interest. Synthesis of metal nanoclusters 

and nanostructures has been broadly classified according to two 

approaches: bottom up and top down. As the name suggests, 

the first method deals with techniques where nanoclusters are 

grown from single atom onwards. Top down approaches start 

exactly in the reverse way: from bulky crystals to nanocrystals of 

nanoclusters. Thus, there are some successful techniques for the 

processing of such novel materials, for example, metal dielectric 

co-sputtering, recoil-implantation, molten salt bath, direct 

implantation of metal ions, sol-gel, evaporation-condensation, 

electron beam lithography, optical lithography, ion-beam 

induced sputtering, etc. Controlled synthesis of size-selective 

metal nanoclusters in various media is of prime importance as 

most of the exotic properties depend primarily on their physical 

dimensions. To realize a better control on the preparations, basic 

understanding of the mechanisms governing formation and 

evolution of metal nanoclusters while processing these novel 

materials is of great interest. 

Rich phenomena such as strong optical responses in the 

ultraviolet-visible to near infrared wavelength ranges of light, 

photoluminescence, local field enhancements, etc. are associated 

with metal nanoclusters and nanostructures. Interaction of 

visible light with surface electrons of metal nanoclusters, for 

example, leads to fascinating colors of glasses through an optical 

phenomenon (known as surface-plasmon resonance). Colors of 

the glass depend on size, shape and number density of the metal 

nanoclusters as well as on dielectric constants of the media. In 

addition, this optical effect leads to large local field enhancements 

in the close vicinity of metal nanoclusters. These novel physical 

Figure 1: Photographic image shows the change of optical features of 

the silver-exchanged soda-glass samples due to the isochronal heat 

treatments 

effects have been motivating fundamental and experimental 

researchers for a long time extensively. Such research driven 

challenging applications of the plasmonic nanostructures 

are numerous. For example, fast-response optical switches, 

high sensitivity nanosensors, information storages, chemical 

catalysis, tumor or cancer diagnosis and treatments, surfaceenhanced 

Raman spectroscopy, solar cell materials and so on. 

Accordingly, besides their exciting scientific and technological 

interests, research studies of nanoscale materials are becoming 

highly relevant in diverse disciplines including biology and 

medicines. However, there are several difficulties in handling, 

detection and measurements of such tiny materials due to their 

physical restrictions. 

Embedded Metal Nanoclusters in Glass Matrices 

Nanoscale silver clusters have been prepared in a soda-glass 

matrix through the silver ion-exchange (Ag + ↔ Na + ) process. 

Ion-exchange of various metal ions in soda glasses followed 

by thermal annealing or light ion irradiations (H + , He + ) are 

methods to modify linear and nonlinear optical properties of 

glasses. The method is commercially viable for applications in 

optoelectronic devices. Due to the technological importance, 

precise spectroscopic studies to elucidate the thermal stability 

of these optical nanomaterials are of great interest. A simple 

photograph is shown in Figure 1 to demonstrate how the colors 

have changed due to the given heat treatments. As seen, with 

the increase of annealing temperature, samples have darkened 

significantly. Darkening, or in other words, increase in the opacity 

implies that optical absorption density has increased consistently 

with the annealing temperature. This qualitative visual observation 

conforms to the precise experimental results of optical absorption 

spectroscopy (Figure 2b). Metal nanoclusters are experimentally 

identified through the characteristic optical resonance (surfaceplasmon 

resonance) wavelengths. In case of Ag nanoclusters in 

a glass matrix, surface-plasmon resonance position is ~420 nm. 

10



(a) 

(b) 

Figure 2: (a) Photoluminescence (with 488 nm excitation) and (b) 

optical absorption spectroscopy of Ag nanoclusters in the matrix 

Figure 3: Rutherford backscattering spectra of silver-exchanged sodaglass 

samples annealed at (a) 320, (b) 450, (c) 550 and (d) 600 o C 

Increase in the absorption intensity with the increase of annealing 

temperature is attributed to the thermal growth of the silver 

nanoclusters in the glass matrix. The observed growth may be 

explained from Mie theory of light scattering. Assuming average 

size of metal nanoclusters to be much smaller than the optical 

wavelength, Mie theory calculates the resonance absorption 

intensity to scale up with volume fractions of metal nanoclusters. 

Photoluminescence spectroscopy results corroborate further 

with the growth of the silver nanoclusters. For example, drastic 

changes in the photoluminescence intensity have been observed 

on post-annealing the silver-exchanged glass samples at various 

temperatures (Figure 2a). Silver monoxide (AgO) formed in the 

as-exchanged soda-glass sample is chemically unstable and it 

decomposes into species like Ag 2 

O and Ag while annealing in 

vacuum around 380 o C. Further increase of annealing temperature 

only helps in the growth of the Ag nanoclusters due to thermal 

decomposition of Ag 2 

O. As a result, the photoluminescence 

intensity quenches (Figure 2a). A strong correlation of the 

growth of the silver nanoclusters and drastic changes in the 

photoluminescence intensity due to thermal annealing of the 

silver-exchanged glass samples has been so established. 

Rutherford backscattering experiments have been carried out in 

these samples to measure the concentration profiles of Ag after 

thermal annealing (1 hour isochronal) at various temperatures. 

An analyzing beam of He + ions at energy of 2 MeV, backscattered 

by an angle of 160 o , was used during the backscattering 

measurements. It is observed from the backscattering spectra 

(Figure 3) that silver got accumulated near the surface of the glass 

during the annealing. Accumulation of silver is higher for samples 

annealed at higher temperatures. Near-surface (within~100 nm) 

accumulation is due to the thermal diffusion of silver ions in the 

soda-glass matrix. This outward diffusion of silver ions relaxes 

the stress (which arises due to size difference of Ag + and Na + 

ions) and minimizes the total energy in the system. Applying 

suitable diffusion theory to the Rutherford backscattering data, 

it has been possible to estimate activation energy for thermal 

diffusion of silver ions in the soda-glass matrix. This short-range 

accumulation of silver ions during annealing allows to consider 

the case as a semi-infinite diffusion system with the bulk acting 

as a constant source of known density (say,c 0 

). Accumulated 

mass of silver per unit area (m) on the surface can be calculated 

as, m = c Dt 

0 p where t is the time of diffusion in the sample held 

at temperature T; D is the diffusion coefficient of silver ions at 

ε a − 

kT 

temperature T. Assuming D to vary as e (ε a 

is the activation 

energy for the diffusion of silver ions and k is the Boltzmann 

constant), m can be rewritten as, 

ε 

a 

ln( m) 

= K1 

− 

2kT 

(1) 

where k 1 

is a constant in the present experimental conditions. 

For samples annealed at different temperatures, m has been 

estimated using the expression m = N 

A 

M / NAvo. 

where 

N A 

(number of Ag atoms/cm2 ) is directly obtained from the 

backscattering data, M is the atomic weight of silver and N Avo 

is the Avogadro number. Plugging the Rutherford backscattering 

data in equation (1), the Arrhenius plot is reported. From the slope 

of the fitted line, activation energy for the diffusion of silver ions in 

the soda-glass is estimated to be about 0.74 eV. 

Apart from the chemical routes, ion implantation has been a very 

popular technique to synthesize metal nanoclusters in various 

matrices. In general, ion implantation techniques provide distinct 

advantages over many other synthetic processes, because: 

embedded species are protected by the matrix and hence 

chemically clean, superior control over depth as well as size 

distributions and the process is not limited by the solubility factor 

of the matrix. As the first example, nanoscale cobalt clusters 

have been synthesized in a silica glass matrix by implanting high 

energy (2 MeV) cobalt ions. Optical and vibrational properties 

of the cobalt nanoclusters are particularly interesting. Surfaceconfined 

acoustic vibration modes (phonons) of these cobalt 

nanoclusters have been detected using the low-frequency 

Raman scattering spectroscopy. Raman scattering spectroscopy 

11



Figure 4: Raman scattering intensity of surface acoustic vibrational 

modes confined to cobalt nanoclusters as a function of excitation 

wavelengths (spectra are offset along the intensity-axis for better 

clarity) 

has been used extensively and effectively as a nondestructive 

experimental means to study the ion implantation-induced 

growth as well as the thermal growth of the metal nanoclusters 

in various glass matrices. As shown in Figure 4, Raman spectra 

have been recorded in the cobalt implanted silica sample using 

different excitation wavelengths. Interestingly, intensity of 

the vibrational modes is found to depend significantly on the 

wavelength of laser excitations (Figure 4). Strong local field of 

surface-plasmon resonance in cobalt nanoclusters with 351.1 nm 

excitation wavelength is thought to be the reason for the observed 

enhancement of Raman scattering intensity. It is because 

the characteristic surface-plasmon resonance wavelength of 

cobalt nanoclusters in silica is around 350 nm. Results thus 

obtained from the Raman scattering spectroscopy experiments, 

particularly, emphasizes the importance of plasmon-phonon 

coupling in the metallic nanoclusters. 

Figure 5: Rutherford backscattering spectra for silver ion implanted 

soda-glass samples with various ion fluences (indicated with symbols) 

In a similar way, using the ion implantation (1 MeV Ag + ions) 

technique, growth of embedded nanoscale silver clusters in a 

soda-glass matrix has been studied mainly to highlight interesting 

optical properties of large scale metal nanoclusters. Prior to the 

discussion on the optical results, information about concentration 

profiles of silver atoms in the soda-glass samples measured 

by the backscattering spectrometry (Figure 5) would be more 

important. Only the partial spectra at high energy channels are 

shown here to emphasize the backscattering from silver atoms. 

Interestingly, in the sample implanted with the highest fluences, 

most of the concentration of the silver atoms is found to be 

close to the glass surface (Figure 5, blue dots) and the atomic 

concentration of silver reduces continuously along the depth in the 

soda-glass matrix. Defect-enhanced diffusion of Ag atoms in 

the soda-glass matrix would lead to the segregation of the Ag 

atoms close to the glass surface. Surface segregation of the Ag 

Figure 6: Ag + ion implanted soda-glass sample with fluences 5 x 10 16 ions cm -2 (Figure a) and ion-beam sputtered (5 x 10 16 Ar + ions cm -2 ) thin film of Ag 

metals on silica glass (Figure c) show dipolar as well as quadrupolar surface-plasmon resonance absorption in samples with larger Ag nanoclusters. 

Only dipolar absorption has been observed for Au thin films sputtered with Ar + ions (5 x 10 16 ions cm -2 ) (Figure b). Corresponding scanning electron 

micrographs display morphologies and various sizes of the Ag and supported Au nanoclusters on the glass substrates. 

12



Figure 7: Rutherford backscattering spectra of the Au film and Ar + ion 

irradiated Au films as a function of fluences (partial spectra to emphasize 

the backscattering from Au are only shown) 

atoms has been confirmed further by the electron microscopy 

measurements (Figure 6a). The microscopy results particularly 

support the observed backscattering results, i.e., the increase 

in the Rutherford backscattering yield as well as the shift in 

the concentration profile of Ag atoms (Figure 5) close to the 

glass surface. In this sample, large clusters of silver atoms 

(sizes ~100 to 200 nm) have been estimated. These largescale 

silver nanoclusters play a dominant role in modifying the 

optical absorption properties. For example, intensity and the 

width of the surface-plasmon resonance are greatly modified, 

as it is clearly observed in the spectral response characteristics 

(Figure 6a). With increasing cluster sizes, additional higher-order 

(e.g., quadrupole) optical resonances become important because 

of the non-zero field gradient across the metal clusters. The 

optical results reveal a shoulder on the low wavelength side of 

the dipole peak. This was assigned to the quadrupolar resonance 

peak (inset, Figure 6a and Figure 6c). 

Supported Metal Nanostructures on Glass Substrates 

Ion-beam sputtering based non-equilibrium synthesis (top 

down approach) is a promising method leading to production 

of tailored nanoclusters as well as nanostructure materials on 

given substrates. The ion-beam sputtering based processing 

is also of interest because it is cost-effective compared to 

direct-write techniques, such as optical or electron beam 

lithography. Ion sputtering is a physical process whereby atoms 

are ejected from the surface due to bombardment of the target by 

energetic particles. It is driven by momentum transfer between 

the ions and atoms in the materials during the atomic collisions. 

In the present case, gold (Au) as well as silver (Ag) metallic films 

were deposited separately on cleaned silica substrates using the 

thermal evaporation set-up. Subsequently, the metal films were 

irradiated using the 100 keV Ar + ions with various ion fluences. 

Rutherford backscattering experiments have been carried out to 

measure the areal density of Au atoms in the as-deposited Au film 

as well as in the ion irradiated Au film samples. Figure 7 displays 

the backscattering spectra of the samples. Systematic decrease 

Figure 8: Log-Linear plot of areal density of Au atoms as a function of 

fluences of the Ar + ions (experimental data points (•) are obtained from 

the backscattering results) 

of the backscattering yield with the increase of Ar + ion fluences 

may be observed. The decrease of area under the Au peak (which 

is proportional to the Au areal density) with increase of Ar + ion 

fluences confirms the loss of Au atoms from the films due to the 

ion sputtering processes. This particular experimental aspect is 

explained here. To describe the observed experimental facts in a 

quantitative way in the case of sputtering of a thin film by the ionbeam, 

a phenomenological model equation is proposed: 

dN 

T 

= −kN 

where dN T 

is the reduction (due to the sputtering) of Au areal 

density on the substrate. Intuitively, the loss should be 

proportional to the instantaneous available areal density of Au 

atoms (N T 

) and the associated increment of the ion-fluences (dø). 

The above differential equation is readily solved to obtain, 

ln( N T 

) = −kφ 

+ c 

T 

dφ 

( 2) 

( 3) 

Phenomenological constants, k and c would depend on the 

projectile ions, ion-beam and target material parameters. 

Experimentally measured areal density of Au atoms (N T 

) is plotted 

against the respective ion-fluences (ø) (shown in Figure 8 as a 

log-linear graph). This result clearly shows that during sputtering 

of the Au thin films, areal density of Au atoms decreases 

exponentially with the increase of ion-fluences, as prescribed by 

the equation 3. 

Presence of the metallic nanoclusters in the ion-beam sputtered 

samples has been elaborated through the optical absorption 

spectroscopy and electron microscopy results (Figure 6b 

and 6c). The optical response peak around 550 nm is attributed to 

the surface-plasmon resonance absorption in Au nanoclusters on 

silica substrates. Electron microscopy results show that nearly 

uniform size (~50 nm) of Au nanoclusters are produced on silica 

due to the ion-beam induced sputtering process. 

Reported by P. Gangopadhyay and colleagues 

Materials Physics Division 

Materials Science Group 

13


Young Officer's Forum 

Young Officer’s 

FORUM 

Design of Elliptical Heat Exchanger 

for Future Fast Breeder Reactors 

The commercialization of fast breeder reactor programme needs 

further optimization of the reactor components for the future 

fast reactors. A considerable portion of the total cost of the pool 

type fast reactor, goes into the material cost which is a function 

of dimensions of the main vessel, which is in turn decided by 

reactor internals. Main vessel dimensions are controlled by the 

diameter of the intermediate heat exchanger and pump in both 

circumferential and radial directions. Diameter of the pump is 

optimised for its performance; further reduction is not possible 

without major design changes. With the dimension of the pump 

as basis, the shape of intermediate heat exchanger is optimised 

for the most economical configuration. 

A novel shape is proposed for the intermediate heat exchanger 

of future fast breeder reactor considering the techno-economical 

feasibilities. Optimization of the configuration of intermediate 

heat exchanger for the most economical benefit is brought out 

in this report along with detailed process design of intermediate 

heat exchanger with a design life of 60 years at 85% load factor. 

The intermediate heat exchanger is a vertical counter current 

flow, shell and tube heat exchanger with primary sodium flowing 

downwards on the shell side and secondary sodium flowing 

upwards on the tube side. Each intermediate heat exchanger 

Shri V. Sudharshan took his B.E. degree 

in Mechanical Engineering from Andhra 

University. He is the Homi Bhabha Award 

winner for topping the Mechanical 

Engineering discipline from the 4 th batch 

of BARC Training School at IGCAR and is 

currently Scientific Officer (C) in Reactor 

Components Division, Reactor Design Group. He is responsible for 

the design of sodium – sodium heat exchangers. 

(Figure 1) is rated for 314.7 MW (t) and consists of a tube bundle 

having straight tubes. Each tube is 8050 mm and is made of 

austenitic stainless steel SS316LN, rolled and welded to the tube 

sheets at both the ends (Figure 1). The tubes are arranged in 

a circumferential pitch around an inner shell. This inner shell is 

welded to the tube sheets at both the ends. 

Choice of Intermediate Heat Exchanger Shape 

The reactor assembly proposed for future fast breeder reactors 

is shown in Figure 2. If the opening for the pump at the roof slab 

level is made to be the governing parameter for the main vessel 

diameter, diameter of main vessel can be further reduced by 

~300 mm. This is possible based on the fact that area available 

for the heat transfer to take place is the parameter and not the 

shape of the heat exchanger especially for liquid metals. With 

this factor as the basis, the area available in the reactor assembly 

is studied for other parameters like interface of internals etc. and 

it is concluded that the maximum dimensions available for heat 

exchanger for a 500 MWe, two loop design with two intermediate 

heat exchanger per loop, are 2140 mm along the circumference 

and 1550 mm along the radial direction for the outer shell 

dimensions. With these dimensions, the possible configurations 

for intermediate heat exchanger shape are worked out and the 

final shapes that are considered for the study are elliptical, oval 

1.Pump 

2.Intermediate heat 

exchanger 

3.Control plug 

4.Top shield 

5.Rotatable plugs 

6.Core 

7.Core support structure 

8.Main vessel 

9.Safety vessel 

10.Reactor vault 

Figure 1: Intermediate heat exchanger for future fast breeder reactors 

Figure 2: Reactor assembly of future fast breeder reactors 

14



Figure 3: Comparison of possible shapes for intermediate heat 

exchanger 

and bean/kidney as shown in Figure 3. 

With two different dimensions along the axes, ellipse appears to 

be a natural choice, but a close examination of Figure 3 shows that 

by adopting kidney shape there is overall optimization of space. 

Kidney shape though utilises the maximum space available, is 

made of segments with different centres that pose problems 

during manufacturing. Further its advantage over the oval shape 

is also minimal. So the oval shape which is a simple extension 

of circular shape with a horizontal portion connecting two semicircles 

is preferred as the shape of intermediate heat exchanger 

for future fast breeder reactors. With oval shape, the scheme for 

the ferrule and anti-vibration belt shall be retained same as that 

for the intermediate heat exchanger of Prototype Fast Breeder 

Reactor. Once the outer shell shape (shape of intermediate heat 

exchanger) is decided, the next parameter is to decide upon the 

shape of the central down comer, through which the secondary 

sodium enters the intermediate heat exchanger. The governing 

parameter for the choice of down comer is that the velocity of 

sodium in the down comer must be restricted to a maximum 

of 9.0 m/s due to erosion of structural material in intermediate 

heat exchanger. Since this is a limiting value, it is retained as a 

guiding parameter to arrive at other parameters for intermediate 

heat exchanger. 

Design Constraints 

1. Maximum pressure drop on shell side (H) = 1.45 mlc Na 

2. Maximum dimension of intermediate heat exchanger outer 

shell (shroud) = 2140/1550 mm 

The other design constraint is the maximum heat transfer length. 

Table 1: Chemical composition of SS316LN (balance-iron) 

Element C N Cr Ni Mo Si Mn S P 

Compositionw(wt%) 0.03 0.085 16 11.2 2.0 0.6 1.3 0.005 0.042 

Table 2: Chemical composition of nuclear grade sodium 

Impurity element O C CI Ca+Mg Fe 

Content, ppm



Figure 5: Graphical representation of 

feasibility study 

It is recommended that the corrosion allowance for 60 year 

design life of intermediate heat exchanger is 0.114 mm. Analysis 

and design of components is proceeded accordingly. 

Prototype Fast Breeder Reactor intermediate heat exchanger 

tube thickness is 0.8 mm and margin on thickness is 0.2 

mm, comprising of both corrosion allowance and negative 

tolerance on tube diameter (10%). Studies also show that for 

Prototype Fast Breeder Reactor, the unaffected base thickness 

of 0.6 mm is adequate for all loadings for 40 year design life. 

Further, optimization studies are planned to reduce the pressure 

transmitted to intermediate heat exchanger tube designed for 

60 year design life based on 0.6 mm unaffected base thickness. 

Considering possible uncertainty, 0.8 and 1 mm thick tubes 

are selected for optimization of intermediate heat exchanger 

configuration. 

Parametric Study on Process Design of Intermediate Heat 

Exchanger for Tube Selecton 

A parametric study is conducted for the selection of tube size 

and arrangement for the specially shaped intermediate heat 

exchanger to check feasibility and optimization with the tube 

sizes (OD/THK), 14/1, 14/0.8, 16/1, 16/0.8, 19/1, 19/0.8, 

24/1 mm. A computer code is written for this purpose and is 

validated with Prototype Fast Breeder Reactor values. Ratio of 

the circumferential pitch and radial pitch (Sc/Sr) = π/3, which is 

adopted same as that for Prototype Fast Breeder Reactor, as the 

arrangement of tubes in the sodium to pass through is turning out 

to be same for any of the other configurations which are made 

to exploit the symmetry in the geometry of the systems which is 

60 0 for Prototype Fast Breeder Reactor and 90 0 for the present 

intermediate heat exchanger. The study included a feasibility study 

for the mentioned sizes which means simultaneous satisfaction 

of all the design constraints and the options are further studied 

for optimising the convex region, which gives most economic 

Figure 6: Variation of number of tubes in 

Intermediate heat exchanger as a function of 

radial pitch 

Figure 7: Variation of shell side pressure drop 

as a function of radial pitch 

benefit. Results of feasibility study is shown in a graph in the 

Figure 5. Variation of optimization parameters with respect to 

tube size and radial pitch for the feasible options (tube size) are as 

shown in the Figures 6, 7 and 8. All the configurations are studied 

from OD+5 mm since at least a 5 mm ligament is required for the 

tube sheet to prevent tearing. Study for 16/0.8 case is carried out 

to with Sr < OD + 5 mm to study the behaviour in that range. 

19/0.8 mm with radial pitch 25 mm is selected as the best suited 

option from economic considerations (material and manufacturing 

costs) for the future fast breeder reactors, the next option being 

16/0.8 and 22 mm radial pitch. Table 3 gives a comparison of 

intermediate heat exchanger configuration for the Prototype Fast 

Table 3: Comparison of intermediate heat exchanger configuration for 

Prototype Fast Breeder Reactor and future fast breeder reactors 

Parameter PFBR Future FBR 

Design life (Y)/cap. factor 40/75% 60/85% 

Number of tubes 3600 3680 

Tube diameter/thickness (mm) 19/0.8 19/0.8 

Number of rows 25 23 

Number of tubes in first row 72 94 

Corrosion allowance (mm) 0.12 0.142 

Shroud dimensions (mm) 1850 2140/1550 

Area margin 24% 28% 

Average primary inlet velocity (m/s) 0.377 0.362 

Velocity of secondary sodium in down 

comer (m/s) 

9.2 7.36 

Shell side pressure drop (mlc Na) 1.45 1.39 

Velocity of secondary sodium in down 

comer (m/s) 

9.2 7.36 

Shell side pressure drop (mlc Na) 1.45 1.39 

Main vessel diameter (m) 

* with oval Intermediate heat 

exchanger 

12.9 11.9* 

16



Figure 8: Variation of available down comer flow 

area as a function of radial pitch 

Figure 9: Average axial temperature profile in 

intermediate heat exchanger 

Figure 10: Radial and circumferential temperature 

distribution in tube bundle 

Breeder Reactor and future fast breeder reactors. 

Thermal Hydraulic Investigation on the Intermediate Heat 

Exchanger 

Intermediate heat exchanger is a counter current heat 

exchanger with primary sodium flow on the shell side and 

heat transfer area is based on the outer diameter of the tube, 

whereas in the actual scenario heat transfer takes place by 

a combination of cross flow and counter current parallel flow. 

These 3-Dimensional features contribute to uncertainties 

in the design vis-a- vis assumptions, correlation, by-pass 

flow near shells (inner and outer shells) etc. Taking these into 

consideration and the possibility of plugging of a few tubes during 

manufacturing, it has been estimated from the CFD studies that 

28% area margin on the rated value is required to overcome 

the uncertainties in thermal design for Prototype Fast Breeder 

Table 4: Comparison of Analytical and CFD results 

Parameter 

Analytical 

Result 

CFD Result 

Deviation 

% 

Heat flux Primary 313.18 MW 319.541 MW + 2.03 

Secondary 313.25 MW 319.538 MW + 2.0 

Mass flux Primary 1649 Kg/s 1648.465 Kg/s - 0.03 

Temperature 

Secondary 1450 kg/s 1450 Kg/s 0 

Primary 

inlet 

Primary 

outlet 

Secondary 

inlet 

Secondary 

outlet 

Pressure drop on shell 

side 

817 K 817 K 0 

667 K 664.1 K -0.4 

628 K 628 K 0 

798 K 801.567 K + 0.45 

11479.679* 

Pa (1.3926 

mlc) * 

11456.191 Pa 

(1.3898 mlc) 

*Considering 10% uncertainty margin for correlations 

-0.2 

Reactor. The same has been adopted in the present study. 

Since the shape is non-circular, there is a possibility for a 

non-uniform flow along the circumferential direction in addition to 

the maldistribution of flow that is happening in the radial direction 

(to the shells) due to the cross flow entry of the primary sodium. 

There can be flow distribution along the peripheral and axial 

direction in the hot pool at intermediate heat exchanger inlet. In 

order to check the adequacy of design margin for the heat transfer 

owing to various uncertainties mentioned earlier, a CFD for a 90 0 

sector model study simulating the full load operation has been 

carried out. Table 4 gives the comparison of analytical results 

with CFD results. The results confirm that the provisions in the 

design are sufficient for the specified rating and the pressure 

drop on the shell estimated using correlations and that calculated 

by CFD simulation are matching within a deviation of 0.2%. This 

sufficiently validates the analysis. Average axial temperature 

distribution is shown in the Figure 9. The heat transfer process 

in the intermediate heat exchanger at various elevations with 

zero meter elevation as the bottom of the top tube sheet and 

-7.75 meter elevation as the top of the bottom tube sheet is 

depicted in the graph. Outer shell is present between the two 

windows, starting at -1 meter elevation, spanning 5.7 meter. 

Figure 10 shows the average temperature of tubes estimated at six 

different locations along with weighted average row temperature 

of tube bundle. 

Summary 

Elliptical intermediate heat exchanger for future Fast Breeder 

Reactors is optimized for achieving overall economics and 

compactness. Detailed 3D thermal hydraulic investigations 

on 90° symmetry sector of intermediate heat exchanger 

conforms the adequacy of design margins for various process 

parameters such as heat transfer area, pressure drop, etc. 

Reported by V. Sudharshan 

Reactor Components Division, Reactor Design Group 

17


Young Researcher’s 

FORUM 

Enhanced Transmission with Tunable Fano 

like Profile in Magnetic Soft Matter 

Resonance exhibiting distinctly asymmetric line shape, well 

known as Fano resonance is a ubiquitous phenomenon observed 

in various condensed matter systems such as quantum dots, 

carbon nanotubes and graphene etc. The observation of the 

enhanced transmission with Fano shape in perforated metallic 

films have also attracted enormous attention due to their 

application in molecular sensing, spectroscopy, photonic 

devices etc. besides fundamental understanding. The observed 

enhanced transmissions, in perforated periodic and aperiodic 

metallic systems are attributed to surface plasmon and localized 

waveguide resonances, respectively. However, the exact origin of 

enhanced transmission and Fano resonance is still not very clear. 

Moreover, till now all the Fano resonances are observed only in 

systems with well-engineered structures. Soft matter systems like 

nanofluids have been a topic of intense research during the last 

one decade due to their interesting properties and technological 

applications. The issues that we tried to address here are the 

following: (i) can Fano resonance be realized in a smart soft matter 

with aperiodic or random tubes and (ii) is it possible to tune the 

Fano profile using external stimuli like magnetic field. We provide 

first experimental evidence of Fano resonance in soft matter. 

Under an external magnetic field, the transmittance spectrum 

of a ferrofluid emulsion containing oil droplet size (diameter) of 

~ 220 nm (polydispersity < 2 %) shows an enhanced peak 

with Fano-like profile, which is attributed to localized waveguide 

resonance from random array of tubes, with charged inner 

surface, formed by the alignment of magnetically polarizable 

droplets. Further, by varying the magnetic field, the Fano profile 

is tuned and an opaque emulsion is turned to a transparent one. 

This finding will have interesting applications in tunable photonic 

devices. 

The ferrofluid (ff) emulsion used in our studies is octane oil 

droplets containing magnetic (Fe 3 

O 4 

, d ~ 6.5 nm) nanoparticles 

dispersed in water. The oil droplets are electrostatically stabilized 

with an anionic surfactant of sodium dodecyl sulphate. On 

applying an external magnetic field H 0 

, the strength of interaction 

between the droplets increases, which is described by the 

Young Researcher's Forum 

Mr. Junaid Masud Laskar did his Masters in 

Physics from Tezpur University, Assam. He is the 

University third rank holder for M.Sc. He joined 

as a research fellow in January 2006 under the 

guidance of Dr. John Philip, Head, SMARTS, MMG 

and has submitted his Ph.D thesis in September, 

2011 to the University of Madras. The title of his 

thesis is “Probing of Structural Transitions in Magnetically Polarizable Soft 

Matters by Light Scattering”. He has published eight papers in reputed 

international journals. He has attended six international conferences and 

won the best poster presentation award at Second International Conference 

on Frontiers in Nanoscience and Technology, Cochin. Presently, he is 

pursuing his post doctoral research at the prestigious Max Planck Institute 

for Polymer Research, Mainz, Germany. 

3 2 2 

coupling constant L = pµ 0 

d χ H0 

72kBT 

where χ and k B 

T 

are the magnetic susceptibility and thermal energy respectively. 

When L > 1, the emulsion undergoes disorder-order structural 

transition, where linear chain-like structures are formed due to 

head on aggregation of oil droplets along H 0 

. To obtain insight into 

the implications of field induced structures, the transmitted light 

intensity is recorded as a function of H 0 

at different ramp rates 

using an automated light scattering set-up. The ff emulsion of 

volume fraction f =0.0033 is observed to be opaque to red light 

(He-Ne Laser, λ=632.8 nm) for cuvette of path length L=1 mm. 

This scattered light emerges from the exit face of the cuvette 

in the form of a cone, which originates from the scattering of 

incident light from the cylindrical surface of field induced chains. 

Figure 1(a) shows the images of the exit face of the cuvette that 

contains the sample, at different H 0 

. The intersection, of this cone 

of scattered light, on a screen placed at far field and perpendicular 

to the incident light forms a ring like pattern as shown in 

Figure 1 (c). A bright spot is also observed on the upper right 

Figure 1: (a) Images of transmitted light as a function of magnetic 

field during increase (ramp rate ~0.6 G/s) just at the exit face of 

quartz cuvette, which contains the ferrofluid emulsion, (b) Variation 

of transmitted light spot [top right corner of ring circumference of (c)] 

intensity during increase in magnetic field for different ramp rates, 

(c) Scattered patterns at four different fields during the increase at three 

ramp rates of 0.6, 1.67 and 10 G/s 

18



part of ring circumference, which is the transmitted light spot in 

the direction of incident light. Figure 1(b) shows the intensity 

variation of this transmitted light spot as a function of increasing 

H 0 

at different ramp rates. The emulsion remains opaque to the 

incident light upto a H 0 

of 50 G, above which the transmitted 

intensity increases with the increase in H 0 

. For low ramp rate 

(0.6 G/s), the transmitted intensity again decreases above 150 G 

with increase in H 0 

. 

Considering the emulsion as a system of random scatterers, the 

transmitted light intensity for a path length L is given by 

I = I exp ( − nQ p 2 

t 0 ext 

a L) 

where I 0 

, a, n and Q ext 

are the 

incident light intensity, scatterer radius, scatterer number density, 

scattering extinction efficiency respectively. The Q ext 

is calculated 

using Mie scattering theory as a function of size parameter (ka) 

and is found to be very high for the ferrofluid emulsion, where the 

scatterer (oil droplet) radius a=110 nm i.e. ka =1.45. At H 0 

=0 G, 

the calculated incident light transmitted intensity I t 

/I 0 

for the given 

system is found to be very small (~ 2.9113×10 -46 ). Therefore, 

significant scattering from the oil droplets in the emulsion forbids 

the light transmission in the absence of any magnetic field. 

On application of H 0 

, due to the aggregation of oil droplets, the 

internal structure inside the ferrofluid emulsion looks like array 

of random tubes (diameter D ~ λ) as shown in Figure 2. Now, 

the behavior of light transmission as a function of H 0 

, through the 

above mentioned structural arrangement, is basically influenced 

by two factors. First, the effect of change in light scattering due 

to changing chain length and secondly, the effect of changing 

dimensions of tubes, both tube diameter (D) and tube length (z). 

With the increase in H 0 

, due to the increase in chain length by the 

aggregation of oil droplets, the space between the chains i.e. the 

tube diameter also opens up. 

This structural rearrangement takes place for the uniform 

distribution of the field induced structures through out the entire 

volume of the sample. In fact due to opening up of the tubes and 

increase in their diameter, effective scattering cross section of 

Figure 2: Schematic of ff emulsion at (a) H 0 

= 0 G, (b) 60 G < H 0 

< 

300 G, the array of chains and tubes and their dimensional variation as 

function of external magnetic field strength, arrow shows the direction 

of incident light and magnetic field, (c) cross sectional view of field 

induced tubes; (d) optical microscopic image of the cross sectional 

view of chains under external field, inset shows the chain formation 

along the field direction 

the system decreases, which results in increase in transmitted 

light, thereby making the transition of the system from opaque 

to transparent above 50 G as shown in Figure 1(b). Therefore, it 

is clear from this observation that the above mentioned second 

factor dominates over the first one on the light transmission 

behavior under external field. 

The specialty of the field induced tubes are discussed in detail 

further. Because of the negatively charged anionic head group 

of surfactant sodium dodecyl sulphate and free π electrons 

present, the inner tube surfaces are highly charged with a typical 

charge density 500 µC/cm 2 (10 12 /cm 2 in terms of electron 

number density), so that electric and magnetic fields of incident 

electromagnetic wave cannot penetrate the inner surface, thereby 

making the tubes behave like waveguides. Now, the system 

looks like an array of aperiodic random tube waveguides, whose 

dimensions are function of H 0 

. The transmitted wave amplitude 

decreases exponentially along the waveguide as exp(-α w 

z) due 

to the finite impedance of inner charged walls of the waveguide, 

where α w 

and z are the waveguide damping coefficient and 

waveguide length respectively. This causes the decrease of 

transmitted intensity with the increase in z, on increasing H 0 

[above 150 G for 0.6 G/s in Figure 1 (b)]. Therefore, opening of 

tubes and increase in their ‘D’ cause the initial transition of the 

system from opaque to transparent around 50 G as shown in 

Figure 1(b). Whereas, the decrease of transmitted intensity above 

150 G for 0.6 G/s is caused by the increase in ‘z’. 

The aggregation time (t c 

), at a given H 0 

depends on the competition 

between the magnetic force and viscous force experienced by 

the oil droplets in the carrier liquid. This t c 

is the time required 

for aggregation of two oil droplets of radius 'a' containing the 

magnetic nanoparticles, when they are separated by a distance 

'r' in a medium with viscosity 'h' . For lower ramp rates, external 

field exposure time is longer and sufficient (> t c 

) so that the tubes 

can attain the maximum permissible dimensions (by aggregation 

of oil droplets) for a given H 0 

. Therefore, both the diameter of the 

tubes and the proportion of the number of tubes to single chains 

increases as the external field ramp rate is decreased. This is also 

the reason why the tube waveguide transmission behavior plays 

a prominent role on transmitted intensity variation at low ramp 

rate (0.6 G/s). For higher ramp rates (field exposure time < t c 

), 

only short chains are able to form, which are unable to arrange 

themselves to form tubes. The scattering effect by the short field 

induced chains dominates on the transmitted intensity output and 

therefore, it does not reach its equilibrium saturation value. 

The experiments mentioned above are also carried out while 

decreasing the H 0 

, immediately after reaching the maximum 

field (300 G), at the same ramp rate at which it is increased. 

Figure 3(b) shows the scattered pattern images, on a 

screen placed perpendicular to the incident light, but during 

19



Figure 3: (a) Variation of transmitted light spot intensity during decrease 

in magnetic field at different ramp rates and (b) scattered patterns at 

four different fields during the decrease at three ramp rates 

the decrese in H 0 

at ramp rates of 0.6, 1.67 and 10 G/s. 

Figure 3(a) shows the intensity variation of the transmitted 

light spot [upper right part of ring circumference of 

Figure 3(b)] as a function of decreasing H 0 

. During the decrease 

in H 0 

, the transmitted intensity increases unusually and peaks at 

68 G before falling sharply to zero value below 50 G. When H 0 

is decreased at 0.6 G/s, the ring structure gradually disappears 

and intensity of the transmitted spot on its circumference 

reaches its maximum at 68 G before complete disappearance 

[Figures 3(a & b)]. We attribute the enhanced transmission peak 

observed for the field induced array of random tubes to the 

localized waveguide resonances related to individual tubes. 

To get further insight into the observed enhanced transmission, 

the zero order transmittance spectra of the emulsion at different 

H 0 

during the decrease in field (ramp rate~ 0.6 G/s) are recorded 

using a fiber optical spectrophotometer and is shown in 

Figure 4. With the decrease in H 0 

, the transmittance of the emulsion 

increases for the entire range of wavelengths (λ=450-800 nm). 

Besides, an enhanced asymmetric peak is also observed in each 

transmission spectrum, which shows a red shift with the decrease 

in H 0 

. The transmittance spectra for H 0 

= G i.e. the disordered 

system of scatterers can be explained from the calculation 

of Q ext 

using the Mie scattering theory. For λ =450-800 nm, 

ka=2.04-1.15, the corresponding Q ext 

is significantly high 

(3.65-1.48) which results in very less transmittance 

I t 

/I 0 

(~ 2.155×10 -36 – 3.451×10 -15 ). But, for λ in the range 

800-1000 nm (ka=1.15-0.91), Q ext 

decreases from 1.48 

to 0.58, thereby reducing the scattering or increasing 

the fraction of incident light intensity that is transmitted, 

I t 

/I 0 

(~ 3.451×10 -15 – 2.15×10 -6 ). 

The transmittance over the entire wavelength range increases 

with the decrease in H 0 

, due to the deaggregation of oil droplets, 

the length ‘z’ of the tubes decreases on decreasing the field. This 

increases the number of tubes and therefore decreases their 

D. This arrangement takes place for the uniform distribution of 

the field induced structures throughout the entire volume of the 

ferrofluid emulsion, so as to reach the minimum energy state. 

The fractional aperture area can be considered to remain more 

or less the same after the redistribution of the tubes at different 

Figure 4: Transmittance spectra of the ff emulsion at different magnetic 

fields when decreased at a ramp rate of 0.6 G/s from 300 G. The solid 

lines are the best fits obtained using Fano resonance profile 

H 0 

. For a given fractional aperture area of an array of aperiodic 

waveguides, the transmittance increases with increase in the 

number of tubes. 

The reasons for the red shift of asymmetric peak, observed in the 

transmittance spectra, on decreasing H 0 

, enumararated below. The 

light transmission process, through an array of tube waveguides 

with their dimensions in the subwavelength regime or of the order 

of the wavelength of incident electromagnetic wave, involves 

two interfering contributions propagating through two different 

scattering paths. The first path is non-resonant and is related to 

direct scattering of the incident light field through the waveguides. 

The observed non-resonant transmittance variation can also be 

characterized well by the extension of Bethe-Bouwkamp theory, 

for a circular hole waveguide with negligible thickness in a 

perfectly electrical conducting film, to that with definite thickness 

and real metal. The non-resonant transmission continuum 

of direct scattered states related to individual waveguides is 

detected as background in the transmission spectra. The second 

path corresponds to a resonant contribution, as it first goes 

through the localized resonance state of the waveguide before 

being scattered to outside continuum. The interference between 

the transition amplitudes associated with each scattering path 

gives the resulting light transmittance with an asymmetric peak in 

the spectra, known as Fano resonance as shown in Figure 4. The 

transmittance spectra have been fitted with the functional form of 

Fano resonance I ∝ ( F + ω − ω ) 

2 

2 2 

[ g ] [( ω − ω ) + ] 

0 0 

g 

and variation of the fit parameters ω 0 

, F and g as a function 

decreasing H 0 

are shown in Figure 5. The actual resonance 

position i.e. the resonant wavelength (ω 0 

) of Fano resonance 

in the transmission spectra appears near the waveguide cut-off 

wavelength (λ c 

) for single hole, array of aperiodic and periodic 

holes in a conducting film. 

For a circular hole waveguide in a perfectly electrical conductor 

film, λ c 

=3.4r , where r is the hole radius. The ω 0 

that appears 

around this λ c 

shows a red shift with the decrease in waveguide 

length, which is demonstrated both numerically in perfectly 

conducting film, real metal and experimentally in single hole 

in a metal (Ag) film. Therefore, we attribute the red shift of ω 0 

[Figures 4 & 5], to the decrease in tube length z on decreasing 

20


Figure 5: Fano resonance fit parameters ω 0 

, F and g as a function 

of external magnetic field H 0 

(during decrease) 

H 0 

. Interestingly, for H 0 

of 70 G, the extracted value of ω 0 

is 

the incident light wavelength (633 nm) at which the resonantly 

enhanced transmission is also observed almost at the same 

field (68 G) [Figure 3 (a)], which corroborates our argument of 

transmission resonance to the localized waveguide resonance. 

The λ c 

of a waveguide is directly related to its lateral dimension 

(‘D’ in the case of tube). Though the ω 0 

of a waveguide is of the 

order of its λ c 

, the exact resonance position depends on the ‘z’ 

of the waveguide. The resonant wavelength, for the circular hole 

waveguide, coincides exactly with the cut off wavelength for the 

waveguide length z=r/3. Therefore, the observed red shift of 

resonance position (ω 0 

) in the transmittance spectra [Figures 4 & 

5] also shows that on decreasing H 0 

, the effect of decreasing ‘z’ 

dominates over the decreasing ‘D’, on determining the resonance 

peak position. Further, on decreasing H 0 

, at first ‘z’ decreases by 

deaggregation of oil droplets from the chains. Then, the spatial 

rearrangement takes place for the uniform distribution of the 

field induced structures throughout the entire volume resulting 

in the decrease of ‘D’, so as to reach the minimum energy state. 

Therefore, the rate of decrease in ‘z’ is faster than their ‘D’, thereby 

making the effect of decreasing ‘z’ more prominent on ω 0 

. 

The discrete localized state corresponding to the resonant state 

of a waveguide depends on its dimension. At higher H 0 

(e.g. 

300 G), due to high coupling constant L, there is very less 

dimensional distribution (z ±Dz & D ±DD) of the waveguides. 

On decreasing H 0 

, this dimensional distribution increases along 

with the decrease in ‘z’ and ‘D’, as mentioned earlier. This leads to 

increase in the number of discrete resonant states of the random 

array of field induced tube waveguides. Therefore, the transition 

amplitude associated with the resonant scattering path i.e. the 

discrete localized states, increases as compared to non-resonant 

direct scattering path as mentioned earlier. The increase in the 

ratio of these two transition amplitudes, defined as the asymmetry 

parameter F, with the decrease in H 0 

, as shown in Figure 5, 

demonstrates this phenomenon. The actual resonant wavelength 

(ω 0 

) lies somewhere between the observed maximum and 

minimum of the asymmetric transmittance spectra indicated in 

Figure 4 and the value of parameter F defines the relative deviation. 

In the situation ⎜ F ⎜→ ∞, the ‘ω 0 

’ coincides with the maximum 


of the spectra, for F=0 the ω 0 

coincides with minimum and for 

F =1 it is located exactly half the distance between the maximum 

and minimum of the spectrum. With the increase in the value 

of F, as H 0 

is decreased, the ω 0 

for a transmittance spectrum 

shifs more towards its maximum. This is also evident from the 

extracted values of ω 0 

[Figure 5] in the observed transmittance 

spectra [Figure 4] for different H 0 

. 

The non-resonant background in the transmittance spectra 

depends on the number of tube waveguides, their dimensions 

(z & D) and their dimensional distribution (z ±Dz & D ±DD) 

at a particular H 0 

. On decreasing H 0 

, if only the ‘z’ would have 

changed while keeping the other factors constant; only a red 

shift of transmittance resonance position (ω 0 

) with similar 

background would have been observed, as discussed earlier. 

At the resonance, the phase of the scattering wave changes 

sharply by p. Thus, the interaction of scattering waves results 

in constructive and destructive interference phenomena located 

very close to each other, corresponding to a maximum E max 

and minimum E min 

of the transmission, respectively. The width 

of the resonance is proportional to the distance between them, 

g ~⎜E max 

- E min 

⎜. Due to the increase in the number discrete 

localized states of the array of random waveguides with the 

decrease in H 0 

, the number of possible resonant scattering paths 

to the continuum through these states also increases. This leads 

to an increase in the number of possible interferences among 

the transition amplitudes corresponding to different resonant 

scattering paths. Since each of these interferences has both 

constructive and destructive interferences, it results in the 

occurrence of many resonances. This leads to the observation of 

many overlapped resonances in a single transmittance spectrum 

and increases the width of transmittance spectra when H 0 

is 

decreased, as demonstrated by the increase in g [Figures 4 & 

5]. Note that similar broad Fano transmission resonance with 

changing background is also observed for an array of aperiodic 

uncorrelated holes on a conducting film. Therefore, the increase 

in transmittance and red shift of the resonance position (ω 0 

), 

observed on decreasing H 0 

, indicates that the decrease in ‘z’ has 

the dominant contribution over other field dependent variable 

parameters on the resulting transmitted intensity behavior 

through the field induced array of randomly uncorrelated tube 

waveguides in the emulsion. Whereas, the increase in asymmetry 

parameter F and resonance width (g), observed on decreasing 

H 0 

, indicates that the increase in dimensional distribution (z ±Dz 

& D±DD) of the tube waveguides also plays significant role on 

the resulting transmitted intensity behavior. On decreasing the H 0 

below 65 G, L becomes less than unity, which leads to complete 

dissolution of the field induced structures. 

Reported by Junaid Masud Laskar 

Smart Materials Section 

Metallurgy and Materials Group 

21



Theme Meeting on Severe Accident Analysis and Experiments 

April 26-27, 2012 

Panel members Shri H. G. Lele, RSD, BARC, Shri S.S. Bajaj, Chairman, AERB, Shri S. K. Mehta, Former Director, Reactor Group, BARC, Prof. 

K. Iyer, Mechanical Engineering Department, IIT Bombay, Dr. P. Chellapandi, Director, RDG, IGCAR and Shri P. K. Malhotra, NPCIL on the dais 

Following the Fukushima events, there is a need to review and 

re-assess the strategies adopted in various nuclear facilities 

for severe accident management. This is essential for evolving 

a robust accident mitigation and management guideline for all 

future nuclear reactors. A theme meeting was organized by 

SRI-AERB in collaboration with IGCAR, at Anupuram during 

April 26-27, 2012 with an aim to take a consolidated look at the 

current status of on-going analytical and experimental research 

work on various aspects of severe accident management, 

within the DAE units as well as at academic institutions. It is 

envisaged that the outcome of the deliberations would provide 

the necessary thrust and direction in focusing research 

activities in challenging areas and reorient collaborative 

research activities among the participating organizations. 

Shri S.S. Bajaj, Chairman, AERB, in his introductory remarks, 

indicated that events at Fukushima have changed the perspective 

of nuclear communities' in responding to such events and 

evolving mitigating measures. Shri S.K. Chande, Vice Chairman, 

AERB delivered the key note address highlighting the shift 

in focus and practices in safety subsequent Fukushima. A 

total of twenty lectures were delivered by eminent invited 

speakers from various R&D organizations and academic 

institutions, on a wide range of issues relating to R&D on 

severe accidents in thermal as well as fast reactors. The 

theme meeting was concluded with a panel discussion chaired 

by Shri S. K. Mehta, Former Director, Reactor Group, BARC. 

Shri S.K. Chande, Vice Chairman, AERB delivering the key note address 

Reported by Seik Mansoor Ali, SRI, AERB 

22



Theme Meeting on Robust Instrumentation and Control for Nuclear Facilities (RINF-2012) 

May 29, 2012 

Dr. P. R. Vasudeva Rao, Director, Chemistry Group, IGCAR inaugurating the theme meeting. Shri S. A. V. Satya Murty, Director, 

EI&RSG, IGCAR, Shri C. K. Pithawa, Head, Electronics Division, BARC and Shri D. Thirugnanamurthy, EID, IGCAR are on the dais 

A one day theme meeting on "Robust Instrumentation and 

Control for Nuclear Facilities" (RINF-2012) was organised 

by Indira Gandhi Centre for Atomic Research at Sarabhai 

Auditorium, Homi Bhabha Building, Kalpakkam on May 29, 

2012. The theme meeting started with welcome address by 

Shri S. A. V. Satya Murty, Convenor, RINF-2012 and Director, 

Electronics, Instrumentation and Radiological Safety Group, 

IGCAR. 

Shri S. A. V. Satya Murty highlighted the importance of the 

theme meeting particularly in the context of development of 

robust instrumentation for nuclear facilities and welcomed 

the eminent speakers, delegates from IGCAR, BARCF, 

BHAVINI and MAPS. 

Dr. P. R. Vasudeva Rao, Director, Chemistry Group 

inaugurated the theme meeting. He highlighted the vital 

role of instrumentation and control with respect to safety 

and availability of the nuclear reactor. He emphasized how 

important it is to provide robust and reliable instrumentation 

for nuclear facilities. He stressed the need for paying attention 

to design and the importance of redundancy. He mentioned 

the challenges faced because of fast developments in the field 

of electronics and computers and resultant obsolescence. 

Shri C. K. Pithawa, Head, Electronics Division, BARC delivered 

the keynote address on 'Neutron detectors for Prototype Fast 

Breeder Reactor'. He explained the methodology followed 

in designing the neutron detectors to work at very high 

temperatures for fast reactors, the challenges faced and their 

solutions to overcome. 

In the theme meeting, there were six invited talks by eminent 

professionals from IITM, Centre for Reliability, CEMILAC, 

BARC, ECIL and Ansh Technologies highlighting the various 

qualification methods to be followed in building robust 

instrumentation and control for nuclear facilities. The meeting 

was attended by more than one hundred and fifty delegates 

from IGCAR, MAPS, BHAVINI and BARC Facilities. There 

were excellent scientific interactions during the technical 

sessions. Shri D.Thirugnana Murthy, EID, Secretary, RINF- 

2012 proposed the vote of thanks. 

Reported by S. A .V Satya Murty, Convenor, RINF-2012 

23



Theme Meeting on Technological Advancement in Production of Enriched Boron 

for the Control Rods of Fast Reactors 

June 22, 2012 

Shri S.C Chetal, Distinguished Scientist and Director, Indira Gandhi Centre for Atomic Research, presenting the inaugural address 

A one day theme meeting on “Technological Advancement 

in Production of Enriched Boron for the Control Rods 

of Fast Reactors” was organized by Indira Gandhi 

Centre for Atomic Research, Kalpakkam and Board of 

Research in Nuclear Sciences, (BRNS) Mumbai at the 

Sarabahai Auditorium, Homi Bhabha Building, IGCAR on 

June 22, 2012. The meeting started with the welcome 

address by Shri K.K.Rajan, Chairman, organizing committee 

and Director, Fast Reactor Technology Group. Shri K.K.Rajan 

highlighted the relevance of the theme meeting in the 

context of the Indian fast breeder reactor programme and 

welcomed the invited speakers, delegates and guests. He 

lauded the efforts of Shri R.Subramaniam, Former Head 

of Chemical Technology Section at IGCAR who laid the 

foundation for the boron enrichment program at IGCAR and 

Dr. C. Anand Babu, Associate Director, Component 

Development Group for his contributions in leading the 

research and development programme for boron enrichment. 

Shri S.C Chetal, Director, IGCAR inaugurated the theme 

meeting and in his inaugural address outlined the importance 

of enriched boron carbide as absorber rod material for control 

of fast reactors. He also informed that boron carbide pellets to 

be used in the control rods of PFBR are ready for shipment at 

BARC. He reiterated that the development of this technology 

is a culmination of the combined efforts of BARC, IGCAR and 

HWB. He stressed the need to initiate research and development 

for recycling the enriched boron carbide from the used control 

rods of fast reactors. During the meeting 5 kg of 90 percent 

enriched boric acid powder produced at the boron enrichment 

plants at IGCAR was handed over to Shri K.Nagarajan, 

Associate Director, Chemistry Group for further processing in 

the inaugural session. 

Dr. C. Anand Babu in his key note address detailed the road 

map of the boron enrichment in the country. He particularly 

recalled the uphill challenges and hurdles that were overcome 

in achieving the present level of technological maturity. In 

the theme meeting there were eight invited lectures. The 

lectures were organized into three different technical sessions 

as process development for boron enrichment, technology 

development for conversion to enriched elemental boron and 

production and operating experience on absorber materials. 

The lectures were delivered by experts in this field from 

IGCAR, BARC and Heavy Water Board. Engineers from 

the various groups of IGCAR, BHAVINI, BARC facilities, 

academic institutions and industries like THERMAX were also 

participants to this theme meeting. There were a total of 90 

participants for the theme meeting. The scientific interactions 

during the technical sessions were beneficial and provided 

valuable inputs for the design, performance assessment 

and further improvement of the processes in the production 

of enriched boron for fast reactors. The meeting concluded 

with a vote of thanks by Dr. B.K.Sharma, Chairman, Techncial 

committee. 

Reported by G. Padmakumar, Convenor 

24



Visit of Dignitaries 

Honorable Justice Shri S. Tamilvanan from Madras High Court 

accompanied with his wife Prof. V. Manimozhi visited the 

Centre on April 14, 2012. During the meeting they were briefed 

about the challenges and opportunities of Atomic Energy by 

Dr. M. Sai Baba, Associate Director, Resources Management 

Group. After the meeting Honorable Justice Shri S. Tamilvanan 

and Prof. V. Manimozhi visited the Fast Breeder Test Reactor and 

Madras Atomic Power Station. 

Honorable Justice Shri S. Tamilvanan from Madras High 

Court and Prof. V. Manimozhi during their visit to the 

Fast Breeder Test Reactor 

Dr. K. Gireesan and Dr. T. S. Radhakrishnan from MSG and collaborators at CIPET-Chennai, have received the 

2 nd National Award (2011) for Technology Innovation under the category, Polymers in Public Health Care, instituted 

in various fields of Petrochemicals and Downstream Plastic Processing Industry by the Department of Chemicals and 

Petrochemicals, Government of India, for their work on the "Design and Development of Sensor array Hemet for whole 

Head Magnetoencephalography System" 

Dr. M. Vijayalakshmi from MMG has been elected, Fellow of the Electron Microscopy Society of India in recognition of her 

outstanding scientific contributions in the field of "Electron Microscopy". 

Best Paper / Poster Awards 


Embedded-System Based Controller for Measuring Displacement of Reactor Vessel of FBTR 

Shri Kalyan Rao Kuchipudi, Shri Sushant Patil, Shri S. Sridhar, Shri M. Muthukrishnan, Shri K. V. Sureshkumar, 

Shri S. Varadharajan, Shri B. Anandapadmanaban and Shri G. Srinivasan from ROMG 

8 th Control and Instrumentation System Conference (CISCON 2011) Manipal University, Manipal, November 2011 

Best Paper Award 

Effective Nondestructive Imaging of Defects in Engineering Components 

Dr. B. P. C. Rao, Dr. T. Jayakumar, Shri S. Thirunavukkarasu, Shri W. Sharatchandra Singh, Shri G.K. Sharma, 

Shri Anish Kumar and Dr. C. Babu Rao from MMG 

18 th World Conference on Nondestructive Testing, Durban, South Africa, April 16-20, 2012 

Best Presentation Award 

Logic Modeling and Benchmark Transients Simulation of Condensate System for Prototype Fast Breeder Reactor Operator 

Training Simulator 

Ms. Rashmi Nawlakha, Ms. N. Jasmine, Ms. H. Seetha, Shri B. Subba Raju, Shri K.R.S. Narayanan, 

Ms. T. L. Priyanka, Ms. T. Jayanthi and Shri S.A.V. Satya Murty from EI&RSG 

International Conference on Recent Advances in Engineering and Technology (ICRAET-2012) 

Hyderabad, April 29-30, 2012 

Best Paper Award

Cassia fistula (Golden shower tree) 

Dr. M. Sai Baba, 

Chairman, Editorial Committee, IGC Newsletter 

Editorial Committee Members: Dr. K. Ananthasivan, Shri M.S. Chandrasekar, Dr. N.V. Chandra Shekar, 

Dr. C. Mallika, Shri K. S. Narayanan, Shri V. Rajendran, Dr. Saroja Saibaba and Dr. Vidya Sundararajan 

Published by Scientific Information Resource Division, IGCAR, Kalpakkam-603102

Volume 93 - Indira Gandhi Centre for Atomic Research

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?