Venkatraman Balasubramaniam

• M.Sc (Phy) PGDCA, Ph.D
• Indira Gandhi Centre for Atomic Research

A ‘Remote sensing enabled Online Chemical Emergency Response System (ROCERS)’ is developed in a generic and geospatial framework integrating sensor data, chemical dispersion model predictions and spatial data for chemical impact assessment and advisory towards decision support in the event of emergencies arising due to accidental release of hazardo...

The combined effect of defect thickness and lateral size on defect characterization in AISI 316 L Stainless Steel material using Pulsed Thermography method is studied numerically. As the defect volume (thickness and lateral width) decreases for the same depth, the magnitude of change in surface temperature decreases, deteriorating the defect visibi...

Studies on the charged aerosol dynamics are essential for addressing the radioactive aerosol behavior suspended in fast reactor containment during severe accident conditions. Towards this, lab-scale experiments are conducted to measure the effect of charge on aerosol dynamics. Polyalphaolefin (PAO) aerosol studied here is spherical, nonporous and c...

A Kalman Filter (KF) algorithm is developed for radionuclide source term estimation based on real-time gamma dose rate and meteorological data. The algorithm uses Gaussian Plume Model (GPM) with nonlinear build-up factor in dose rate model to eliminate one source of uncertainty in source term estimation. The estimated release rate from the KF algor...

Dose estimation using unconventional dosimeters during radiological/nuclear emergencies remains challenging and essential for medical triage. In this work, we have explored the potential of utilizing eggshells as an unconventional dosimeter using electron spin resonance (ESR) spectroscopy. Eggshell particle size was optimized (210 to 250 µm) to rem...

Though sodium is the most preferred coolant for fast breeder reactors due to excellent heat transfer capabilities, its high chemical reactivity poses a concern during accidental leaks. Despite defense in depth in various levels for protecting the sodium leaks in the heat transport circuits, small undetected leaks may lead to localized degradation o...

This study investigated the optically stimulated luminescence (OSL) characteristics of hydroxyapatite (HAp) derived from chicken eggshells, a readily available bio-waste, for low-level radiation dosimetry applications which is less explored. The eggshells were employed as a calcium source in HAp synthesis. The X-ray diffraction and Fourier transfor...

The study of the dynamics of aerosols produced during a severe accident is vital to the safety analysis of a Sodium-cooled Fast Reactor (SFR). Sodium leakage into the containment following a severe accident may result in the production of sodium aerosols along with fission product aerosols. The in-containment radioactive source term depends upon th...

Accurate Meteorological forecasts are crucial for the assessment of plume dispersion and dose prediction in nuclear power plant (NPP) sites. In this work the forecast sensitivity of the Weather Research and Forecasting (WRF) model is tested by running a series of forecast simulations for horizontal resolution, and land surface models (LSM) in the c...

Metal–organic frameworks (MOF) have been vigorously investigated as hybrid materials in recent decades due to their exceptional structural versatility and applications in diverse fields. The development of novel MOFs for radiation detection and luminescence-based dosimetry is the latest topic of interest. In this contribution, we have synthesized a...

Extremely severe cyclonic storm (ESCS) ‘Fani’ formed in the North Indian Ocean and crossed at Puri in Orissa State on the east coast of India on 03 May 2019. In this study, we examine the sensitivity of convection permitting WRF simulations (3 km) of ‘Fani’ to cloud microphysics (CMP) schemes using radar and multi-satellite data products. Five CMP...

Natural and fallout radionuclides in selected marine fishes from Kalpakkam were analyzed to ascertain the internal exposure from the consumption of these seafood and related radiological and food safety aspects. Using alpha and gamma spectrometry, activity concentrations of 210Po, 40K, 238U, and 232Th were determined in finfish, shellfish, and seaw...

The initial size distribution and morphological parameters of sodium aerosols are critical in evaluating the accidental suspended aerosol behaviour in Sodium-cooled Fast Reactor (SFR) containment. Mass-based measurements were more familiar in characterizing the sodium aerosols. Real-time number size distribution measurements are carried out in this...

Precise estimation of individual radiation dose utilizing biomaterials (fingernail, bone, and tooth) is very challenging due to their complex sample processing. Despite, tooth enamel, the most mineralized tissue of tooth is used for this purpose due to its high radiation sensitivity and ability to produce radiation induced long lived CO2⁻ radicals....

Despite a hypothetical event, whole core melt accident in a sodium cooled fast reactor is investigated as a part of plant safety analysis. To prevent breach of primary boundary in such accidents, a Core Catcher (CC) is provided at the bottom of the main vessel for retention of corium in subcritical and coolable state. For future Indian FBRs, refrac...

The interaction of molten fuel and coolant occurring during a severe accident case in a nuclear reactor is studied in this paper. The molten jet of MOX interacts with the sodium in dripping flow regime. An in-house code DROP formulated using slenderjet approximation of Navier–stokes equations is used in the present analysis. Usually in the study of...

During a severe accident, the molten nuclear fuel jet breakup in a liquid sodium pool received considerable attention from the Sodium-cooled Fast Reactor (SFR) community. The jet breakup phenomenon assumes importance in the in-vessel cooling of core debris on the core catcher after the accident. The Volume-of-Fluid (VoF)-based solver available in A...

During Molten Fuel Coolant Interaction (MFCI) occurring in a Sodium-cooled Fast Reactor (SFR) following a severe accident, the corium jet breaks up into coarse droplets due to hydrodynamic instabilities and fine flaked debris are generated due to the thermal stress cracking occurring on the solidifying droplet. In particular mixed oxide core debris...

Cables are important components in nuclear reactors, which are used to power and control the various equipments of the reactor systems. The presence of combustible, plastic materials in large quantity pose a significant fire risk to nuclear reactors and the safety of reactor systems could be jeopardized by the loss of functionality of cables due to...

Electrostatic Aerosol Neutralizer (Make: TOPAS, Model: EAN581) is used to condition the pre-charges of aerosols by exposing the aerosols to bipolar ion field in the mixing chamber generated from two independent ionization heads operated at high voltages of opposite polarity. EAN581 is also be used as a unipolar charger if operated with one ionizati...

The accidental leaks of coolant from the heat transport circuit of Sodium-cooled Fast Reactor (SFR) can create fire events due to the reactivity of sodium with atmospheric oxygen, which can pose threat to safe operation of the reactor. The leaked sodium eventually reaches the cell floor, spreads gradually, and forms a burning pool. The thermal cons...

A two-phase flow model for sodium-argon mixture flow through the reactor vessel head penetrations under the energetic core disruptive accident in a sodium fast reactor (SFR) is presented. The model evaluates the total sodium mass in sodium-argon mixture released to the reactor containment building (RCB) through penetrations. The driving pressure at...

Horizontal convective rolls (HCR) are sub-mesoscale motions that influence the transport of heat, momentum, and pollutants within the boundary layer. In this work, a high-resolution (0.666 km) Weather Research and Forecasting (WRF) model is employed to simulate the structure of the HCRs over Kalpakkam along the southeast coast of India. The sensiti...

RESD is involved in characterization of sodium aerosols in the cover gas region as a part of Fast Reactor Safety Studies. The study is conducted in two phase. In the first phase experimental and theoretical work has been carried out in the SILVERINA Loop (non-reactor environment). In the second phase, experiments are carried in the FBTR reactor env...

This study aims to examine the recirculation effect of land and sea breeze flows on atmospheric releases from Chennai and Kalpakkam stations in Southeast coast of India using the WRF and FLEXPART models. High-resolution (2 km) simulations conducted with WRF for 4–6 April 2016 and 13–16 July 2016 showed development of sea breeze circulation under st...

In nuclear reprocessing piping applications, oxidation is one of the most prevalent weld defects experienced in welding of small bore AISI 304L pipes due to ineffective inert gas purging at root side of weld. This has been attributed to complexity of system design, access limitations and increased procedure costs and schedule in joints such as term...

Nuclear fuel pins arranged inside a hexagonal stainless steel wrapper form a fuel subassembly. The subassemblies are supported on the grid plate making the nuclear reactor core. In the unforeseen event of the core disruptive accident, these fuel pins melt through the grid plate and interact with the coolant sodium in the reactor main vessel in sodi...

Estimating the time evolution of the suspended aerosol concentration in nuclear reactor containment is critical in assessing the environmental source term during severe accident conditions. Morphological properties of porous and non-spherical aerosol particles are necessary to convert the measured equivalent size distributions to actual size distri...

In case of a Core Disruptive Accident in sodium-cooled fast reactor, sodium will be ejected from the reactor vessel into the Reactor Containment Building (RCB) and results in sodium fire. Liquid sodium combustion generates aerosol, which gets dispersed and remains suspended in RCB based on geometry of the building and degree of turbulence. The Envi...

Sodium boiling in a fuel subassembly of a sodium-cooled fast breeder reactor is a very critical phenomenon as void propagation may lead to loss of heat removal and increase in reactivity. Hence, sodium boiling behavior from the incipient stage and evolution of bubble dynamics need to be thoroughly understood toward validating various thermal-hydrau...

The abstract can be seen in the abstract book of NUCAR2023. Pl follow the link below https://www.iancas.org.in/newsfiles/IANCAS-12194-NUCAR-2023%20Abstract%20E-book.pdf

Though liquid sodium is most desirable coolant for fast breeder reactors, its high chemical activity poses a concern, as even a small leak in to the atmosphere may result in a fire. Usually, sodium piping is constructed with austenitic stainless steel material. Leak before Break (LBB) philosophy is adopted for prevention and early detection of leak...

This study investigates the impact of inversion layers on the dose due to air-born radioactive effluents at tropical coastal site Kalpakkam. Observations from a meteorological tower, GPS Sonde and SODAR are used to identify the presence of inversion conditions. A high resolution mesoscale model WRF is used to simulate the boundary layer meteorologi...

Detection and evaluation of fatigue cracks in structural materials are extremely important for life prediction analysis as part of the structural integrity procedure. In this article, we present a novel ultrasonic measurement methodology, based on the diffraction of elastic waves at the crack tips, to monitor the fatigue crack growth near the thres...

This work investigates the mechanism of the extremely heavy rainfall event during 7–10 August 2019 in Kerala. As the skill of WRF model for simulating the heavy rainfall strongly depends on the choice of cloud microphysics (CMP), sensitivity analysis is performed using cloud resolving WRF simulations with different CMP schemes to assess their perfo...

The combined effect of grain size variation and plastic deformation on the acoustic nonlinearity parameter has been investigated in an austenitic stainless-steel material of grade 304. The nonlinear behavior of this parameter with grain growth has deviated to linear fit with deformation. This is due to the interaction of elastic waves with the stra...

Source term is an important input for dose projections using atmospheric dispersion models during accident condition. Back calculation using atmospheric models and environmental data is one of the widely used approaches of source term estimation. In this method, the dispersion models are run using inversion techniques. Among different inversion tec...

A self-sustained waste treatment technology entails the integration of various cultivation and harvesting processes cost-effectively. Activated algae are a unique microalgae-based technological platform with diverse applications and superior performance compared to the conventional methodologies. An attempt has been made to develop marine activated...

A study on radon and thoron exhalation rate measurements in beach sand samples collected along east coastal region of Tamil Nadu, India, at 45 locations are carried out. Activity concentration of 238 U and 232 Th are determined in the collected samples by subjecting it into gamma spectrometry. Radon/thoron exhalation rates are measured by employing...

The present study is intended towards development of high resolution CFD based models for the prediction of single-phase and two-phase flow and heat transfer characteristics of liquid sodium in a 7-pin subassembly. The single-phase CFD study is carried out for low Peclet number flow conditions with Kays correlation for turbulent Prandtl number and...

The impact of Sea-breeze circulation on the convective thunderstorms over the southeast coast of Tamilnadu, India is studied using the Weather Research and Forecasting (WRF) model. High-resolution (2-km) simulations are conducted with WRF for two severe thunderstorm events on 24 April 2015 in summer 22 July 2015 in the southwest monsoon. Surface ob...

Salient modifications and validations performed on a Point Kernel method based code QADCGPIC, which are important for optimizing shield design is presented in the paper. The geometric progression method based build–up factors (BUFs) for penetration depths of medium up to 100 mean free path is incorporated into the modified QADCGPIC–M code. Further...

Gas Tungsten Arc Welding (GTAW) is widely used in nuclear industry owing to its better root quality and greater control of weld pool in real time. However, the process is quite slow (75-100 mm/min) compared to other slag-based processes. This is a disadvantage especially when thicker sections need to be welded. In this work, authors have proposed c...

Sodium aerosol characterstization is one of the important feature in Safety Analysis of Sodium Cooled Fast Reactor. The sodium aerosol released in the environment has two very important consequences viz. (i) on radio-toxicity (ii) on chemical toxicity. The sodium aerosols are generated in three important ways in SFR and released to the environment...

A Gaussian Plume based simple numerical model, named DIFFUSE is developed to simulate the long-term sector-average plume gamma dose due to radioactive plume released during normal operation of nuclear facilities. DIFFUSE calculates site specific joint frequency distributions of wind speed, wind direction and atmospheric stability using micrometeoro...

Breast cancer is the most common cancer among women in the world today. Mammography screening gives vital information about normal and abnormal regions. The task is to detect the lesion in mammograms using computer-aided diagnosis techniques. The automated detection of cancer decreases the mortality rate and manual error. In this work, the statisti...

Breast cancer has been and continues to be a cause of major health concern for women. It is also more prevalent in the younger age group. According to the Indian Council of Medical Research (ICMR) 2020, 50% of all the cases are in the age group of 25–50 where the numbers are staggering and constantly rising. The increase in incidence over the years...

Melting of the nuclear core is one of the severe accident scenarios in a Sodium-cooled Fast Reactor (SFR). During such an event, molten corium may come into contact with the coolant sodium. This interaction of the molten fuel and the coolant is commonly termed molten fuel–coolant interaction (MFCI) in the nuclear industry. In this study, a numerica...

A novel method of loading phosphor materials in a plastic scintillator (here on PS) is developed to improve light output. In the present work, phosphor materials ZnS(Ag) and ZnO are loaded into the PS medium through the thin-film coating, and the effect of these phosphors on radiation detection is investigated. PS are prepared using polystyrene as...

Bio-dosimetry is defined as estimation of dose received by individuals based on biological end points induced by ionizing radiation. By using cytogenetic assay, it is possible to quantify the absorbed dose. High linear energy transfer (LET) radiation produces dense ionizations along their path and causes more clustered DNA damage compared to low LE...

The gamma-ray spectrometry using long run used hyper pure germanium(HPGe) detector needs a stringent full energy peak(FEP) efficiency calibration for environmental radioactivity measurements. The FEP efficiency calibration were carried out using the complementary methods like analytical estimations and Monte Carlo(MC) simulations. In our work, for...

In case of a hypothetical core meltdown accident in Sodium cooled Fast Reactor (SFR), the molten fuel comes in contact with sodium (coolant) resulting in Molten Fuel Coolant Interaction (MFCI). In such scenario, the molten fuel jet undergoes fragmentation due to various instabilities associated with thermal hydraulics. The fragmented fuel debris co...

Breast cancer is the most common cancer among women in the world today. Mammography screening gives vital information about normal and abnormal regions. The task is to detect the lesion in mammograms using computer-aided diagnosis techniques. The automated detection of cancer decreases the mortality rate and manual error. In this work, the statisti...

Breast cancer is one among the most common cancers in women. The early detection of breast cancer reduces the risk of death. Mammograms are an efficient breast imaging technique for breast cancer screening. Computer aided diagnosis (CAD) systems reduce manual errors and helps radiologists to analyze the mammogram images. The mammogram images are ty...

Core melt accident is a very low probability event in Sodium Cooled Fast Reactors (SFRs) due to presence of several inherent and engineered safety features. However, such accidents are considered in the design of reactor to ensure safe mitigation and containment. Core Catcher (CC) is a passive device installed below the core in lower plenum of reac...

Due to the ongoing pandemic, various types of facemasks such as certified N-95, non-woven fiber and fabric/textile masks are being used as an essential protective measure to reduce the risk of spread of the SARS-Cov-2 virus. The aerosols size-dependent filtration efficiency and breathing resistance of these masks were tested before and after steril...

In the present ongoing pandemic, the N95 respirator is an essential protective barrier to suppress the spread of the SARS-Cov-2 virus and protect the frontline worker from exposure. The N95 respirators are meant for single usage; however, they can be used after sterilization, considering the economy and shortfall in availability. At this juncture,...

Sea-breeze (SB) is a predominant mesoscale atmospheric circulation over coastal areas and its detection sometimes is complicated mainly due to change in weather pattern. In this study the SB frequency between Chennai and Pondicherry over the east coast of India is studied for the period 2016–2019 using an objective selection method based on backgro...

The early detection of breast cancer can lower the risk of mortality among women. Mammography has been considered as standard tool for screening breast cancer today. Despite its ability in detecting breast condition, mammography has some drawbacks. Mammography technique is less effective for younger patients and it is not suitable for women with de...

An innovative sodium loop has been conceptualised for irradiation of material specimens in sodium at high temperature, in Fast Breeder Test Reactor (FBTR). The loop consists of a specimen chamber and an oscillating sodium column heat exchanger to maintain the test specimen at required temperature during the irradiation campaign. To validate the des...

In this study the influence of atmospheric conditions, release height and particle size are studied on the radiological impact due to a hypothetical 15 KT nuclear explosion using the HotSpot model. Simulations show that among different parameters, the height of burst produces the highest impact on the total effective dose (TED). It is found that th...

The nuclear reactor research community is interested in charged aerosol dynamics in a confined environment. Various aerosol charging theories described for bipolar and unipolar ion field exposures are reviewed using experimental measurements with PSL aerosols and ELPI. The (n+/n-) ratio of bipolar ions marginally increases as more negative ions get...

The premature chromosome condensation (PCC) assay is considered as complementary bio-dosimetry tool for chromosome aberration assay and the PCC assay can be used to estimate high dose exposure. Though the PCC ring is considered as prospective biomarker, chromosome length ratio (ratio of longest and shortest chromosome length in PCC spreads) of chem...

International Conference on Fast Reactors and Related Fuel Cycles FR22: Sustainable Clean Energy for the Future (CN-291)