Linu Malakkal

Profile Information
Name
Dr Linu Malakkal
Institution
Idaho National Laboratory
Position
Staff Scientist
h-Index
13
ORCID
0000-0003-4895-0323
Biography

Dr. Linu Malakkal is a computational material scientist post-doctoral research associate in the Computational Mechanics and Materials Department at Idaho National Laboratory (INL), USA. His technical skills include Density Functional Theory (DFT), Molecular Dynamics (MD) simulations of material behavior in nuclear fuels and structural materials. He has also worked on the fabrication and characterization of nuclear fuels using novel sintering techniques. Dr. Linu joined INL in Jan 2021 with a principal focus on modeling the thermal conductivity degradation in U-Mo nuclear fuels in support of the United States High-Performance Research Reactor (USHPRR) Program and calculation of transport properties of defect species in support of the Nuclear Energy Advanced Modeling and Simulation Program (NEAMS). He also works in understanding the thermal transport in irradiated nuclear fuel material for the center for Thermal Energy Transport under Irradiation (TETI). He has authored more than twenty international journal papers on the computational and experimental determination of thermal and mechanical properties of novel nuclear materials in journals such as Nature Scientific Reports, Journal of Physical Chemistry C, Journal of Physical Chemistry Chemical Physics, Journal of Nuclear Materials, Journal of Alloys and Compounds, and Computational Material Science. Before joining INL, he spent a year at Thermtest Inc. Fredericton Canada, where he worked as a thermal analysis scientist. Dr. Linu holds a bachelor’s degree in Mechanical Engineering from GEC Kozhikode, Kerala, India, and a master’s degree in Nanotechnology from the Indian Institute of Technology, Roorkee (IIT-R) India, and a Ph.D. in Mechanical Engineering from the University of Saskatchewan, Canada.

Expertise
DFT, Fuel Performance, Molecular Dynamics, Nuclear Fuels, Thermal Conductivity
Additional Publications:
"Enhanced thermal conductivity of spark plasma-sintered thorium dioxide-silicon carbide composite fuel pellets" Anil Prasad, Jayangani Ranasinghe, Ericmoore Jossou, Lukas Bichler, Jerzy Szpunar, Linu Malakkal, [2023] Nuclear Engineering and Technology · DOI: 10.1016/j.net.2023.06.038 · ISSN: 1738-5733
"Evaluation of thermophysical properties of UO2-10 Vol% Mo nuclear fuel pellets" Jerzy A. Szpunar, Anil Prasad, Linu Malakkal, Lukas Bichler, Murali Krishna Tummalapalli, [2022] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2021.153444 · ISSN: 0022-3115
"Thermal conductivity of α-U with point defects" W. Ryan Deskins, Linu Malakkal, Anter El-Azab, Jie Peng, [2021] Journal of Applied Physics · DOI: 10.1063/5.0064259 · ISSN: 0021-8979

We develop a theoretical model for thermal conductivity of α-U that combines density functional theory calculations and the coupled electron–phonon Boltzmann transport equation. The model incorporates both electron and phonon contributions to thermal conductivity and achieves good agreement with experimental data over a wide temperature range. The dominant scattering mechanism governing thermal transport in α-U at different temperatures is examined. By including phonon–defect and electron–defect scatterings in the model, we study the effect of point defects including U-vacancy, U-interstitial, and Zr-substitution on the thermal conductivity of α-U. The degradation of anisotropic thermal conductivity due to point defects as a function of defect concentration, defect type, and temperature is reported. This model provides insights into the impact of defects on both phonon and electron thermal transport. It will promote the fundamental understanding of thermal transport in α-U and provide a ground for investigation of coupled electron–phonon transport in metallic materials.

"First principles investigation of thermal properties of thorium mononitride" Jayangani I. Ranasinghe, Linu Malakkal, Jerzy A. Szpunar, Barbara Szpunar, [2021] Journal of Alloys and Compounds · DOI: 10.1016/j.jallcom.2021.160467 · ISSN: 0925-8388
"DFT and experimental study on the thermal conductivity of U3O8 and U3O8-X; (X=Al and Mo)" Linu Malakkal, Barbara Szpunar, Anil Prasad, Ericmoore Jossou, Jerzy A. Szpunar, Lukas Bichler, Jayangani I. Ranasinghe, [2021] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2021.152900 · ISSN: 0022-3115
"First-principles investigation of electrons’ thermal excitations in UN, UAl2 and ThN" Jayangani I. Ranasinghe, Linu Malakkal, Jerzy A. Szpunar, Barbara Szpunar, [2021] Solid State Communications · DOI: 10.1016/j.ssc.2020.114131 · ISSN: 0038-1098
"Density Functional Theory Study of Oxygen Adsorption and Dissociation on Lower Miller Index Surfaces of ThN" Ericmoore Jossou, Jayangani Inoka Ranasinghe, Barbara Szpunar, Jerzy Szpunar, Linu Malakkal, [2020] The Journal of Physical Chemistry C · DOI: 10.1021/acs.jpcc.0c07770 · ISSN: 1932-7447
"Density functional theory study of the structural, mechanical and thermal conductivity of uranium dialuminide (UAl2)" L. Malakkal, E. Jossou, B. Szpunar, J.A. Szpunar, J.I. Ranasinghe, [2020] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2020.152359 · ISSN: 0022-3115
"First principles investigation of thermal transport of uranium mononitride" Jayangani I. Ranasinghe, Linu Malakkal, Jerzy A. Szpunar, Barbara Szpunar, [2020] Journal of Physics and Chemistry of Solids · DOI: 10.1016/j.jpcs.2020.109636 · ISSN: 0022-3697
"Thermophysical properties of (UxAm1−x)O2 MOX fuel" Linu Malakkal, Jayangani Ranasingh, Barbara Szpunar, Jerzy Szpunar, Ericmoore Jossou, [2020] Computational Materials Science · DOI: 10.1016/j.commatsci.2019.109324 · ISSN: 0927-0256
"Comprehensive study on the electronic and optical properties of α-U3O8" Linu Malakkal, Ericmoore Jossou, Barbara Szpunar, Jerzy A. Szpunar, Jayangani I. Ranasinghe, [2020] Computational Materials Science · DOI: 10.1016/j.commatsci.2019.109264 · ISSN: 0927-0256
"Atomistic and experimental study on thermal conductivity of bulk and porous cerium dioxide" Anil Prasad, Dotun Oladimeji, Ericmoore Jossou, Jayangani Ranasinghe, Barbara Szpunar, Lukas Bichler, Jerzy Szpunar, Linu Malakkal, [2019] Scientific Reports · DOI: 10.1038/s41598-019-42807-5 · ISSN: 2045-2322
Abstract

Cerium dioxide (CeO2) is a surrogate material for traditional nuclear fuels and an essential material for a wide variety of industrial applications both in its bulk and nanometer length scale. Despite this fact, the underlying physics of thermal conductivity (kL), a crucial design parameter in industrial applications, has not received enough attention. In this article, a systematic investigation of the phonon transport properties was performed using ab initio calculations unified with the Boltzmann transport equation. An extensive examination of the phonon mode contribution, available three-phonon scattering phase space, mode Grüneisen parameter and mean free path (MFP) distributions were also conducted. To further augment theoretical predictions of the kL, measurements were made on specimens prepared by spark plasma sintering using the laser flash technique. Since the sample porosity plays a vital role in the value of measured kL, the effect of porosity on kL by molecular dynamics (MD) simulations were investigated. Finally, we also determined the nanostructuring effect on the thermal properties of CeO2. Since CeO2 films find application in various industries, the dependence of thickness on the in-plane and cross-plane kL for an infinite CeO2 thin film was also reported.

"The effect of SPS processing parameters on the microstructure and thermal conductivity of ThO2" Anil Prasad, Jayangani Ranasinghe, Ericmoore Jossou, Dotun Oladimeji, Barbara Szpunar, Lukas Bichler, Jerzy Szpunar, Linu Malakkal, [2019] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2019.151811 · ISSN: 0022-3115
"DFT + U Study of the Adsorption and Dissociation of Water on Clean, Defective, and Oxygen-Covered U3Si2{001}, {110}, and {111} Surfaces" Linu Malakkal, Nelson Y. Dzade, Antoine Claisse, Barbara Szpunar, Jerzy Szpunar, Ericmoore Jossou, [2019] The Journal of Physical Chemistry C · DOI: 10.1021/acs.jpcc.9b03076 · ISSN: 1932-7447
"Thermal conductivity of bulk and porous ThO2: Atomistic and experimental study" Anil Prasad, Ericmoore Jossou, Jayangani Ranasinghe, Barbara Szpunar, Lukas Bichler, Jerzy Szpunar, Linu Malakkal, [2019] Journal of Alloys and Compounds · DOI: 10.1016/j.jallcom.2019.05.274 · ISSN: 0925-8388
"Atomistic modeling of thermo‐mechanical properties of cubic SiC" Linu Malakkal, Jahidur Rahman, Jerzy A. Szpunar, Barbara Szpunar, [2018] Journal of the American Ceramic Society · DOI: 10.1111/jace.15712 · ISSN: 0002-7820
Abstract

SiC is an important multifunctional material with application in electronics and as a structural material. Many investigations of SiC have been done using both classical molecular dynamics and first principles methods. However, they are of limited scope and, in particular, SiC properties at finite temperatures have not been adequately evaluated. The good mechanical, thermal, and chemical properties of SiC such as high stiffness, high hardness, high mechanical strength at high temperature, and high thermal conductivity, make SiC a candidate for various applications in nuclear industries. In this work, we evaluated thermomechanical properties at finite temperatures obtained by LAMMPS code with traditionally used Tersoff potential (TR89 with PRB 41 correction), and the newer GW 2002 (GW02) potential. We compared them with the calculations made using MEAM 1995 (MEAM 95) and with our first principles DFT predictions. It is demonstrated that the thermal expansion and mechanical properties calculated as a function of temperature for classical potentials TR89 and GW02 do not agree well with first principles calculations while better agreement is found for the MEAM95 potential. Classical molecular dynamics calculations made with the use of two earlier potentials under‐predict thermal conductivity by one order of magnitude for the TR89 potential and by more than 30% for the GW02.

"Study on Radial Temperature Distribution of Aluminum Dispersed Nuclear Fuels: U3O8-Al, U3Si2-Al, and UN-Al" Ericmoore Jossou, Linu Malakkal, Barbara Szpunar, Jerzy A. Szpunar, Jayangani I. Ranasinghe, [2018] Journal of Nuclear Engineering and Radiation Science · DOI: 10.1115/1.4039886 · ISSN: 2332-8983

The understanding of the radial distribution of temperature in a fuel pellet, under normal operation and accident conditions, is important for a safe operation of a nuclear reactor. Therefore, in this study, we have solved the steady-state heat conduction equation, to analyze the temperature profiles of a 12 mm diameter cylindrical dispersed nuclear fuels of U3O8-Al, U3Si2-Al, and UN-Al operating at 597 °C. Moreover, we have also derived the thermal conductivity correlations as a function of temperature for U3Si2, uranium mononitride (UN), and Al. To evaluate the thermal conductivity correlations of U3Si2, UN, and Al, we have used density functional theory (DFT) as incorporated in the Quantum ESPRESSO (QE) along with other codes such as Phonopy, ShengBTE, EPW (electron-phonon coupling adopting Wannier functions), and BoltzTraP (Boltzmann transport properties). However, for U3O8, we utilized the thermal conductivity correlation proposed by Pillai et al. Furthermore, the effective thermal conductivity of dispersed fuels with 5, 10, 15, 30, and 50 vol %, respectively of dispersed fuel particle densities over the temperature range of 27–627 °C was evaluated by Bruggman model. Additionally, the temperature profiles and temperature gradient profiles of the dispersed fuels were evaluated by solving the steady-state heat conduction equation by using Maple code. This study not only predicts a reduction in the centerline temperature and temperature gradient in dispersed fuels but also reveals the maximum concentration of fissile material (U3O8, U3Si2, and UN) that can be incorporated in the Al matrix without the centerline melting. Furthermore, these predictions enable the experimental scientists in selecting an appropriate dispersion fuel with a lower risk of fuel melting and fuel cracking.

"First-principles study of defects and fission product behavior in uranium diboride" Dotun Oladimeji, Linu Malakkal, Simon Middleburgh, Barbara Szpunar, Jerzy Szpunar, Ericmoore Jossou, [2017] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2017.07.027 · ISSN: 0022-3115
"A first principles study of the electronic structure, elastic and thermal properties of UB2" Linu Malakkal, Barbara Szpunar, Dotun Oladimeji, Jerzy A. Szpunar, Ericmoore Jossou, [2017] Journal of Nuclear Materials · DOI: 10.1016/j.jnucmat.2017.04.006 · ISSN: 0022-3115
"Thermal conductivity of wurtzite and zinc blende cubic phases of BeO from ab initio calculations" Barbara Szpunar, Ravi Kiran Siripurapu, Juan Carlos Zuniga, Jerzy A. Szpunar, Linu Malakkal, [2017] Solid State Sciences · DOI: 10.1016/j.solidstatesciences.2017.01.005 · ISSN: 1293-2558
"Thermal conductivity of bulk and nanowire of cubic-SiC from ab initio calculations" Barbara Szpunar, Ravi Kiran Siripurapu, Jerzy A. Szpunar, Linu Malakkal, [2017] Computational Materials Science · DOI: 10.1016/j.commatsci.2016.11.040 · ISSN: 0927-0256
"First principles calculations of hydrogen storage on Cu and Pd-decorated graphene" Linu Malakkal, Ravi Kiran Siripurapu, Barbara Szpunar, Jerzy Szpunar, Aditya Choudhary, [2016] International Journal of Hydrogen Energy · DOI: 10.1016/j.ijhydene.2016.07.147 · ISSN: 0360-3199
"First principles calculation of thermo-mechanical properties of thoria using Quantum ESPRESSO" Barbara Szpunar, Juan Carlos Zuniga, Ravi Kiran Siripurapu, Jerzy A. Szpunar, Linu Malakkal, [2016] International Journal of Computational Materials Science and Engineering · DOI: 10.1142/s2047684116500081 · ISSN: 2047-6841

In this work, we have used Quantum ESPRESSO (QE), an open source first principles code, based on density-functional theory, plane waves, and pseudopotentials, along with quasi-harmonic approximation (QHA) to calculate the thermo-mechanical properties of thorium dioxide (ThO[Formula: see text]. Using Python programming language, our group developed qe-nipy-advanced, an interface to QE, which can evaluate the structural and thermo-mechanical properties of materials. We predicted the phonon contribution to thermal conductivity ([Formula: see text] using the Slack model. We performed the calculations within local density approximation (LDA) and generalized gradient approximation (GGA) with the recently proposed version for solids (PBEsol). We employed a Monkhorst-Pack [Formula: see text] k-points mesh in reciprocal space with a plane wave cut-off energy of 150 Ry to obtain the convergence of the structure. We calculated the dynamical matrices of the lattice on a [Formula: see text] mesh. We have predicted the heat capacity, thermal expansion and the phonon contribution to thermal conductivity, as a function of temperature up to 1400[Formula: see text]K, and compared them with the previous work and known experimental results.

Source: ORCID/CrossRef using DOI