- E. Georgieva, Kostadin N Ivanov and R. Stieglitz, 2015, "Explicit modeling of a VVER-1000 radial reflector by a ring of assembly-size nodes", ICAPP 2015, Nice (France)

- J. Shi, S. Levine and Kostadin N Ivanov, 2015, "Innovative approach to reloading an initial cycle", Advances in Nuclear Fuel Management V (ANFM 2015), Hilton Head Island, South Carolina, USA

- A. Bennett, Kostadin N Ivanov and M. Avramova, 2015, "Development and testing of a coupled MCNP6/CTF code", ANS MC2015 - Joint International Conference on Mathematics and Computation (M&C), Supercomputing in Nuclear Applications (SNA) and the Monte Carlo (MC) Methods, Nashville, Tennessee

- F. Reitsma, G. Strydom, F. Bostelmann and Kostadin N Ivanov, 2014, "The IAEA Coordinated Research Program on HTGR Uncertainty Analysis: Phase I status and initial results", HTR 2014, Weihai, China

- I. Clifford, Kostadin N Ivanov and M. Avramova, 2014, "A hierarchical multi-scale approach to modelling heat conduction in prismatic HTGRs using OpenFOAM", 9th OpenFOAM® Workshop, Zagreb, Croatia

- J. Hou, H. Choi and Kostadin N Ivanov, 2014, "Assessment of MICROX-2 code with new ENDF/B-VII.0 master libraries", Nuclear Technology,
**186**, pp. 305-316

- A. Rosenkrantz, M. Avramova, Kostadin N Ivanov, R. Prinsloo, D. Botes and K. Elsekhawy, 2014, "Coupled 3D neutronics/thermal hydraulics modeling of the SAFARI-1 MTR", Annals of Nuclear Energy,
**73**, pp. 122-130

- S. Ghrayeb, A. Ougouag, M. Ouisloumen and Kostadin N Ivanov, 2014, "Multi-group formulation of the temperature dependent resonance scattering model and its impact on reactor core parameters", Annals of Nuclear Energy,
**63**, pp. 751-762

- T. Ngeleka, Kostadin N Ivanov and S. Levine, 2014, "Examination and improvement of fine energy group structure for high temperature reactor analysis", Annals of Nuclear Energy,
**80**, pp. 279-292

- T. Kozlowski, A. Wysocki, I. Gajev, Y. Xu, T. Downar, Kostadin N Ivanov, J. Magedanz, M. Hardgrove, J. March-Leuba, N. Hudson and W. Ma, 2014, "Analysis of the OECD/NRC Oskarshamn-2 BWR stability benchmark", Annals of Nuclear Energy,
**67**, pp. 4 - 12

- S. Levine, T. Blyth and Kostadin N Ivanov, 2014, "The effect of changing enrichments on core performance", Annals of Nuclear Energy,
**75**, pp. 139-145

- R. Bratton, M. Avramova and Kostadin N Ivanov, 2014, "Benchmark for uncertainty analysis in modeling (UAM) for LWRs - Summary and discussion of neutronics cases (phase I)", Journal of Nuclear Engineering & Technology,
**46**, (3), pp. 313-349

- J. Hou, Kostadin N Ivanov and H. Choi, 2014, "Development of an iterative lattice-core coupling method based on MICROX-2 cross section libraries", PHYSOR 2014 International Conference "The Role of Reactor Physics toward a Sustainable Future", Kyoto, Japan

- M. Avramova, Kostadin N Ivanov, E. Royer, A. Yamaji and J. Gilford, 2014, "Summary and status of OECD/NEA UAM-LWR benchmark", Proceedings: PHYSOR 2014 International Conference, "The Role of Reactor Physics toward a Sustainable Future", Kyoto, Japan

- R. Bratton, Kostadin N Ivanov, M. Jessee and W. Wieselquist, 2014, "Bias and uncertainty assessment of pressurized water reactor fuel isotopics", PHYSOR 2014 International Conference "The Role of Reactor Physics toward a Sustainable Future", Kyoto, Japan

- S. Thompson and Kostadin N Ivanov, 2014, "Explicit transverse leakage treatment using an analytic basis function expansion", PHYSOR 2014 International Conference "The Role of Reactor Physics toward a Sustainable Future", Kyoto, Japan

- A. Aures, K. Velkov, W. Zwermann, P. Rouxelin, Kostadin N Ivanov, J. Lapins and W. Bernnat, 2014, "Uncertainty and sensitivity analysis for an OECD/NEA HTGR benchmark with XSUSA", PHYSOR 2014 International Conference "The Role of Reactor Physics toward a Sustainable Future", Kyoto, Japan

- D. Uçar, K. Ünlü, B. Heidrich, Kostadin N Ivanov and M. Avramova, 2014, "Neutronic designs and analyses of new core-moderator assembly and neutron beam ports for the Penn State Breazeale Reactor", PHYSOR 2014 International Conference "The Role of Reactor Physics toward a Sustainable Future", Kyoto, Japan

- M. Avramova, Kostadin N Ivanov, T. Kozlowski, I. Pasichnyk, W. Zimmerman, K. Velkov, E. Royer, A. Yamaji and J. Gilford, 2014, "Multi-physics and multi-scale benchmarking and uncertainty quantification within NEA/OECD framework", Annals of Nuclear Energy

- Kostadin N Ivanov, V. Sanchez, R. Stieglitz and K. Ivanov, 2014, "Large-scale Monte Carlo neutron transport calculations with thermal hydraulic feedback", Annals of Nuclear energy

- A. Ivanov, V. Sanchez, R. Stieglitz and Kostadin N Ivanov, 2014, "Internal multi-scale multi-physics coupled system for high fidelity simulation of light water reactors", Annals of Nuclear Energy,
**66**, pp. 104-112

- E. Georgieva, Y. Dinkov and Kostadin N Ivanov, 2014, "A cycle-specific cross-section update for real-time simulation of VVER-1000 core", Progress in Nuclear Energy,
**74**, pp. 222-231

- J. Hou, H. Choi and Kostadin N Ivanov, 2014, "Self-shielding models of MICROX-2 code: Review and updates", Annals of Nuclear Energy,
**64**, pp. 256-263

- D. Colameco, B. Ivanov and Kostadin N Ivanov, 2013, "Iterative transport-diffusion methodology for LWR core analysis", Joint International Conference on Supercomputing in Nuclear Applications and Monte Carlo 2013 (SNA + MC 2013)

- A. Ivanov, V. Sanchez and Kostadin N Ivanov, 2013, "High-fidelity coupled Monte-Carlo/thermal-hydraulics calculations", Joint International Conference on Supercomputing in Nuclear Applications and Monte Carlo 2013 (SNA + MC 2013)

- S. Levine, T. Blyth and Kostadin N Ivanov, 2013, "Optimizing PWR low leakage cores with genetic algorithms and other techniques", 2013 Annual ANS Meeting

- S. Evans and Kostadin N Ivanov, 2013, "Evaluation of the use of color-set geometry during lattice physics constants generation for boiling water reactor simulation", International Conference on Mathematics and Computational Methods Applied to Nuclear Science & Engineering (M&C 2013)

- O. Courty, I. Davis, M. Avramova, Kostadin N Ivanov and A. Motta, 2013, "Modeling hydrogen re-distribution in Zircaloy under a temperature gradient", Proceedings of TMS 2013, 142 Annual Meeting

- Kostadin N Ivanov, C. Parisi and O. Cabellos, 2013, "Uncertainty analysis in reactor physics modeling", International Journal of Science and Technology of Nuclear Installations,
**2013**

- A. Ivanov, V. Sanchez, R. Stieglitz and Kostadin N Ivanov, 2013, "High fidelity simulation of conventional and innovative LWR with the coupled Monte-Carlo thermal-hydraulic system MCNP-SUBCHANFLOW", Nuclear Engineering and Design,
**262**

- M. Ellis, J. Watson and Kostadin N Ivanov, 2013, "Progress in the development of an implicit steady state solution in TRACE and PARCS", Progress of Nuclear Energy,
**66**, pp. 1-12

- F. Puente Espel, M. Avramova, Kostadin N Ivanov and S. Misu, 2013, "New developments of the MCNP/CTF/NEM/NJOY code system - Monte Carlo based coupled code for high accuracy modeling", Annals of Nuclear Energy,
**51**, pp. 18-26

- I. Clifford, Kostadin N Ivanov and M. Avramova, 2013, "A multi-scale homogenization and reconstruction approach for solid material temperature calculations in prismatic high temperature reactor cores", Journal of Nuclear Engineering and Design,
**256**, pp. 1-13

- S. Levine, T. Blyth and Kostadin N Ivanov, 2013, "Understanding using the Haling power depletion (HPD) as a guide for designing PWR cores", Annals of Nuclear Energy,
**53**, pp. 120-128

- L. Mercatali, Kostadin N Ivanov and V. Sanchez, 2013, "SCALE modeling of selected neutronics test problems within the OECD UAM LWR's benchmark", Journal of Science and Technology of Nuclear Installations, Special Issue on Uncertainty Analysis in Reactor Physics Modeling,
**2013**, pp. 11

- C. Arenas, R. Bratton, F. Reventos and Kostadin N Ivanov, 2013, "Uncertainty analysis of light water reactor fuel lattices", Journal of Science and Technology of Nuclear Installations, Special Issue on Uncertainty Analysis in Reactor Physics Modeling,
**2013**, pp. 10

- I. Davis, O. Courty, M. Avramova, A. Motta and Kostadin N Ivanov, 2013, "High fidelity multi-physics coupling for prediction of anisotropic azimuthal power and temperature distribution on fuel rod: Impact on hydride distribution", Proceedings: The 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15)

- R. Pericas, Kostadin N Ivanov and F. Reventós, 2013, "Comparison of best estimate plus uncertainties and conservative methodologies for a PWR MSLB analysis using coupled 3D neutron kinetics/thermal-hydraulics code", Proceedings: The 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15)

- Mark Biery, Maria Avramova and Kostadin N Ivanov, 2013, "Investigations of the effects of soluble boron tracking on coupled CTF/NEM LWR simulations", International Conference on Mathematics and Computational Methods Applied to Nuclear Science & Engineering (M&C 2013)

- Z. Karriem, Kostadin N Ivanov, C. Rabiti and H. Gougar, 2013, "The development and testing of the HELIOS-2 lattice code for use in on-line cross-section generation", International Conference on Mathematics and Computational Methods Applied to Nuclear Science & Engineering (M&C 2013)

- J. Hou, Kostadin N Ivanov and H. Choi, 2013, "Self-shielding models of MICROX-2 code", International Conference on Mathematics and Computational Methods Applied to Nuclear Science & Engineering (M&C 2013)

- G. Strydom, F. Reitsma, H. Gougar, B. Tyobeka and Kostadin N Ivanov, 2012, "IAEA CRP on HTGR uncertainty analysis: Benchmark definition and test cases"

- J. Hou*, H. Choi and Kostadin N Ivanov, 2012, "Pin cell benchmark calculations of MICROX-2 library"

- Justin Wats andn*, , 2012, "Verification of implicit coupling of TRACE/PARCS using simplified one-dimensional problems", Nuclear Technology,
**180**, (2), pp. 174-190

- D. Sahin, Kostadin N Ivanov and K. Unlu, 2012, "Modeling transient mechanisms for Penn State Breazeale Nuclear Reactor neutronic analysis"

- Javier Jiménez, Maria Avramova, Victor Hugo Sanchez and Kostadin N Ivanov, 2012, "Recent developments in KTF: Code optimization and improved numerics", KTG 2012 International Conference

- Kostadin N Ivanov, M. Avramova, S. Kamerow, I. Kodeli, E. Sartori, E. Ivanov and O. Cabellos, 2012, "Benchmark for uncertainty analysis in modeling (UAM) for design, operation, and safety analysis of LWRs, Volume 1: Specification and support data for the neutronics cases (phase I) - Version 2.0 (final specifications)", NEA/NSC/DOC

- Shadi Z. Ghrayeb*, Mohamed Ouisloumen, Abderrafi M. Ougouag and Kostadin N Ivanov, 2012, "Multi-group computation of the temperature-dependent resonance scattering model (RSM) and its implementation", American Nuclear Society, LaGrange Park, IL

- S. Levine, T. Blyth and Kostadin N Ivanov, 2012, "Understanding the Haling power depletion (HPD) method", American Nuclear Society, LaGrange Park, IL

- T. Kozlowski, T. Downar, Y. Xu, A. Wysocki, Kostadin N Ivanov, J. Magedanz, M. Hardgrove, J. March-Leuba and N. Hudson, 2012, "TRACE/PARCS analysis of the OECD/NEA Oskarshamn-2 BWR stability benchmark", American Nuclear Society, LaGrange Park, IL

- J. Hou*, Kostadin N Ivanov and H. Choi, 2012, "MICROX-2 cross-section library generation based on ENDF/B-VII", American Nuclear Society, LaGrange Park, IL

- T. Blyth, M. Avramova, Kostadin N Ivanov, E. Royer, E. Sartori and O. Cabellos, 2012, "Benchmark for uncertainty analysis in modeling (UAM) for design, operation, and safety analysis of LWRs, Volume 2: Specification and support data for the core cases (phase II) - Version 1", NEA/NSC/DOC

- Shadi Z. Ghrayeb*, Mohamed Ouisloumen, Abderrafi M. Ougouag and Kostadin N Ivanov, 2012, "Computation of the resonant neutron scattering to higher angular moments"

- Frederik Reitsma, Bismark Tyobeka and Kostadin N Ivanov, 2012, "The IAEA coordinated research program on HTGR reactor physics, thermal-hydraulics and depletion uncertainty analysis", HTR 2012 International Conference

- I. Clifford*, Kostadin N Ivanov and M. Avramova, 2012, "A multi-scale homogenization and reconstruction approach for solid material temperature calculations in the MHTGR core", HTR 2012 International Conference

- Kamron Fazel*, Qi Li and Kostadin N Ivanov, 2012, "Effects of superconductor electron screening on fusion reaction rates", Fusion Science and Technology,
**61**, (1T), pp. 469-474

- Armando Miguel Gomez Torres, Victor Hugo Sánchez Espinoza, Kostadin N Ivanov and Rafael Macián Juan, 2012, "DYNSUB: A high fidelity coupled code system for the evaluation of local safety parameters. Part I: Development, implementation and verification", Annals of Nuclear Energy,
**48**, pp. 108-122

- Armando Miguel Gomez Torres, Victor Hugo Sánchez Espinoza, Kostadin N Ivanov and Rafael Macián Juan, 2012, "DYNSUB: A High fidelity coupled code system for the evaluation of local safety parameters. Part II: Comparison of the different temporal schemes implemented", Annals of Nuclear Energy,
**48**, pp. 123-129

- V. Sanchez Espinoza and Kostadin N Ivanov, 2011, "Importance of LWR best-estimate safety calculations for analysis of Fukushima-like accidents", Proceedings of the International Conference Proceedings GLOBAL 2011

- M. Avramova, C. Arenas Moreno and Kostadin N Ivanov, 2011, "Extension of BEPU methods to sub-channel thermal-hydraulics and to coupled three-dimensional neutronics/thermal-hydraulics codes", Proceedings of OECD/CSNI Workshop

- Kostadin N Ivanov, M. Avramova, E. Royer and G. Gillford, 2011, "Discussion of OECD LWR uncertainty analysis in modelling benchmark", Proceedings of OECD/CSNI Workshop

- Shadi Z. Ghrayeb, Kostadin N Ivanov, Samuel H. Levine and Eric P. Loewen, 2011, "Burnup performance of sodium-cooled fast reactor by utilizing thorium-based fuels", Nuclear Technology,
**176**, (2), pp. 188-194

- Shadi Z. Ghrayeb, Mohamed Ouisloumen, Abderrafi M. Ougouag and Kostadin N Ivanov, 2011, "Multi-group formulation of the resonance scattering model (RSM) and its implementation", Proceedings of PHYTRA 2 , The Second International Conference on Physics and Technology of Reactors and Applications

- B. Neykov, V. Palazov, T. Downar and Kostadin N Ivanov, 2011, "TRACE/PARCS validation for BWR stability based on OECD/NEA Oskarshamn-2 benchmark", Proceedings of the 14th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-14)

- I. Clifford, Kostadin N Ivanov and M. Avramova, 2011, "A general coarse and fine mesh solution scheme in fluid flow modeling in VHTRS", Proceedings of the International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2011)

- S. Kamerow, Kostadin N Ivanov and C. Arenas Moreno, 2011, "Uncertainty analysis of light water reactor unit fuel pin cells", Proceedings of the International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2011)

- Z. Karriem, O. Zamonsky and Kostadin N Ivanov, 2011, "Development of a consistent Monte Carlo-deterministic transport methodology based on the method of characteristics and MCNP5", Proceedings of the International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2011)

- K. Fazel, Q. Li and Kostadin N Ivanov, 2011, "Fusion cross-section enhancement in superconductors", Proceedings of the 15th International Conference on Emerging Nuclear Energy Systems (ICENES-2011)

- Kostadin N Ivanov, S. Khodyachykh and S. Levine, 2011, "An updated syllabus for the Penn State graduate fuel management course"

- S. Kamerow, M. Avramova and Kostadin N Ivanov, 2011, "Update on the OECD LWR uncertainty analysis in modeling (UAM) benchmark"

- B. Tyobeka, A. Pautz and Kostadin N Ivanov, 2011, "Application of time-dependent neutron transport theory to high temperature reactors of pebble bed type", Nuclear Science and Engineering,
**168**, pp. 93-114

- R. Mphahlele, A. Ougouag, Kostadin N Ivanov and H. Gougar, 2011, "Spectral zones determination for pebble bed reactor cores", Annals of Nuclear Energy,
**38**, pp. 80-87

- Federico Puente Espel, Chanatip Tippayakul, Kostadin N Ivanov and Stefan Misu, 2011, "MCOR - Monte Carlo depletion code for reference LWR calculations", Annals of Nuclear Energy,
**38**, pp. 731-741

- Shadi Z. Ghrayeb, Mohamed Ouisloumen, Abderrafi M. Ougouag and Kostadin N Ivanov, 2011, "Deterministic modeling of higher angular moments of resonant neutron scattering", Annals of Nuclear Energy,
**38**, pp. 2291-2297

- S. Ghrayeb, M. Ouisloumen, A. Ougouag and Kostadin N Ivanov, 2010, "The resonance neutron scattering angular moments using the deterministic approach",
**103**

- I. Clifford and Kostadin N Ivanov, 2010, "PBMR 400 MW benchmark calculations using the simplified P3 approach", 2010 International Conference on the Hight Temperature Reactors (HTR-2010)

- S. Ghrayeb, M. Ouisloumen, A. Ougouag and Kostadin N Ivanov, 2010, "Effect of the resonance scattering model on reactor core neutronics calculations", 2010 International Conference on the Hight Temperature Reactors (HTR-2010)

- H. Gougar, A. Ougouag, W. Terry and Kostadin N Ivanov, 2010, "Automated design and optimization of pebble-bed reactor cores", Nuclear Science and Engineering,
**165**, (3), pp. 245-269

- C. Parisi, M. Pecchia, F. D'Auria, Kostadin N Ivanov and O. Mazzantini, 2010, "Validation of Atucha-2 PHWR HELIOS and RELAP5-3D model by Monte Carlo cell and core calculations", 2010 International Conference on the Physics of Reactors (PHYSOR-2010)

- F. Puente Espel, M. Avramova, Kostadin N Ivanov and S. Misu, 2010, "New developments of the MCNP/CTF/NEM/NJOY code system - Monte Carlo based coupled code for high accuracy modeling", 2010 International Conference on the Physics of Reactors (PHYSOR-2010)

- D. Colameco, M. Ouisloumen, L. Mayhue and Kostadin N Ivanov, 2010, "Improved reflector modeling for LWR analysis", 2010 International Conference on the Physics of Reactors (PHYSOR-2010)

- D. Roberts, M. Ouisloumen, V. Kuckboyaci and Kostadin N Ivanov, 2010, "Development of iterative transport-diffusion methodology for LWR analysis", 2010 International Conference on the Physics of Reactors (PHYSOR-2010)

- A. Nelson and Kostadin N Ivanov, 2010, "Monte-Carlo methods for neutron transport on graphics processing units using CUDA", 2010 International Conference on the Physics of Reactors (PHYSOR-2010)

- P. Mkhabela and Kostadin N Ivanov, 2010, "Improvements to the NEM-THERMIX coupled code analysis of high temperature reactors", 2010 International Conference on the Physics of Reactors (PHYSOR-2010)

- J. Watson and Kostadin N Ivanov, 2010, "Implicit time-integration method for simultaneous solution of a coupled non-linear system", 2010 International Conference on the Physics of Reactors (PHYSOR-2010)

- F. Puente Espel, S. Ghrayeb, Kostadin N Ivanov and S. Tarantola, 2010, "Application of global sensitivity analysis approach to exercise I-2 of the OECD LWR UAM benchmark", 2010 International Conference on the Physics of Reactors (PHYSOR-2010)

- G. Strydom, F. Reitsma, P. Ngeleka and Kostadin N Ivanov, 2010, "The OECD/NEA/NSC PBMR 400 MW coupled neutronics thermal hydraulics transient benchmark: Transient results", 2010 International Conference on the Physics of Reactors (PHYSOR-2010)

- F. Puente Espel, Kostadin N Ivanov, M. Avramova and S. Misu, 2010, "New developments of the MCNP/CTF/NEM/NJOY code system - Monte Carlo based coupled code for high accuracy modeling", Nuclear Science and Engineering, Special Issue of PHYSOR-2010 Conference 2010

- N. Krianchaiporn, Kostadin N Ivanov, A. Haghighat and C. F. Sears, 2010, "Transport model based on three-dimensional cross-section generation for TRIGA core analysis", Annals of Nuclear Energy,
**37**, (1254-1260)

- F. Reitsma, B. Tyobeka and Kostadin N Ivanov, 2010, "IAEA proposed coordinated research program on HTGR reactor physics, thermal-hydraulics and depletion uncertainty analysis"

- F. Aydogan, L. Hochreiter, Kostadin N Ivanov, M. Martin, H. Utsuno and E. Sartori, 2010, "NUPEC BWR full-size fine-mesh bundle test (BFBT) benchmark volume II: Uncertainty and sensitivity analyses of void distribution and critical power - Specification"

- M. Avramova and Kostadin N Ivanov, 2010, "Verification and validation and uncertainty quantification in multi-physics modeling for nuclear reactor design", Progress in Nuclear Energy,
**52**, pp. 601-614

- B. Akdeniz, Kostadin N Ivanov and A. Olson, 2010, "BWR TT benchmark. Volume IV: Summary results of exercise 3"

- D. Colameco, Kostadin N Ivanov, R. Prinsloo, D. Tomasevic and S. Theron, 2009, "A comparison between recent advances in cylindrical nodal diffusion methods", Journal of Engineering for Gas Turbines and Power,
**131**

- F. Puente Espel, M. Avramova and Kostadin N Ivanov, 2009, "High accuracy modeling for advanced nuclear reactor core designs using Monte Carlo based coupled calculations", Proceedings of International Conference on Mathematics, Computational Methods & Reactor Physics (M&C 2009)

- M. Avramova, Kostadin N Ivanov, B. Krzykacz-Hausmann, K. Velkov, A. Pautz and Y. Perin, 2009, "Uncertainty analysis of COBRA-TF void distribution predictions for the OECD/NRC BFBT benchmark", Proceedings of International Conference on Mathematics, Computational Methods & Reactor Physics (M&C 2009)

- F. Puente Espel, S. Ghrayeb, Kostadin N Ivanov and S. Tarantola, 2009, "Application of global sensitivity analysis approach to exercise I-1 of the OECD LWR UAM benchmark", Proceedings of International Conference on Mathematics, Computational Methods & Reactor Physics (M&C 2009)

- S. Ghrayeb, Kostadin N Ivanov, S. Levine, F. Puente-Espel and E. Loewen, 2009, "Improving burnup performance of fast sodium cooled reactor by utilizing thorium based fuels", Proceedings of International Conference on Mathematics, Computational Methods & Reactor Physics (M&C 2009)

- Kostadin N Ivanov and M. Avramova, 2009, "Verification & validation and uncertainty analysis in multi-physics modeling for nuclear reactor design and safety", Proceedings of International Conference on Mathematics, Computational Methods & Reactor Physics (M&C 2009)

- Kostadin N Ivanov, M. Avramova, S. Kamerow, I. Kodeli and E. Sartori, 2009, "Overview and discussion of phase I of the OECD LWR UAM benchmark activity", Proceedings of International Conference on Mathematics, Computational Methods & Reactor Physics (M&C 2009)

- F. Alim, S. Yilmaz, Kostadin N Ivanov and S. Levine, 2009, "Genetic algorithms to automatically optimize PWR fuel management calculations", Proceedings of Advances in Nuclear Fuel Management IV (ANFM 2009)

- F. Puente Espel, Kostadin N Ivanov and S. Misu, 2009, "Further development of MCOR - Monte Carlo depletion code for reference LWR calculations", Proceedings of Advances in Nuclear Fuel Management IV (ANFM 2009)

- J. Magedanz, A. Soler, B. Neykov, Kostadin N Ivanov and Z. Wang, 2009, "Testing of real-time version of RELAP5-3D for a boiling water reactor", The 13th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-13)

- B. Neykov, M. Avramova and Kostadin N Ivanov, 2009, "CFD and sub-channel code validation utilizing the OECD/NRC BFBT benchmark", The 13th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-13)

- Y. Xu, T. Downar, R. Walls, Kostadin N Ivanov, J. Staudenmeier and J. March-Lueba, 2009, "Application of TRACE/PARCS to BWR stability analysis", Annals of Nuclear Energy,
**36**, pp. 317-323

- S. Ghrayeb, Kostadin N Ivanov, S. Levine and E. Lowen, 2008, "Development of Monte Carlo models to investigate thorium-based fuel in sodium cooled fast reactors"

- F. Puente Espel, C. Tippayakul, S. Misu and Kostadin N Ivanov, 2008, "MCOR as a reference tool for benchmarking spectral codes"

- J. Jiménez, M. Avramova, D. Cuervo and Kostadin N Ivanov, 2008, "Comparative analysis of neutronics/thermal-hydraulics multi-scale coupling for LWR analysis", PHYSOR-2008 International Conference

- F. Reitsma, J. Han, Kostadin N Ivanov and E. Sartori, 2008, "The OECD/NEA/NSC PBMR400 MW coupled neutronics thermal-hydraulics transient benchmark - Status and comparative analysis", PHYSOR-2008 International Conference

- A. Pautz, B. Tyobeka and Kostadin N Ivanov, 2008, "Application of time-dependent neutron transport theory to high-temperature reactors of pebble bed type", PHYSOR-2008 International Conference

- B. Tyobeka, A. Pautz and Kostadin N Ivanov, 2008, "DORT-TD/THERMIX solutions for the OECD/NEA/NSC PBMR400 MW coupled neutronics thermal hydraulics transient benchmark", PHYSOR-2008 International Conference

- R. Mphahlele, A. Ougouag, H. Gougar and Kostadin N Ivanov, 2008, "Spectral zones selection methodology for pebble bed reactors", PHYSOR-2008 International Conference

- P. Mkhabela, J. Han and Kostadin N Ivanov, 2008, "DLOFC transient analysis for PBMR with NEM/THERMIX", PHYSOR-2008 International Conference

- B. Akdeniz, E. Müller, D. Panayotov and Kostadin N Ivanov, 2008, "Improved nodal kinetics model for BWR coupled transient calculations", PHYSOR-2008 International Conference

- B. Ivanov, E. Müller, M. Ouisloumen and Kostadin N Ivanov, 2008, "Embedded lattice transport calculations based on PARAGON-NEM code system for reactor core analysis", PHYSOR-2008 International Conference

- Y. Xu, T. Downar, B. Akdeniz, R. Walls, Kostadin N Ivanov, J. Staudenmeier and J. March-Lueba, 2008, "The application of TRACE/PARCS to BWR stability analysis", PHYSOR-2008 International Conference

- C. Parisi, O. Mazzantini, F. D. Auria and Kostadin N Ivanov, 2008, "RELAP5-3D© three-dimensional coupled neutron kinetics/thermal-hydraulics analyses of the ATUCHA2 PHWR", PHYSOR-2008 International Conference

- J. Watson, J. Mahaffy and Kostadin N Ivanov, 2008, "Implicit time-integration method for simultaneous solution of a coupled nonlinear system"

- Kostadin N Ivanov, S. Langenbuch, A. Pautz, A. Seubert and K. Velkov, 2008, "International activities of development and validation of coupled codes and their significance for realistic accident analyses", TK2008 International Conference

- Kostadin N Ivanov, M. Avramova, I. Kodeli and E. Sartori, 2008, "Uncertainty analysis in modeling (UAM) and safety implications", TopSafe International Conference

- B. Tyobeka, A. Pautz and Kostadin N Ivanov, 2008, "Systematic qualification of the coupled neutron transport and thermal-hydraulics code DORT-TD/THERMIX", 4th International Topical Meeting on High Temperature Reactor Technology

- D. Colameco, Kostadin N Ivanov, R. Prinsloo, D. Tomasevic and S. Theron, 2008, "A comparison between recent advances in cylindrical nodal diffusion methods", 4th International Topical Meeting on High Temperature Reactor Technology

- R. Mphahlele, A. Ougouag, Kostadin N Ivanov and H. Gougar, 2008, "Spectral zones determination for pebble bed reactor cores using diffusion theory spectral indices", 4th International Topical Meeting on High Temperature Reactor Technology

- F. Alim, Kostadin N Ivanov and S. Levine, 2008, "The Haling power depletion method for in-core fuel management analysis", Annals of Nuclear Energy,
**35**, (1), pp. 933-945

- F. Alim, Kostadin N Ivanov and S. Levine, 2008, "Simultaneous optimization of loading pattern and burnable poison placements for the TMI-1 reactor", Annals of Nuclear Energy,
**35**, (1), pp. 113-120

- F. Alim, Kostadin N Ivanov and S. Levine, 2008, "GA loading pattern and burnable poison placement optimization technique for PWR", Annals of Nuclear Energy,
**35**, (1), pp. 93-112

- F. D'Auria, S. Soloviev, V. Malofeev, Kostadin N Ivanov and C. Parisi, 2008, "The three-dimensional neutron kinetics coupled with thermal-hydraulics in RBMK accident analysis", Nuclear Design and Engineering,
**238**, (4), pp. 1002-1025

- V. Xulubana, C. Tippayakul, Kostadin N Ivanov, S. Levine and M. Mahgerefteh, 2008, "Accuracy evaluation of pin exposure calculations in current LWR core design codes", Annals of Nuclear Energy,
**35**, (3), pp. 414-424

- C. Tippayakul, Kostadin N Ivanov and F. Sears, 2008, "Development of a practical Monte Carlo based fuel management system for the Penn State University Breazeale Research Reactor (PSBR)", Annals of Nuclear Energy,
**35**, (3), pp. 539-551

- B. Tyobeka, Kostadin N Ivanov and A. Pautz, 2008, "Evaluation of PBMR control rod worth using full three-dimensional deterministic transport methods", Annals of Nuclear Energy,
**35**, (6), pp. 1050-1055

- C. Tippayakul, M. Avramova, F. Espel and Kostadin N Ivanov, 2007, "Investigations on Monte Carlo based coupled core calculations", ICAPP-2007 Conference

- B. Ivanov, L. Zikatanov and Kostadin N Ivanov, 2007, "Feasibility study on embedded transport core calculation", ICAPP-2007 Conference

- Kostadin N Ivanov and M. Avramova, 2007, "Progress and challenges in the development and qualification of multi-level multi-physics coupled methodologies for reactor analysis", ICAPP-2007 Conference

- B. Tyobeka, Kostadin N Ivanov and A. Pautz, 2007, "Analysis of PBMR transients using a coupled neutron transport/thermal-hydraulics code DORT-TD/THERMIX", ICAPP-2007 Conference

- M. Avramova, Kostadin N Ivanov and L. Hochreiter, 2007, "Analysis of steady state and transient void distribution predictions for phase I of the OECD/NRC BFBT benchmark using CTF/NEM", NURETH-12 Conference

- F. Audogan, N. Neykov, M. Avramova, L. Hochreiter and Kostadin N Ivanov, 2007, "Overview and status of the OECD/NRC BFBT benchmark activities", NURETH-12 Conference

- F. Audogan, L. Hochreiter, Kostadin N Ivanov and J. Mahaffy, 2007, "PIRT for the BWR steady state void distribution", NURETH-12 Conference

- F. Audogan, L. Hochreiter and Kostadin N Ivanov, 2007, "Evaluation of the sub-channel code COBRA-TF for prediction of BWR fuel assembly void distribution", NURETH-12 Conference

- F. Audogan, L. Hochreiter, Kostadin N Ivanov and J. Mahaffy, 2007, "PIRT for BWR steady state fuel assembly critical power", NURETH-12 Conference

- P. Mkhabela, A. Ougouuag, Kostadin N Ivanov, H. Gougar and J. Han, 2007, "Systematic method of neutron energy group structure selection for HTR reactor",
**96**

- J. Han, A. Ougouag, Kostadin N Ivanov, H. D. Gougar and P. Mkhabela, 2007, "Broad energy group structure sensitivity studies for the PBMR",
**97**, pp. 511-513

- F. Aydogan, L. Hochreiter and Kostadin N Ivanov, 2007, "Correlation for void fraction measurements of the BFBT X-ray densitometers",
**97**, pp. 441-443

- B. Akdeniz, E. Müller, D. Panayotov and Kostadin N Ivanov, 2007, "Enhancing the accuracy of the simplified K-ratio method of estimating the delayed neutron importance factor",
**97**, pp. 501-503

- F. Aydogan, L. Hochreiter and Kostadin N Ivanov, 2007, "Evaluation of thermal time constant for the BFBT heater rods",
**97**, pp. 749-751

- F. Alim, S. Yilmaz, Kostadin N Ivanov and S. Levine, 2007, "PWR core design optimization using genetic algorithms",
**97**, pp. 384-386

- B. Neykov, E. Popov, Kostadin N Ivanov and L. Hochreiter, 2007, "Utilization of the OECD/NRC BFBT benchmark data base for single phase CFD code validation",
**97**, pp. 667-669

- B. Ivanov and Kostadin N Ivanov, 2007, "OECD/DOE/CEA V1000CT-1 benchmark. Volume III - Summary of exercise 2 results",
**23**

- B. Ivanov, Kostadin N Ivanov and S. Aniel-Buchheit, 2007, "VVER-1000 coolant transient benchmark - Phase I (V1000CT-1) volume 3: Summary results of exercise 2 on coupled 3-D kinetics/core thermal-hydraulics",
**18**

- Kostadin N Ivanov, M. Avramova, I. Kodeli and E. Sartori, 2007, "Benchmark for uncertainty analysis in modelling (UAM) for design, operation and safety analysis of LWRs: Volume I version 1.0: Specification and supporting data for the neutronics cases (phase I)",
**23**

- Kostadin N Ivanov and M. Avramova, 2007, "Challenges in coupled thermal-hydraulics and neutronics simulations for LWR safety analysis", Annals of Nuclear Energy,
**34**, (6), pp. 501-513

- B. Tyobeka, Kostadin N Ivanov and A. Pautz, 2007, "Utilization of two-dimensional deterministic transport methods for analysis of pebble-bed reactors", Annals of Nuclear Energy,
**34**, (5), pp. 396-405

- E. Popov, B. Ivanov, Kostadin N Ivanov and S. Mladenova, 2007, "Flow rotation and mixing in the downcomer of a VVER-1000 reactor", Nuclear Technology,
**158**, (3), pp. 358-366

- Kostadin N Ivanov, E. Sartori, E. Royer, S. Langenbuch and K. Velkov, 2007, "Validation of coupled thermal-hydraulic and neutronic codes for safety analysis by international cooperation", Nuclear Technology,
**157**, (2), pp. 177-195

- S. Yilmaz, Kostadin N Ivanov, S. Levine and M. Mahgerefteh, 2006, "Genetic algorithm to optimize the UO2/Gd2O3 fuel pin designs in a pressurized water reactor", Nuclear Technology,
**156**, (2), pp. 168-179

- S. Yilmaz, Kostadin N Ivanov, S. Levine and M. Mahgerefteh, 2006, "Genetic algorithm application for burnable poison placement in PWRs with optimized UO2/Gd2O3 fuel pin configurations", Nuclear Technology,
**156**, (2), pp. 180-190

- F. Audogan, L. Hochreiter and Kostadin N Ivanov, 2006, "Using OECD/NRC BFBT benchmark for consistent assessment of a subchannel code for BWR applications", ICONE-14 Conference

- B. Ivanov and Kostadin N Ivanov, 2006, "OECD/DOE/CEA V1000CT-1 benchmark. Volume II - Summary of exercise 1 results"

- A. Bousbia Salah, J. Vedovi, F. D'Auria, G. Galasi and Kostadin N Ivanov, 2006, "Analysis of the VVER-1000 coolant transient benchmark using the coupled RELAP5/PARCS code", Progress in Nuclear Energy,
**48**, (8), pp. 806-819

- A. Shkarupa, I. Kadenko, M. Malanich, A. Kovtonyuk and Kostadin N Ivanov, 2006, "Comparative RELAP-3D analysis in support of the NPP DBA analysis in Ukraine", Progress in Nuclear Energy,
**48**, (8), pp. 891-911

- N. Kolev, N. Petrov, B. Ivanov and Kostadin N Ivanov, 2006, "Simulation of the VVER-1000 pump start-up experiment of OECD V1000CT benchmark with CATHARE and TRAC-PF1", Progress in Nuclear Energy,
**48**, (8), pp. 922-936

- F. Reitsma, G. Strydom, J. B. M. De Haas, Kostadin N Ivanov, B. Tyobeka, R. Mphahlele, T. Downar, V. Seker, H. Gougar, D. F. Da Cruz and U. Sikik, 2006, "The PBMR steady-state and coupled kinetics core thermal-hydraulics benchmark test problems", Nuclear Design and Engineering,
**236**, pp. 657-668

- D. Cuervo, M. Avramova, Kostadin N Ivanov and R. Miro, 2006, "Evaluation and enhancement of COBRA-TF efficiency for LWR calculations", Annals of Nuclear Energy,
**33**, pp. 837-847

- C. Tippayakul, Kostadin N Ivanov and S. Misu, 2006, "Improvements of MCOR: New Monte Carlo depletion code system for fuel assembly reference calculations", PHYSOR 2006 Conference

- C. Parisi, V. Malofeev, B. Ivanov and Kostadin N Ivanov, 2006, "RBMK coupled neutronics/thermal-hydraulics analyses by two independent code systems", PHYSOR 2006 Conference

- C. Bergier, B. Ivanov and Kostadin N Ivanov, 2006, "Establishment of consistent benchmark framework for performing high-fidelity whole core transport/diffusion calculations", PHYSOR 2006 Conference

- F. Alim and Kostadin N Ivanov, 2006, "Simultaneous optimization of loading pattern and burnable poison placement for PWRs", PHYSOR 2006 Conference

- M. Avramova, D. Cuervo and Kostadin N Ivanov, 2006, "Improvements and applications of COBRA-TF for stand-alone and coupled LWR safety analyses", PHYSOR 2006 Conference

- B. Tyobeka, A. Pauttz and Kostadin N Ivanov, 2006, "Utilization of deterministic transport methods for analysis of pebble bed reactors", PHYSOR 2006 Conference

- B. Ivanov, E. Popov and Kostadin N Ivanov, 2006, "TRACE/PARCS calculations of exercises 1 and 2 of the V1000CT-2 benchmark", PHYSOR 2006 Conference

- B. Akdeniz, E. Muller, D. Panayotov and Kostadin N Ivanov, 2006, "Consistent neutron kinetics data generation for nodal transient calculations", PHYSOR 2006 Conference

- N. Kriangchaiporn, Kostadin N Ivanov, A. Haghighat and F. Sears, 2006, "Transport model based on three-dimensional cross-section generation for TRIGA core analysis", PHYSOR 2006 Conference

- N. Krianchaiporn, M. Ouisloumen, H. Huria and Kostadin N Ivanov, 2006, "The resonance interference model for PARAGON", PHYSOR 2006 Conference

- V. Bilovsky, E. Redmond, C. Walker and Kostadin N Ivanov, 2006, "Criticality evaluation of control component credited mixed zone", PHYSOR 2006 Conference

- P. Mhkabela, J. Han, B. Tyobeka, Kostadin N Ivanov, F. Reitsma and E. Sartori, 2006, "Summary of comparison and analysis of results from exercises 1 & 2 of the OECD PBMR coupled neutronics/thermal hydraulics transient benchmark", PHYSOR 2006 Conference

- J. Ortensi, H. Gougar, P. Mkhabela, J. Han, B. Tyobeka and Kostadin N Ivanov, 2006, "PBMR 400 coupled code benchmark: Challenges and successes with NEM-THERMIX"

- B. Neykov, F. Audogan, L. Hochreiter, Kostadin N Ivanov, H. Utsuno, E. Sartori and G. Rhee, 2006, "Development of OECD/NRC BFBT benchmark for validation and improvement of two-phase flow modeling"

- S. Yilmaz, Kostadin N Ivanov, S. Levine and M. Mahgerefteh, 2006, "Application of genetic algorithm to optimize burnable poison placement in PWRs", Annals of Nuclear Energy,
**33**, (5), pp. 446-456

- J. Gozalvez, S. Yilmaz, F. Alim, Kostadin N Ivanov and S. Levine, 2006, "Sensitivity study on determining efficient fuel assembly parameters in training data for designing of neural networks in hybrid genetic algorithms", Annals of Nuclear Energy,
**33**, (5), pp. 457-465

- B. Ivanov, Kostadin N Ivanov, E. Royer, S. Aniel, U. Bieder, N. Kolev and P. Groudev, 2006, "OECD/DOE/CEA VVER-1000 coolant transient (V1000CT) benchmark - A consistent approach for assessing coupled codes for RIA analysis", Progress in Nuclear Energy,
**48**, (8), pp. 728-745

- B. Ivanov, S. Aniel, P. Siltanen, E. Royer and Kostadin N Ivanov, 2006, "Impact of cross-section generation procedures on the simulation of the VVER-1000 pump start-up experiment in the OECD/DOE/CEA V1000CT benchmark by coupled 3-D thermal-hydraulics/neutron kinetics models", Progress in Nuclear Energy,
**48**, (8), pp. 746-763

- B. Akdeniz, Kostadin N Ivanov and A. Olson, 2006, "BWR TT benchmark. Volume III: Summary results of exercise 2"

- Y. Hu, T. Downar, T. Kozlowski, Kostadin N Ivanov and J. Staudenmeier, 2006, "Multi-physics coupled code reactor analysis with the U.S. NRC code system TRACE/PARCS", PHYSOR 2006 Conference

- F. Alim, K. Bekar, Kostadin N Ivanov, K. Unlu, J. Brenizer and Y. Azmy, 2006, "Modeling and optimization of existing beam port facility of PSBR", Annals of Nuclear Energy,
**33**, pp. 1391-1395

- B. Tyobeka, Kostadin N Ivanov and A. Pautz, 2006, "DORT-TD/THERMIX: A time-dependent neutron transport theory code coupled with thermal hydraulics and its applications for the PBMR 268 MW design"

- F. Reitsma, Kostadin N Ivanov, T. Downar, H. Haas and H. Gougar, 2006, "The OECD/NEA/NSC PBMR coupled neutronics/thermal hydraulics transient benchmark: The PBMR-400 core design", PHYSOR 2006 Conference

- S. Yilmaz, Kostadin N Ivanov, S. Levine and M. Mahgerefteh, 2005, "Development of enriched Gd-155 and Gd-157 burnable poison designs for a PWR core", Annals of Nuclear Energy,
**33**, (5), pp. 439-445

- S. Yilmaz, Kostadin N Ivanov, S. Levine and M. Mahgerefteh, 2005, "Optimizing the placement of burnable poisons in PWRs", Nuclear Technology,
**151**, (1), pp. 86-95

- J. Secker, B. Jahansen, D. Stucker, O. Ozer, Kostadin N Ivanov, S. Yilmaz and E. Young, 2005, "Optimum discharge burnup and cycle length for PWRs", Nuclear Technology,
**151**, (2), pp. 109-119

- N. Kriangchaiporn, Kostadin N Ivanov, A. Haghighat and F. Sears, 2005, "Three-dimensional cross-section generation for TRIGA core analysis", pp. 619-621

- V. Xulubana, C. Tippayakul, Kostadin N Ivanov and S. Levine, 2005, "Accuracy evaluation of pin exposure calculations in current LWR core design codes (phase 2)", pp. 664-666

- B. Tyobeka, A. Pauttz and Kostadin N Ivanov, 2005, "Preliminary investigations on the importance of using deterministic transport methods for the analysis of the PBMR", pp. 939-941

- B. Neykov, F. Aydogan, L. Hochreiter, Kostadin N Ivanov, H. Utsuno, K. Fumio, E. Sartori and M. Martin, 2005, "NUPEC BWR full-size fine-mesh bundle test (BFBT) benchmark. Volume I: Specifications",
**5**

- Kostadin N Ivanov, E. Sartori, E. Royer, S. Langenbuch and K. Velkov, 2005, "Validation of coupled thermal-hydraulic and neutronics codes in international co-operation", EuroSafe 2005 Conference

- A. Pertruzzi, Kostadin N Ivanov and F. D'Auria, 2005, "Methodology for internal assessment of uncertainty for safety analysis code", Nuclear Science and Engineering,
**149**, pp. 211-236

- B. Sarikaya, F. Alim, Kostadin N Ivanov, K. Unlu, J. Brenizer and Y. Azmy, 2005, "Validation of the MCNP5 model of beam-port facility at the PSBR", Monte Carlo 2005 Conference

- C. Tippayakul, N. Kriangchaiporn, Kostadin N Ivanov, F. Sears, B. Heindrich and M. Morlang, 2005, "Validation of the MCNP5 core model of the PSU research reactor", Monte Carlo 2005 Conference

- F. Alim and Kostadin N Ivanov, 2005, "Heuristic rules embedded genetic algorithm to solve in-core fuel management optimization problem", GECCO 2005 Conference

- S. Yilmaz, Kostadin N Ivanov and S. Levine, 2005, "Application of genetic algorithm to optimize burnable poison placement in PWRs", GECCO 2005 Conference

- B. Ivanov, S. Aniel, P. Siltanen, E. Royer and Kostadin N Ivanov, 2005, "Impact of cross-section generation procedures on simulation of the VVER 1000 pump start-up experiment in the OECD/DOE/CEA V1000CT benchmark by coupled 3-D thermal-hydraulic/neutron kinetics models", NURETH-11 Conference

- B. Ivanov, Kostadin N Ivanov, E. Royer, S. Aniel, N. Kolev and P. Groudev, 2005, "OECD/DOE/CEA VVER-1000 coolant transient (V1000CT) benchmark - A consistent approach for assessing coupled codes for RIA analysis", NURETH-11 Conference

- F. Alim and Kostadin N Ivanov, 2005, "Heuristic rules embedded genetic algorithm loading pattern optimization"

- F. Alim, B. Sarikaya, Kostadin N Ivanov, K. Unlu, J. Brenizer and Y. Azmy, 2005, "Optimization of beam port facility at PSBR"

- Y. Hu, T. Downar, Kostadin N Ivanov, J. Vedovi, A. Petruzzi and J. Staudenmeier, 2005, "Analysis of the OECD/NEA Ringhals instability benchmark with TRACE/PARCS", M&C 2005 Conference

- Y. Hu, T. Downar, Kostadin N Ivanov, A. Petruzzi, F. Mangini, R. Miro and J. Stawdenmeier, 2005, "Methodologies for stability analysis with TRACE/PARCS", M&C 2005 Conference

- D. Cuervo, R. Miro, M. Avramova and Kostadin N Ivanov, 2005, "Implementation and performance of Krylov methods for the solution of the two-fluid hydrodynamic equations in COBRA-TF", M&C 2005 Conference

- J. Vedovi, M. Hibband, D. Todd and Kostadin N Ivanov, 2004, "Analysis of pressure wave phenomena in steam line piping", ICONE 12

- B. Sarikaya, F. Alim, Kostadin N Ivanov, J. Brenizer, K. Unlu and Y. Azmy, 2004, "Modeling of existing beam-port facility at PSU Breazeale Reactor by using MCNP", PHYSOR 2004

- N. Todorova, Kostadin N Ivanov, E. Rigaut and E. Royer, 2004, "Sensitivity studies on cross-section generation and modeling for BWR core simulation using SAPHYR code system", PHYSOR 2004

- Kostadin N Ivanov, A. Olson and E. Sartori, 2004, "OECD/NRC BWR TT benchmark as a basis for comprehensive qualification and studying best estimate coupled codes", Nuclear Science and Engineering,
**148**, (2), pp. 195-207

- C. Tippayakul, S. Levine, Kostadin N Ivanov and M. Mahgerefteh, 2004, "Minimizing the gamma radiation effects to spent fuel pool walls", Annals of Nuclear Energy,
**31**, pp. 459-480

- C. Guler, S. Levine, Kostadin N Ivanov, J. Svarny, V. Krysl, P. Mikolas and J. Sustek, 2004, "Development of the VVER core loading optimization system", Annals of Nuclear Energy,
**31**, pp. 747-772

- A. Salah, J. Vedovi, F. D. Auria, Kostadin N Ivanov and G. Gallasi, 2004, "Analysis of the PB TT2 experiment by coupled codes RELAP5/PARCS three-dimensional codes", Nuclear Science and Engineering,
**148**, (2), pp. 337-353

- D. Lee, T. Downar, A. Ulses, B. Akdeniz and Kostadin N Ivanov, 2004, "Analysis of the OECD/NRC BWR TT transient benchmark with the coupled thermal-hydraulics and neutronics code TRAC-M/PARCS", Nuclear Science and Engineering,
**148**, (2), pp. 291-305

- D. Ziabletsev, M. Avramova and Kostadin N Ivanov, 2004, "Development of PWR integrated safety analysis methodology using multi-level coupling algorithm", Nuclear Science and Engineering,
**148**, (3), pp. 414-425

- D. Hahn, Kostadin N Ivanov, P. Ravetto and M. Rostagno, 2004, "Efficient hybrid NEM/BEM transient method", PHYSOR 2004

- A. Petruzzi, F. D'Auria and Kostadin N Ivanov, 2004, "Uncertainty evaluation of the results of the MSLB benchmark by CIAU methodology", PHYSOR 2004

- H. Gougar, A. Ougouag, W. Terry and Kostadin N Ivanov, 2004, "Design of pebble-bed reactors using genetic algorithms", PHYSOR 2004

- A. Ougouag, H. Gougar, W. Terry, R. Mphahlele and Kostadin N Ivanov, 2004, "Optimal moderation in the pebble-bed reactor for enhanced passive safety and improved fuel utilization", PHYSOR 2004

- C. Parisi, Kostadin N Ivanov and F. D'Auria, 2004, "Study of nuclear fuel behavior with coupled 3d neutronics/thermal-hydraulic code", PHYSOR 2004

- D. Cuervo, M. Avramova and Kostadin N Ivanov, 2004, "Improving the computation efficiency of COBRA-TF for LWR safety analysis of large problems", PHYSOR 2004

- C. Tippayakul, Kostadin N Ivanov, F. Sears, B. Heidrich and M. Morlang, 2004, "Automated three dimensional depletion capability for the Pennsylvania State University research reactor", PHYSOR 2004

- B. Ivanov, Kostadin N Ivanov, E. Royer, N. Kolev and P. Groudev, 2004, "OECD/DOE/CEA VVER-1000 coolant transient (V1000CT) benchmark for assessing coupled neutronics/thermal-hydraulics system codes for VVER-1000 RIA analysis", PHYSOR 2004

- B. Ivanov, Kostadin N Ivanov and R. Stammler, 2004, "HELIOS, current-coupling collision probability method, applied for solving the NEA C5G7 MOX benchmark", Progress in Nuclear Energy,
**45**, (2-4), pp. 119-124

- J. Solis, M. Avramova and Kostadin N Ivanov, 2004, "Multi-level methodology in parallel computing environment for evaluating BWR safety parameters", Nuclear Technology,
**146**, (3), pp. 267-278

- F. Reitsma, G. Strydom, H. Haas, Kostadin N Ivanov, B. Tyobeka, R. Mphahlele, T. Downar, V. Seker, H. Gougar and D. Cruz, 2004, "The PBMR steady state and coupled kinetics core thermal-hydraulics benchmark test problems", HTR 2004

- B. Ivanov, Kostadin N Ivanov, E. Royer, S. Aniel, U. Bieder, N. Kolev and P. Grouev, 2004, "Overview and status of the OECD/DOE/CEA V1000CT benchmark", 14th Symposium of AER, Finland

- B. Ivanov, S. Aniel, Y. Kozmenkov, E. Royer, U. Grundmann and Kostadin N Ivanov, 2004, "Analysis of the neutronic specifications of the OECD/DOE/CEA V1000CT-1 exercise 2 benchmark", 14th Symposium of AER

- E. Sartori, L. Hochreiter, Kostadin N Ivanov and H. Utsuno, 2004, "The OECD/NRC BWR full-size fine-mesh bundle tests benchmark (BFBT) - General description", NUTHOS-6

- L. Hochreiter, Kostadin N Ivanov, M. Avramova, A. Ireland, M. Gluck, P. Knape, J. Kronenberg, R. Muller, F. Burtak and F. Welle, 2004, "Sub-channel analysis needs for fuel assembly design", NUTHOS-6

- A. Petruzzi, A. Boushiba, F. D'Auria and Kostadin N Ivanov, 2004, "Boil-off sub-channel analysis using the RELAP-5 system code", NUTHOS-6

- A. Petruzzi, W. Giannotti, F. D'Auria and Kostadin N Ivanov, 2004, "Development, qualification, and use of a code with the capability of internal assessment of uncertainty", 6th International Conference on Simulation Methods in Nuclear Engineering

- J. Vedovi, Kostadin N Ivanov and F. D'Auria, 2004, "Analysis and sensitivity studies on VVER-1000 using the best-estimate model RELAP5/PARCS", 6th International Conference on Simulation Methods in Nuclear Engineering

- A. Petruzzi, W. Giannotti, F. D'Auria and Kostadin N Ivanov, 2004, "Enlargement of uncertainty database of the CIAU methodology", BE 2004

- B. Tyobeka and Kostadin N Ivanov, 2004, "Coupled NEM/THERMIX-DIREKT calculation scheme for HTR analysis",
**90**, pp. 530-532

- J. Vedovi, Kostadin N Ivanov and F. D'Auria, 2004, "V1000CT-1 benchmark exercise 3 results using coupled three-dimensional kinetics/thermal-hydraulics", pp. 527-529

- F. Alim and Kostadin N Ivanov, 2004, "Genetic algorithm development for in-core fuel management",
**90**, pp. 597-598

- J. Vedovi, Kostadin N Ivanov, J. Gan, T. Downar and J. Staudenmeier, 2004, "Analysis of Ringhals 1 stability benchmark with TRACE/PARCS: Steady-state initialization",
**90**, pp. 560-562

- T. Downar, D. Lee, Kostadin N Ivanov, B. Tyobeka and R. Mphahlele, 2004, "Development of advanced multi-dimensional coupled code computational capability for design and safety analysis of NGNP",
**90**, pp. 52-53

- F. Reitsma, J. Haas, B. Tyobeka, Kostadin N Ivanov and D. Da Cruz, 2004, "PBMR steady state and coupled kinetics core thermal-hydraulics test problems",
**90**, pp. 563-564

- B. Akdeniz, E. Muller, D. Panayotov and Kostadin N Ivanov, 2004, "State representation of the delayed neutron importance factor for two-group nodal transient calculations",
**91**, pp. 743-746

- A. Petruzzi, Sh. Chin, Kostadin N Ivanov, A. Ray and F. Cheung, 2004, "Development of methodology for early detection of BWR instabilities",
**91**, pp. 902-905

- C. Tippayakul, S. Levine, Kostadin N Ivanov, R. Wolfgang and M. Mahgerefteh, 2004, "Accuracy evaluation of pin exposure calculations in current LWR core design codes (phase 1)",
**91**, pp. 716-718

- S. Yilmaz, Kostadin N Ivanov, S. Levine and M. Mahgerefteh, 2004, "Optimized innovative burnable poison concepts for advanced PWR fuel management",
**91**, pp. 747-749

- F. Alim and Kostadin N Ivanov, 2004, "Modeling genetic algorithms for loading pattern optimization",
**91**, pp. 756-758

- B. Tyobeka, Kostadin N Ivanov, N. Casula and R. Mphahlele, 2004, "Analysis of PBMR-268 benchmark transient cases with the NEM/THERMIX coupled code",
**91**, pp. 263-265

- H. Gougar, A. Ougouag, W. Terry and Kostadin N Ivanov, 2004, "Design of pebble-bed reactors using genetic algorithms", HTR 2004

- Kostadin N Ivanov, 2004, "Neutronics/thermal-hydraulics coupling in LWR technology",
**1**

- Kostadin N Ivanov, 2004, "Neutronics/thermal-hydraulics coupling in LWR technology",
**2**

- Kostadin N Ivanov, 2004, "Neutronics/thermal-hydraulics coupling in LWR technology",
**3**

- C. Tippayakul, S. Levine, Kostadin N Ivanov and M. Mahgerefteh, 2003, "Minimizing the gamma radiation effects to spent fuel pool walls",
**88**, pp. 157-159

- M. Avramova, Kostadin N Ivanov, J. Kronenberg and F. Burtak, 2003, "PWR MSLB simulations using COBRA-TF advanced thermal-hydraulic code",
**89**

- R. Mphahlele and Kostadin N Ivanov, 2003, "Cross section generation for pebble bed reactors",
**89**

- J. Vedovi, Kostadin N Ivanov and F. D'Auria, 2003, "Modeling and results for exercise 1 of the OECD/DOE/CEA VVER1000 cooling transient (CT-1)",
**89**

- S. Yilmaz, F. Alim and Kostadin N Ivanov, 2003, "Gadolinium fueled pin placement optimization using genetic algorithms",
**89**

- N. Krianchaiporn, Kostadin N Ivanov, A. Haghighat and F. Sears, 2003, "Multi-group cross-section generation for TRIGA core analysis",
**89**

- Kostadin N Ivanov, N. Todorova and E. Sartori, 2003, "Using the OECD/NRC PWR MSLB benchmark to study current numerical and computational issues of coupled calculations", Nuclear Technology,
**142**, (2), pp. 95-115

- N. Todorova and Kostadin N Ivanov, 2003, "Investigation of spatial coupling effects for coupled code application in PWR safety analysis", Annals of Nuclear Energy,
**30**, pp. 189-209

- S. Yilmaz, Kostadin N Ivanov, S. Levine and M. Mahgerefteh, 2003, "Optimizing the placement of burnable poisons in PWRs", ANFM 2003

- S. Yilmaz, Kostadin N Ivanov, S. Levine and M. Mahgerefteh, 2003, "Automating the optimization of burnable poisons in PWRs", ANFM 2003

- J. Secker, B. Johansen, D. Stucker, O. Ozer, Kostadin N Ivanov, S. Yilmaz and B. Young, 2003, "Optimum discharge burnup and cycle length for PWRs", ANFM 2003

- A. Petruzzi, F. D'Auria and Kostadin N Ivanov, 2003, "A novel methodology of internal assessment of uncertainty for three-dimensional neutronics/thermal-hydraulics system codes", SNA 2003

- A. Petruzzi, Kostadin N Ivanov and F. D'Auria, 2003, "Methodology for internal assessment of uncertainty for safety analysis code", M&C 2003

- B. Tyobeka, Kostadin N Ivanov, F. Reitsma, D. Lee and T. Downar, 2003, "Comparative analysis of PBMR core physics test problems", M&C 2003

- N. Todorova, Kostadin N Ivanov and B. Taylor, 2003, "PWR MSLB benchmark volume 4: Summary of results of phase 3 (coupled core/plant calculations)",
**3**, (28)

- M. Avramova, Kostadin N Ivanov, J. Kronenberg and F. Burtak, 2003, "COBRA-TF PWR core wide and hot sub-channel calculations",
**88**, pp. 302-304

- A. Petruzzi, Kostadin N Ivanov and F. D'Auria, 2003, "Internal assessment of uncertainty for neutronics/thermal-hydraulics coupled codes",
**88**, pp. 305-306

- C. Delfino, A. Ray, Kostadin N Ivanov and B. Cheung, 2003, "A new concept for early detection of BWR instabilities",
**88**, pp. 292-294

- J. Vedovi, Kostadin N Ivanov and F. D'Auria, 2003, "Coupled three-dimensional kinetics/thermal-hydraulics modeling and transient analysis of VVER-1000",
**88**, pp. 589-591

- J. Watson and Kostadin N Ivanov, 2002, "Improved cross-section modeling methodology for coupled three-dimensional transient calculations", Annals of Nuclear Energy, pp. 937-966

- J. Solis, J. H. Fu, Kostadin N Ivanov, Y. Matsui and A. Hotta, 2002, "Developing and modeling of the Laguna Verde BWR CRDA benchmark", Annals of Nuclear Energy,
**29**, pp. 585-593

- J. Solis, M. Avramova and Kostadin N Ivanov, 2002, "Temporal adaptive algorithm for synchronization and optimization of the performance of multi-level coupled calculations", Annals of Nuclear Energy,
**29**, pp. 2127-2141

- N. Kriangchaiporn, Kostadin N Ivanov and R. Stammler, 2002, "Analysis of MOX experiments using HELIOS", Annals of Nuclear Energy,
**29**, pp. 1633-1640

- Kostadin N Ivanov, 1999, "PWR MSLB benchmark. Volume 1: Final specifications"

- B. Akdeniz, Kostadin N Ivanov and A. Olson, , "OECD/NRC BWR TT benchmark. Volume II: Summary results of exercise 1"

- B. Neykov, Kostadin N Ivanov and L. E. Hochreiter, , "Utilization of the OECD/NRC BFBT benchmark data base for assessing CFD codes for two-phase applications"

- J. Han, A. Ougouag, Kostadin N Ivanov and H. Gougar, , "Sensitivity study on optimal energy group structure in HTRs", Science and Technology of Nuclear Installations

- M. Avramova, B. Neykov, Kostadin N Ivanov, H. Utsuno, E. Royer and E. Sartori, , "Overview of the OECD/NRC benchmark based on NUPEC BWR full size fine-mesh bundle tests (BFBT) for validation of best-estimate models with high-quality data", Nuclear Engineering and Design journal - Special Issue on OECD/NRC BFBT Benchmark

- Dagistan Sahin, Kenan Kenan Ünlü and Kostadin N Ivanov, , "Burnup coupled MCNP simulation for the PSBR core", Nuclear Technology

- A. Ivanov, V. Sanchez, Kostadin N Ivanov and R. Stieglitz, , "Optimized large-scale coupled Monte Carlo - thermal hydraulics calculations using on-the-fly material definition", Special Issue of Annals of Nuclear Energy