Pavel Tsvetkov | Texas A&M University (original) (raw)
Papers by Pavel Tsvetkov
Nuclear Technology
The objective of this thesis is to quantify the uncertainty in radiation dose rate estimates outs... more The objective of this thesis is to quantify the uncertainty in radiation dose rate estimates outside of a used fuel dry cask storage unit due to the parametric variability of concrete composition and density. This requires the selection of a limited number of concrete compositions from a standardized database and the development of a reference dry cask model, which can be used to estimate dose rate from neutrons and gamma rays. The model was developed using the Monte Carlo N-Particle code, with reference data from a used fuel assembly source provided by operators at Comanche Peak Nuclear Power Plant and geometry based on the Holtec HI-STORM 100S used fuel dry cask storage system. The majority of the model was then fixed and the dose rates were compared when different concrete compositions at their nominal densities were substituted. Additional cases compared results for different concrete compositions at a fixed density, different densities for a fixed composition, and a different gamma energy source term for fixed compositions and densities. The comparison of model results confirmed that the parametric variability of concrete composition is a major source of uncertainty for dry cask dose rates. While precise results depend on the compositions compared, general trends cam be identified. The majority of the dose in all cases, typically 70%, depended on gamma rays produced by the fission products. Density was the dominant factor in determining the dose rate, as expected. Composition variation while density was held fixed, however, indicated that the precise composition has a large effect on the dose rates produced by neutrons and iii gamma rays produced by neutron capture, on the order of 70% or higher for test cases, with only a moderate impact on the dose rate from gamma rays produced by other sources, on the order of 20% for test cases. Alterations to the gamma energy spectra produced by additional decay uniformly lowered the dose, and did not significantly change comparative concrete performance. Overall results indicate that, due to the lack of standardization of concrete poured on site, additional safety factors may be necessary due to variation of shielding effectiveness. iv DEDICATION For my family, thank you for all of the support, and for being there when I needed someone to listen.
AIP Conference Proceedings, 2006
Planetary Surface Power and Interstellar Propulsion Using Fission Fragment Magnetic Collimator Re... more Planetary Surface Power and Interstellar Propulsion Using Fission Fragment Magnetic Collimator Reactor. [AIP Conference Proceedings 813, 803 (2006)]. Pavel V. Tsvetkov, Ron R. Hart, Don B. King, Gary E. Rochau. Abstract. ...
Nuclear Power - Deployment, Operation and Sustainability, 2011
Volume 2: Plant Systems, Structures, and Components; Safety and Security; Next Generation Systems; Heat Exchangers and Cooling Systems, 2012
ABSTRACT The Integrated Multi-Modular Fast reactor is a pre-conceptual small modular fast reactor... more ABSTRACT The Integrated Multi-Modular Fast reactor is a pre-conceptual small modular fast reactor design consisting of 7 self-consist subcritical modules, each utilizing a BeO-MOX concept fuel with complete supercritical CO2 brayton cycle turbo-machinery. The subcritical modules, when brought into proximity of one another, form a complete critical reactor core. The feasibility of the reactor is assessed on a full core level, which includes a neutronics, thermal hydraulics, balance of plant, economics, and economics analysis. It has been shown that a critical configuration lasting for 14 years at 10 MWth can be achieved. A hot channel thermal hydraulics and safety analysis shows that the reactor can operate within safety limits with negative temperature coefficients of reactivity as well as stay within fuel temperature limits. A plant thermal efficiency of 36% was achieved and there is room for optimization to achieve higher efficiencies. An economical feasibility assessment shows that the reactor can be economical based on an economy of serial production argument. The analysis also leads to a licensing discussion.
Annals of Nuclear Energy, 2015
10th International Energy Conversion Engineering Conference, 2012
10th International Energy Conversion Engineering Conference, 2012
Science, Technology, and Applications, 2011
Science, Technology, and Applications, 2011
Science, Technology, and Applications, 2011
Science, Technology, and Applications, 2011
12th International Conference on Nuclear Engineering, Volume 2, 2004
The United States Department of Energy, Nuclear Energy Research Initiative (NERI) Direct Energy C... more The United States Department of Energy, Nuclear Energy Research Initiative (NERI) Direct Energy Conversion Proof of Principle (DECPOP) project has as its goal the development of a direct energy conversion process suitable for commercial development. We define direct energy ...
Nuclear Technology
The objective of this thesis is to quantify the uncertainty in radiation dose rate estimates outs... more The objective of this thesis is to quantify the uncertainty in radiation dose rate estimates outside of a used fuel dry cask storage unit due to the parametric variability of concrete composition and density. This requires the selection of a limited number of concrete compositions from a standardized database and the development of a reference dry cask model, which can be used to estimate dose rate from neutrons and gamma rays. The model was developed using the Monte Carlo N-Particle code, with reference data from a used fuel assembly source provided by operators at Comanche Peak Nuclear Power Plant and geometry based on the Holtec HI-STORM 100S used fuel dry cask storage system. The majority of the model was then fixed and the dose rates were compared when different concrete compositions at their nominal densities were substituted. Additional cases compared results for different concrete compositions at a fixed density, different densities for a fixed composition, and a different gamma energy source term for fixed compositions and densities. The comparison of model results confirmed that the parametric variability of concrete composition is a major source of uncertainty for dry cask dose rates. While precise results depend on the compositions compared, general trends cam be identified. The majority of the dose in all cases, typically 70%, depended on gamma rays produced by the fission products. Density was the dominant factor in determining the dose rate, as expected. Composition variation while density was held fixed, however, indicated that the precise composition has a large effect on the dose rates produced by neutrons and iii gamma rays produced by neutron capture, on the order of 70% or higher for test cases, with only a moderate impact on the dose rate from gamma rays produced by other sources, on the order of 20% for test cases. Alterations to the gamma energy spectra produced by additional decay uniformly lowered the dose, and did not significantly change comparative concrete performance. Overall results indicate that, due to the lack of standardization of concrete poured on site, additional safety factors may be necessary due to variation of shielding effectiveness. iv DEDICATION For my family, thank you for all of the support, and for being there when I needed someone to listen.
AIP Conference Proceedings, 2006
Planetary Surface Power and Interstellar Propulsion Using Fission Fragment Magnetic Collimator Re... more Planetary Surface Power and Interstellar Propulsion Using Fission Fragment Magnetic Collimator Reactor. [AIP Conference Proceedings 813, 803 (2006)]. Pavel V. Tsvetkov, Ron R. Hart, Don B. King, Gary E. Rochau. Abstract. ...
Nuclear Power - Deployment, Operation and Sustainability, 2011
Volume 2: Plant Systems, Structures, and Components; Safety and Security; Next Generation Systems; Heat Exchangers and Cooling Systems, 2012
ABSTRACT The Integrated Multi-Modular Fast reactor is a pre-conceptual small modular fast reactor... more ABSTRACT The Integrated Multi-Modular Fast reactor is a pre-conceptual small modular fast reactor design consisting of 7 self-consist subcritical modules, each utilizing a BeO-MOX concept fuel with complete supercritical CO2 brayton cycle turbo-machinery. The subcritical modules, when brought into proximity of one another, form a complete critical reactor core. The feasibility of the reactor is assessed on a full core level, which includes a neutronics, thermal hydraulics, balance of plant, economics, and economics analysis. It has been shown that a critical configuration lasting for 14 years at 10 MWth can be achieved. A hot channel thermal hydraulics and safety analysis shows that the reactor can operate within safety limits with negative temperature coefficients of reactivity as well as stay within fuel temperature limits. A plant thermal efficiency of 36% was achieved and there is room for optimization to achieve higher efficiencies. An economical feasibility assessment shows that the reactor can be economical based on an economy of serial production argument. The analysis also leads to a licensing discussion.
Annals of Nuclear Energy, 2015
10th International Energy Conversion Engineering Conference, 2012
10th International Energy Conversion Engineering Conference, 2012
Science, Technology, and Applications, 2011
Science, Technology, and Applications, 2011
Science, Technology, and Applications, 2011
Science, Technology, and Applications, 2011
12th International Conference on Nuclear Engineering, Volume 2, 2004
The United States Department of Energy, Nuclear Energy Research Initiative (NERI) Direct Energy C... more The United States Department of Energy, Nuclear Energy Research Initiative (NERI) Direct Energy Conversion Proof of Principle (DECPOP) project has as its goal the development of a direct energy conversion process suitable for commercial development. We define direct energy ...