@inproceedings{MTMT:35294285,
	title = {Optimization of the Forced Fission Coefficient via Stochastic Calculus},
	url = {https://m2.mtmt.hu/api/publication/35294285},
	author = {Hajas, Tamás Zoltán and Tolnai, Gábor and Pázmán, Előd and Légrády, Dávid},
	booktitle = {Proceedings of the International Conference on Physics of Reactors PHYSOR 2024},
	doi = {10.13182/PHYSOR24-43571},
	unique-id = {35294285},
	abstract = {This paper uses Stochastic Differential E quations (SDEs) t o m odel t he v ariance o f t he Dynamic Monte Carlo (DMC) method.The Non-Analog Monte Carlo (NAMC) model was applied to the Stochastic Point-Kinetics equations (SPKe).The focus of this paper is modelling forced fission as a variance reduction technique with a general analytic representation for the variance.As a result, this paper shows an analytic derivation for the optimal fission biasing verifying that similar end result is obtained with time-dependent calculations. © 2024 AMERICAN NUCLEAR SOCIETY. All rights reserved.},
	keywords = {Optimization; Monte Carlo methods; Stochastic models; stochastic systems; Differentiation (calculus); Fission reactions; Random variables; Optimisations; Choquet integral; STOCHASTIC CALCULUS; STOCHASTIC CALCULUS; stochastics; Monte Carlo model; Point-kinetics; Dynamic Monte Carlo method; forced fission; non-analog Monte Carlo model; stochastic point-kinetics; Analog monte-carlo; Dynamic Monte Carlo method; Forced fission; Non-analog monte carlo model; Stochastic point-kinetic},
	year = {2024},
	pages = {1591-1599}
}

@techreport{MTMT:34865770,
	title = {RELAP5, TRACE and APROS Model Benchmark for the IAEA SPE-2 Experiment},
	url = {https://m2.mtmt.hu/api/publication/34865770},
	author = {Orosz, Róbert and Varju, Tamás and Aranyosy, Ádám and Holl, Viktor and Hajas, Tamás Zoltán and Aszódi, Attila},
	unique-id = {34865770},
	year = {2024},
	orcid-numbers = {Varju, Tamás/0000-0002-2969-1867}
}

@article{MTMT:34231211,
	title = {Noise term modeling of dynamic Monte Carlo using stochastic differential equations},
	url = {https://m2.mtmt.hu/api/publication/34231211},
	author = {Hajas, Tamás Zoltán and Tolnai, Gábor and Margóczi, Márk and Légrády, Dávid},
	doi = {10.1016/j.anucene.2023.110061},
	journal-iso = {ANN NUCL ENERGY},
	journal = {ANNALS OF NUCLEAR ENERGY},
	volume = {195},
	unique-id = {34231211},
	issn = {0306-4549},
	abstract = {Dynamic Monte Carlo (DMC) method recently became a relevant tool to perform kinetic calculations even on the scale of power plants and further to simulate coupled neutronics - thermal-hydraulics problems. DMC offers time-dependent, high fidelity calculations in very detailed and complex geometries in return for the high computational need. DMC provides stochastic results which is an indescribable property by the mathematics of the deterministic neutron transport. The stochasticity of the results also rises the unsolved problem of stability and convergence during the nonlinear, coupled DMC and thermal-hydraulics simulation. This paper aims to introduce the Stochastic Differential Equations (SDEs) in the field of Monte Carlo neutron transport for connecting the DMC method and differential equation formalism. The derivation of a Non-Analog Monte Carlo (NAMC) model is shown for the Stochastic Point-Kinetics equation (SPKe) to determine a noise model capable to approximate one trajectory of DMC. The theoretical framework allows the reader to observe analytic solutions for a random variate, the expectation and the variance of the reactor power. Also, analytic formulas are given for a simple system of coupled reactor physics and thermal-hydraulics without feedback. The analytic variance of the Monte Carlo simulated reactor power were compared to the calculations of GUARDYAN (GpU Assisted Reactor DYnamic ANalysis) code in a subcritical, a critical and a supercritical reactor models.},
	keywords = {Dynamic MOnte Carlo; Stochastic differential equations; Stochastic point-kinetics equation; Non-analog Monte Carlo noise model},
	year = {2024},
	eissn = {1873-2100}
}

@inproceedings{MTMT:34886488,
	title = {Variance Analysis of the Coupling of Thermal-hydraulics and Point Kinetics with Stochastic Noise Term Modeling Dynamic Monte Carlo Behavior for later use in GUARDYAN},
	url = {https://m2.mtmt.hu/api/publication/34886488},
	author = {Hajas, Tamás Zoltán and Tolnai, G. and Legrady, D.},
	booktitle = {2022 International Conference on Physics of Reactors, PHYSOR 2022, Proceedings of TopFuel 2022 Light Water Reactor Fuel Performance Conference},
	doi = {10.13182/PHYSOR22-37834},
	unique-id = {34886488},
	abstract = {This paper demonstrates that the mathematical tool of stochastic analysis is capable to create a mathematical base for the analysis of coupled dynamic Monte Carlo (MC) and thermal-hydraulics (TH) systems. Dynamic Monte Carlo (DMC) is evolving into a well-established method for neutron transport calculations, still, little has been analyzed the convergence properties of coupled DMC and thermal-hydraulics. Inspired by the GPU-based GUARDYAN DMC code, this research attempts to analyze the stochastic interaction between high fidelity stochastic neutronics and thermal-hydraulics codes thereby establishing the fidelity of the coupled results. One way for describing a stochastic system with the definitions of analysis is using stochastic analysis where the solution contains randomness. The goal of this paper is to introduce a heuristically created time-dependent noise model that is capable of reproducing the most important stochastic properties of DMC and to insert this noise term into point kinetics - thermal-hydraulics coupled system as confirmed by the obtained analytical solutions. Results were analyzed using stochastic analysis regarding convergence to steady-state values. In simulations we have found variance amplitude evolutions dependent on the heat removal boundary condition types, these results were supported by analytical solutions as well. © 2022 Proceedings of the International Conference on Physics of Reactors, PHYSOR 2022. All Rights Reserved.},
	keywords = {KINETICS; Monte Carlo methods; Stochastic models; stochastic systems; Hydraulics; Codes (symbols); Stochastic; Dynamic MOnte Carlo; variance analysis; Thermal hydraulics; Noise models; stochastic analysis; Coupled dynamics; stochastics; Point-kinetics; point kinetics; dynamic Monte Carlo noise model; Dynamic monte carlo noise model; Noise terms},
	year = {2022},
	pages = {2502-2511}
}

@techreport{MTMT:33141001,
	title = {RELAP5, TRACE and APROS Model Benchmark for the IAEA SPE-4 Experiment},
	url = {https://m2.mtmt.hu/api/publication/33141001},
	author = {Orosz, Róbert and Varju, Tamás and Aranyosy, Ádám and V., Holl and Hajas, Tamás Zoltán and Aszódi, Attila},
	unique-id = {33141001},
	year = {2022},
	orcid-numbers = {Varju, Tamás/0000-0002-2969-1867}
}

@article{MTMT:32836401,
	title = {Full Core Pin-Level VVER-440 Simulation of a Rod Drop Experiment with the GPU-Based Monte Carlo Code GUARDYAN},
	url = {https://m2.mtmt.hu/api/publication/32836401},
	author = {Légrády, Dávid and Tolnai, Gábor and Hajas, Tamás Zoltán and Pázmán, Előd and Parko, T. and Pos, I.},
	doi = {10.3390/en15082712},
	journal-iso = {ENERGIES},
	journal = {ENERGIES},
	volume = {15},
	unique-id = {32836401},
	issn = {1996-1073},
	year = {2022},
	eissn = {1996-1073}
}

@article{MTMT:32683975,
	title = {Sensitivity analysis of the IAEA SPE-2 small-break LOCA experiment with RELAP5, TRACE and APROS system codes},
	url = {https://m2.mtmt.hu/api/publication/32683975},
	author = {Varju, Tamás and Orosz, Róbert and Aranyosy, Ádám and Holl, Viktor and Hajas, Tamás Zoltán and Aszódi, Attila},
	doi = {10.1016/j.nucengdes.2021.111630},
	journal-iso = {NUCL ENG DES},
	journal = {NUCLEAR ENGINEERING AND DESIGN},
	volume = {388},
	unique-id = {32683975},
	issn = {0029-5493},
	abstract = {The Hungarian PMK-2 test facility is a scaled-down model of the VVER-440/213 type pressurized water reactors of Paks NPP, on which several measurement series have been carried out since the 80s. One of these series include four Standard Problem Exercises (SPE), primarily small-break loss-of coolant accident (SBLOCA) transients, performed in cooperation with IAEA. New RELAP5, TRACE and APROS models have already been developed and a comparative analysis of the results has been published recently for the PMK SPE-4 experiment. In that SBLOCA scenario, no high-pressure injection system (HPIS) was available, but a secondary side bleed and feed operation has been performed during the transient. This paper is a continuation of the previous one and presents the required model modifications and the analysis of the second SPE. The initiating event, similarly to the SPE-4 experiment, is a 7.4% break located at the top of the downcomer, while the main differences are that one line of the HPIS is available and no secondary side feed and bleed operation is performed in this case. One of the main objectives of the experiment was to verify that these safety measures are enough to prevent core dry-out. In addition to the investigation of this question, a sensitivity study was also carried out with respect to selected parameters that might have a significant impact on the characteristic of the simulated processes. The assessment of the results has also been performed with two quantitative methods, namely the Fast Fourier Transform Based Method with Signal Mirroring (FFTBM-SM) and Stochastic Approximation Ratio Based Method (SARBM).},
	year = {2022},
	eissn = {1872-759X},
	orcid-numbers = {Varju, Tamás/0000-0002-2969-1867}
}

@article{MTMT:31936687,
	title = {Analysis of the IAEA SPE-4 small-break LOCA experiment with RELAP5, TRACE and APROS system codes},
	url = {https://m2.mtmt.hu/api/publication/31936687},
	author = {Varju, Tamás and Aranyosy, Ádám and Orosz, Róbert and Holl, Viktor and Hajas, Tamás Zoltán and Aszódi, Attila},
	doi = {10.1016/j.nucengdes.2021.111109},
	journal-iso = {NUCL ENG DES},
	journal = {NUCLEAR ENGINEERING AND DESIGN},
	volume = {377},
	unique-id = {31936687},
	issn = {0029-5493},
	year = {2021},
	eissn = {1872-759X},
	orcid-numbers = {Varju, Tamás/0000-0002-2969-1867; Aranyosy, Ádám/0000-0002-6699-8219; Aszódi, Attila/0000-0002-4618-1076}
}

@article{MTMT:31598097,
	title = {Tranziens reaktorfizikai folyamatok végeselem-módszeren alapuló diffúziós modellezése},
	url = {https://m2.mtmt.hu/api/publication/31598097},
	author = {Babcsány, Boglárka and Hajas, Tamás Zoltán and Mészáros, Péter},
	journal-iso = {NUKLEON},
	journal = {NUKLEON},
	volume = {13},
	unique-id = {31598097},
	issn = {1789-9613},
	year = {2020}
}

@article{MTMT:31311023,
	title = {Environmental sustainability assessment of a biomass-based chemical industry in the Visegrad countries: Czech Republic, Hungary, Poland, and Slovakia},
	url = {https://m2.mtmt.hu/api/publication/31311023},
	author = {Cséfalvay, Edit and Hajas, Tamás Zoltán and Mika, László Tamás},
	doi = {10.1007/s11696-020-01172-8},
	journal-iso = {CHEM PAP},
	journal = {CHEMICAL PAPERS / CHEMICKÉ ZVESTI},
	volume = {74},
	unique-id = {31311023},
	issn = {0366-6352},
	year = {2020},
	eissn = {2585-7290},
	pages = {3067-3076}
}