Absorption additives to ensure the subcriticality of spent Nuclear fuel

Předkládaná bakalářská práce se zabývá výběrem vhodných prvků jako příměsi pro zajištění podkritičnosti skladování vyhořelého jaderného paliva. První metoda byla založena na informacích ze softwaru NEA JANIS, potřebné výpočty v druhé metodě byly provedeny v programovém prostředí Serpentu. Výsledkem je jednak potvrzení dobrých vlastností boru, ale zároveň i přehled případných dalších prvků, o kterých by bylo vhodné uvažovat při budoucím návrhu absorpčních trubek skladovacích zařízení, například gadolinium.ObhájenoThe bachelor theses presents choice of suitable elements as additives to ensure criticality safety of spent nuclear fuel storage. The first method is based on information from NEA JANIS software, the second one employ calculations in Serpent software framework. The results confirmed good properties of boron. Moreover, a list of prospective additional elements that should be considered in further design of spent fuel storage absorber tubes, like gadolinium, is presented

Power distribution calculation of VVER-1000 reactor

Hlavním cílem předkládané diplomové práce je validace výpočetního kódu Serpent založeném na metodě Monte Carlo prostřednictvím výpočtu rozložení výkonů v palivových souborech a dílčích palivových proutcích v realistické palivové vsázce pro reaktor typu VVER-1000 a porovnáním získaných dat s referenčním řešením. Vypočítané řešení je velmi přesné, což potvrdila i analýza symetrie daného řešení. Řešený model byl využit i pro další vybrané analýzy dílčích vlivů na výsledky. Tyto analýzy jsou vhodné pro další porovnání přesnosti výpočtu s deterministickými kódy jako je například Moby-dick.ObhájenoThe main goal of this master thesis is to validate the Serpent calculation code based on the Monte Carlo method by calculating the power distribution in fuel assemblies and partial fuel rods in a realistic fuel charge for the VVER-1000 reactor and comparing the obtained data with a reference solution. The calculated solution is very accurate, which was confirmed by the symmetry analysis of the solution. The solved model was also used for other selected analyzes of partial effects on the results. These analyzes are suitable for further comparison of calculation accuracy with deterministic codes such as Moby-dick

Role of Simulation of Power Output in the Design of Small-scale Hydro Power Plant

Article focuses on importance of time power-output simulation performed in Matlab in order to identify real hydroelectric potential in selected locations of river flows in the Czech Republic. The difference of simulation and the usual total generated power in a time-period might play a significant role in decision making during realization of a small-scale hydro power plant. The greatest difference is the view on generation from the time perspective throughout the year which can show the critical periods in the year when the generation is low or when it’s maximal. This simulation approach also shows the difference between annual generated electricity using average flows and the actual hourly flows. In the modern plant design real data time simulation should play nowadays a stadard role

Prediction of the degradation process of mono-Si photovoltaic panels in Ukrainian and Czech conditions

This paper focuses on project studying the influence of various technical, meteorological, and specific local factors influencing power generation from photovoltaic plant. This problem is analysed on model PV plants installed in Ukraine and Czech Republic. The Fault tree analysis (FTA) method is applied on photovoltaic power plant damage tree. The most significant technical problems of PV modules and entire photovoltaic plants are identified and discussed. Also mathematical method computing coefficient of the total residual resource of the plant and to calculate predicted energy generation of the plant taking into account general degradation is discussed. Indicator coefficients describing abnormal PV modules operation are described. Structural diagram of the model of the coefficient of the residual resource of the PV module was developed Basic data originate from measurements on monocrystalline Si PV panels installed in commercial plants commissioned in Ukraine and the Czech Republic. Data show important differences in behavior and operational conditions. It is evident that prediction the of technical condition of the plant, degradation of PV modules and actual electricity generation strongly depends on local conditions. Ignoring the gradual reduction of capacity leads to ertrors in assessment of the total energy efficiency, profitability, payback time and necessary power reserve to compensate the unstable RES generation

"Full-Core" VVER-1000 calculation benchmark

This work deals with the “Full-Core” VVER-1000 calculation benchmark which was proposed on the 26th Symposium of AER [1]. Recently, the calculation benchmarks “Full-Core” VVER-440 [2] and its extension [3] have been introduced in the AER community with positive response [4, 5]. Therefore we have decided to prepare a similar benchmark for VVER-1000. This benchmark is also a 2D calculation benchmark based on the VVER-1000 reactor core cold state geometry, explicitly taking into account the geometry of the radial reflector. The loading pattern for this core is very similar to the fresh fuel loading of cycle 9 at Unit 1 of the Temelin NPP (Czech Republic). This core is filled with six types of fuel assemblies with enrichment from 1.3%w 235U to 4.0%w 235U with up to 9 fuel pins with Gd burnable absorber per FA. The main task of this benchmark is to test the pin-by-pin power distribution in fuel assemblies predicted by macro-codes that are used for neutron-physics calculations especially for VVER reactors. In this contribution we present the overview of available macro-codes results