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Provisions for mitigation of consequences in case of major accidents in GFR nuclear reactors
Mlčúch, Adam ; Suk, Ladislav (referee) ; Martinec, Jiří (advisor)
This thesis deals with the severe accident of the gas-cooled fast reactor GFR. At the beginning of the study there is a review of the gas-cooled fast reactor subject. Next part is focused on description of possible solutions for severe accidents with emphasis on the solution applied in the Generation III+ reactors. Chapters that deal with material and thermal balance with severe accident of GFR demonstration unit, along with the chapter which analyses features of the corium, create a basis for the conceptual design of core catcher of GFR demonstration unit, which forms the final part of this thesis.
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Radiation damage of VVER-440 based Dukovany NPP reactor pressure vessel investigation
Říha, Tomáš ; Martinec, Jiří (referee) ; Šen, Hugo (advisor)
This master‘s thesis deals with radiation damage of reactor pressure vessels, specifically of NPP Dukovany Unit No. 3. In general damage mechanisms of reactor steels are described and possibilities of monitoring of material degradation and its recovery used at NPP’s all over the world are mentioned as well. A practical part of the thesis is focused on interpretation of analyses carried out with the assistance of MOBY DICK code. The ground of these analyses is a neutron fluence value development on different locations of RPV for the whole life of operation up to 24th cycle. The analyses results are put into context with performed in-service inspections. The thesis follows up with neutron fluence computation for the future cycles containing new types of nuclear fuel up to 34th cycle. The outcome of practical part of the master‘s thesis is a comparison between new types of nuclear fuel with respect to radiation damage of RPV’s.
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Application possibilities of systems with heat accumulation in nuclear power
Sklenářová, Lenka ; Maar, Tomáš (referee) ; Martinec, Jiří (advisor)
This dissertation covers the application of heat accumulation systems in nuclear power engineering, namely in nuclear power plants. It is mainly a case of passive emergency systems, whose task is to accumulate the heat produced in the reactor’s active zone and in spent fuel pools during DBA (design-basis accidents) or beyond DBA. A particular example of heat accumulation is steam condensation after LOCA (loss of coolant accident). The primary circuit steam leakage increases containment pressure and has to be decreased by the steam condensation. This thesis deals with a theoretical substitute for ice condensers, which are used as a passive safety measure in some nuclear power plants. The substitute involves a choice of an alternative material, whose melting temperature (for heat accumulation) is closer to nuclear power plant operating temperatures. The other part of the dissertation discusses heat accumulation in spent fuel pools in case of all cooling systems failure.
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The concept for passive cooling of the VVER-1000 reactor
Lamoš, Pavel ; Suk, Ladislav (referee) ; Martinec, Jiří (advisor)
This thesis is focused on the design of passive cooling system for a nuclear reactor VVER- 1000.This type of reactor is located in the Czech Republic in the location of Nuclear power plant Temelín. The thesis states an overview of the different cooling systems of nuclear power plants. The thesis is focused on passive safety system especially on passive cooling system, so there was done an overview of currently used passive safety system. In the work is discussed nuclear safety and the maximum projected accident of VVER-1000, which is called LOCA accident. In the design part of the thesis was done thermal calculation of heat exchangers. Exchangers are designed as condensers with a natural flow, where cooling of system is provided by outside airflow in case an accident. The results are evaluated at the end of the thesis.
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Unsuccessful conceptions of combustion engines
Martinec, Jiří ; Blaťák, Ondřej (referee) ; Zháňal, Lubor (advisor)
The main aim of the bachelor thesis was to study unsuccessful conceptions of combustion engines. It determines a brief summary of abortive directions in development of combustion engines, classifying them by structial design, as well specifying reasons of failure. It clarifies working principles and summarize possible pros and cons of each conception.
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Intermediate heat exchanger natrium - natrium
Kupčík, Petr ; Martinec, Jiří (referee) ; Šen, Hugo (advisor)
This paper deals with intermediate heat exchangers in nuclear power plants. First section of this paper is devoted to analysis and divide of construction designs of intermediate heat exchangers in commercial and experimental power plants. There is a description of thermal, hydraulic and strength calculations during projection of IHX in the second chapter. There has been made a blueprint of loop type IHX in the final chapter of this paper.
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The flange gasket modification of SG VVER 440 primary collector
Blažková, Eva ; Martinec, Jiří (referee) ; Šen, Hugo (advisor)
The aim of this thesis is to address issues concerning the sealing of the lid for the primary collector within the steam generator (SG) of the nuclear power plant VVER 440. These steam generators are sealed in the original design by nickel rings. Modifying the existing method of sealing by a new type of sealing material, primarily from expanded graphite, can significantly reduce the pressure in the sealing surface and also stress in bolts and flanged joints. The new solution of sealing between the joint of collector and the lid should extend the life of joints and thus the nuclear and technical safety. The text is divided into the theoretical and computational part. A principle of the SG, the SG design, and a description of the joint and lid are mentioned in the theoretical part. The computational part shows calculations of the new joint, the original one, and comparison of both solutions in terms of technical and nuclear safety. The work contains drawing of the new joint.
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Fundamentals of cogeneration and its application in Brno
Kubiš, Zdeněk ; Škvařil, Jan (referee) ; Martinec, Jiří (advisor)
The bachelor’s thesis deals with the cogeneration – Combined Heat and Power. It describes its main principles and advantages. It presents the most important types of cogeneration technologies with an emphasis on high-power units and summarizes the main areas where the cogeneration can be applied. Further, the State Energy Policy of the Czech Republic in the heat production is introduced. In the last part, the thesis is concerned with the history and the current state of heat production in Brno and gives an overview of the heating stations in the city.
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Role of Czech NPP within grid power regulation
Kostečka, Jan ; Martinec, Jiří (referee) ; Katovský, Karel (advisor)
The aim of the Bachelor’s thesis is the involvement of Czech nuclear power plants in the Czech energy networks, but also in the European Network and their adaptation. Effect of expansion of renewable electrical energy produces the asymmetry in the network and places formed with an excess of electrical energy and places with lack of electrical energy. Flows of electric energy can affect the security and safety of distribution lines. Excessive overloading can cause them to collapse. Therefore, this work is focused on solutions and avoids this problem and minimizes this potential damage. However, the impact of energy revolution has a giant proportion about these overflows network energy. Uncontrollable wind and solar power source may create regionally region surge and flow of this energy goes to areas with shortages of electrical power. The regulation has an impact on fuel. This renegade production could extend fuel cycle, or expand the campaign to more years at least a year. The calculations can show the amount of fuel that can still be used, and thereby increase the yield and economic benefit conditions for extending the life of the reactor units.
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Concept of a small nuclear reactor for the heat supply purposes
Bobčík, Marek ; Skála, Zdeněk (referee) ; Martinec, Jiří (advisor)
The objective of this diploma thesis is to assess the suitability of a small nuclear reactor for the purpose of heat supply in small towns and cities. First, all the heat demands of these towns and cities are analysed. Then, a small nuclear reactor to serve these needs is designed and a computational model for burn-up fuel is created. The thesis aims to propose a design of a new heat exchanger. Economic and environmental criteria are taken into account as well and including safety measures. The outcome of this thesis is an evaluation of the whole concept with respect to potential future implementation.
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