PhD Topics

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prof. Jerzy Cetnar

  1. Investigation of alternative option of HTR configuration dedicated for mixed fuel cycle with thorium utilization
    HTR is a versatile reactor in terms of utilised fuel. As thorium-uranium cycle can be an attractive alternative to uranium-plutonium one it has its challenges due to lack of U233 in nature. Th-U cycle in existing solutions involves thorium irradiation in a reactor blanket and then its reprocessing after discharge from the reactor. As the thorium fuel reprocessing brings many challenges an alternative options that are based on once-through cycle or applying simplified separation (fission products removal only) will be examined in terms of reactor core design and separation feasibility.

Part III of exam topics proposals:

  1. Lead cooled reactor characteristics
  2. Basics of reactor fuel cycle
  3. Radiotoxicity

prof. Konrad Czerski

  1. High-temperature corrosion of ceramic materials – includes corrosion oven construction
    One of the main problem of the high temperature reactors is to have very good refractory materials which could be resistant to corrosion and other mechanical and embrittlement factors. These materials should be very resilient in ambient temperatures up to 1100 C and even up to 1700 C for short times. The best known candidates are carbides SiC, ZrC, TiC and their compounds ZrC-TiC. As for the fluids some eutectics made of natural uranium U238 for fuel loop and natural lead (Pb) for cooling loop should be tested. This Ph.D. topic will contain the problem of creating a high temperature facility – the corrosion oven, which could make some precise remote-handled mechanical testing. The program contains: oven construction, electronic control system construction, long-period studies under high temperature, stirring equipment preparation (rotating up to 300 rpm to 1000 rpm depending on bath size) to simulate Pb coolant velocity, decontamination of samples, some diagnostic experiments at nanoscale. The final output will be the choice of best construction material chosen for the metallic DFR/m. The facility will also allow to measure the physical and chemical parameters simulated by prepared independently computer model of the reactor.

Part III of exam topics proposals:

  1. Thorium fuel cycle in thermal reactors
  2. Thorium fuel cycle in fast reactors
  3. High-temperature corrosion of ceramic materials
  4. Stability analysis of nonlinear dynamical systems

prof. Mariusz Dąbrowski

Part III of exam topics proposals:

  1. Energy Returned on Invested (EROI) definition and applications
  2. Molten salt reactor characteristics
  3. Generations of nuclear reactors – classification and basic features
  4. The laws of thermodynamics in nuclear engineering

prof. Wacław Gudowski
(in collaboration with USNC – Ultra-Safe Nuclear Corporation)

  1. Very high temperature molten salt technology
    Solar molten salt can be used as heat carrier up to 570˚C. Above this temperature there are problems of stability of this molten salt. The objective of the PhD is to select molten salts that are stable at higher temperature and materials for the IHX that are compatible both with these molten salts and with impure helium atmosphere, in order to be able to increase the operating temperature of Micro Modular Reactor (MMR). Corrosion phenomena in impure He and in the molten salt will have to be addressed, as well as the mechanical properties of the materials, which will be considered, at operating temperature. The benefit of this PhD is to enable efficient very high temperature heat transport (> 600˚C), without which any step forward of HTGR technology towards VHTR would be useless for application to industrial process heat supply.
  2. Assessment of the source term
    HTGR fuel has very low fission product release during operation and even in case of an accident. Nevertheless the fission products accumulating in the primary system during the whole lifetime of the reactor form the source term that can be released in the environment in case of a break in the primary containment. It is important for safety to have an assessment of the global activity that can be released into the environment. But even if measuring the circulating activity is easy and if some of the plated out activity could also be measured (e.g. the activity plated out in the Intermediate Heat Exchanger – IHX), part of the activity in the primary circuit remains inaccessible (e.g. activity adsorbed in graphite).  The objective of the PhD is to define a strategy for assessing continuously the global activity in the primary system through a limited number of accessible measurements (e.g. only the circulating activity or the circulating activity + the plated-out activity in the IHX). For this purpose, existing data and models on fission product transport, plate-out and lift-off should be revisited and the possibility to get new data on existing HTGR test reactors (HTTR, HTR-10) should be investigated, to improve the knowledge on the distribution of fission products in the primary system. An assessment of the uncertainty of the evaluation of the global activity should be made. The result of this PhD will be very useful for the licensing of the FOAK reactor.
  3. Impact assessment of introducing HTGRs in the Polish energy system
    HTGRs can supply industrial facilities with heat and electricity, and possibly basic raw materials like hydrogen and oxygen. Introducing them will have a large impact on the overall Polish energy system such as: reduction of CO2 emissions of the Polish industry, improving human health through better air quality, limiting the energy dependency and geostrategic risk of fuel supply disruption, limiting the consumption of local coal resources with a social impact or enabling the valorisation of unused coal resources into added value chemicals, generating low-carbon electricity, providing price certainty, improving local science, technology and industrial skills and capabilities, etc. To enable policy-making, these positive and negative impacts could be thoroughly assessed with a PhD, to make an overall balance of the interest of introducing HTGRs in Poland, learning from previous cases such as France. It could run Monte Carlo simulations to generate long-term scenarios. Collaboration with an energy model developer in Poland or abroad could be also fruitful to model the overall energy system in Poland (including non-industrial applications like buildings, services and transport). The PhD would feed policy-making with relevant data on HTGRs. USNC has experts with experience in EU energy policy-making and impact assessment, as well as cost-benefit analyses that could supervise a PhD. USNC could also carry out similar assessments for other countries where it operates.

Part III of exam topics proposals:

  1. Temperature feedbacks in [HTGR/DFR/MSR/SFR/LFR] reactor
  2. Fuel separation/reprocessing options for [HTGR/DFR/MSR/SFR/LFR] reactor
  3. Comparison of LWR and [HTGR/DFR/MSR/SFR/LFR] fuel cycle
  4. Capabilities and limitations of CFD turbulence models for HTGR modeling

prof. Tomasz Kozłowski

  1. Multi-Physics Uncertainty Analysis of High Temperature Gas Cooled Reactor
    The development of the High Temperature Gas Cooled Reactors (HTGRs) requires verification of HTGR design and safety features with reliable high fidelity physics models and robust, efficient, and accurate codes. The predictive capability of coupled neutronics/thermal-hydraulics simulations for reactor design and safety analysis can be assessed with sensitivity analysis (SA) and uncertainty analysis (UA) methods. Uncertainty originates from errors in physical data, manufacturing uncertainties, and modelling and computational algorithms. SA is helpful to partition the prediction uncertainty to various contributing sources of uncertainty and error. SA and UA is required to address cost, safety, and licensing needs and should be applied to all aspects of reactor multi-physics simulation. Current SA and UA rely either on derivative based methods, stochastic sampling methods, or on generalized perturbation theory to obtain sensitivity coefficients. The proposed project will develop and new hybrid multi-physics uncertainty method to quantify the impact of different sources of uncertainties on the design and safety parameters of HTGRs. Only a parallel effort in advanced simulation and in nuclear data improvement will be able to provide designers with more general and well-validated calculation tools to meet design target accuracies.

Part III of exam topics proposals:

  1. Validation process the nuclear thermal-hydraulics codes/models
  2. Validation process the nuclear reactor physics codes/models

prof. Rafael Macian-Juan

  1. Technical safety-related assessment of transmutation plant with liquid fuel (DFR)
    In the framework of this PhD work, safety-critical issues on the transient and accident behavior of transmutation plants are being examined in detail with the aid of the DFR system code(s) developed at TUM and NCBJ.  Based on event trees that take into account all significant component failures, transient analyzes, including startup and shutdown simulations and stability analyzes are performed, including consideration of the mechanical integrity of the component materials as a result of abnormal occurrence or accidents, i.e. possible (component) consequential damages of abnormal occurrence or accidents are to be estimated. The aim is to prove that the plant fulfills all safety requirements that are set within the scope of the licensing procedure. The work within the PhD project will be carried out in the following four steps.
    1. Compilation of the principles of safety design of the MSR/DFRs. Development of event trees, which are the basis for the transient analyzes to be carried out in the next work step.
    2. Performing transient analyzes based on the event trees in 1. These are simulations with the calculation codes provided by TUM/NCBJ.
    3. Critical analysis of the simulation results from 2. and estimation of possible consequential damages.
    4. Development of a clear presentation of the safety characteristics and comparison of the different reactor variants.

Part III of exam topics proposals:

  1. Minor actinide transmutation behavior in thermal reactors
  2. Minor actinide transmutation behavior in fast reactor