In recent years, one of the most exiting nuclear related research field is the design of Small Modular Reactors (SMRs). SMRs, by definition, are reactors of significantly smaller capacity than those usually designed/installed in nuclear power plants. On the other hand, SMRs are fully manufactured at a plant and then shipped to the site of operation. There are a number of reasons why a number of countries with advanced nuclear industry, such as Canada, China and the US have ongoing projects to design SMRs.
In parallel, the other hottest field of development is related to Generation IV reactor types, which are highly innovative designs, usually utilizing emerging technologies. One of the six Gen IV reactor types is the Supercritical Water Reactor (SCWR), which applies water at supercritical pressure for cooling and neutron thermalization, thus providing grounds for various advantages over conventional reactor types, such as PWRs.
The idea that an SCWR design may be made in a relatively small format as an SMR serves as the fundamental idea of a research project funded by Euratom starting from this year. One of the work packages, the leader of which is BME NTI, is aimed at studying the design- and safety-related neutronic parameters and reactor physics behavior of the SCW-SMR in order to support the pre-conceptual design, also containing preliminary core design calculations in order to obtain and evaluate potential core layouts. As the other packages focus on the thermal-hydraulics, safety analyses and other aspects of the design, the reactor physics research is not a standalone topic but is rather embedded in a very interesting and multi-disciplinary environment. The purpose of the PhD work is directly related to the reactor physics design of the SCW-SMR, with links to thermal-hydraulics and safety analyses investigations.
The PhD work will be performed in the above outlined research environment, which contains international partner universities and research institutes, following the below guidelines:
- Study of the literature published regarding the reactor physics of SCW reactors and the peculiarities of SMRs. BME NTI has studied SCWs for more than a decade.
- According to the literature published in this field, computational reactor physics analysis of a supercritical water cooled reactor is not straightforward, mainly due to the necessity of 3D modelling of rapidly changing moderator properties and availability of cross sections. Therefore, the effect of code selection should be assessed by comparing different neutron-physics codes.
- The results of the mentioned calculations should be compared to benchmark data available for the PhD student in the mentioned EU project.
- The neutron physics parameters relevant to the safety and feasibility of the SCW-SMR should be studied. The particular characteristics of SCW and the influence of the supercritical pressure coolant on the neutronic parameters should be investigated. Of particular interest are the reactivity feedback coefficients of SCW-SMR, the cross-sectional properties of fuel applied in SCW-SMR as a function of temperature and pressure.
- In order to properly account for the extreme spatial variation of the density of the coolant, the reactor physics models should be coupled with 1D thermal-hydraulics models, practically transforming the calculations into a multi-physics approach.
- As it is also critical to analyze how actual reactor cores of the planned dimensions and layout could be designed, calculations should be carried out using full core Monte Carlo models in order to yield information on the achievable cycle lengths, spatial distribution of power density and its variation with burnup.
The PhD student will have the opportunity to spend a few months at one of the participating institutions of the mentioned project.
The applicant should have a proper level of knowledge in reactor physics, Monte Carlo theory, English language and programming (no constraint on programming language). Deeper knowledge / experience in the use of a neutron trasport code, either deterministic or Monte Carlo, is an advantage.