Investigation of thermodynamic performance of cooling a modular nuclear reactor with different secondary coolants

The aim of this thesis is to investigate the thermodynamic performance of cooling a modular nuclear reactor with different secondary coolants. In this regard, the cooling and power generation cycles of a 8.1 MW thermal power-modular nuclear reactor with LiF-BeF2 salt as the main coolant are designed. Designed modes are; i) Utilization of s-CO2 as secondary coolant, ii) Utilization of s-Water as secondary coolant, iii) Integrated utilization of s-CO2, s-Water and FLiNaK as additional coolants. By developing the suitable cycles for these operation modes, energy and exergy analyzes are performed. In this context, the thermal capacity of the nuclear reactor used in the study is taken to be 8.1 MW refering the small modular nuclear reactor at Oak Ridge National Laboratory. Furthermore, turbine operating parameters for s-CO2 cycle are taken to be 22.1 MPa and 883 K; 25 MPa, 1050 K for s-water cycle. Consequently, energy and exergy efficiencies are respectively calculated to be 42.3% and 54.9% for the first mode; 40.1% and 52.01% for the second mode; 46.79% and 60.7% for the integrated mode. Thus, at the end of the calculations for energy and exergy calculations it can be said that although the third mode is a new design and has high performance, it is suggested that, in terms of manufacturing and operational safety, a new comprehensive study should be conducted for future studies.