Review of Thermal-Hydraulic Modeling Methods of Printed Circuit Steam Generators for Small Modular Reactors

Small Modular Reactors (SMRs) are promising to address a wide range of energy needs. Steam generator (SG) is usually one of the largest and most expensive components in a nuclear energy system. Therefore, the overall economics of an SMR plant employing a steam Rankine cycle is strongly influenced by its SG selection. Previous case studies conducted at the Idaho National Laboratory, assessing the techno-economic performance of advanced reactors for water desalination and hydrogen production, have mostly focused on reactor system options with conventional U-tube SGs or helical-coil SGs. Incorporating a two-phase Printed Circuit Heat Exchanger (PCHE) as a SG, termed a Printed Circuit Steam Generator (PCSG), has the potential to further improve the plant economics by significantly reducing the system volume through its enhanced compactness. This paper summarizes an ongoing effort to access the thermal-hydraulic performance of a PCSG for SMRs and establishes a reference model using the correlations that have been adopted and benchmarked by the latest PCSG modeling study. Our results suggest that using a one-dimensional (1-D) code for outlet temperature calculations (i.e., the hot and cold sides) and a pressure drop calculation for the single-phase flow (i.e., the hot side) can be as accurate as those in the three-dimensional (3-D) code used in Ocampo’s study in 2020 (typically less than 0.5 % and 7 % differences, respectively). However, it is noted that the calculated pressure drop for the cold side shows as high as 4 % and 25 % of discrepancies between the correlations and the dimension of simulation (i.e., 1-D and 3-D), respectively. The identified ranges of the uncertainties from this inter-model comparison would support the development of PCSG designs for SMRs while urging researchers to develop validated thermal-hydraulic models for PCSG.