Designs of Printed Circuit Steam Generator for the Modular Integrated Gas-cooled High Temperature Reactor

Abstract

Advanced reactors, such as the Horizontal Compact High Temperature Gas Reactor (HC-HTGR), require compact steam generators for near-term deployment as an alternative to the traditional shell-and-tube steam generators to achieve a relatively high level of compactness for the reactors. The recently proposed Modular Integrated Gas-cooled High Temperature Reactor (MIGHTR) that is under development by one of the U.S. Department of Energy’s Advanced Reactor Demonstration Program projects is an HC-HTGR design, aiming to increase its reactor building power density by four to five times. Therefore, printed circuit steam generator (PCSG) has gained interest as a compact steam generator potentially applicable to the MIGHTR. Previous work on printed circuit heat changers is primarily focused on single-phase flow applications, and thus two-phase experimental data involving flow boiling in such heat exchangers are hardly available. The present work presents a prototypic PCSG design by employing zigzag-shaped flow channels to minimize its volume and pressure drop. A genetic algorithm (NSGAII) was utilized to perform PCSG volume optimization. Based on the optimization results, two lab-scale PCSGs were designed for testing under close-to-prototypic conditions with a reduced thermal duty of 24 kW each to investigate their thermal performance and density wave oscillations on the cold side due to phase change. A test facility that couples an existing high-temperature helium loop with a newly designed water/steam loop is currently under construction to test these PCSGs with an anticipated hot-side helium inlet temperature of 687 °C at 3.0 MPa and a cold-side feedwater inlet temperature of 193 °C at 7.0 MPa.