Thermal-hydraulic design of a supercritical, once-through steam generator for the molten-salt breeder reactor plant

This paper presents the thermal/hydraulic design aspects of the once-through steam generators for the 1000-MWe Molten Salt Breeder Reactor Power Plant. The steam generator under consideration is a vertical, L-shaped, counterflow, shell-and-tube heat exchanger with a sodium fluoroborate salt flowing downward on the shell side and water/steam flowing upward in the tubes. Due to the relatively high melting point of the salt, a supercritical steam cycle is utilized to produce 253 kg/cm$sup 2$ (3600 psia), 538 C (1000 F) steam. The design is governed by the provisions of adequate thermal expansion, flow distribution, better volume utilization, mechanical arrangement, nearly equal active flow circuit length, tube side inspection, relative simplicity, salt drainability, as well as performance requirements. The paper outlines the thermal/hydraulic design criteria and analyses for the steam generator under full- and part-load operating conditions