Testing the steam generator model with helical coiled lead-heated tubes

Results obtained from testing the model of a lead-heated steam generator containing helical coiled tubes with longitudinal flow of coolants and consisting of two identical three-tube modules are presented. The program for investigating the steam generator model during operation of one module and during joint operation of two modules was aimed at studying heat transfer and, to a larger extent, the thermalhydraulic stability of steam-generating tubes during parallel (joint) operation of two modules at the parameters of partial-load and startup modes of operation. With the parameters of rated operating mode, the steam temperature at the module outlet corresponded to its design values even with a longitudinal flow pattern of coolants. No pulsation modes involving circulation reversal in the secondary coolant circuit were revealed in the entire variation range of operating parameters during operation in both partial-load and startup modes under the conditions of the considered lead circuit of the SPRUT experimental setup. The data obtained in the course of tests on this steam generator model will be conservative in regard of heat transfer in the post-burnout region and in terms of thermodynamically nonequilibrium conditions of steam-water flow for the steam generator used as part of the BREST-OD-300 reactor plant that is being developed at the Dollezhal Research and Development Institute of Power Engineering (NIKIET). These data should be used for verifying computation codes.