Thermal analysis and optimization of the heat exchange system in the test loop for the fuel assembly steady-state irradiation based on a re-evaluation method

In order to verify the rationality of the design and reliability of the manufacturing process and provide a basis for the final design of the fuel assembly, it is necessary to carry out a steady-state irradiation test for the new fuel assembly in the pressurized water test loop with high temperature. Based on the historical experimental data feedback, a re-evaluation method for acquiring heat transfer performance of the regenerative heat exchanger was established for the fuel assembly steady-state irradiation in the pressurized water test loop with high temperature to accurately predict the ability of the test loop under different irradiation test parameters. It is shown that the heat exchange power prediction of the heat exchanger is accurate and effective by correcting the heat transfer coefficient of the regeneration section and the cooling section of the regenerative heat exchanger at the same time coupled with carrying out the re-evaluation of the heat exchange capacity. The traditional calculation power is generally higher than the re-evaluation power, and the magnitude of the increase is closely related to the primary water flow, but is weakly affected by the primary water inlet temperature. Meanwhile, it has an obvious effect on increasing the heat exchange power of the heat exchanger at low parameters that shortcircuited water bypass pipes in the regeneration section are set. Furthermore, the heat exchange system in the steady-state test loop should be designed as a series-parallel switchable scheme to satisfy the wide range of power requirements.