| 摘要 |
PURPOSE:To form a wide nuclear boiling heat transfer region under fluidized state having a high heat transfer function by constituting the precooling unit of a plate-fin type heat exchange portion having an outlet for cooled helium, and a downcomer portion disposed so as to place the boiling side outlet portion of the heat exchange portion in communication with the inlet portion thereof. CONSTITUTION:When a supercritical pressure helium gas is caused to flow from a primary side inlet 8 to the primary side 4 of a heat exchange portion 2, and a low pressure liquid helium is supplied into a downcomer portion 3 through a secondary side inlet 10, liquid helium flows from a secondary side inlet portion 7 to a secondary side 5 and is guided to a secondary side outlet 6. Upon this occasion, a heat exchange is carried out between the primary side 4 and the secondary side 5, and the supercritical pressure helium gas which has passed the primary side 4, is cooled end discharged through the primary side outlet 9. Since the liquid helium flows on the secondary side 5 is boiled and partly converted into a vapor, the liquid helium flows between the downcomer portion 3 and the secondary side 5 in the form of a return circulating flow by the floating effect of the vapor. Accordingly, the membrane boiling can be evaded by the fluidization and the secondary side 5 becomes a nuclear boiling region under a forced fluidization having a high heat transfer characteristic. |
