抄録
The water cooled pebble bed reactor with the pebble diameter from 2-10 mm has both the characteristics of high temperature gas-cooled pebble bed reactor and the traditional light water one. In the conceptual design of high temperature gas-cooled reactor and supercritical water-cooled reactor, pebble bed reactor has attracted much interest because of its outstanding advantages in the safety and fuel cycle. As far as china is concerned, it is worth researching and designing the water cooled pebble bed reactor, and the formers' researches were focused on the water cooled reactor. So it is great important to investigate the thermal-hydraulic characteristics of coolant in a pebble bed reactor core. The 3-D physical and geometrical models of the water cooled pebble bed reactor were built using the commercial software Pro/E and CFX, in which the thermal-hydraulic characteristics of the reactor core were studied. The velocity and temperature fields and pressure distribution of the coolant as well as the distribution of internal temperature of the fuel are obtained and analyzed in the case of diameter of 3mm and diameter of 6mm, and its effects on the core safety are also analyzed. The results indicate that the tendency of the same parameter values under different diameters are nearly identical, and it is larger with the diameter of 6mm, contrary, the flow disturbance with the diameter of 6mm is weaker than that of 3mm. The two maximum temperature of the pebble were found at the gap area. The maximum velocities of the first layer pebbles were found at the gap area, thereafter the maximum velocity was found between the gap areas. The pressure gradually reduces from bottom to top and the minimum values of pressure were generated at the gap area.
