PRESSURE DROP INVESTIGATION ON LABYRINTH STRUCTURES OF A NOVEL PASSIVE FLOW LIMITER APPLIED TO NUCLEAR HEATING REACTOR

抄録

A novel passive flow limiter has been designed for the integral nuclear heating reactor of NHR200-II to mitigate the consequences of LOCA (loss of coolant accident). To hold the spherical disc of the flow limiter under various external disturbances, restricting rods with labyrinth structures were designed to support the spherical disc. The circular-grooved square cavity labyrinth structure was chosen for the passive flow limiter, and the pressure drop characteristics of the labyrinth structure were studied numerically. The influences of three parameters, i.e., the clearance between the piston and the cylindrical side wall (δ), the number of cavities (N), and the distance between the piston and the front wall (L), were analyzed by numerical simulation of labyrinth structures with nine different configurations and two working conditions (water at 20℃,1MPa and water at 280℃,8MPa). The results showed that the pressure drops of the labyrinth structure increased rapidly when the clearance δ narrowed. The impact of cavity number N on the pressure drop was less than the clearance δ. The pressure drop of the labyrinth structure reduced slightly as the distance L between the piston and the front wall increased.