Full scale test results as part of the development of a large diameter nozzle with thicker sleeve for the ABWR internal pump

To provide better earthquake-proof performance of the reactor internal pump (RIP) in the advanced boiling water reactor (ABWR), the optimum nozzle diameter (492 mm) with the thicker sleeve was decided from previous 1/5-scale tests and calculations, taking hydraulic performance and flow characteristics into consideration. The purposes of the present study were to verify the hydraulic performance of the actual full-scale RIP with the 492 mm nozzle and to evaluate the coast-down and the RIP vibration characteristics. The RIP full-scale tests were carried out in the Hitachi ABWR RIP Test Center for cooperative studies between Hokuriku Electric Power Company and Hitachi, Ltd.. The head-capacity curves, the rotating inertia time constant in the coast-down and the casing and the impeller vibration were investigated for RIPs with the current (445 mm) and the 492 mm nozzles under actual plant operating conditions of fluid temperature of 549 K and pressure of 7.4 M Pa. The increase of pressure losses of the 492 mm nozzle from the 445 mm nozzle in the full-scale test was about 1 m (total head of 2.5%) at the design point and almost the same as that in the 1/5-scale test result. This variation of the hydraulic performance was within the allowable level of the current RIP. Moreover, the rotating inertia time constant and the intensity of the casing and the impeller vibration were within the design specifications of the current RIP with the 445 mm nozzle. Results of full-scale tests showed the RIP with the 492 mm nozzle could maintain the good performance, so use of the 492 mm nozzle was judged appropriate for the RIP in the ABWR. (author)