Pressure drop across the moisture separator installed in the steam generator of a nuclear power plant affects the power generation efficiency, and so accurate pressure drop prediction is important in generator design. In this study, an empirical correlation is proposed for predicting the two-phase pressure drop through a moisture separator. To ensure the applicability of the correlation, a series of two-phase air-water experiments were performed, and the results of the present test and of the benchmark test of high-pressure steam-water were used in developing the correlation. Based on the experimental results, quality, dimensionless superficial velocity, density ratio of the working fluid, and the geometrical factor were considered to be important parameters. The two-phase pressure drop multiplier was expressed in terms of these parameters. The empirical correlation was found to predict the experimental results within a reasonable range.

The most important design parameters of a moisture separator to optimize the efficiency of a nuclear power plant are the moisture carry over and pressure drop. An air-water test facility was constructed to evaluate the design parameters for various types of conventional moisture separators in Korea. In this study, a half scale of swirl-vane separator was designed, and test conditions were defined based on the scaling law to cover a wide range of operating conditions. The moisture carry over was measured using an isokinetic sampling system for 34 different flow conditions. The MCO was in range of 0.30–7.05% according to the test conditions. Single and two-phase flow experiments were also carried out to identify the two-phase pressure drop characteristics. Based on the obtained results, the proposed empirical correlation model was extended to a submerged separator and applying these results to a full scale system is discussed in this paper.

We report a new junction leakage generation phenomenon which was found at specific junction edges on top of which poly-Si gates ran nearby in a 0.35 /spl mu/m design rule actual DRAM chip. As more advanced isolation schemes that enabled less bird's beak were applied, the phenomenon was more evident. After characterizing a set of junction leakage patterns where the relative position of poly gate to the junction edge was systematically varied, a problematic combination of process window and design rule was found and screened out of the actual circuit layout. This leakage component has to be considered to improve the refresh characteristics and stand-by current.

The experimental data of core flow distribution are indispensable for obtaining licensing and facilitating the design of fluid systems of nuclear reactors. In this study, an Advanced power reactor Core flow and Pressure (ACOP) test facility was established to experimentally simulate the internal flow of the Advanced Power Reactor 1000 (APR1000) on a reduced length scale of 1/5. The core region was simulated by using 177 core simulators representing the fuel assemblies of the APR1000. The APR1000 flow distributions were synthetically identified by accurately measured parameters: the core inlet flow rate and outlet pressure under the four-pump balanced and unbalanced flow conditions. The overall inlet flow rates ranged from 87.7% to 112.0% relative to the averaged flow rate. Here, we scrutinize the flow distributions considering the flow conditions and internal structures and briefly describe the applied scaling method and design concept of the test facility.

The pressure drop of the moisture separator in a steam generator is the important key parameter to design the moisture separator and ensure the efficiency of a nuclear power plant. In this research, the low pressure air/water test facility was constructed to simulate the steam/water condition for the full-scale moisture separator. The experimental method based on the similarity law was presented and the pressure drop was measured for a mass quality ranged from 0.269 to 0.538 using the air/water test facility. The obtained results were verified by comparing with the results of the prototype condition. It is discovered that the viscosity ratio and two-phase centrifugal force are the factors influencing the pressure drop.