Pages 165-166
A steam generator of PWR plant has moisture separators which have the function to separate water from two-phase flow of water and steam. Recently, corresponding to the request for power uprating of operating plants and /or construction of future plants with large thermal capacity, a development of moisture separator with high performance which can correspond to an increase of steam flow rate has been required. Therefore, we have developed the moisture separator with high performance (J model) by performing the verification test under actual plant operating conditions (high pressure and high temperature). The developed separator features are the followings, (1) to have small diameter of swirl vane hub, (2) to have horizontal slits at riser barrel, (3) to have slots with lips at the top of downcomer barrel. Based on the combination of the high pressure test results and thermal hydraulic analyses results, value of SG moisture carry over (MCO) is evaluated. As a result, evaluated MCO value is less than 0.01%, which is less than our target value of 0.1%.
