Kuplan muodostumisen ja luhistumisen arviointi lauhdutusaltaissa hahmontunnistuksen avulla

摘要

During a possible loss of coolant accident in BWRs, a large amount of steam willbe released from the reactor pressure vessel to the suppression pool. Steam willbe condensed into the suppression pool causing dynamic and structural loads tothe pool.The formation and break up of bubbles can be measured by visual observationusing a suitable pattern recognition algorithm. The aim of this study was toimprove the preliminary pattern recognition algorithm, developed by Vesa Tanskanenin his doctoral dissertation, by using MATLAB. Video material from thePPOOLEX test facility, recorded during thermal stratification and mixing experiments,was used as a reference in the development of the algorithm.The developed algorithm consists of two parts: the pattern recognition of thebubbles and the analysis of recognized bubble images. The bubble recognitionworks well, but some errors will appear due to the complex structure of thepool. The results of the image analysis were reasonable. The volume and thesurface area of the bubbles were not evaluated. Chugging frequencies calculatedby using FFT fitted well into the results of oscillation frequencies measured inthe experiments.The pattern recognition algorithm works in the conditions it is designed for. Ifthe measurement configuration will be changed, some modifications have to bedone. Numerous improvements are proposed for the future 3D equipment.