THEORETICAL STUDY ON THE CHARACTERISTICS OF THE AP1000 PASSIVE CONTAINMENT COOLING SYSTEM BY WATER FILM

• Main Author: HIDAYANTI SUKARNO (NIM : 24907003); Tim Pembimbing : Prof. Dr. Aryadi Suwono; Dr. Ari Darmawan, DIAH
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/15373
• Institution: Institut Teknologi Bandung

One of mechanism utilized by the next-generation PWR power reactor for cooling its containment passively is gravitationally falling water film cooling. Since the <br /> <br /> <br /> <br /> water film flow performance in the Passive Containment Cooling System (PCCS) application is closely related to the safety, film cooling characteristics should be studied experimentally or theoretically. This paper focuses on the theoretical study of water mass flow rate and heat flux level effects on the characteristics of AP1000 containment wall cooling by laminar highly subcooled water film. <br /> <br /> <br /> <br /> Numerical tool used in this work is FLUENT 6.3 computer code. <br /> <br /> <br /> <br /> The procedure of this numerical study is composed of 3 stages as follows: physical modeling using GAMBIT program, numerical modeling using FLUENT, and numerical simulation. The geometry of containment model made by GAMBIT is axisymmetric 1:40 length scaled of the AP1000 containment. The multiphase model used in FLUENT is the Volume of Fluid (VOF) model by including gravitational force effect. The numerical simulation was conducted in the steady-state and constant heat flux. Calculations were made in a range of film Reynolds numbers (Re) from 400 to 1600 and the heating power is permitted up to 35 kW. <br /> <br /> <br /> <br /> The result shows that the film thickness increases with increasing water film flow rate and decreases with increasing wall heat flux. For constant heat flux condition, the film and containment wall temperature gradually rises as the film flow downwards. The lower film mass flow rate causes the higher film and containment wall temperature. For laminar flow condition, the heat transfer <br /> <br /> <br /> <br /> coefficient decreases as film mass flow rate increases due to the increase of film thickness which causes the increase of the thermal resistance. Moreover, the heat <br /> <br /> <br /> <br /> transfer coefficient increases as the wall heat flux increases since the increasing heat flux will decrease the film thickness which is finally causing the decrease of <br /> <br /> <br /> <br /> the thermal resistance. The resultant equation of the overall heat transfer correlation proposed in this work is expressed as: h* = 1,28Re-0,19. In principle, for laminar subcooled film flow condition, the film mass flow rate <br /> <br /> <br /> <br /> can be kept at a minimum to enhance the heat transfer coefficient. But, the heat flux effect on the thinning of the film and the breakdown phenomena promotion must be always considered.