الفهرس | Only 14 pages are availabe for public view |
Abstract The thermal-hydraulic behaviour of the dry storage cask contains 21 spent nuclear fuel assemblies which discharged from nuclear power reactors is presented in this thesis. Investigations for the cooling process of cask is performed for normal, upnormal conditions and with changing of some design factors. For this purpose, a test rig is designed and constructed to simulate the cooling process of cask. The test rig is equipped with 21 electrical heaters, a steel cylinder made from steel 304 and insulated cylinder. The heaters power is changed by using two voltage regulators. The inlet air velocity is changed by using air velocity control unit which is consisted from an acrylic box and variable speed fan. The test rig is provided with 38 thermocouples to measure the temperatures of heaters surfaces, steel cylinder surface and in air flow channel. The experimental results are used for verification of the theoretical computational results performed by using ANSYS - CFX code. The effects for changing of the following parameters are investigated: Aspect ratio (B* = steel cylinder height / diameter difference of insulated and steel cylinders) is changed at values of (5, 6.7, 10 and 20). Input heaters power (Qt) are changed at values of (210, 420, 630, 840,1050 and 1260 watts) Inlet coolant velocity (Vin) is changed at values of (1.1, 1.5, 2, 2.5 and 2.8 m/sec) Simulation for the blockage in the inlet and outlet are investigated. The results obtained from code is good in agreement with the experimental results. This agreement gives the code validation for being used in another analysis in this branch. The code is used to investigate the effect of variation of inlet air temperature which is changed for values of (300, 310, 4 320 and 330 0k). A new correlation of Nusselt Number as a function of Modified Rayleigh number for steel cylinder under natural cooling system is developed and verified with other published correlation. Also a new correlation of Nusselt Number as a function of Reynolds number for steel cylinder under forced cooling system is developed. Scenarios for an accident by blockage at the inlet and outlet of air is also investigated |