Steady-state subchannel analysis of partially blocked coolant channels in a pool-type triga reactor

Additional instrumentation tubes (neutron detectors, thermocouples) are scheduled for deployment in Texas A&M University's TRIGA core in order to collect measurements for multiphysics code validations. This instrumentation will displace water and reduce coolant flow in some areas between fuel bundles. Thermal-hydraulic analyses are carried out using COBRA-TF and STAR-CCM+ to analyze the change in cooling capabilities. Results show that the coolant exit temperature increases by ~9°C and that DNBR margins are not affected. Additionally, since the instrumentation tubes act as flow straighteners, an overall reduction in hot spots is observed. The study also provided insight into the comparison of COBRA-TF with the higher fidelity code; STAR-CCM+.