IFPE/IFA-507-TF3-TF5, Database For Transient Temperature Experiment Ifa-507

1 - Description: At the Halden reactor a test at a power of ∼15 MW was performed to study the transient temperature response of the two thermo-coupled rods to a rapid power increase. At the time of the experiment the burn-up of these rods was ∼18 MWd/kgUO2. The experiment consisted of two parts, firstly to establish the steady state relationship between fuel temperature and shield position and secondly, a rapid withdrawal of the shield and continuous monitoring of the dynamic fuel temperature changes versus both shield position and time. The approach adopted in the second part of the test was to lower the shield past the thermocouple tips (∼10 cm below) to suppress the local rating at these locations and pull it rapidly upwards to uncover the portion of the fuel column containing the central oxide thermocouples. The rods were subjected to a reactor SCRAM and temperatures monitored by the two thermocouples. 2 - Methods: Data for the two rods equipped with thermocouples TF3 and TF5 were obtained from the following sources: - ENIGMA code input files in electronic form, - Halden report HWR-120 by E Kolstad, - Halden Data Sheets compiled in HWR-273. The 6 rod cluster in IFA-507 was surrounded by a moveable silver shield encased in stainless steel which was capable of reducing the power to about 50% of the full power rating. A schematic diagram of the assembly with the axial power profile is shown in the accompanying figure. The rods in the cluster were BWR design with Zr-2 cladding two of which contained centreline thermocouples designated TF3 and TF5